MEMORIAS AMMVEPE CURSO CIRUGIA TEJIDOS BLANDOS 2014

AMMVEPE 

1968 - 2014 

MEMORIAS CURSO DE CIRUGÍA 

AVANZADA EN TEJIDOS BLANDOS, 

DICIEMBRE 2014 

“DR. ERIC MONNET”

Asociación Mexicana de Médicos Veterinarios Especialistas en Pequeñas Especies, S. C. 

www.ammvepe.com.mx


www.ammvepe.com.mx


www.ammvepe.com.mx

Eric Monnet, DVM, PhD, FAHA 

Diplomate ACVS and ECVS 

Colorado State University, Fort Collins, Colorado 

El Dr. Eric Monnet es graduado de la Escuela de Veterinaria en 

Maisons Alfort, Francia en 1985. 

Trabajó por cuatro años en Paris, realizando práctica privada en 

medicina y cirugía en animales pequeños. 

En 1994, el Dr. Monnet completó una residencia en la 

Universidad del Estado de Colorado relacionada a cirugía en 

animales pequeños, y últimamente ha terminado una Maestría 

en Ciencias. 

En 1997, el Dr. Eric Monnet recibió su Doctorado en Ciencias 

Clínicas estudiando la eficiencia cardiaca en perros. 

En el año 2003, llega a ser miembro de la Asociación 

Americana del Corazón (American Heart Association). 

Actualmente es profesor en cirugía de animales pequeños 

(tejidos blandos) en la Universidad del Estado de Colorado. 

El Dr. Monnet fue presidente fundador en 2001 - 2003 de la 

Sociedad Veterinaria para la Cirugía en Tejidos Blandos y de la 

Sociedad de Endoscopia Veterinaria. 

Es editor de los libros de texto; “Mecanismos de Enfermedad 

en la Cirugía de Animales Pequeños” (Disease Mechanisms 

in Small Animal Surgery 3rd. edition) y la primera edición del 

libro “Cirugía de Tejidos Blandos en Animales Pequeños” (Small 

Animal Soft Tissue Surgery). 

Parte de sus actividades y habilidades personales son; 

la Cirugía, Medicina Veterinaria, Investigación Clínica, 

Enseñanza Universitaria, Investigación y Diseño, Conferencias 

y presentaciones, Biotecnología, Estadística, Fisiología, 

Experimentación, Enseñanza Académica, Escritor científico. 

Dr. Eric Monnet 

PERFIL PROFESIONAL


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INDICE GENERAL 

CÓMO REALIZAR CIRUGÍA GASTROINTESTINAL DE FORMA SEGURA 

DILATACIÓN Y VOLVULO GÁSTRICO 

PERITONITIS 

CIRUGÍA DEL HÍGADO Y VESÍCULA BILIAR 

TRATAMIENTO QUIRÚRGICO DE LOS CÁLCULOS URINARIOS 

CIRUGÍA DEL PÁNCREAS 

PARÁLISIS LARINGEA 

SÍNDROME DEL BARQUICEFÁLICO 

LAPAROSCOPIA EN LA PRÁCTICA DE PEQUEÑAS ESPECIES 

TORACOTOMÍA Y TORACOSCOPÍA 

CIRUGÍA PULMONAR 

EFUSIÓN PLEURAL 

PERSISTENCIA DEL DUCTO ARTERIOSO


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PRINCIPLES OF GASTROINTESTINAL SURGERY 

How to perform a safe gastrointestinal surgery? 




Gastrointestinal surgery is performed very commonly in small animal for biopsy, 

removal of a foreign body, upper gastrointestinal bleeding, resection of a non-viable 

segment of intestine, resection of non-viable portion of the stomach, and resection of a 

neoplasia. Gastrotomy, gastrectomy, enterotomy, and enterectomy are the procedures 

routinely performed. General principles common to all of these procedures have to be 

followed. 

Peritonitis is life threatening complication that can happen in 13 to 20% of the cases. 

To reduce the risk of peritonitis it is important to minimize the trauma to the tissue and to 

recognize the tissue viability. Peritonitis can develop in the immediate post-operative 

period because of severe contamination during the surgery or leakage of the suture line. 

Leakage happens if the tissue are not viable or when the surgical technique was not 

appropriate. Peritonitis can happen also 3 to 4 days after surgery at the peak of 

debridement. Dehiscence of an anastomosis happened because the debridement phase 

goes beyond the suture line. If the tissue handling or the surgical technique were not 

appropriate, the debridement will be exacerbated and dehiscence can occur. 

ANTIBIOTIC PROPHYLAXIS 

Gastrointestinal surgery without a peritonitis is considered as a clean-contaminated 

surgery. Therefore antibiotics are required during the procedures. Most common bacteria 

encountered during gastrointestinal surgery are: Escherichia coli, Enterococcus spp, 

Streptococcus, Staphylococccus aureus, Proteus, and Bacteroides fragilis. In the 

stomach, the bacteria population is more limited than in the rest of the intestine because 

of the acidic environment. In the colon the population of anaerobic bacteria is elevated. 

Before surgery the patient is placed on prophylactic intravenous antibiotic. For the 

surgery of the stomach, ampicillin or first generation cephalosporin (20 mg/kg IV every 

60 min) can be used. For the rest of the intestine, second generation antibiotics are 

preferable because they a have a broad sprectrum against gram + and -. Cefoxitin (20 mg 

/ kg IV every 90 min) is the antibiotic of choice. A combination of ampicillin 

enrofloxacin can be used also especially if a peritonitis is present. Antibiotics are 

interrupted at the end of the procedure unless the animal has peritonitis. The animals 

need to be watch closely for signs of infection. 

CHOICE OF SUTURE MATERIAL AND NEEDLES 

A wide range of suture materials has been used during gastrointestinal surgery. It is 

recommended to use synthetic absorbable monofilament suture materials. Synthetic 

absorbable sutures are absorbed primarily by hydrolysis, which is very predictable.

Monofilament sutures are less traumatic than braided sutures when they are placed 

through the wall of the gastrointestinal tract. However, they have more memory which 

makes them harder to work with. A monofilament suture size 4.0 or 3.0 is 

recommended for gastrointestinal surgery. A small suture material will more likely trigger 

less inflammation. Glycomer 631 (Biosyn) or Monocryl are a very good choice since it 

retains 50% of its tensile strength for 3 weeks. A taper needle is recommended for 

placement sutures in the stomach wall and the intestine because it does not cut the fibers 

of collagen. 

SUTURE PATTERN 

The gastrointestinal tract is closed with a simple continuous suture pattern to provide 

apposition of all the layers of the wall of the gastrointestinal tract. It is important to place 

the suture full thickness to make sure the submucosa is incorporated. This suture 

technique will provide primary healing of the wall of the gastrointestinal tract. When a 

simple continuous pattern is used it is recommended to place the first and the last stitches 

with knots outside the incision because it may provide a very good seal. When the 

sutures are placed it is important to avoid to traumatize the wall of the gastrointestinal 

tract. It is then better not to grab the wall the gastrointestinal with grasping forceps as 

much as possible. When the sutures are placed it is important to follow the curvature of 

the needle to reduce trauma to the soft tissue. 

ASEPSIS 

Every effort should be made to prevent contamination of the abdominal cavity during 

gastrointestinal surgery. The stomach or the loop of intestine are “packed off” the rest of 

the abdominal cavity. Layers of moist laparotomy sponges are used. Intestinal content is 

moved away for the surgical site with gentle manipulation and atraumatic clamps are 

placed to prevent the intestinal content to come back. Stay sutures are placed in the 

stomach to elevate the stomach wall and prevent spillage of stomach content into the 

peritoneal cavity. 

After completion of the surgery, the peritoneal cavity is lavaged with warm sterile 

saline solution to removed gastrointestinal spillage and blood clots. Usually 1 liter of 

saline is used for a 10 kg dog. The entire fluid is eliminated with surgical suction to get 

the peritoneal cavity as dry as possible. 

Gloves and instruments are then changed. New surgical towels are placed on the edges 

of the laparotomy. The abdominal cavity is then closed routinely. 

ASSESSMENT OF VIABILITY 

Stomach 

No objective criteria exist to evaluate the gastric wall viability. Absence of peristaltic 

wave, pale greenish to gray serosal color, thin gastric wall, and lack of bleeding after 

partial thickness incision are signs of gastric wall devitalisation.

Intestine 

Viability is assessed by coloration of the serosa, peristalsism, pulse in the jejunal 

arteries, and utilization of intravenous fluorescein. Fluorescein at the dose of 15 mg/kg is 

injected intravenously. Fluorescein emits a gold green fluorescence when exposed to 

ultraviolet light. Viable intestine has a smooth uniform green gold fluorescence. 

Hyperemic intestine has a brighter color than normal. Non viable intestine has patchy 

fluorescence or no fluorescence. The fluorescence can also be located around blood 

vessel. 

SURGERY OF THE STOMACH 

Gastrotomy 

Gastrotomy incision is performed in a relatively avascular area, midway between the 

lesser and the greater curvature of the stomach. One stay suture is placed at each end of 

the planed gastrotomy incision. Stay sutures are used to manipulate the stomach and 

bring the stomach wall to the edge of the abdominal incision. The stomach is walled off 

with moist laparotomy sponges to prevent contamination of the abdominal cavity with 

gastric content. An 11 blade is used to stab the gastric wall next to one stay suture. Then, 

a Metzembaum scissors is used to extend the gastrotomy incision. The incision should be 

long enough to remove the foreign body without tearing the stomach wall. Hemorrhage 

occurs mainly in the seromuscular layer and can be controlled by ligation with fine 

absorbable sutures. The foreign body is extracted and the gastrotomy closed. 

Gastrotomy is closed with one layer simple apposition pattern with 3-0 monofilament 

absorbable suture. The abdominal cavity is lavage with warm saline prior to closure. 

Surgical gloves are changed and a new pack of instruments is then used to complete the 

abdominal closure. 

Gastrectomy 

Gastrectomy is required to resect the non viable part of the stomach wall during GDV, 

or resection of an ulcer or a neoplasia. Stomach wall resection for a gastric ulcer requires 

wide margin since gastric ulceration could be associated with gastric adenocarcinoma or 

gastric lymphoma. 

Two options are available: gastrectomy with either traditional suture technique or 

stapling suture. Gastrectomy with automatic stapling equipment is associated with the 

best post surgical outcome during GDV. This is the recommended technique. 

Gastrectomy during GDV 

Branches of the short gastric arteries and left gastro-epiploic artery supplying the area 

to be resected are ligated. Non-viable gastric wall is resected with Metzembaum scissors 

to the level of healthy gastric tissue. Closure with suture material is possible. This 

technique is associated with 60% mortality. If autostapling equipment is available a 

Thoraco-Abdominal device (TA 55 or 90) can be used to perform the gastrectomy (Figure

1). The TA 55 or 90 placed two staggered row of staples respectively 55 or 90 mm long. 

The length of staples for stomach wall resection 

should be 4.8 mm. The TA 55 or 90 is first clamped 

on healthy stomach wall. The two row of staples are 

then fired and a 15 blade is used to resect the 

devitalized stomach wall. The TA is then released. 

The suture line is then inspected to be sure that all the 

staples are in correct position and then a simple 

inverting suture line is applied. The advantages of 

Figure 1 

this technique include decrease surgical time and 

decreased abdominal contamination from gastric 

spillage. Mortality rate with the autostapling 

equipment is close to 10%. Stomach rupture at the time of surgery is associated with 

severe peritonitis. 

Gastrectomy for ulcer or mass. 

After identification of the stomach ulcer or tumor, the healthy stomach is retracted with 

stay sutures to prevent gastric spillage. The stomach wall is then resected around the 

lesion. The stomach wall is highly vascular. Bleeding blood vessels on the line of 

incision are ligated with 4.0 monofilament absorbable sutures. Staples can be used to 

close the gastrectomy. Hand suture can be performed if stapling equipment is not 

available. Two inverting continuous sutures have been used to close the stomach after 

gastrectomy. A Cushing suture followed by a Lembert is the traditional technique. 

However, one simple continuous apposition suture can be used to close the stomach. 

SURGERY OF THE INTESTINE 

Enterotomy 

A variety of foreign bodies can be ingested by young animals. Linear foreign bodies 

are more common in cats. Once, an object has passed through the pylorus, the next 

smallest lumen are the distal duodenum and the proximal jejunum. 

Plication of the intestinal indicates the presence of a linear foreign body. Usually one 

end of the linear body is still located in the stomach and need to be released first. 

Particular attention is paid to mesenteric border especially with a linear foreign material. 

Linear foreign body can cut through the mesenteric border and induce leakage of 

intestinal content. Multiple enterotomy may be required to remove the entire linear 

foreign body. Enterectomy is required if the mesenteric border has been damaged. 

Enterotomy is performed immediately distal to the foreign material. Intestine is walled 

off the abdominal cavity to prevent leakage of intestinal content inside the abdominal 

cavity. The incision on the antimesenteric border should be long enough to extract the 

foreign body without tearing the intestine.

The enterotomy is then closed with a simple interrupted appositional pattern with 4-0 

monofilament absorbable suture. Since the submucosa is the only holding layer, it needs 

to be incorporated in the suture. The submucosa tends to retract away from the edge of 

the incision. The everted mucosa can be trimmed away to allow better exposure of the 

submucosa. 

A serosal patch can be performed to improve blood supply to the enterotomy site and 

increase its tensile strength. The abdominal cavity is lavage with warm saline prior to 

closure. Surgical gloves are changed and a new pack of instruments is then used to 

complete the abdominal closure. 

Enterectomy 

An enterectomy is indicated if the intestine is not viable (intussusception, volvulus) 

perforated by a linear foreign material at the 

mesenteric border, or if a intestinal neoplasia 

Figure 2 

is present. End to end anastomosis is the 

preferred technique to perform an 

enterectomy. Intestine is walled off the 

abdominal cavity to prevent leakage of 

intestinal content inside the abdominal cavity. 

Enterectomy requires double ligation of the 

branches of the arterio-venous supply of the 

portion of intestine to resect (Figure 2). 

The terminal arcade is also double ligated. Transection is performed between the 

double ligations. Crushing clamps are then placed on the portion of intestine that is going 

to be resected. 

Figure 3 The clamps are 

either placed 

perpendicular 

or at a slight 

angle toward 

the normal 

intestine. Noncrushing 

clamps 

are placed on 

Figure 4 

the normal 

intestine 4 to 5 cm away from the enterectomy 

site after milking away the intestinal content. 

The intestine is transected with a scalpel blade 

using the crushing clamps as guide. Since the 

submucosa is the only holding layer, it needs to 

be incorporated in the suture. The submucosa 

tends to retract away from the edge of the

incision. The everted mucosa can be trimmed away to allow better exposure of the 

submucosa (Figure 3). Anastomosis is performed with simple interrupted or continuous 

appositional pattern with 4-0 monofilament absorbable suture (Figure 4). 

If the two extremities of the intestine are not of equivalent diameter the smaller 

diameter segment can is incised on the antimesenteric border to create a larger spatulated 

edge (Figure 4). A serosal patch can be placed around the enterectomy site to improve 

blood supply and tensile strength. 

The abdominal cavity is lavage with warm saline prior to closure. Surgical gloves are 

changed and a new pack of instruments is then used to complete the abdominal closure. 

POSTOPERATIVE MONITORING 

Postoperatively the patients should be monitored for signs of peritonitis, hypotension, 

disseminated intravascular coagulation, and pain. Patients can be fed 8 hours after 

surgery unless the patients is vomiting. Feeding tubes might be required to support those 

patients. Peritonitis occurs in 13 to 20% of the cases. Leakage after gastrointestinal 

surgery can happen within 24 hours of surgery because of non viable tissue or 

inappropriate surgical technique. It can also happen 3 to 4 days after surgery at the peak 

of the debridement phase. Clinical signs of peritonitis will be tachycardia, tachypnea, 

acute abdominal pain, hypoglycemia, and hyperthermia. An abdominocenthesis is then 

required to confirm the presence of bacteria in the abdomen. If bacteria are presented 

pass 8 hours after surgery, the anastomosis is leaking and a second surgery is required.

GASTRIC DILATATION VOLVULUS SYNDROME 




Gastric dilatation volvulus syndrome is an acute medical and surgical condition due to 

several pathophysiological effects occurring secondary to gastric distension and mal-positioning. 

It occurs most commonly in large, deep chested dogs. Gastric dilatation volvulus should be 

differentiated from food engorgement. Food engorgement results from the over consumption of 

food and can result in severe dilation of the stomach. Large and giant breed dogs appear to have 

a 7% risk of death from GDV throughout their lifetime. Great Danes, however, have a 42.4% 

chance of developing GDV, and a 12.6% chance of dying from GDV in their lifetimes. 

Chronic gastric dilatation volvulus has been recognized at several occasions in dogs. The 

diagnosis is more subtle because the clinical signs are not as dramatic as for an acute gastric 

dilatation volvulus. Dogs with chronic dilatation volvulus have an history of chronic vomiting, 

flatulence, and weight loss. 

Aerophagia is the most likely source of gas accumulation. Bacterial fermentation of 

carbohydrate, gas production from acid-bicarbonate reactions may contribute to gas 

accumulation. The fluid component of gastric contents is a combination of ingesta, gastric 

secretions, and transudate from venous obstruction. 

The mechanism of gastric outflow obstruction is unknown. As gastric dilatation progresses, 

the normal means of relief, such as eructation, vomiting, or pyloric emptying fail to occur. 

Pyloric function seems to be normal in dog treated for gastric dilatation volvulus. Acute gastric 

dilatation volvulus has been recognized for many years in dogs however its exact cause is still 

not clearly understood in dogs. Only risk factors have been identified. Increased gastrin level, 

decreased stomach motility and delayed gastric emptying have been mentioned as a risk factor 

but never been demonstrated. Diet, the amount of food ingested, the frequency of feeding, 

behavior (fast eating style), exercise and stress after a meal are contributing factors for the 

development of gastric dilatation volvulus. Large breed dogs (Great Danes, Irish Setter, 

Standard Poodle, Weimaraner, Labrador, Golden Retreiver), dogs with large thoracic depth-towidth 

ratio, dogs of history of GI disease, dogs with family history of GDV, underweight dogs, 

and older animals are at higher risk to develop a gastric dilatation volvulus. Dogs with an happy 

personality might be at less risk. 

The pyloric antrum rotates in a clockwise fashion. Displacement of the pylorus occurs from 

right toward ventral midline, passing along the gastric fundus and body to an area along the left 

abdominal wall close to the lower esophageal sphincter. At the same time the fundus goes in a 

ventral direction toward the right abdominal wall. Because of the attachment of the omentum to 

the greater curvature of the stomach, the omentum covers the stomach after volvulus. The 

displacement of the spleen may vary from the degree of volvulus. The spleen is usually 

engorged or can undergo torsion on its own pedicle. Thrombosis of the splenic artery can also 

occur. Most commonly 180 0 degree of rotation is seen but 360 0 rotation is possible.

Gastric dilatation causes compression of the caudal vena cava and portal vein. Sequestration of 

blood in the spleen, kidney, and gastrointestinal tract occurs. Compression of the caudal vena 

cava and portal vein induces a decreased venous return resulting in hypovolemic shock. 

Hypotension and venous stasis result in cellular hypoxia and anaerobic metabolism. Focal 

myocardial ischemia and hypoxia will reduce contractility and induce arrhythmias. Vascular 

stasis, hypoxia and acidosis can predispose to the development of disseminated intravascular 

coagulopathy. Respiratory dysfunction results from decreased pulmonary compliance and 

mechanical restriction of diaphragmatic movement by a dilated stomach. Tissue hypoxia results 

from decreased cardiac output and respiratory impairment. Increased gastric intraluminal 

pressure, portal hypertension, and venous stasis with thrombosis result in gastric mucosa stasis, 

hypoxia, and edema. Gastric wall necrosis can then develop in the fundus along the greater 

curvature Vascular wall disruption results in mucosal hemorrhage. Avulsion of branches from 

the short gastric arteries contributes to the blood loss, hypovolemia, and restriction of blood flow 

to the stomach. 

CLINICAL SIGNS 

Dogs with gastric dilatation volvulus are presented with progressive distension and tympanic 

cranial abdomen. They are restlessness, retching, and hypersalivating. Weak peripheral pulse, 

pale mucous membrane, increased heart rate, prolonged capillary time, and tachypnea are present 

too. Abdominal pain is usually not present on palpation. 

Dogs with a gastric dilatation volvulus are presented with a weak femoral pulse, increased 

heart rate, pale mucous membrane, decreased capillary refill time, and tachypnea. Dogs present 

clinical signs similar to hypovolemic shock because their venous return is limited by the stomach 

dilation. If decompression is not performed rapidly they can develop septic shock during to 

congestion and ischemia of the gastrointestinal tract. 

DIAGNOSIS 

Very often the diagnosis is made from the history, the signalment and the physical 

examination. Radiographic evaluation is rarely required for the diagnosis of gastric dilatation 

volvulus. 

Dogs are usually presented for unproductive vomiting, retching and hypersalivation. The 

abdomen is distended and as the severity increases the animal can become weak, lateral 

recumbent with tachypnea. 

Signalment 

Gastric dilatation volvulus is most commonly seen in large and giant breed dogs. It also can 

be seen in small dogs and cats. Dogs from 10 month to 14 years old have been diagnosed with 

gastric dilatation volvulus. No sex predilection have been demonstrated. 

Physical examination 

On physical examination is classic to find a large distended abdomen. On percussion, a 

tympanic sound is produced. Abdominal palpation could be uncomfortable. Animals 

hypersalivate and are retching.

Gastric dilatation volvulus induces different degree of shock that needs to be recognized 

during the evaluation of the patient. First, the animals are presented with clinical signs similar to 

hypovolemic shock because most of their blood volume is restricted in the caudal vena cava and 

the portal vein. Therefore, the animals are going to be tachycardic and tachypnic with a normal 

femoral pulse, a slow capillary refill time, pale mucous membrane, and cold extremities. With 

progression of the syndrome, the patients are going to go in endotoxemic shock with tachycardia, 

tachypnea, weak femoral pulse, injected mucous membrane, fever, slow capillary refill time. 

Finally the patients are going to decompensate with severe hypotension, bradychardia, 

hypothermia, white mucous membranes and cold extremities. 

The severity of the presentation is indicator of survival for the patients. 

presented bright and alert have better prognosis than dogs that lateral recumbent. 

Blood work 

Dogs that are 

Complete blood count and biochemistry profile are indicated for dogs with GDV. Coagulation 

profile might be required for dogs with advance shock because of the increased risk of DIC in 

those patients. If the platelet count is low on the CBC it is also indicated to evaluate the 

coagaulation profile 

Lactate level needs to be evaluated too. Since dogs with GDV are in some degree of shock, very 

often they are presented with an elevated lactate level. It is important to evaluate the level of 

lactate at the time of presentation and after initiation of fluidotherapy. Response to medical is an 

important prognosis indicator. If the lactate level decreased by 50% after initiation of medical 

treatment the prognosis is good. 

Radiographs 

Radiographs help to differentiate between gastric dilation and gastric dilation volvulus 

syndrome. Radiographs if necessary for the diagnosis are not performed until the patient is 

stable. Since the pylorus is displaced on the left side of the abdominal cavity in a dorso-cranial 

position to the fundus a right lateral recumbency radiographs are required to be able to have a 

double bubble image. The two bubbles are due to the accumulation of air in the pylorus and the 

fundus. Free gas is present in the abdomen when the stomach has ruptured. 

If only gastric dilatation is present without volvulus, radiographs show a dilated stomach with 

dilated loop of jejunum. 

Radiographs will also help differentiate between gastric dilatation volvulus and mesenteric 

volvulus. Dogs with mesenteric volvulus have very large loop of jejunum lined up parallel to 

each other. 

TREATMENT 

Emergency treatment 

Emergency medical treatment of the hypovolemic shock and gastric decompression is 

required before surgical treatment for gastric dilatation volvulus. Venous catheters of the largest 

size possible are placed in the cephalic or jugular vein to deliver shock dose of intravenous fluid. 

Isotonic fluids are delivered at an initial rate of 90 ml/kg during the first 30 to 60 min. The rate 

and volume of fluids administered can be adjusted according to assessment of several clinical

parameters: heart rate, pulse, mucous membrane, capillary refill time and measurement of central 

venous pressure. It is very common to start with a quarter of the total shock dose and evaluate 

the response of the patient. Colloids at the dose of 4 ml/kg are recommended during 

hypovolemic shock treatment. Blood gas and electrolyte evaluations are required before acidbase 

and electrolyte imbalances corrections are attempted. A dog presented with a gastric 

dilatation volvulus can be either alkalotic or acidotic, hypokalemic or normokalemic. 

Gastric decompression is attempted first with an orogastric tube after initiation of fluid 

therapy. Patients' compliance, the amount of gastric distension, and the degree of gastric 

volvulus determine the ease and feasibility of passing a tube. Difficulties or easiness to pass a 

tube does not have a diagnostic value for the magnitude of the volvulus. Perforation of a 

compromised stomach can happen with orogastric tube. Measurement from the chin to the 

xiphoid before introduction of the tube may help prevent perforation of the stomach. If the 

intubation is successful stomach lavage is required to empty the stomach. Color and content of 

the fluid coming back after stomach lavage need to be looked at. Hemorrhagic fluid or black 

necrotic fragments are indications of stomach wall necrosis. To help intubation, it could be 

beneficial to place the dog in an upstanding position on its hind leg. If intubation is not 

successful, percutaneous gastrocentesis with 18 gauge needles is an option to decompress the 

stomach. Percutaneous gastrocentesis is performed on the right side. Abdominal contamination 

is a risk after percutaneous gastrocentesis especially if large trocars are used. After percutaneous 

gastrocentesis orogastric intubation can be tried again. 

Cardiac rhythm needs to be evaluated before surgery. Supraventricular tachycardia and 

ventricular tachycardia are the most common arrhythmias associated with a gastric dilatation 

volvulus. Atrial fibrillation has been reported in some dogs with GDV without cardiomyopathy. 

Usually the arrhythmias occur postoperatively. Twenty-five percent of dogs presented for gastric 

dilatation volvulus already have cardiac arrhythmias. 

Surgical intervention is required after medical stabilization of the patient. Surgical 

intervention is recommended as soon as possible. Delayed surgery increased the potential for 

gastric wall edema and necrosis, and venous stasis especially if the stomach is rotated 360 o . If 

the surgery is delayed potential cardiac arrhythmias can develop. Seventy-five percent of the 

dogs that have arrhythmias develop them 36 hours after the gastric dilatation episode. Delaying 

surgery increases the risk of stomach necrosis. It has also been shown that dogs with more than 

5 or 6 hours of clinical signs related to GDV have a poor prognosis. 

SURGICAL TREATMENT 

The purpose of the surgery is to derotate the stomach, evaluate the stomach wall and the spleen 

for ischemic injury, and perform a gastropexy. Gastropexy decreases the chances of recurrence 

from 80% to 5%. Dogs after a gastropexy can still dilate but not rotate their stomach. 

The dogs are placed on dorsal recumbency and a midline celiotomy is performed. The 

surgeon stays on the right side of the dog. Upon opening the abdominal cavity, the omentum is 

covering the stomach which confirmed the diagnosis of gastric dilatation volvulus. The stomach 

can be decompressed again before derotation with a large orogastric tube. After identification of 

the pylorus and the fundus with a clockwise rotation, the pylorus is grasped with the right hand

and pulled ventrally toward the abdominal incision while the left hand pushed the fundus 

dorsally into the abdominal cavity. The spleen follows the motion of the stomach. If a splenic 

torsion is present a splenectomy is performed without untwisting the vascular pedicle. 

After derotation, the stomach and spleen are evaluated for ischemic injuries. Usually the 

spleen shows signs of venous congestion that resorb quickly after derotation of the stomach. 

Splenectomy is indicated if thrombosis of the splenic artery is present. Evaluation of gastric wall 

perfusion is difficult. Approximately 10% of dogs have a devitalized gastric wall requiring 

gastrectomy. Ischemic injury occurs most commonly in the fundic area along the greater 

curvature. No objective criteria exist to evaluate the gastric wall. Absence of peristaltic wave, 

pale greenish to gray serosal color, thin gastric wall, and lack of bleeding after partial thickness 

incision are signs of gastric wall devitalisation. Gastrectomy is required to resect the necrotic 

stomach wall. Two options are available: gastrectomy with either traditional suture technique or 

stapling suture. 

The stomach is packed off from the abdominal cavity with multiple moistened laparotomy 

sponges. The healthy stomach is retracted with stay sutures to prevent gastric spillage. Branches 

of the short gastric arteries and left gastroepiploic artery supplying the area are ligated. Necrotic 

gastric wall is resected with Metzenbaum scissors to the level of healthy gastric tissue. A two 

layers closure with inverting pattern using 3-0 absorbable monofilament suture is necessary to 

close the stomach. This technique was associated with a 60% mortality. If autostapling 

equipment is available a Gastro-Intestinal Anastomosis device (GIA 50) or a Thoraco-Abdominal 

device (TA 90) can be used to perform the gastrectomy (Figure 1). Advantages of this technique 

include decrease surgical time and decreased abdominal contamination from gastric spillage. 

Mortality rate with the autostapling equipment is close to 10%. Stomach rupture at the time of 

surgery is associated with severe peritonitis. Placement of a close suction drain is recommended 

to help control the peritonitis. 

After gastrectomy, a gastropexy is required. A belt loop gastropexy, a circumcostal gastropexy 

and an incisional gastropexy are the most commonly 

performed with similar outcome. The circumcostal 

gastropexy is probably more technically demanding than 

any other technique. It is also associated with a risk of 

pneumothorax if the diaphragm is incised. 

For a belt loop gastropexy (Figure 2), two small transverse 

stab incisions are made in the parietal peritoneum and 

transverse abdominalis muscle. The incisions are located 2 

Figure 1 

to 3 cm caudal to the last rib, and one third the distance 

from the ventral to dorsal midline (Figure 2 A). The 

incisions are made 3 cm apart, and a flap of transverse 

abdominalis muscle is elevated (Figure 2 B) A 4 cm by 3 

cm seromuscular flap is created in the pyloric antrum (Figure 2 C-D). A branch of the right 

gastroepiploic artery is incorporated in the flap. One simple interrupted suture can be placed 

between the stomach wall and the ventral part of the transverse abdominalis muscle flap (Figure 

2 E). Using a stay suture, the seromuscular flap is passed through the belt loop in the abdominal

wall (Figure 2 F) The seromuscular flap is sutured back on its original position using 3-0 

absorbable monofilament with simple interrupted pattern 

(Figure 2 E). 

POSTOPERATIVE COMPLICATIONS 

Several complications can occur after surgical 

treatment of gastric dilatation volvulus. They result 

from the pathophysiology of the gastric dilatation 

volvulus syndrome. Shock after surgery results usually 

from inappropriate treatment prior to surgery, surgical 

blood loss, anesthetic depression and fluid sequestration 

due to ileus. Septic shock can result from toxins and 

bacterial absorption from gastric mucosa necrosis and 

peritonitis. 

Prognostic indicators are gastrectomy with 

Figure 2 

splenectomy, hypotension, DIC, arrhythmias, and 

peritonitis. Gastrectomy alone is not a prognostic 

indicator for survival, however it increases the risk of complications: peritonitis, arrhythmias, 

and hypotension. 

Ventricular arrhythmias are common after gastric dilatation volvulus, especially 36 hours after 

surgery. It occurs in 50% of the cases. They result from poor myocardial perfusion, ischemia, 

acidosis, electrolyte imbalance, thromboembolic event, and myocardial depressant factor. 

Treatment requires correction of acid-base and electrolyte imbalances, and hydration. Lidocaine, 

2 to 4 mg/kg as a slow bolus is given intravenously followed by a constant rate infusion of 50 to 

100 microgm/kg/mn is the drug of choice for treatment of ventricular tachycardia. Sotalol will 

then be administered for 2 weeks. An electrocardiogram will be repeated 2 weeks after surgery 

to make sure the arrythmias are not present anymore. 

Hypokalemia, blood loss, and disseminated intravascular coagulopathy need to be 

recognized and treated accordingly. Gastric rupture occurs rarely postoperatively but is due to 

inappropriate assessment of the viability of the stomach at time of surgery. Gastritis secondary to 

mucosal ischemia is treated with famotidine, and sucralfate.

PERITONITIS 




Peritonitis is a life threatening condition in dogs and cats that causes serious metabolic 

alterations and organ dysfunction Peritonitis is an inflammatory process that involves all, 

or a portion, of the peritoneal cavity. It results from contamination of the abdominal 

cavity by either microorganisms or inflammatory chemicals. Peritonitis is characterized 

by acute abdominal pain. 

ETIOLOGY 

Peritonitis can be caused by the introduction of microorganism into the serosal-lined 

peritoneal cavity. This may results from traumatic injury, surgical induced lesions, 

strangulation-necrosis of the gastrointestinal tract, perforation of the bowel, rupture of 

gastrointestinal ulcers, incarcerated loop of intestine, mesenteric volvulus, or pyometra 

rupture. Inflammation of the peritoneal cavity may also results from release of neoplastic 

tissues, blood, urine, or bile into the abdominal cavity. Pancreatitis can trigger peritonitis 

by local inflammation. 

PATHOPHYSIOLOGY 

Irritation or injury to the peritoneal lining results in direct cellular damage with the 

release of lysosomal enzymes, kinin and histamine. Cellular damage to capillaries and 

serous surfaces allows white blood cells, fibrin, fibronectin and fluid to enter the area. 

Sympathetic stimulation inhibits peristalsis, which localizes and helps inhibit movement 

of contaminants through the peritoneal cavity. Omentum moves in the area to increase 

oxygen tension, deliver white blood cells and absorb bacteria, foreign material or debris. 

If the initial response is insufficient to localize the insult, the inflammatory reaction 

takes place over a larger area and a generalized peritonitis occurs. Bacteria embolize and 

sepsis is developing. Activation of the arachidonic acid pathway occurs after damage to 

the cell membrane with production of toxic free radicals, activation of the coagulation 

cascade. Endotoxins also activate the extrinsic coagulation pathway. Increased amounts 

of interstitial fluid lead to accumulation of free peritoneal fluid with protein and sodium. 

As more peritoneal fluid accumulates there is a decrease in circulating blood volume and 

hypovolemic shock occurs. Continued accumulation of endotoxin, bacteria, chemicals 

and white blood cells increases the severity of the inflammatory process. Hemoglobin if 

present interferes with the chemotactic response of white blood cells, retarding clearance 

of bacteria. The addition of 4 gm of free hemoglobin/100ml of fluid results in 90% 

mortality when bacteria are present. Fibrin clots isolates bacteria from the white blood 

cells. Bacteremia develops with septic shock. 

As more fluid accumulates in the abdominal cavity hypotension develops with 

reduction of the cardiac output. Sympathetic activation results in augmentation of

contractility and vasoconstriction. Pain and increased metabolic rate contributes also to 

the augmentation of heart rate. Reduction of kidney perfusion stimulates reninangiotensin 

system. It results in severe vasoconstriction. After stimulation of aldosterone 

secretion by renin-angiotensin, water and sodium retention occur which help maintain 

plasma volume. Augmentation of osmolality stimulates the secretion of anti-diuretic 

hormone. Renal vasoconstriction, aldosterone and anti-diuretic hormone release 

contributes to the reduction of urine production. Decrease cardiac output and 

vasoconstriction result in poor tissue perfusion leading to myocardial ischemia, brain 

damage and renal tubulonecrosis. Electrolyte imbalance plus myocardial ischemia 

trigger arrhythmia with further reduction of cardiac output. 

Bile will produce intense peritoneal irritation. Bacteria might be present if there is an 

associated cholangiohepatitis. A certain level of endogenous flora is present in the liver 

and hepatic circulation as a result of normal entero-hepatic circulation. Numerous 

species have been cultured including Staphylococcus, Streptococcus, E Coli, Klebsiella, 

Enterobacter, Clostridia, Bacteroides and Fusobacterium. Death will not occur from bile 

contamination alone. The concentration of bile salts is important in the toxicity of bile 

peritonitis. Bile salts enhance bacterial proliferation. Bile salts reduce surface tension, 

bacterial adherence and subsequently neutrophils activity. Bile salts lyse red blood cells, 

releasing hemoglobin, which enhances bacterial proliferation. 

Gastric fluids and pancreatic enzyme are more irritant than bile salts. They cause 

immediate cellular damage. The acid pH of the gastric fluid prevents bacterial growth 

initially but if blood is present or foreign material bacterial will develop. 

Urine may or may not be contaminated with bacteria. Urine does not create a 

significant inflammation. Urine peritonitis can cause profound azotemia subsequent to 

absorption of urine constituents across the peritoneum. 

Barium produces an intense chemical peritonitis with hemorrhagic, granulomatous 

reactions. When combined with bowel perforation, the toxic effect is greater than with 

either contaminant alone. The morbidity and mortality of peritonitis induced by barium 

has been correlated to the amount of barium in the peritoneal cavity. Water soluble 

contrast materials are less toxic but are still associated with a high morbidity if there is 

concurrent bowel perforation. 

Blood causes minimal irritation of the peritoneum and is completely absorbed from the 

peritoneal cavity within 24 hours. Blood interferes with chemotactic influx of white 

blood cells. It may impede lymphatic clearance of bacteria. 

CLINICAL FINDINGS 

Local or generalized tenderness may be present in peritonitis. The pain is usually 

diffuse and the abdomen is tender and tympanic. Splinting of the abdominal wall is 

common with the slightest touch. Pyrexia, tachycardia, tachypnea and vomiting then 

develop. Inflammation of the peritoneal cavity causes cessation of normal peristaltic 

activity and accumulation of fluid and gas.

Marked leukocytosis with a severe left shift is present on the complete blood 

count. Biochemistry is also helpful to further define the cause of the peritonitis. Platelet 

counts should be carefully evaluated because lot of dogs with peritonitis will develop 

DIC. 

Abdominal paracentesis with cytology is more likely to confirm the diagnosis of 

peritonitis. Abdominal lavage may help in the diagnosis of a peritonitis if the first 

abdomocenthesis is negative. In per-acute situations since peritoneal leukocytes counts 

do not rise until 2-3 hours after contamination the abdominocenthesis may not help in the 

diagnosis. Peritoneal fluid is an exudate (1,000 to 2,000 white blood cells/microliters, 

toxic neutrophils) with or without bacteria. An exsudate with a high white blood cell 

count but without any bacteria is very commonly associated to a perforation of the upper 

GI. Cytology of the exudate is necessary to evaluate the neutrophils. Aerobic, 

anaerobic, and fungal culture is required from the exudate. Presence of bile, blood, or 

urine (creatinine) obtained after tapping the abdomen suggests specific diagnosis. Also 

dehydrated patients may not have a severe effusion but after rehydration the effusion will 

get worse. Therefore it is important to constantly evaluate those patients because the 

diagnosis will change when more fluid is present in the abdomen. 

RADIOGRAPHIC EXAMINATION 

Radiographs may be helpful for the diagnosis of peritonitis. Radiographic 

examination shows a lack of abdominal contrast and a ground glass appearance. Fluid 

accumulation and pneumoperitoneum can be seen on radiographs. Pneumoperitoneum is 

more characteristic of stomach rupture. Free gas in the abdomen may be seen between 

the liver and the diaphragm; however, this is considered a normal finding for at least 1 

week after abdominal surgery. Intraluminal gas pattern may be suggestive of ileus or 

obstruction. Contrast studies are helpful for assessment of the urinary tract but should 

otherwise be avoided, particularly if gastrointestinal perforation is suspected or if surgery 

is inevitable. Ultrasound can be used to evaluate parenchymatous organs and intraabdominal 

masses. 

TREATMENT 

Treatments of peritonitis have 3 goals: administer appropriate supportive medical 

treatment (antibiotics, fluid therapy, shock therapy), lavage thoroughly the abdominal 

cavity with sterile warm saline to flush bacteria or debris, and surgical correction of the 

primary problem if possible. 

Antibiotic therapy is initiated as soon as peritonitis is diagnosed and samples are 

collected for culture and sensitivity. Usage of intravenous bactericidal drugs that are 

active against anaerobic and gram negative aerobic organisms is recommended. We are 

using the combination of Ampicillin (20 mg/kg three times a day) and Enrofloxacin (5 

mg/kg 2 times a day). Intraperitoneal administration of antibiotic is contraindicated. 

Fluid therapy with crystalloid, colloids should be initiated first with a shock dose since 

the patients are in hypovolemic shock. Colloids such as Dextran 70, Hetastrach or

plasma are highly recommended for patients with septic shock and endotoxemia. 

Hypoglycemia and electrolyte imbalance should be corrected when recognized. 

Surgery is necessary to halt ongoing contamination, remove foreign material and 

adjuvant substances, provide drainage and provide access for enteral nutrition. After 

correction of primary lesion, animal with generalized peritonitis should undergo lavage of 

the abdominal cavity with 3 to 4 liters of warm sterile saline. The abdominal cavity is 

then dried as much as possible. 

At the time of closure of the abdominal cavity there are four options for the surgeon: 

close the abdomen completely, perform a second surgery 24 hours alter to have a second 

look, place a closed suction drain, or leave the abdomen open with an heavy bandage to 

contain the abdominal organs. Decision of placing a drain is purely subjective and there is 

no data in the literature to demonstrate the benefit of draining the abdominal cavity. 

Drainage of the abdominal cavity will prevent a compartmental syndrome that can induce 

anuria. If the contamination was mild and the source of the peritonitis well controlled 

then the abdomen can be closed. If the peritonitis is mild but has a tendency to be very 

exudative (bile peritonitis) or the source not well controlled then a drain can be placed. If 

the contamination of the abdominal cavity is severe or if the source of the contamination 

is not controlled or if lot of foreign materials are present the abdomen should be left open 

to drain. Colon trauma, intestinal necrosis after incarceration, strangulation of a loop of 

bowel, rupture of a pyometra with generalized peritonitis, and necrotico-hemorrhagic 

pancreatitis are amenable to open abdominal drainage. 

Second look surgery: Twenty-four hours after surgery the patient is anesthetized and 

brought to the operating room. The abdominal cavity is open again. A fluid sample is 

collected for cytology. A full exploration is performed to evaluate the surgical site and 

also brake down adhesion to eliminate pockets of fluid. Foreign materials are eliminated 

mechanically during the exploration. If the surgical site is showing signs of leakage it is 

then repaired. The abdominal cavity is then flushed aggressively with 3 to 4 liters of 

warm sterile isotonic solution. A drain can then be placed if needed. The abdomen is 

then closed. This operation can be repeated 24 hours later if needed. 

Surgical technique for placement of drains: Jackson Pratt drained should be placed 

in the cranial part of the abdominal cavity. The drain should extend between the liver and 

the diaphragm. The drain then exit in the lateral side of the cavity and connected to a 

closed suction device that generate between 5 to 10 mm Hg. The drains are maintained 

for several days until the daily cytology of he abdominal fluid shows significant 

improvement. The tip of the drain should be cultured at the time of removal. This 

technique does not allow flushing of the abdominal cavity. The drain allows collection of 

fluid that can be evaluated daily. 

Surgical technique for open abdomen: At the end of the surgical procedure, a loose 

lace of heavy suture material (#2 monofilament non-absorbable suture) is placed on the 

edge of the abdominal incision to maintain the abdomen organs inside the abdomen. The 

two edges of the abdominal incision are not brought close together. Subcutaneous tissue

and skin are not sutured. A layer of 2 or 3 sterile laparotomy sponges is placed on the 

loose lace. Loops of 2-0 nylon are placed every 2 to 3 cm on the skin 5 to 6 cm away 

from the edge of the incision and umbilical tap is laced through those loops to maintain 

the laparotomy sponges. Sterile surgical towels are the applied and maintained in place 

with an adhesive incises surgical drape. If the patient is a male dog, a urinary catheter is 

placed and the penis can be incorporated under the adhesive incise surgical drape. Under 

heavy sedation and analgesia or general anesthesia, bandages are changed every 12 to 24 

hours. At each bandage change, the abdomen is flushed with warm sterile saline. 

Cytology of the fluid present in the abdominal cavity is performed. When the cytology 

shows healthy neutrophils and decreased number of bacteria per high power field, the 

abdomen can be closed. During the open abdomen treatment the patient is kept under 

appropriated intravenous antibiotherapy. Usually, a combination of ampicillin and 

enrofloxacin is used until the results from the culture and sensitivity are known. With an 

open abdomen patients are loosing a great amount of proteins which placed them very 

quickly in severe hypoproteinemia. Fresh frozen plasma transfusions should then be 

administered to maintained their preload and oncotic pressures. To limit the severity of 

the hypoproteinemia a jejunostomy tube is placed at the first surgery to try to supplement 

the patient in high catabolic stage. Also the plasma transfusions bring coagulation factors 

that very important for these patients since they are at high risk of disseminated 

intravenous coagulation (DIC). Since these patients are septic or are at high risk to 

become septic heart rate, arterial blood pressures, central venous pressure, activated 

coagulation time, and blood glucose should be monitored closely. Open abdominal 

drainage is associated with a high morbidity and mortality. In a study, 63% of the 

patients treated with an open abdomen died in the early postoperative period from 

complications associated with the open abdomen. The major complications from open 

abdominal drainage are hypoproteinemia, DIC, and nosocomial infection. 

Feeding tube placement: 

A combination of gastrostomy and jejunostomy tube are used for the management of 

patients with peritonitis. 

Gastrostomy tubes are placed for long term management of the patient and also for 

decompressing the stomach in the post-operative period. The greater curvature of the 

body of the stomach is identified. The greater curvature of the body of the stomach is 

manipulated to identify the are with e least amount of tension after placement against the 

left abdominal wall behind the last rib. A purse-string suture with 3-0 monofilament 

absorbable suture is placed in the gastric fundus in the identified area. A Foley catheter 

(18 to 20 French) is inserted first through the left abdominal wall just behind the last rib. 

A stab incision is made in the middle of the purse-string suture and the tip of the Foley 

introduced in the stomach. The balloon of the Foley catheter is inflated with appropriate 

amount of saline and the purse-string suture tied. Four gastropexy sutures (3-0 

monofilament absorbable material) are placed between the stomach wall and the 

abdominal wall. The sutures are evenly distributed around the Foley catheter. A Chinese 

finger trap suture is placed around the Foley catheter on the skin.

A jejunostomy tube is placed when bypass of the upper part of the gastrointestinal is 

required. A loop of jejunum is selected distal to the part of the intestine that needs to be 

bypassed. A purse-string of 3-0 monofilament absorbable suture is placed on the 

antimesenteric border of the jejunum. The jejunostomy tube (3 to 5 French) is first 

inserted through the abdominal wall. A stab incision is made in the middle of the pursestring 

and the jejunostomy tube is introduced in the jejunum 20 cm aborally. The pursestring 

is tied. Then, 4 jejunopexy sutures are placed evenly around the jejunostomy tube 

between the abdominal wall and the jejunum. 

Feeding can be started immediately after placement of the jejunostomy tube. A liquid 

diet is administered continuously through a feeding pump. The catheter needs to be 

flushed every 4 hours to prevent its obstruction. The tube needs to stay in place for at 

least 4 days before its removal to allow appropriate sealing of the pexy. Usually, the 

jejunostomy tube is for short-term usage because a pump is required to deliver the diet. 

Jejunostomy tube is advantageous for patients requiring multiple anesthesia (open 

abdominal drainage) or being profusely vomiting before surgery. 

Prognosis is worse for young and very old animals, or in the presence of delayed 

diagnosis, greater or more virulent contamination or poor nutrition. Mortality rate is high 

if organ failure is present. Poor prognosis is associated with refractory hypotension, 

cardiovascular collapse and development of DIC. Mortality could be as high as 68% for 

peritonitis. Mortality rate with open abdomen has been reported as high as 48%. 

SURGERY OF THE LIVER AND GALL BLADDER 




Surgery of the liver and gall bladder is indicated for liver trauma, liver neoplasia, liver 

abscess, liver torsion, bile duct obstruction, and gallbladder mucocele. Liver and spleen 

are the two most common organs to induce a hemodabdomen after trauma. It rarely 

requires surgery unless the patient cannot be stabilized with appropriate fluid-therapy and 

blood transfusion. Liver trauma is treated surgically by compression, tamponnade with 

the omentum or liver lobectomy. Liver neoplasia is rare in dogs. Liver adenocarcinoma 

and lymphoma are the most common tumors found in dogs. Massive adenocarcinoma are 

well amenable to surgical treatment since they are slow growing and metastasize slowly. 

Liver abscess are rare in dogs and cats and usually their cause is not well known. Gramnegative 

aerobic bacteria are the most commonly found in the liver abscess. Liver lobe 

torsion usually involves the left liver lobes. Cholelithiasis has to be considered when 

obstructive icterus is present Stones could be solitary, numerous or sandlike. Most canine 

and feline stones are calcium salts of bilirubinate. Bile stasis and inflammation might be 

cause for the formation of bile stones. Cholecystitis has been reported in dogs. It could 

be acute or chronic and a necrotizing or emphysematous form has been described. 

Extrahepatic biliary obstruction occurs when disease processes interfere with normal flow 

of bile from the liver and the gallbladder into the intestine. 

General considerations 

Regenerative capacity 

Removal of 70% of the liver is tolerated. The general condition of the patient 

conditions how much liver can be removed safely. If more is resected it will result in 

portal hypertension because there is not enough liver parenchyma left to access the entire 

blood flow from the portal vein. Regeneration of the liver starts with 24 hours of the 

surgery and peaks at 3 days. There is hyperplasia and compensatory hypertrophy of the 

remaining hepatocytes. The liver mass can be restored within six weeks after 70% 

hepatectomy. 

Metabolic alterations 

Coagulation is evaluated in any patients with hepatobiliary disease. In one study, 

prothrombine time was elevated in 66% of the animal with liver disease. Plasma 

fibrinogen remain normal until almost liver function is lost 

Vitamin K deficiency resulting in coagulopathy may occur with prolonged complete 

bile duct obstruction. Vitamin K administration (1 to 2 mg/kg subcutaneously) is

sufficient to increase their level in 3 to 12 hours. Fresh frozen plasma is administered if 

the coagulation times are still prolonged. 

Hypoglycemia can occurs with 48 hours of partial liver lobectomy but does not always 

happened after major hepatectomy. Intravenous infusion f glucose (10%) would then be 

required. Albumin concentration is reduced after massive liver lobectomy because of the 

low level of production. Bilirubin can increase but usually goes back to normal within 

one week. Increased liver enzymes will occur after major resection and will persist for 4 

to 6 weeks. 

Antibiotherapy 

Portal venous blood is an important source of bacteria for the liver. Infections of the 

liver and biliary tract commonly involve Gram-negative aerobic bacteria (E coli, 

Enterococcis faecalis, Proteus, Klebsiella). Anaerobic bacteria can also colonize the liver 

in dogs (Clostridium). 

Antibiotics are routinely administered when hepatobiliary surgery is performed. 

Cephalosporins provide broad spectrum coverage. When anaerobic bacteria are 

suspected metronidazole or enrofloxacine should be used. 

Anatomy 

The liver has 6 lobes: left medial and lateral, right medial and lateral, quadrate lobe and 

the caudate lobe with two processes. The liver lobes are attached to the diaphragm by the 

triangular ligaments. There are also the hepato-gastric ligament, duodeno-hepatic 

ligament with the bile duct and hepato-renal ligament stabilizing the liver. The liver 

receives 70 % of its blood supply from the portal vein and 30 % from the hepatic artery. 

The blood from the hepatic artery and the portal vein mixes in the hepatic sinusoids and 

is released in the caudal vena cava through the hepatic vein. There is on hepatic vein per 

liver lobe. 

Surgical techniques 

Liver 

Surgical biopsy 

Liver biopsies are commonly taken during abdominal exploration. The guillotine 

technique with a 3-0 braided suture is commonly used to remove a small fragment of the 

liver. Forceps can be used to make small indentation in the edges of the liver lobes. 

Several biopsy can be taken from different liver lobes. Biopsy can be submitted also for 

cultures. If the edges of the biopsy are bleeding, cautery can be used to control the 

bleeding or gelfoam can be applied.

Partial liver lobectomy 

Partial liver lobectomy can be performed to remove the distal end of a liver lobe with a 

small lesion. Occlusion of the blood flow to the liver can be accomplish by compressing 

the hepatic artery and the portal vein with a vascular clamp or a Bulldog clamp. 

After the line of resection has been decided, mattress sutures with 2-0 monofilament 

absorbable suture material are placed across the liver parenchyma and tighten to crush the 

tissue. This technique allows crushing of the parenchyma and ligation of the major 

vessels. Several mattress sutures are placed across the section of the liver lobes. 

Mattress sutures should be 2 to 3 cm long. After all the sutures have been placed the 

blood vessels are cut with a scissors. Stapling equipment can laso be used to performed a 

partial liver lobectomy. Usually the section the liver lobs is bleeding significantly with 

this technique. Cautery can be used to cauterize the small vessels that are still bleeding. 

Alos Gelfoam can be applied to the liver or omentum can be patched to the liver to 

tamponnade the section of the liver. 

Liver lobectomy 

Liver lobectomy requires ligation of the blood vessels and hepatic duct at the hilus of 

the liver. Each liver lobe can be removed separately. Right liver lobes and caudate lobes 

are the most difficult lobes to remove because of their close proximity to the vena cava. 

The dissection starts from caudally with exposure of the branch of the portal. IT is 

dissected and double ligated. Then hepatic artery and the hepatic duct draining the liver 

lobes are dissected and ligated next. Finally, the hepatic vein is identified after finger 

fragmentation of the liver parenchyma at the base of the liver lobe. Finger fragmentation 

reduces the amount of bleeding from the liver parenchyma and prevents laceration of 

major blood vessels. After the hepatic vein has been exposed it is double ligated and 

divided. The hepatic vein of the right caudal liver lobes is better clamped with a vascular 

clamp divided and then sawn as an open vessel. This technique avoid kinking of the vena 

cava or slippage of the suture of the stub of the hepatic vein. If the quadrate lobe has to 

be removed the gall bladder is dissected away from the liver parenchyma. At the end of 

the procedure either the gall bladder is removed or pexied to another liver lobes to 

prevent torsion and obstruction of the cystic duct. 

Stapling equipment (TA 30 V3 or TA55) can be used to perform a liver lobectomy of 

the left liver lobes. 

Gallbladder and bile duct 

Cholecystotomy 

Cholecystotomy is indicated to removed inspissated bile or biliary sludge, gelatinous 

bile or gallstones and bile duct stones. It is also performed to cannulate the bile duct to 

evaluate its patency.

Two stay suture of 3-0 monofilamet are placed on the gall bladder. A small incision is 

made between the two stay sutures and suction is used to aspirate the bile overflow 

before it contaminates the abdominal cavity. The incision is then enlarged with 

Metzembaum scissors. The incision should be long enough to perform the procedure. 

The bile duct needs to be catheterized before closure. It could be difficult to achieve a 

good catheterization because of the angle of the cystic duct with the common bile duct. 

A biopsy of he wall of the gallbladder is taken for histology and culture before closure. 

The gallbladder is then closed with a simple suture pattern with 4-0 monofilament 

absorbable suture. A one-layer closure is sufficient. 

Cholecystectomy 

A cholecystectomy is required when the gallbladder is the primary cause of the 

pathological process or if the damages to the gall bladder are too severe and might 

contribute to the recurrence of the disease. Cholecystitis and gallbladder mucocele are 

best treated by cholecystectomy. 

Cholecystectomy requires the dissection of the gallbladder form the quadrate lobe. The 

gallbladder is lodged in the hepatic fossa and it is covered by visceral peritoneum. The 

dissection starts at the fundus of the gall bladder by an incision through the visceral 

peritoneum. The dissection should not be in the liver parenchyma because severe 

bleeding will occur. The dissection is then carried with cautery toward the infudibulum 

of the gall bladder. The cystic duct and the cystic artery are isolated, clamped, and 

ligated. The cystic duct is ligated at a sufficient distance from the common bile duct to 

prevent kinking of the common bile duct. If the liver parenchyma is bleeding, cautery 

could be used to control the bleeding or gentle pressure could be applied for 5 minutes. 

Gelfoam could also be applied on the bleeding surface of the liver. 

Cholecystectomy can also be performed with laparoscopy. Only cases without 

occlusion of the common bile duct can be operated with minimally invasive surgery. 

Usually the cystic duct is dissected first and ligated with clips. After successful ligation 

of the cystic duct the gall bladder is dissected from the hepatic fossa of the quadrate lobe. 

If the gall bladder is too large the dissection can be started at the level of the apex. IT is 

then important to establish a good plane of dissection between the gall bladder and the 

liver parenchyma. The cystic is then ligated last. 

Cholecystoduodenostomy 

Cholecystoduodenostomy is the procedure of choice for bile diversion in dogs and cats 

when the gall bladder is not directly involved in the disease process that is causing the 

bile duct obstruction. It could be a palliative procedure for bile duct obstruction due to 

neoplasia. 

The gall bladder is detached for the hepatic fossa as described for the cholecystectomy. 

Then the gall bladder is brought in contact with the duodenum with two stay sutures. 

Special attention should be placed on the cystic duct to avoid twisting and occlusion. The

stoma between the gall bladder and the duodenum should be between 2 and 4 cm. A first 

layer of suture is applied between serosal layers on the back side of the duodenum. The 

gall bladder and the duodenum are then incised. A simple continuous suture is placed 

between the muscosa layers of the gall bladder and the duodenum. Finally, another layer 

of simple continuous suture is placed between the serosa of the duodenum and the serosa 

of the gall bladder. 4-0 monofilament absorbable suture material is used for the 

procedure. 

After cholecystoduodenostomy, the patients are at risk for ascending cholangiohepatitis 

and needs to be maintained on enrofloxacin for long term. 

Choledochoduodenostomy 

Choledochoduodenostomy can be performed if a benign obstruction occurs at the distal 

end of the bile duct. Significant dilation of he proximal art of the common bile has to be 

present to be able to perform this procedure. 

The distal part of the common bile duct is separated form the pancreas and the 

duodenum. It is then implanted more proximal into the wall of the duodenum with two 

simple interrupted sutures.


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SURGERY FOR URINARY STONES  

LOWER URINARY TRACT 




The most common cause of urinary obstruction in small animal surgery is urinary 

stones in the urethra. Other causes of obstruction are neoplasia in the urethra, and 

neoplasia compressing the urethra. Generally, small cystic calculi migrate to the neck of 

the bladder during micturition and pass into the urethra. In the male, urethral calculi 

most commonly lodge caudal to the os penis. In the female, calculi may lodge at any 

location along the length of the urethra. Urethral obstruction is more common in the male 

than female. 

Urinary obstruction requires medical treatment to stabilize the patient to surgery and 

surgical treatment to release the obstruction. Dogs and cats with urinary obstruction are 

presented with hematuria, stranguria, and pollakiuria. Plain radiographs or radiographs 

with contrast material (excretory radiographs, cystourethrograms) will confirm the 

presence of a urinary stones in the urethra. 

MEDICAL MANAGEMENT 

Blood work with complete blood count, and biochemistry is required to evaluate 

kidney function of the patient. Urinary obstruction is associated with severe post renal 

azotemia and severe electrolytes imbalance. Hyperkalemia is the most common 

electrolyte abnormality. Hyperkalemia can induce severe bradycardia if the concentration 

is over 5 me/dl. Therefore it is important to reduce the hyperkalemia before anesthetizing 

patients with urinary obstruction. 

The most efficient technique to lower the potassium concentration is to diaries the 

patient. If the patient can still urinate on its own intravenous fluid therapy will induce a 

diuresis. If the patient cannot urinate cystocenthesis can be performed to empty the 

bladder. The concentration of potassium is monitored very closely to be able to 

anesthetize the patient as soon as the potassium is back to normal limits. If diuresis is not 

efficient insuline/glucose and bicarbonate can be used. While the glusoce moves 

intracellular it brings the potassium in the intracellular space. Potassium and hydrogen 

particles are exchanged which results in metabolic acidemia. Therefore bicarbonate is 

required to control the acidosis. This technique lowers the potassium within 30 minutes. 

If the potassium concentration is not reduced then calcium gluconate is used to protect 

the myocardium form the effect of potassium. 

SURGICAL MANAGEMENT 

When the potassium concentration is within normal limits general anesthesia can be 

performed. After induction of general anesthesia the urinary stones lodged in the urethra

can be retropulsed in the bladder. All the efforts should be made to retroflux the uroliths 

in the bladder. It is easier to performed a cystotomy than an urethrotomy, and there is 

less morbidity associated. 

Retropulsion 

To perform a successful repulsion the following steps have to be performed after 

inducing deep general anesthesia with intubation 

a) Thoroughly mix 45 cc of sterile saline and 15 cc of Surgilube in a 60 cc syringe and 

attach to the largest high density polyethylene urinary catheter that will pass through the 

os penis (5 to 8 French). 

b) Pass the catheter up to and against the calculus. If the patient is a male place a gauze 

sponge around the tip of the penis and occlude the penis around the catheter by squeezing 

it with thumb and finger. 

c) Using a back and forth action on the catheter, simultaneously inject the saline/ 

lubricant mix under pressure. The calculi and urethra are lubricated and the viscosity of 

the mix encourages the calculus to dislodge and flush into the bladder. This technique is 

attempted regardless of how many stones are in the urethra. 

d) If the above technique fails, place a finger in the rectum, palpate the urethra, and 

occlude its lumen, repeat step C above and when maximum pressure is exerted on the 

urethra by the saline/lubricant mix, suddenly release digital urethral occlusion allowing 

lodged calculi to flush into the bladder. This technique allows maximal dilatation of 

the urethra. 

This technique is successful in most of the cases. Lidocaine can also be injected while 

the catheter is in contact with the stone to release a spasm of the urethra around the 

stones. 

If the stones are successfully retroflux in the bladder, the urinary catheter is left in place 

to prevent migration of the stones back into the urethra. 

If the stone cannot be retroflux in the bladder then a urethrotomy is performed. 

Cystotomy 

After a midline incision in the caudal abdomen, a ventral cystotomy is performed to 

expose the inside of the bladder. After placing three or four stay sutures in the wall of the 

bladder to minimize trauma during manipulation of the bladder, the uroliths are removed 

either with a spoon, or suction. The bladder neck and lumen should be explored with a 

finger to detect remaining large uroliths. A biopsy of bladder wall should be performed 

then for culture and sensitivity. Bladder wall culture gives more reliable results 

regarding bacterial infection than urine culture. Bladder neck is flushed with warm 

sterile saline to remove small uroliths. The urethra is flushed with the catheter placed to 

retroflushed the stones in the bladder. While sterile saline is flushed profusely in the 

urethra the catheter is removed. With this technique little uroliths left in the urethra are

flushed in the bladder. Then a catheter is introduced in the proximal urethra and large 

amounts of saline are used to flush the urethra normograde. Before closing the bladder a 

catheter is introduced from the bladder in the urethra to confirm patency of the urethra. It 

is not necessary to maintain a urinary catheter postoperatively. 

It is recommended to take a post-operative radiographs to make sure all the stones have 

been removed. 

Urethrotomy 

A urethrotomy (an incision over the calculi) may be performed to remove calculi that 

cannot be retropulsed. It is usually performed in the prescrotal or perineal region. With a 

urinary catheter in place to the obstruction a 5 cm midline incision is made over the 

uroliths. The subcutaneous tissue is dissected and the retractor penis muscle is retracted 

on one side. The urethral is dorsal to the retractor penile muscle. A 15 scalpel blade is 

use to longitudinally incise the urethra over the uroliths. The uroliths are removed and 

the catheter advanced. If other uroliths are present they can either be retrieved through 

the urethrotomy or they can be flushed back in the bladder. Then a cystotomy is required. 

The urethrotomy incision can be left open or suture with an absorbable suture in a 

continuous pattern on the urethra . Subcutaneous tissue and skin are closed. If the 

incision is left open it is going to granulate and closed by second intention. Urine is 

leaking through the incision for several days. The corpus spongiosum will bleed when 

the dog urinates or becomes excited. 

Urethrostomy 

A urethrosotmy (a permanent opening to allow calculi to pass) may be indicated in 

animals that are chronic recurrent calculi formers (e.g., urate calculi in Dalmatians). 

Scrotal urethrostomy 

Scrotal urethrostomy is the technique of choice in male dogs because the urethra has its 

largest diameter at the level of the scrotum. The dog is placed in dorsal recumbency and 

a urethral catheter is placed. After castration and scrotal ablation, the retractor penile 

muscle is retracted on the side to expose the ventral aspect of the urethra. The urethra is 

incised longitudinally over 3-4 cm. The periurethral tissue is sutured to the subcutaneous 

tissue with a 4-0 absorbable suture in a simple interrupted pattern. The urethral mucosa 

is then sutured to the skin with 4-0 non-absorbable monofilament in a simple continuous 

pattern. The urethra is more superficial in the scrotal area, surrounded by less cavernous 

tissue. Complications of an urethrostomy are hemorrhage, stricture, and dermatitis from 

urine scalding. Hemorrhage happens for 6 to 7 days after surgery when the dog urinates 

or becomes excited. Sedation might be required for a week to 10 days after surgery to 

help control bleeding. Stricture mostly occurs is the dogs is self-traumatizing the surgical 

site. An E collar is recommended for 10 days. After a urethrostomy dogs are at more risk 

of ascending UTI because the urethra is shorter. 

Perineal urethrostomy

In cats a perineal urethrostomy is performed. The cat is positioned in ventral 

recumbency at the end of the table. An elliptical incision is performed around the 

prepuce and the scrotum. The cat is castrated. The penis is isolated and the 

ischiocavernosus muscles are exposed by blunt dissection and transected to their 

attachment to the ischium. After care blunt dissection ventrally posterior displacement of 

the penis is possible. The retractor penile muscle is transected near the external anal 

sphincter muscle. The penile urethral is incised dorsal to the bulbourethral glands. At 

this point the urethra is wide (4 mm). The pelvic urethra and 3 cm of the penile urethra 

are sutured to the skin with 4-0 monofilament in a simple interrupted pattern. The 

remaining of the penile urethra and penis are amputated. An Elizabethan collar is used to 

prevent self-mutilation. Complications are hemorrhage, cystitis, urethral stricture, selfmutilation, 

and wound dehiscence. 

PATIENT MONITORING 

Post operatively patient needs to be monitored for signs of uroabdomen. Animals 

presenting with complete urinary obstruction and postrenal azotemia are continued on 

crystalloid IV therapy until serum urea nitrogen and creatinine return to normal. Postobstruction 

diuresis happened after the obstruction has been released. Fluid rate should 

be increased to maintain the hydration status of the patient. Treatment for UTI and dietary 

management are required to prevent reoccurence. After a cystotomy hematuria is 

possible for 2 - 3 days postoperatively. After a urethrotomy or a urethrostomy, 

hemorrhage from the urethral stoma is common in the immediate postsurgical period. It 

generally occurs 4 - 5 days postoperatively, but occasionally will last up to 2 weeks. 

Apply an Elizabethan collar to prevent self-mutilation.

SURGERY OF THE PANCREAS 




Pancreatic surgery is indicated for lesions of the pancreas such as neoplasms, 

abscesses, and pseudocysts. Surgery is usually not indicated for acute pancreatic unless 

there is indication of abscess formation and severe peritonitis, or obstruction of the 

duodenum and the bile duct. In some cases, the presence of pancreatic pathology may 

not be obvious until the surgeon is in the midst of an abdominal exploration. Therefore it 

is important for the surgeon to have some general knowledge on pancreatic surgery and 

to be prepared to perform pancreatic surgery when needed. 

ANATOMY 

The pancreas develops from the first part of the duodenum to which it retains a close 

association. The pancreas has a V shape with an angle located against the cranial part of 

the duodenum. The largest segment is located along the duodenum and it is called the 

right limb of the pancreas. It shares it blood supply with the duodenum through the 

pancreatico-duodenal artery and it lies in the mesoduodenum. The smaller and thicker 

segment of the pancreas or left limb of the pancreas lies in the deep leaf of the greater 

omentum and extend obliquely caudally, dorsally and to the left. It is not intimately 

associated to any other organ in the abdomen. The left limb of the pancreas receives its 

blood supply form the splenic artery and the hepatic artery. The left and right limbs of 

the pancreas meet at the apex of a V (body of the pancreas). 

The exocrine portion of the pancreas drains through the pancreatic duct. It is totally 

concealed in the parenchyma of the pancreas. It extends longitudinally in the middle of 

the gland and terminates in the duodenum with a straight angle. Usually there are two 

ducts present in dog and cat. The anatomy of the ducts is highly variable and most of the 

time they communicate with each other within the parenchyma. The ducts enter the 

duodenum usually 3 to 4 cm apart. The pancreatic duct ( of Wirsung) usually opens with 

the bile duct in the major duodenal papilla situated 4 to 5 cm distal to the pylorus. It is 

the principal and usually the only duct for cats. It is usually small for dogs and drained 

only the left lobe of the pancreas. The accessory pancreatic duct (of Santorini) is the 

major duct for dogs and it is present in only 20 % of the cats. It opens in the minor 

duodenal papilla 2 cm distal to the major papilla. 

SURGICAL PROCEDURES 

Principles of pancreatic surgery 

Access to the pancreas is gained by a midline laparotomy from the xyphoid to the 

pubis. Balfour retractors are used to provide adequate exposure of the abdominal cavity. 

First a complete abdominal exploration should be performed. The free border of the

greater omentum is brought forward out of the abdominal cavity and wrapped in moist 

towels. The duodenum is brought into view to visualize the right limb of the pancreas. 

The colon is moved caudally to expose the tip of the right limb. The left limb of the 

pancreas is seen within the deep leaf of the greater omentum after a cranial retraction of 

the stomach. The body of the pancreas is visualized at the junction of the pylorus and the 

duodenum. 

The pancreas should be manipulated gently during the surgery. However the risk of 

inducing a pancreatitis with surgical manipulation is very limited even if a biopsy is 

taken. 

Pancreatic biopsy 

Pancreatic biopsy can be harvested with a shaving technique. A # 15 blade is used to 

shave a small part of a pancreatic lobule. This technique only allows small biopsies 

specimens. 

The guillotine technique with a loop of absorbable suture can be used to take a bigger 

specimen. Placement of a suture avoid leakage of pancreatic enzyme or bleeding if the 

pancreatic duct or a vessel are damaged during the biopsy. Usually several lobules can be 

isolated with sharp dissection and the loop of suture placed at their base. 

Pancreatic biopsy can also be collected with laparoscopy and special biopsy forceps. 

This technique is very efficient and only require sedation. 

Partial pancreatectomy 

Partial pancreatectomy can be performed with a suture fracture technique or with a 

dissection-ligation technique of the pancreatic parenchyma down to the ducts and 

ligature. Both techniques are acceptable and do not induce severe pancreatitis in dogs 

and cats. Partial pancreatectomy involving the central part of the pancreas are more 

difficult because the surgeon should pay attention not to ligate the common duct. 

In both procedures the part of pancreas that will be removed needs to be isolated. The 

mesoduodenum or the deep leaf of the greater omentum are dissected away for the 

pancreas. Partial pancreatectomy of the right limb of the pancreas requires careful blunt 

separation of the pancreas from the duodenum without inducing a trauma to the 

pancreatico-duodenal artery. During partial pancreatectomy of the left limb of the 

pancreas it is important to preserve the splenic artery. 

In the suture fracture technique, an incision is made in the omentum or the 

mesoduodenum on each side of the tissue to be removed. A non-absorbable suture is 

passed around the pancreas proximal to the area to resect. The suture is then tied to crush 

through the parenchyma. Blood vessels will be ligated as well as the duct. The specimen 

distal to the ligature can be excised, leaving a small amount of tissue caudal to the suture. 

In the dissection ligation technique the lobules are separated with blunt and sharp 

dissection. The dissection is completed when the ducts and the blood vessels are

exposed. These structures are then ligated with a non-absorbable suture. The tissue 

distal to the ligature can then be resected leaving some tissue distal to the suture. 

Extensive partial pancreatectomy can be performed without impairing endocrine or 

exocrine function. No metabolic abnormalities have been reported after resection of 80% 

of the pancreas if the pancreatic duct has been left intact. 

Complete pancreatectomy 

Complete pancreatectomy is indicated for neoplasia involving most of the pancreas, 

severe necrotico-hemorrhagic pancreatitis not improving with appropriate medical 

treatment. This procedure is extremely rarely performed. Patients are then diabetic and 

pancreatic insufficient. 

POSTOPERATIVE CARE 

Lavage and drainage of pancreatic surgery are important is sepsis and necrotic tissue 

are present to eliminate inflammatory cells and mediators. Antibiotics are maintained as 

long as needed if peritonitis is present. Intravenous fluids are maintained to prevent 

dehydration and treat electrolytes imbalance. Feeding with a jejunostomy tube is started 

immediately after surgery until the patient can eat on its own without vomiting. If a 

complete pancreatectomy has been performed exocrine pancreatic supplementation is 

required. Also endocrine deficiency will be treated with insulin. 

SPECIAL CONSIDERATIONS 

Pancreatitis 

Acute and chronic pancreatitis are common pathology in dogs and cats. Several factors 

have been associated with the conditions; high fat diet, hyperlipidemia, hypercalcemia, 

drugs, infection, trauma, and ischemia. Pancreatitis is due to an early activation and 

release of proteolytic and lipolytic enzymes, which causes an autodigestion of the 

pancreas. The activation factor for a pancreatitis is the transformation of the 

trypsinogenin trypsin within the pancreatic parenchyma. Other enzymes will then be 

activated leading to the destruction of the fibrous tissue, interstitial tissue, elastic tissue in 

the arteries. It results in an edematous hemorrhagic process with thrombosis of the blood 

vessels. The release of different proteolytic enzymes, inflammatory mediator results in a 

multisystemic effect that can lead to a septic shock and a multiorgan failure. 

Phospholipase activation can reduce the amount in surfactant in lungs and induces a 

severe pulmonary edema. A phlegmon is the result of an acute pancreatitis and it is a 

solid mass of indurated pancreatic tissue and surrounding tissue. It is the result of edema, 

inflammation and necrosis. 

The treatment of pancreatitis is not clearly established. Medical treatment with fluid 

therapy, antibiotic and antiemetic therapy is tried first. Transfusion with plasma is 

recommended to maintain the oncotic pressure and provide macroglobulin. The role of 

surgery for an acute pancreatitis has not been established. However, the abdominal 

exploration with abdominal lavage, biopsy, and placement of a jejunostomy tube is

indicated. The placement of jejunosotmy tube is paramount to allow delivery of calories 

and proteins to a patient in a high catabolic state without activating the pancreas. Chronic 

pancreatitis is usually associated with an obstruction of the bile duct. It is then necessary 

to release the obstruction by performing a choledocostomy or a cholecystoduodenostomy. 

Pancreatic abscess 

Pancreatic abscess is a serious complication of an acute or chronic pancreatitis. It 

results from a hematogenous or retrograde contamination of a pancreatic phelgmon. An 

abscess is visible on ultrasound. At the time of surgery, it appears as a pancreatic and 

peripancreatic collection of hemorrhagic, necrotic and purulent tissue. Pancreatic abscess 

is associated with an extremely poor prognosis. 

Surgery is indicated to debride the abscess. If the debridement with partial 

pancreatectomy is not possible, marsupialization in the stomach has been described for 

the abscess of the left limb of the pancreas. Abdominal drainage is recommended to 

improve survival after surgery. It will provide continuous drainage of the abdominal 

cavity and daily flushing will be required. Closed suction drains can be used instead of 

open abdominal drainage. During surgery a gastro-jejunostomy tube is placed to aspirate 

the stomach and feed the patient in the jejunum. 

In the postoperative period, animals with pancreatic abscess need to be watched for 

sepsis, disseminated intravascular coagulation, hyporproteinemia, hypotension, and renal 

failure. 

Pancreatic pseudocyst 

Pancreatic pseudocyst is an accumulation of pancreatic fluid within the pancreatic 

parenchyma. It is usually surrounded by granulation tissue. It is associated with chronic 

pancreatitis. Pseudocysts have the tendency to resolve in their own in 2 to 3 weeks. 

Pseudocyst can hemorrhage, become infected and produce and abscess or rupture. 

Pseudocysts that are not resorbing need to be removed surgically. 

A partial pancreatectomy is indicated to remove a pseudocyst if it is located in the 

distal part of the right or left pancreas. If a partial pancreatectomy is not possible then the 

pseudocyst needs to be drained and omentalized. 

Pancreatic neoplasia 

Insulinoma 

Insulinoma is a tumor of the beta cells. It is most commonly seen in older dogs. It 

results in hypoglycemia, weakness, seizures, muscle tremors,exercise intolerance, and 

lethargy. Diagnosis is based on hypoglycemia with a high level of insulin. Exploratory 

celiotomy is indicated even if it is not a cure because of functional metastasis. It usually 

allows a better control of the clinical signs. 

Insulinoma could be either a single or multiple discrete masses or diffuse. Careful 

palpation of the entire pancreas is important because the insulinoma might be extremely

small. Insulinoma is firm on palpation and it can occur in any part of the pancreas. 

Methylene blue has been used to stain pancreatic tissue. A dose of 3 mg/kg intravenously 

has been recommended 30 min prior to surgery. However, hemolytic anemia can result 

from the methylene blue injection. 

Wide excision of the pancreas is recommended because insulinomas are not 

encapsulated. Metastasis is common with insulinoma. They are located in lymph nodes 

and liver. Metastasis need to be removed if possible because they are functional. 

Postoperatively, the blood glucose is monitored every 4 to 6 hours. The blood glucose 

will increase shortly after surgery and hyperglycemia is not unusual because the other 

beta cells are atrophied. Insulin may then be required for one to two weeks. 

Pancreatic exocrine carcinoma 

Pancreatic exocrine carcinoma is not a common tumor that is usually diagnosed late in 

the progression of the disease. Animals are anorexic, weak and they are presented for 

weight loss and vomiting. Icterus due to obstruction of bile duct is usually present. 

Ultrasound diagnoses a pancreatic mass. At the time of surgery, the tumor is so invasive 

that resection is impossible.


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LARYNGEAL PARALYSIS 




The laryngeal functions are to regulate airflow, voice production, and prevent 

inhalation of food. If the intrinsic muscles and/or the nerve supply of the larynx are not 

normal laryngeal functions are compromised. 

The dorsal cricoarytenoide muscle abducts the arytenoid cartilages at each inspiration. 

The laryngeal recurrent nerve innervates this muscle. Central lesions or lesions to the 

laryngeal recurrent nerve or to the dorsal cricoarytenoide muscle result in laryngeal 

paralysis in dogs and cats. Laryngeal paralysis can be unilateral or bilateral 

ETIOLOGY 

Congenital and acquired forms of laryngeal paralysis have been recognized in dogs and 

cats. 

Congenital Laryngeal Paralysis 

Congenital laryngeal paralysis has been reported in Bouvier des Flandres, bull terrier, 

Dalmatian, Rottweiller and Huskies. Bouvier des Flandres and bull terrier have mostly 

been reported from Europe while the Dalmatian and Huskies from United States. 

Laryngeal paralysis has a hereditary transmission in Bouvier des Flandres with an 

autosomal dominant trait. Dogs with congenital laryngeal paralysis are clinical at an 

early age (before one year old) than dogs with acquired laryngeal paralysis. Usually dogs 

with congenital laryngeal paralysis have several neurological deficits like ataxia. 

Acquired Laryngeal Paralysis 

Acquired laryngeal paralysis is most commonly reported in Labrador retriever, Golden 

retriever, St Bernard and Irish Setter at an age of 9 years old. It has been reported in cats. 

Acquired laryngeal paralysis is more frequently idiopathic; however, other causes should 

be ruled out. Several diseases and conditions may contribute to laryngeal paralysis. A 

cranial mediastinal or neck mass stretching or compressing the laryngeal recurrent nerves 

can induce a laryngeal paralysis. Trauma to the laryngeal recurrent nerve during 

dogfights or during surgery in the neck can cause of laryngeal paralysis. Laryngeal 

paralysis in the cat has been diagnosed after bilateral thyroidectomy. Finally, a 

ployneuropathy involving the laryngeal recurrent nerve is the most common cause of 

laryngeal paralysis. The polyneuropathy can be due to an endocrine insufficiency 

(hypthyroidism) . However most of the time a diagnosis of idiopathic polyneuropathy is 

made because no causes can be identified. A myopathy involving the intrinsic muscle of 

the larynx.

CLINICAL FINDINGS 

History 

The presenting signs are similar for the congenital and acquired forms. Progression of 

signs is often slow; months to years may pass before an animal develops severe 

respiratory distress. Early signs include change in voice, followed by gagging and 

coughing, especially during eating or drinking. Endurance decreases and laryngeal stridor 

(especially inspiratory) increases as the airway occlusion worsens. Episodes of severe 

difficulty breathing, cyanosis, or syncope occur in severely affected patients. Male dogs 

are approximately three times more affected than female. Laryngeal paralysis can be 

accompanied with various degrees of dysphagia, which significantly enhances the 

probability of aspiration pneumonia after surgical correction of the laryngeal paralysis. 

Physical Examination 

The physical examination of dogs with laryngeal paralysis is fairly unremarkable. Dogs 

have a difficulty breathing on inspiration that is not alleviated with open mouth breathing. 

Mild lateral compression of the larynx significantly increases inspiratory effort. Referred 

upper airway sounds are present during auscultation of the thoracic cavity. Auscultation 

of the thoracic cavity and the lung field may reveal the presence of pneumonia in the 

cranial lung lobe due to aspiration. Palpation of the muscle mass may reveal skeletal 

muscle atrophy in cases of polyneuropathy. The tibial cranial muscle is very commonly 

atrophied in dogs with endocrine polyneuropathy. A complete neurological examination 

is required to evaluate the animal for a polyneuropathy. 

Laboratory Findings 

Complete blood count and chemistry profile are usually within normal limits. 

Hypercholesterolemia, hyperlipidemia, and augmentation of liver enzymes activity are 

present on the chemistry profile for dogs with hypothyroidism. A thyroid profile with 

endogenous TSH and free T4 is then required to further define the diagnosis. Laryngeal 

paralysis has inconsistent correlation with hypothyroidism. 

Radiographic Examination 

It is necessary to perform a radiographic examination of the thoracic cavity for the 

evaluation of the lung parenchyma and the esophagus. Aspiration pneumonia is common 

finding pre-operatively in dogs with laryngeal paralysis. If aspiration pneumonia is 

present the surgical intervention should be delayed until the aspiration pneumonia 

resolved. Pulmonary edema is not uncommon in dogs with an acute exacerbation of their 

clinical signs. Pulmonary edema needs to be treated aggressively and the surgery for the 

laryngeal paralysis does not need to be delayed. Megaesophagus might be present in 

dogs with laryngeal paralysis especially if the paralysis is due to polyneuropathy or 

polymyopathy. Megaesophagus places the animal at more risk for aspiration pneumonia 

after surgery. Radiographic examination of the larynx is unremarkable.

Laryngeal Examination 

A laryngeal examination under general anesthesia is required for the diagnosis of 

laryngeal paralysis. A light plane of anesthesia is required to be able to evaluate the 

laryngeal function during each inspiration. Thiopental or propofol is used intravenously 

as needed for the anesthesia. The animal should be anesthetized to the point at which the 

mouth can be opened easily and a laryngeal reflex is still present. If the animal is too 

deeply anesthetized the larynx looks paralyzed even in the normal animal. If the plane is 

too deep it is important to let the animal approach consciousness and examine the 

laryngeal function during this time. During the laryngeal examination, motion of the 

arytenoid cartilage is observed during inspiration. Dopram intravenously can be used to 

stimulate the central respiratory center and have a better laryngeal examination. The 

animal should be placed in sternal recumbency and the head elevated to the level that it is 

normally carried. In the normal animal the vocal fold and the arytenoids should abduct 

during inspiration and passively relax during expiration. The arytenoid cartilages and the 

vocal cords are immobile and drawn toward midline during inspiration if the animal has 

laryngeal paralysis. If the paralysis is unilateral only one cartilage is not moving. Edema 

and erythema of the mucosa of the arytenoid cartilages is present on the dorsal part of the 

larynx and appear to be due to repeat trauma of the arytenoid touching each other at each 

inspiration. Paradoxical motion of the arytenoid can be present and makes the diagnosis 

more difficult. With paradoxical motion the arytenoid cartilages are sucked in the airway 

during inspiration and are moving back to a normal position during expiration. This 

gives the impression the patient does not have laryngeal paralysis. 

TREATMENT 

Medical treatment is reserved for the emergency treatment while the surgical treatment is 

for the long term treatment of the condition. Surgery will improve the quality of life of 

the patient 

Medical Treatment: Emergency Treatment 

Animals are usually presented with acute cyanosis or collapse as a result of upper 

airway obstruction. Most animals in a cyanotic crisis precipitated by upper airway 

obstruction recover initially with medical therapy. Excitement or increase in the ambient 

temperature can trigger an acute onset of inspiratory dyspnea. Excitement or increase in 

the ambient temperature increases the respiratory rate, which results in trauma to the 

mucosa of the arytenoid cartilage. Inflammation and acute swelling of the mucosa of the 

arytenoid cartilages can exacerbate the chronic airway obstruction and induce an acute 

onset of inspiratory dyspnea. A vicious circle is then initiated. 

Corticosteroids are given intravenously (dexamethasone, 0.2 to 1.0 mg/kg BID) to 

reduce laryngeal inflammation and edema. At the same time, oxygen is administered by 

mask or oxygen cage to alleviate hypoxia. Hyperventilating hyperthermic animals 

(temperature > 105 0 F) must be cooled. Sedation with acepromazine intravenously is 

indicated (0.1 mg/kg with a maximum dose of 3 mg) if the animal is still stressed. Fluid 

therapy is administered with caution, because some animals with severe upper respiratory

tract obstruction develop pulmonary edema. Diuretics are indicated in these patients. If 

the patient condition is deteriorating, an emergency tracheostomy is recommended to 

bypass the upper airway. Temporary tracheostotomy increases the risk of complication 

nine time in the post-operative period. 

Surgical Treatment 

Laryngeal surgery is directed at removing or repositioning laryngeal cartilages that 

obstruct the rima glottidis. The surgical procedures commonly used to correct laryngeal 

paralysis are a unilateral arytenoid cartilage lateralization, aventricular cordectomy and 

partial arytenoidectomy via the oral or ventral laryngotomy approach, and a permanent 

tracheostomy. Arytenoid cartilage lateralization is getting the gold standard technique. 

Arytenoid Cartilage Lateralization 

This procedure has been used successfully to treat laryngeal paralysis in cats and dogs. 

Arytenoid lateralization has been performed bilaterally or unilaterally. Unilateral 

arytenoid lateralization is sufficient to reduce clinical signs of laryngeal paralysis. A 

unilateral lateralization can be performed through a ventral or a lateral incision. It is our 

preference to perform lateralization through a lateral incision. 

The animal is positioned in lateral recumbency for a unilateral lateralization, and a skin 

incision is made over the larynx just ventral to the jugular groove. The sternohyoid 

muscle is retracted ventrally to expose the lateral aspect of the thyroid and cricoid 

cartilages. The larynx is rotated to expose the thyropharyngeal muscle, which is 

transected at the dorsocaudal edge of the thyroid cartilage. The wing of the thyroid 

cartilage is retracted laterally. The dorsal cricoarytenoide muscle or the fibrous tissue left 

is dissected and transected. The joint capsule of cricoarytenoid articulation is partially 

opened with Metzembaum scissors. The opening oft joint capsule should be minimal to 

prevent excessive abduction while tightening the suture. The sesamoid band connecting 

the arytenoid cartilages dorsally is left intact. 

The arytenoid cartilage is sutured to the caudo-dorsal part of the cricoid cartilage. This 

provides an adequate laryngeal airway with only a unilateral tieback. Placement of the 

suture on the caudo-dorsal part of the cricoid provides a physiologic position of the 

suture. One 2-0 non-absorbable suture is placed in a simple interrupted suture pattern 

from the muscular process of the arytenoid cartilage to the caudo-dorsal edge of the 

cricoid cartilage and tightened to maintain the arytenoid in position. The amount of 

tension on the suture should be limited to avoid to over abduct the arytenoids cartilage. In 

cats, it is recommended to use small suture material 3-0 or 4-0 mounted on a pledget to 

prevent tearing through the cartilage. The arytenoid cartilage does not need to be 

displaced caudally. It is the authors’ impression that the arytenoid cartilage needs only to 

be maintained in position and stabilized at inspiration. The wound is closed by suturing 

the thyropharyngeal muscle and routinely closing the subcutaneous tissue and skin.

At the time of extubation it is important to observe per os the size of the laryngeal 

opening achieved to ensure that adequate abduction of the laryngeal cartilages has been 

obtained. Excessive abduction may lead to aspiration of food or fluid. 

Complications associated with laryngeal lateralization include aspiration pneumonia, 

persistent cough exacerbated after drinking, seroma, and breaking of the suture and 

fragmentation of the arytenoid cartilage. Breaking of the suture and fragmentation of the 

cartilage induce recurrence of the clinical signs of laryngeal paralysis. Laryngeal 

lateralization should then be performed on the other side. If the procedure has been 

performed bilaterally a partial laryngectomy needs to be performed. Seroma formation is 

very common and is self-limited. Aspiration pneumonia is present in 10 to 20% of the 

cases. Dogs are at risk for aspiration pneumonia during the rest of their life. The 

incidence of aspiration pneumonia is more common in bilateral laryngeal lateralization 

compared to unilateral. In a study, 42% of the dogs with bilateral lateralization 

experienced an episode of aspiration pneumonia. Metoclopramide peri-operatively can be 

used to try to reduce the incidence of regurgitation and aspiration pneumonia in the perioperative 

period. Limited utilization of opiod is also recommended to allow sternal 

recumbency as soon as possible after surgery. A local skin block with bupivacaine might 

be valuable to control pain post-operatively and minimize the utilization of opioids. 

Water and food should be completely withdrawn after surgery for 24 hours. Two or three 

meatballs should be delivered 24 hours after surgery under constant direct supervision. If 

the animal can handle meatballs with aspirating, ice cube and then water can be 

delivered. The animal should be closely watched for the next 2 weeks. The animal is at 

risk for aspiration pneumonia for its entire life after surgery. The quality of life of the 

dogs is significantly improved in the long term. 

Permanent Tracheostomy 

Permanent tracheostomy is a surgical option for the treatment of dogs with laryngeal 

paralysis. The permanent tracheostomy bypasses the upper airway obstruction without 

inducing any modification in the size of the rima glottidis. This surgical technique is 

therefore more valuable for dogs at high risk of aspiration pneumonia (myopathy, 

megaesophagus, hiatal hernia, gastrointestinal disorder). Animals responded well to the 

treatment and owners were satisfied. Permanent tracheostomy requires attention and 

maintenance from the owners.


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BRACHYCEPHALIC AIRWAY SYNDROME 




Brachycephalic breeds (Shih Tzu, boxer English and French Bulldog, Pekingese, pug 

and Boston terrier) have a shortened skull compared to the other breeds. Compression of 

the nasal passage and distortion of the pharyngeal tissue result in an increase in airway 

resistance. Brachycephalic airway syndrome includes stenotic nares, elongated soft 

palate, everted laryngeal saccules and laryngeal collapse. There is a high incidence of 

hypoplastic trachea found in brachycephalic dogs that contributes to airway distress. 

Stenotic nares and elongated soft palate are the primary anatomic components of the 

syndrome while everted laryngeal saccules with laryngeal collapse are thought to be 

secondary. Excessive negative pressure generated at inspiration because of stenotic nares 

creates inflammation and stretching of soft tissue and eventually eversion of the laryngeal 

saccules and laryngeal collapse. Stenotic or obstructed nares affect the mechanics of the 

lungs and provoke degenerative changes of the nasal mucous membrane. Severe upper 

airway obstruction can result in pulmonary edema because of a reduction of intrathoracic 

pressure. The greatest changes are observed in dogs with partial bilateral nasal 

obstruction and high nasal resistance. Inadequate pulmonary ventilation due to upper 

airway obstruction can lead to a reduction of arterial oxygen content. The hypoxia is a 

potent pulmonary vasoconstrictor to divert away blood from poorly ventilated alveoli. 

Pulmonary vasoconstriction and pulmonary hypertension result in cor pulmonale and 

right sided heart failure. 

CLINICAL FINDINGS AND DIAGNOSIS 

Brachycephalic breeds are presented for excessive noisy breathing and inspiratory 

dyspnea. Inspiratory dyspnea is exacerbated by exercise and augmentation of the ambient 

temperature. Some English Bulldogs have been presented for vomiting not associated 

with meals. An increase frequency of hiatal hernia seems to be present in English 

Bulldogs with brachycephalic airway syndrome. The mean age for dogs presented is 3 to 

4 years old. Many of these animals have a high potential to decompensate and develop 

acute respiratory distress. Therefore, they must be handled carefully to prevent stress and 

acute decompensation. It is important to keep the animal calm and in a cool environment. 

Supplemental oxygen might be required. 

Physical examination of the nares for stenosis should be performed. Breathing pattern 

should be observed. Brachycephalic dogs are presented with an inspiratory dyspnea that 

is corrected by open mouth breathing if only the nares are involved in the syndrome. If 

the soft palate is elongated, the laryngeal saccules and/or the larynx collapse the dyspnea 

is inspiratory and expiratory. The severity of inspiratory dyspnea depends on the length 

and congestion of the soft palate and other restrictive or obstructive conditions present. 

An obstructive breathing pattern, characterized by a slow inspiratory phase followed by a

apid expiratory phase is seen frequently in brachycephalic breed even if the airway 

diameter is not comprised more than 50%. In nonbrachycephalic breed, a reduction of 

more than 50% of the airway diameter is required to modify the breathing pattern. The 

greatest airway noise is usually noticed in the larynx. Auscultation of the lung field is 

difficult because of enhanced upper airway sounds. 

A radiological examination of the larynx shows an elongated soft palate protruding in 

the rima glottidis. It is also important to evaluate the diameter of the trachea in dogs with 

brachycephalic syndrome. It is very common to diagnose an hypoplastic trachea, which 

worsens the prognosis. Comparison of the diameters of the thoracic inlet (TI) and the 

tracheal lumen (TD) makes the diagnosis of tracheal hypoplasia. In normal Bulldogs the 

ratio TD/TI is 0.106 English Bulldogs have the highest incidence of hypoplastic trachea 

within brachyocephalic breeds (55%). Thoracic radiographs allow evaluation of lung 

fields for signs of pulmonary edema, pneumonia and the heart for signs of right-sided 

dilation. If there is cardiac enlargement an echocardiography and an electrocardiogram 

are required to evaluate myocardial function and arrhythmias. Diagnosis of hiatal hernia 

can also be done with radiographs. 

Blood work is usually within normal limits since the animals are young at the time of 

diagnosis. An augmentation of the pack cell volume might be indicative of a mild to 

moderate hypoxia. 

A laryngeal examination is required under light general anesthesia to visualize the soft 

palate, the laryngeal saccules and the function of the larynx. The soft palate should not 

extend passed the tip of the epiglottis. Position of the soft palate is influenced by the 

position of the head, traction on the tongue and presence of an endotracheal tube. 

Evaluation of the soft palate should be performed without an endotracheal tube in place 

and with the tongue in a normal position. Everted laryngeal saccules are white shiny 

dome shape structures located cranial to the vocal cords. Tonsils should also be evaluated 

as well as the presence of redundant mucosal folds in the pharynx/larynx. A medial 

tipping of both corniculate processes both and medial flattening of the cuneiform 

processes of the arytenoid cartilage characterize a laryngeal collapse. The vocal cords are 

usually not visualized if the larynx is collapse. Usually the corrective surgery is 

performed during the same anesthesia because recovery from anesthesia with 

compromise airways could be life threatening. 

Stenotic nares are frequently diagnosed in younger, brachycephalic dogs (less than 2 

years) with an overlong soft palate and have a favorable prognosis after surgical 

treatment. In brachycephalic dogs older than 2 years, stenotic nares are associated with 

additional airway obstruction, and these patients have a guarded prognosis even with 

treatment. Surgical treatment is therefore recommended as soon as possible to prevent 

further deterioration of the animal condition and prognosis. English Bulldogs are not 

responding as well as the other breeds to surgery probably because of the higher 

incidence of hypoplastic trachea in this breed.

SURGICAL TREATMENT 

Stenotic Nares 

In brachycephalic breed the cartilage plates are short, thick and displaced medially. 

Stenotic nares are present in 48% of dogs presented for brachycephalic airway syndrome. 

Stenotic nares are frequently found in brachycephalic dogs and interference with 

inspiration by the obstructed nares leads to secondary airway changes (i.e., everted 

saccules, laryngeal collapse, tracheal collapse). Stenotic nares have also been reported in 

cats. 

The wing of the nostril is examined to determine the amount of tissue to be removed 

for optimal airflow. The technique of removing a vertical wedge from the wing of a 

nostril and extending the incision caudally to include part of the alar cartilage has been 

useful in eliminating stenosis. The incision is made with a # 11 BardParker blade. The tip 

of the blade is introduced at the apex of the wedge and directed caudally, with the cutting 

edge directed medially to the free edge of the wing of the nostril. The apex of the wedge 

is the pivot point of the flap created to allow the edges of the incision to come together 

evenly and without tension. The blade is again introduced at the apex of the wedge, and 

the cutting edge directed ventrolaterally as the tip is pushed in caudally to end at the same 

point as the first incision. The width of the base of the wedge (free edge) determines the 

opening of the nostril. The wedge is removed, and the edges are sutured with two or three 

interrupted sutures performed with 30 or 40 absorbable material using a small halfcircle 

cutting needle. 

The surgical site is kept clean and protected from rubbing (selfmutilation) with an 

Elizabethan collar. Additional medical care is usually not needed. 

Elongated Soft Palate 

In brachycephalic breed the soft palate extends beyond the epiglottis obstructing the 

airway passage. Vibration of the soft palate in the pharynx induces inflammation and 

swelling that will obstruct even more the airway. Approximately 80 per cent of cases of 

overlong soft palate are found in brachycephalic dogs, English and French bulldogs being 

the most frequently afflicted. Edematous pharyngeal mucosa and enlarged, protruding 

tonsils are common. The intention of palate resection is to shorten the soft palate so that 

its free border lies at the tip of the epiglottis or just covers it with the tongue in a normal 

position. 

The mouth is held open with a mouth gag, and the tongue is extended to provide 

adequate exposure of the oral pharynx. A pair of malleable ribbon retractors is helpful in 

moving soft tissues while the resection level is being determined. The free border of the 

palate is grasped with forceps, and both sides of the palate as well as the oral cavity are 

swabbed with antiseptic. 

The tongue is relaxed, and the point at which the tip of the epiglottis touches the soft 

palate is noted and marked with a scalpel cut or a sterile felttipped marking pen. The 

caudo-dorsal part of tonsils can also be used as a cranial landmark for the soft palate. A 

pair of Allis forceps or a traction suture is placed in the free edge of the palate and 

retracted rostrally. An absorbable suture (40 to 50) is placed in the mucosa at the lateral 

edge of the free soft palate. The visualization is not always good in the mouth of

achycephalic dogs. It will open the surgical field and improve the visualization if the 

procedure is performed with long and curved instruments. The palate is incised from the 

lateral traction suture to the reference mark at its midline with a scalpel or scissors while 

low tension is applied on the forceps and lateral traction suture. The soft palate is 

completely excised. The incised edge is sutured with a simple continuous pattern, with 

sutures placed through both the nasal and oral mucosa, 1 mm from the cut edge and 2 mm 

apart. The layer of muscle is avoided so that the mucosa is pulled over the exposed 

muscle when the sutures are tightened. The closely placed sutures provide a smooth 

hemostatic closure and do not shorten the width of the soft palate. Postoperative 

hemorrhage or edema is minimal. 

Everted Laryngeal Saccules 

Everted laryngeal saccules are most frequently encountered in brachycephalic breeds, 

with a prolonged history of upper airway obstruction. Everted laryngeal saccules have 

been present in 48% of the brachycephalic dogs in a study. The mucosa of the laryngeal 

saccules evertes in the larynx because of the high negative pressure during inspiration. 

The prolapse mucosa is edematous and creates a mass in the larynx that contributes to the 

obstruction of the ventral rima glottidis. Resection of everted saccules is not performed 

routinely. Correction of other components of the syndrome might result in the reduction 

of the everted saccules. 

A temporary tracheostomy is necessary to ensure an adequate airway during surgery 

and during postoperative recovery. Temporary tracheostomy allows removal of the 

endotracheal tube from the surgical site and helps manage the airway after the surgery. 

A patient is placed in sternal recumbency with the mouth held open as described for 

partial laryngectomy. The saccule is grasped with long hemostats or Allis forceps, and 

rostral traction applied. The saccule is amputated at its base with scissors or a 

longhandled scalpel. Hemorrhage is minor and controlled by pressure. Avoiding the 

electroscalpel reduces inflammation 

Resection of everted saccules is associated with edema and swelling of the larynx. 

Dexamethasone intravenously (1 mg/kg) is used to reduce the amount of edema after 

surgery. The temporary tracheostomy is maintained for 24 hours after surgery. The patient 

is challenged before removal of the temporary tracheostomy tube. 

Laryngeal Collapse 

Laryngeal collapse occurs as a result of a loss of the supporting function of the 

cartilages. It represents a very advance form of the brachycephalic airway syndrome. The 

cuneiform and corniculate cartilages are drawn medially by the excessive inspiratory 

negative pressure. Laryngeal collapse is a progressive disease in which the prognosis 

worsens with time. Collectively, stenotic nares, elongated soft palate and everted 

laryngeal saccules predispose dogs to abnormal stresses within the larynx that lead to 

progressive distortion and ultimate collapse of the arytenoid cartilages. 

Three stages of laryngeal collapse have been described (stages 1 to 3) stage 3 being the 

most advance. The first stage in the pathogenesis of laryngeal collapse involves eversion 

of the laryngeal saccules into the cavity of the glottis. This is caused by an abnormal 

negative pressure created at the glottis during inspiration. The vacuum that develops in

the glottis results from the increased inspiratory effort necessary to ventilate through the 

stenotic nares or elongated soft palate. Inflammation and edema of the mucosa usually 

accompany saccule eversion and contribute to the dyspnea. During stage 2, the cuneiform 

process of each arytenoid cartilage, which normally extends to the caudolateral region of 

the pharynx during inspiration, loses its rigidity and gradually collapses into the laryngeal 

lumen. In stage 3, the corniculate process of each arytenoid cartilage, which normally 

maintains the dorsal arch of the glottis, collapses toward the midline, resulting in 

complete collapse of the larynx. Loss of laryngeal cartilage rigidity is speculated to 

contribute to the collapse of the cuneiforme and corniculate process. Dogs with stenotic 

nares, an elongated soft palate, or everted laryngeal saccules are treated for these 

conditions first. A dog is allowed to recover, and the clinical response suggests whether 

further resection is necessary. 

Dogs with persistent stage 2 disease, even after resection of the soft palate and nares, 

may require partial arytenochordectomy to enlarge the laryngeal opening. Dogs with 

stage 3 laryngeal collapse may not show significant improvement when treated with 

partial laryngectomy. An alternative treatment for dogs with severe laryngeal collapse 

that does not improve after resection of the elongated soft palate, stenotic nares, or 

laryngeal saccules is a permanent tracheostomy.


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LAPAROSCOPY 

IN SMALL ANIMAL PRACTICE 




There is a number of minimally invasive surgical (MIS) procedures that are 

currently performed using laparoscopy. Many of these procedures require multiple 

trocar/cannula portals, specific minimally invasive surgical instruments, loop ligatures, 

clip applicators and monopolar electrosurgery. The techniques described below are the 

“tip of the iceberg” in as far as the potential for MIS in veterinary medicine. They can be 

performed in a small animal practice. 

Intestinal Biopsy 

Small intestinal biopsies can be obtained using laparoscopy simply by exteriorizing 

a piece of intestine through the abdominal wall and then collecting the sample externally 

as would be done with a standard surgical biopsy. A 5-mm atraumatic grasping forceps 

with multiple teeth is used to grasp the intestine at the site to be biopsied. It may be 

necessary to “run” the bowel with two grasping forceps to select a location to biopsy. The 

antimesenteric boarder is firmly grasped with the forceps. The intestine is then pulled to 

the cannula. A 3-4 cm loop of intestine is exteriorized. A small full thickness biopsy is 

then obtained in the same manner as one would use when performing an open abdominal 

surgical technique. The intestine is then returned to the abdominal cavity. If too much 

intestine is exteriorized it is difficult to return it to the abdominal cavity through a small 

incision. 

Intestinal Feeding Tube Placement 

Duodenostomy or jejunostomy feeding tubes can be placed using the laparoscope 

simply by exteriorizing a respective piece of intestine through the abdominal wall and 

inserting the tube externally. Once the location of the bowel for tube placement is 

determined the antimesenteric boarder is firmly grasped with the forceps. The intestine is 

then pulled close to the cannula in which the intestine will be exteriorized. A 3-4 cm loop 

of intestine is exteriorized and four stay sutures (4-0 monofilament absorbable) are placed 

in the intestine to prevent the intestine from falling back into the abdominal cavity. A 

purse-string suture is placed on the antimesenteric border of the intestine. A number 11 

blade is used to puncture the intestine in the middle of the purse-string suture and the 

jejunostomy feeding tube (5 French for cats and 8 French for dogs) is introduced in the 

loop of bowel in the aboral direction. The purse string suture is closed and the intestine is 

returned to the abdominal cavity except for the segment containing the feeding tube. The 

stay sutures are then used to pexy the intestine to the abdominal wall using 4.0 

monofilament absorbable sutures. The abdominal wall is then closed with simple

continuous suture pattern. Subcutaneous tissue and skin are closed in a routine fashion. 

The feeding tube exits through the incision. 

Intestinal foreign body 

Single, non-linear foreign body in the jejunum or ileum can be removed under 

laparoscopy. Dogs or cats with signs of peritonitis are not good candidates for this 

procedure. The surgical technique is the same as for a jejunostomy tube placement. The 

loop of intestine with the foreign body is exteriorized and an enterotomy or an 

enterectomy is performed outside of the abdominal cavity. The loop of intestine is then 

returned into the abdominal cavity at the end of the procedure. 

Gastropexy 

A preventive gastropexy can be performed using the laparoscope simply by 

exteriorizing the pyloric antrum region of the stomach through the right abdominal wall. 

The animal is placed in dorsal recumbency and the telescope portal is placed on the 

midline at the level of the umbilicus. A 5-mm atraumatic grasping forceps with multiple 

teeth is used to grasp the pyloric antrum mid-distance between the lesser and the greater 

curvature. The pyloric antrum is exteriorized after extension of the cannula site situated 

behind the last rib on the right side. An incisional gastropexy is then performed. 

Ovariohysterectomy /Ovariectomy 

Ovariohysterectomy or ovariectomy can be performed using laparoscopy in any 

size dogs. The space in the abdominal cavity of small dogs and cats make the procedure 

technically difficult. The advantage of this technique is the perceived rapid patient 

recovery following the procedure and the improved visualization of the ureters and the 

pedicle for hemostasis. 

The procedure is performed on dorsal recumbency and tilting the dog on the right 

and the left side to expose the ovaries. 

Two cannulas are enough to perform an ovariectomy or an ovariohysterectomy. 

The ovariohysterectomy is laparoscopically assisted then. The cannula for the endoscope 

is placed caudal to the umbilicus. 

For an ovariohysterectomy the second cannulas is placed caudal in the abdomen. 

The ovaries are suspended with a transcutaneous suture on the abdominal wall. Each 

ovarian pedicle is ligated with either suture, endoclips, electrocautery, or a vessel sealant 

device. After ligation of both ovarian pedicles, the uterus is exteriorized in the caudal 

abdomen through the caudal cannula. The cervix is ligated outside the abdominal cavity 

like during a regular ovariohysterectomy. The cervix is then returned to the abdomen. 

For an ovariectomy the second cannula is placed cranial to the umbilicus. The 

ovarian pedicles are ligated as described above. Another ligature will be placed on each 

uterine horn before transecting the ovaries from the uterus. Electrocautery or vessel 

sealant device can be used to transect the uterus at the level of the proper ligament. Both 

ovaries will be removed through one cannula site.

The enlarged cannula sites are sutured with a simple continuous suture pattern 

with 2-0 monofilament absorbable suture material. Subcutaneous tissue and skin are 

closed in a routine fashion. The other cannula site requires only subcutaneous and skin 

sutures. 

Cryptorchid Surgery 

A testicle that is located in the abdominal cavity can be removed easily with 

laparoscopy. Laparoscopic vasectomy can also be performed through this technique. The 

dog is placed in dorsal recumbency. The monitor is placed at the end of the table as 

described for ovariohysterectomy surgery. The procedure is performed with two 

cannulas. One is placed cranial to the umbilicus while the other is caudal to the 

umbilicus. 

The ectopic testicle is usually readily visible upon entering the abdominal cavity. 

The ectopic testicle of one side rarely ever crosses the midline but stays lateral to the 

bladder on the effected side. The testicle is grabbed with a fine tooth grasper and a 

transcutaneous suture is placed through the abdominal wall to stabilize the ectopic 

testicle. The vascular pedicle and the vas deference are ligated with a pre-tied suture, 

clips, or electrocautery. The ectopic testicle is removed through one the cannula holes 

that generally must be enlarged. The enlarged cannula site is sutured with a simple 

continuous suture pattern with 2-0 monofilament absorbable suture material. 

Subcutaneous tissue and skin are closed in a routine fashion. The other cannula sites 

require only subcutaneous and skin sutures. 

Laparoscopic Cystoscopy 

Laparoscopic cystoscopy is an alternate method that allows placement of a 

laparoscopic telescope into the urinary bladder that has been exteriorized through the 

abdominal wall for examination, biopsy and calculi removal. The technique involves a 

standard laparoscopic entry with the telescope placement on the abdominal midline 

cranial to the umbilicus. Once the urinary bladder is visualized a second trocar cannula is 

placed directly over the urinary bladder at the location of exteriorization. Using 

atraumatic forceps with multiple teeth the bladder is grasped and pulled into the trocar 

cannula as described in intestinal biopsy section. Once the apex of the bladder is 

exteriorized stay sutures are placed from the bladder wall. The bladder is temporally 

pexied to the abdominal wall. A small incision is made in the bladder wall, the bladder is 

then flushed with sterile saline and the telescope is introduced into the bladder. Forceps 

can be placed in the lumen along the telescope to obtain a biopsy or remove calculi. At 

the conclusion of the procedure the bladder is closed in a standard manner and placed 

back into the abdomen. The cannula ports are then closed. The pexy is released and the 

abdominal wall closed in a routine fashion. 

Laparoscopy is a minimally invasive technique for diagnostic and surgical 

procedures. Once the basic technique of laparoscopy is mastered and the appropriate 

indications are applied to the procedures it becomes a simple and rewarding addition to

small animal veterinary medicine and surgery. As our ability advances newer diagnostic 

and therapeutic procedures will no doubt be developed.

SURGICAL APPROACHES TO THE THORACIC CAVITY 




Thoracic approaches provide access to the thoracic cavity and as such are fundamental 

techniques for thoracic surgery. Two thoracic approaches, intercostal thoracotomy and median 

sternotomy, are used most often in small animals. Other thoracic approaches such as rib 

resection or transsternal thoracotomy are used less often. The choice of a thoracic approach 

depends mostly on the type of access to the thoracic cavity that is needed. 

INTERCOSTAL THORACOTOMY 

Intercostal thoracotomy is employed when exposure to a specific region of the thoracic cavity 

is needed. This approach provides good access to thoracic structures in the immediate area of the 

thoracotomy, but access to structures not in the area of the thoracotomy is limited. As a general 

rule, intercostal thoracotomy allows access to about one-third of the ipsilateral thoracic cavity 

and mediastinal structures. Access to structures in the contralateral thorax is very limited when 

using this approach. The exposure gained by intercostal thoracotomy can be increased 

approximately 33% by performing two small osteotomies, one dorsal and one ventral, on the rib 

just cranial or caudal to the intercostal incision. It is not necessary to routinely perform 

osteotomies of a rib, but the technique is useful on occasion when increased exposure is 

necessary. 

The site of an intercostal thoracotomy may be the third through the tenth intercostal space 

depending on the structures being exposed. The intercostal spaces most commonly used to 

approach selected thoracic structures in dogs and cats are listed in Table 1. A lateral thoracic 

radiograph also can help determine the intercostal space that best exposes a desired thoracic 

structure. A caudal intercostal thoracotomy may be combined with an incision in the diaphragm 

to provide exposure to the cranial abdominal cavity. Complications associated with intercostal 

thoracotomy are uncommon as long as air-tight closure of the intercostal space is achieved. 

MEDIAN STERNOTOMY 

Median sternotomy is the only thoracic approach that allows access to the entire thoracic 

cavity, and therefore is indicated when exploration of the thoracic cavity is necessary. Structures 

in the dorsal thoracic cavity such as the great vessels and bronchial hilus are more difficult, but 

not impossible, to reach when this approach is used. Median sternotomy can be combined with a 

ventral midline celiotomy or cervical incision if a combined approach to the abdomen or neck is 

desired. 

An important technical consideration when performing a sternotomy is that either the 

manubrium or xiphoid, or both, should be left intact. Doing so greatly enhances the ability to 

achieve a stable closure of the sternotomy, and thereby decreases the risk of postoperative 

complications. Reluctance to use this approach because of a perception that it is associated with 

excessive postoperative pain or complications is not justified. Pain and complication rates with

this approach are not different from intercostal thoracotomy. In fact, median sternotomy 

probabily causes less postoperative discomfort than intercostal thoracotomy. Sternotomy and 

thoracotomy are comparable in the degree of cardiopulmonary impairment that they cause. 

Thus, the decision to employ a sternotomy or thoracotomy approach should be based on the kind 

of access to the thoracic cavity needed, and not on a perception that one approach is superior 

with regard to intraoperative or postoperative morbidity. 

THORACOSCOPY 

Thoracoscopy is examination of the pleural cavity and its organs with a rigid scope. With the 

development of high-resolution micro-cameras, video optics, and fiberoptic light delivery 

systems, clear magnified images of the surgical field can be transferred to a video screen. In 

combination with minimally invasive surgical instruments, the ability to perform diagnostic and 

advanced therapeutic procedure is possible. 

Thoracoscopy is indicated for exploration of pleural space and biopsy of the pleural surface for 

a patient with a pleural effusion of unknown origin, partial or complete lung lobectomy, biopsy 

of the lung, pericardectomy and exploration for the right atrium. Thoracoscopy can also be used 

to perform biopsies for frozen section to establish a diagnosis prior to thoracotomy. Cranial 

mediastinal mass may represent a challenge to the clinician to establish a definitive diagnosis. 

Therefore, thoracoscopy and frozen section of a biospy from a mass in the cranial mediastinum 

might help differentiating a lymphoma from a thymoma. Thoracoscopy is used commonly in 

human thoracic surgery for diagnosis of intra-thoracic neoplasia and staging of oncology patients 

The basic equipment to perform a thoracoscopy includes a surgical telescope, trocar-cannulas, 

a basic set of thoracoscopic surgical instruments, a light source, a video camera and a video 

monitor. Thoracoscopy does not require CO2 insufflation since the rib cage is maintaining the 

thoracic cavity expanded. Telescope comes with different angles. The most commonly used are 

the 00-degree and the 300-degree angled telescopes. Laparascope trocar-cannula can be used to 

perform a thoracoscopy. Since the laparoscope trocar-cannulas have a valve, the thorax is not 

opened and a control pneumothorax needs to be established. Disposable thoracic cannulas do 

not have a valve. After insertion of the cannula, the thoracic cavity is opened to room air. The 

lungs are collapsing and positive ventilation is then required. One-lung ventilation with selective 

intubation of either the left or the right lungs will allow a better exposure of specific area of the 

thoracic cavity. Cannulas are placed in a triangular position. The cannula for the thoracoscope 

can be placed in a sub-xyphoid position. The cannulas for the instruments are then placed in the 

left and right hemithorax at the level of the 7th intercostal space. 

Thoracoscopy can be performed with a trans-xyphoid or an intercostal approach. Transxyphoid 

approach gives access to the left and right hemithorax after partial resection of the 

mediastinum. Trans-xyphoid approach is the approach of choice for exploration of the thoracic 

cavity since the right and the left sides of the thoracic cavity can be visualized. Pericardectomy 

can be performed with this approach. Intercostal approach requires positioning of the animal in 

lateral recumbency. Only one side of the thoracic cavity can be explored. However, 

visualization of the hilus of the lung is better for lung resection, and lymph nodes evaluation. In 

human thoracic surgery, approach through the thoracic inlet has been described for exploration of 

the cranial mediastinum.

INTRAOPERATIVE CONSIDERATIONS 

Thoracic surgery is always associated with some degree of cardiopulmonary compromise 

during surgery. Thoracotomy and sternotomy differ somewhat in the type of cardiopulmonary 

compromise they are most often associated with. Because animals undergoing thoracotomy are 

laterally recumbent, they are more likely to develop congestion of the dependent lung and 

impairment of pulmonary gas exchange. This tendency is countered by maintaining good 

ventilation to the dependent lung and by avoiding overzealous administration of crystalloid fluids 

during surgery. On occasion, positive end expiratory pressure (PEEP), applied by immersing the 

expiratory portion of the ventilator into 5 to 7 cm of water, may be necessary to maintain 

adequate gas exchange during thoracotomy. On the other hand, animals undergoing median 

sternotomy in dorsal recumbency are more likely to develop some degree of cardiovascular 

compromise during surgery because the weight of non-suspended thoracic structures compresses 

the base of the heart and impedes venous return. This tendency is compensated for somewhat by 

volume loading the patient to increase cardiac filling pressures. In the end, while it is useful to 

be aware of these tendencies, it is most important to closely monitor each animal during surgery 

and provide supportive therapies that best address specific problems and needs. 

Placement of a thoracostomy tube before closure of the thoracic cavity is essential to ensure 

proper and timely evacuation of the pleural space during and after surgery. Failure to place a 

thoracostomy tube invites substantial risk of developing life-threatening complications. The 

period of transition from an open to closed thoracic cavity is especially critical. During this 

period, inadvertent tension pneumothorax can be avoided by keeping the thoracostomy tube open 

to atmosphere during initial closure of the thoracotomy. Then, after the closure is airtight, the 

pleural space can be evacuated and the thoracostomy tube closed. It is also important to be 

aware that pulmonary compliance can decrease suddenly when the thoracic cavity is closed, and 

that inspiratory pressures may have to be increased to maintain an adequate tidal volume. 

POSTOPERATIVE CARE 

The period immediately after surgery is critical for animals undergoing thoracic surgery. 

Hypoventilation, hypoxemia, hypothermia, acid base disorders, hypotension, shock, and oliguria 

are among the problems that may arise after surgery. Ventilation may be depressed by anesthetic 

drugs, pneumothorax, or somatic pain. Hypoventilation causes hypoxemia and respiratory 

acidosis; neither is well tolerated postoperatively. A tidal volume less than 10 ml/kg measured 

with a Wright's respirometer suggests that ventilation may be inadequate. Suspected 

hypoventilation in the recovery period is confirmed by a PaCO2 > 50 mm Hg. Impaired 

pulmonary gas exchange resulting from pulmonary shunt or VA/Q mismatch also can cause 

hypoxemia after surgery. The most common cause of pulmonary shunt or VA/Q mismatch after 

thoracic surgery is pulmonary congestion. For this reason, it is very important that animals 

recovering from surgery be turned over at least every two hours as long as they remain laterally 

recumbent. A PaO2 < 60 mm Hg or PA-aO2 > 25 mm Hg while the patient is breathing room 

air suggests that serious gas exchange impairment is present. Serious hypoxemia due to 

impaired gas exchange may require treatment with supplemental oxygen or PEEP therapy. 

Animals that are hypothermic after surgery should be slowly surface warmed with warm water 

bottles or circulating water blankets. Hypothermia, hypovolemia, anesthetic drugs, or pain may

cause varying degrees of hypotension during the recovery period. Appropriate treatment of 

circulatory compromise with fluids is essential. Titrating fluid therapy to central venous or 

pulmonary wedge pressure is the best way to ensure adequate volume loading and avoiding 

overhydration. Ideally, central venous pressure should be maintained between 5 and 10 cm of 

water in animals with cardiovascular compromise. Animals also should be evaluated for acid 

base and electrolyte disorders. Urine production should be monitored to assure adequate renal 

function. 

Analgesia is indicated in all animals after thoracic surgery. Selective intercostal nerve block, 

intrapleural anesthetics, epidural morphine, or parenteral opiate drugs are all viable methods for 

postoperative analgesia. Chest bandages aid in sealing and protecting a thoracotomy incision, 

however bandages should be wrapped loosely after thoracic surgery as they can impair 

ventilation. Placement of a thoracostomy tube during thoracic surgery is always indicated since 

it allows close monitoring the pleural space for the presence of air or blood during the recovery 

period. The thoracostomy tube should be hand-aspirated every hour for four hours, and then 

every two to four hours until it is removed.

TABLE 1: 

Location of Thoracic Structures via Intercostal Thoracotomy 

Thoracic Structure 

Left 

Intercostal Space 

Right 

Heart and pericardium 4, 5 4, 5 

Ductus arteriosus 4, 5 

Pulmonic Stenosis 4 

Pericardiectomy 5 5 

Lungs 4-6 4-6 

Cranial lobe 4, 5 4, 5 

Middle lobe 5 

Caudal lobe 5, 6 5, 6 

Esophagus 

Cranial 3-5 3-5 

Caudal 7-9 7-9 

Thoracic Duct 

Dog 8-10 

Cat 8-10


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SURGERY OF THE LUNG 




The trachea divides into two principle bronchi which in turn subdivide into lobar bronchi that 

supply each lung lobe. Within each lung lobe, lobar bronchi divide into segmental bronchi that 

supply bronchopulmonary segments within each lobe. Dichotomous branching of the airway 

continues through subsegmental bronchi, terminal bronchioles, and respiratory bronchioles. 

Respiratory bronchioles give rise to alveolar ducts, alveolar sacs, and pulmonary alveoli. The 

pulmonary arteries follow a lobar distribution in close proximity to the cranial dorsal aspect of 

each bronchi. Bronchial branches of the bronchoesophageal arteries provide oxygenated blood 

to the airways down to the level of the respiratory bronchioles where they terminate in capillary 

beds continuous with the pulmonary arteries. Pulmonary veins course on the caudal and ventral 

aspect of each bronchi collecting blood from both the pulmonary and bronchial arteries. 

The left lung of dogs and cats is divided into cranial and caudal lobes. The left cranial lung 

lobe is divided into a cranial and caudal portion, but shares a common lobar bronchus. The right 

lung is divided into four distinct lobes: cranial, middle, caudal and accessory. The accessory 

lobe passes dorsal to the caudal vena cava and is located medial to the plica vena cava. 

PNEUMOTHORAX 

Pneumothorax results from the accumulation of air in the pleural space. The air can come 

from the respiratory tract, the esophagus and through the skin. Spontaneous pneumothorax are 

classified as primary or secondary. Primary pneumothorax are usually resulting from the rupture 

of a bleb or a bullae. Primary spontaneous pneumothorax are more common in large breed dog 

with deep chest. Secondary spontaneous pneumothorax results from a lung pathology that 

eroded through a bronchioles (pneumonia, abscess0 or from chronic obstructive lung disease 

(emphysema). Primary spontaneous pneumothorax are treated with drainage of the pleural space 

by thoracocenthesis or thoracostomy tube. If a bullae is visible on thoracic radiographs, a lung 

lobectomy is then recommended. A pleurodesis can also be performed at the time of surgery to 

prevent recurrence. 

NEOPLASIA 

Primary neoplasia of lung is the most common indication for pulmonary surgery in small 

animals. Presumptive diagnosis of primary lung neoplasia is based on characteristic 

radiographic appearance of a solitary lung mass. Fine needle aspiration can be undertaken prior 

to surgery. Pulmonary lobectomy is indicated for suspected primary lung tumors without prior 

biopsy. Excision biopsy of hilar lymph nodes is indicated for staging if they are visualized. 

Diagnosis is confirmed by histopathologic examination of the excised specimen. 

Adenocarcinoma is the most common primary lung neoplasia in dogs, representing 

approximately 75% of the cases. Alveolar carcinoma and squamous cell carcinoma also occur. 

Pulmonary carcinomas are classified as differentiated or undifferentiated. Prognostic indicators

for primary lung neoplasia include involvement of hilar lymph nodes at surgery, histologic type, 

tumor size, and presence of pleural effusion. The prospect for cure or long term remission with 

surgery alone is good for small differentiated adenocarcinomas. Undifferentiated carcinomas 

have over a 50% incidence of metastasis. The prognosis for squamous cell carcinoma is poor 

with a metastasis rate of over 90%. 

Metastatic lung neoplasia is treatable by surgical excision under certain circumstances. 

Guidelines for surgical treatment of metastatic pulmonary disease include: control of the primary 

site for at least several months, no evidence of metastasis to sites other than lung, favorable 

histology (i.e. sarcomas are better than carcinomas), slow growth of metastatic tumors (i.e. size 

doubling time > 30 days), and less than 5 metastatic nodules present. Metastatic lung tumors 

should be excised by partial lung resection whenever possible to preserve lung volume. 

LUNG LOBE TORSION 

Lung lobe torsion is a rare condition that occurs most often in large deep-chested dogs. The 

condition may occur secondary to one of several predisposing factors including thoracic trauma, 

pleural effusion, diaphragmatic hernia, pneumothorax, or thoracic surgery. Lung lobe torsion 

occurs most often in the right middle lung lobe and less often in the left cranial lung lobe. 

Clinical findings associated lung lobe torsion include acute depression, weakness, dyspnea, 

tachypnea, cyanosis, nonproductive cough, hemoptysis, and tachyarrhythmias. Radiographically, 

lung lobe torsion appears as an isolated atelectasis of the right middle or left cranial lung lobes. 

Air bronchograms may be present early, but disappear over time. Pleural effusion is often 

apparent on radiographs. Evacuation of sanguinous effusion fails to expand the collapsed lobe. 

Confirmation of the diagnosis can be made by contrast bronchography, bronchoscopy, or 

exploratory surgery. At surgery, the involved lung lobe appears as a solid liver-like mass due to 

engorgement of the lung with blood. Surgical treatment consists of complete lung lobectomy of 

the affected lung, preferably without derotation of the lung lobe. 

PULMONARY ABSCESS 

Pulmonary abscesses occur secondary to severe pulmonary infections or pulmonary foreign 

bodies. Foreign bodies can enter by inhalation or impalement through the thoracic wall. 

Pyothorax can occur concurrently with pulmonary abscesses. Persistent pulmonary atelectasis 

and signs of pneumonia despite appropriate antibiotic therapy suggests the presence of a 

pulmonary abscess. Pulmonary lobectomy of the affected lung lobe is indicated for suspected 

pulmonary abscesses. Caution during surgical manipulation of an abscessed lung lobe is 

necessary to prevent expulsion of purulent material into adjacent lung lobes. Morbidity and 

mortality associated with this procedure is high in animals that have active diffuse pneumonia at 

the time of surgery. 

PULMONARY RESECTION TECHNIQUES 

Possible indications for pulmonary resection include pulmonary neoplasia, pulmonary trauma, 

pulmonary abscess, lung lobe torsion, bronchoesophageal fistula, and spontaneous 

pneumothorax. Normal animals can tolerate resection of as much as 50% of their lung capacity 

and still survive. However, generalized pulmonary disease substantially decreases the amount of

lung resection that can be tolerated. Chronic obstructive lung disease and pulmonary 

hypertension in particular limit the extent of pulmonary resection that can be undertaken. 

Lung Lobectomy 

Lung lobectomy is indicated for severe traumatic injury, neoplasia, lobe torsion, or abscesses 

that are primarily confined to a single lung lobe. Lung lobes that can undergo separate 

lobectomy in small animals include the left cranial, left caudal, right cranial, right middle, and 

right caudal lobes. The accessory lobe divides incompletely from the right caudal lobe and 

generally is resected with the caudal lobe. The standard surgical approach for lung lobectomy is 

a fifth intercostal thoracotomy in dogs and a sixth intercostal thoracotomy in cats. The procedure 

can be performed one intercostal space cranial or caudal to the ideal intercostal space, if 

necessary. Lung lobectomy also can be accomplished from a median sternotomy, if this 

approach is indicated for other reasons. Lung lobectomy is performed by dividing the 

pulmonary vessels and oversewing the lobar bronchus. Lung lobes should be manipulated 

carefully during resection to avoid embolization of neoplastic cells or extrusion of purulent 

material into adjacent airways. The bronchus should be checked for leaks after closure by 

flooding the chest with saline and applying a positive pressure breath. Placement of a 

thoracostomy tube prior to closure of the thoracotomy is absolutely indicated. 

Partial Lung Resection 

Partial lung resection is indicated for lung biopsy or excision of localized pulmonary lesions 

that do not require complete lung lobectomy. Partial lung resection can be performed by a 

standard suturing technique or with a surgical stapling device. Standard partial lung resection 

can be accomplished with readily available materials, but some leakage of air from the surgery 

site can be anticipated after surgery. Stapling devices, when available, are fast and less likely to 

leak after surgery. Partial lung resection can be performed using either the TA or GIA surgical 

stapling device. The 3.5 mm (blue) staples are most appropriate for stapling lung tissue. Any 

leakage of air after surgery is readily evacuated by a thoracostomy tube and usually will be self 

limiting after several hours.


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PLEURAL EFFUSIONS 




The thoracic cavity is lined entirely by a serous membrane known as pleura. The pleura is 

divided into visceral pleura which covers the lungs and parietal pleura which covers the 

remaining thoracic cavity. The pleura is composed of a single layer of mesothelial cells 

supported by a delicate network of elastic connective tissue. The visceral and parietal pleura 

contain a rich capillary network that originates from the pulmonary and systemic circulations, 

respectively. In addition, the parietal pleura contains a rich lymphatic network responsible for 

lymphatic drainage of the pleural space. Under normal conditions, the pleural space is only a 

potential cavity. The visceral and parietal pleura are separated by a thin layer of pleural fluid, the 

average volume of which is 2.4 ml in a 10 kg dog. Liquid coupling between the thoracic wall 

and lungs provides instantaneous transmission of thoracic volume changes to the lungs, and yet 

allows low friction sliding between the pleural surfaces. 

Because high pleural permeability causes the pleural space to be continuous with the 

interstitial fluid of the thoracic wall, the dynamics of pleural fluid formation and absorption are 

controlled by Starling's forces. Since hydrostatic pressure in the systemic capillaries that supply 

the parietal pleura is a 30 cm of water and hydrostatic pressure of the pulmonary capillaries that 

supply the visceral pleura is approximately 11 cm of water, one theory suggests pleural fluid is 

formed by the parietal pleura and absorbed by the visceral pleura under physiologic conditions. 

More recent evidence suggests that pleural fluid filters through the parietal pleura and is drained 

by parietal lymphatics. 

HYDROTHORAX 

Hydrothorax is the result of transudative effusion caused by a disturbance in the balance 

of Starling forces responsible for pleural fluid formation and absorption. Hypoalbuminemia 

reduces capillary colloid osmotic pressure and causes fluid to remain in interstitial compartments 

including the pleural space. Congestive heart failure causes hydrothorax by disturbing 

pulmonary and systemic capillary hydrostatic pressures. Right-sided congestive heart failure 

increases pleural fluid formation, whereas left-sided congestive heart failure decreases pleural 

fluid absorption. Hydrothorax may result from obstruction of venous or lymphatic drainage such 

as occurs with lung lobe torsion or incarcerations of liver through a diaphragmatic herniation. 

These effusions result from transudation of fluid through the organ capsule. 

Diagnosis of hydrothorax is based on identification of an effusion as a transudate or 

modified transudate. Transudates typically have a specific gravity less than 1.018, a total protein 

less than 1.5 gm/dl, and a nucleated cell count less than 3 X 103 cells/ul. Large (5-20 u) pale 

staining mesothelial cells predominate comprising 70% of the nucleated cell count. Single 

mesothelial cells are most common, although multicellular clusters of mesothelial cells are 

occasionally observed and must be differentiated from neoplastic cells. Macrophages and

lymphocytes account for the remaining nucleated cells. As a transudative effusion becomes 

longstanding, mesothelial cells degenerate and attract neutrophils to the pleural space. Total 

nucleated cell counts may approach 5 X 103 cells/ul with a significant percentage of the cells 

being neutrophils. These effusions are termed modified transudates. Effusions associated with 

obstructive phenomenon such as lung lobe torsion or liver incarceration present a distinctive 

picture on fluid analysis. Because the obstructive process causes lymphatic as well as venous 

obstruction, the effusions generally will have a total protein of 1.5 to 5 gm/dl. Red blood cells 

and lymphocytes often are present in numbers higher than is typical for a transudate. Pleural 

effusions with these characteristics are termed high-protein modified transudates or obstructive 

effusions. These effusions quickly develop an inflammatory component if organ necrosis is 

occurring. The treatment of hydrothorax consists of pleural drainage if respiratory distress is 

present and correction of its underlying cause if possible. 

PLEURITIS AND PYOTHORAX 

Inflammatory conditions of the pleura may be dry, serofibrinous, pyogranulomatous, or 

purulent. Dry pleuritis often precedes inflammatory pleural effusions. Dry pleuritis may be 

caused by bacteria, viruses, or trauma. A diagnosis of dry pleuritis is suggested by clinical 

findings of a rapid and shallow respiratory pattern, obscure thoracic pain, nonproductive cough, 

and auscultation of a pleural friction rub.Serofibrinous pleuritis is reported with canine hepatitis, 

canine leptospirosis, canine distemper, canine and feline upper respiratory viruses, and parasitic 

diseases such as Aelurostrongylus in cats and Spirocerca lupi in dogs. Bile and tuberculosis are 

unusual causes of severe serofibrinous pleuritis. Pyogranulomatous pleuritis is associated with 

feline infectious peritonitis. The effusion is secondary to virus-induced vasculitis affecting all 

serous membranes.Purulent pleuritis, also referred to as pyothorax or empyema, is invariably the 

result of bacterial or fungal sepsis of the pleural space. Sources of bacterial contamination 

include penetrating thoracic wounds, extension of bacterial pneumonia, migrating foreign bodies, 

esophageal perforations, extension of cervical, lumbar or mediastinal infections, and 

hematogenous spread. Thoracic bite wounds are frequently implicated in feline pyothorax. 

Inhalation and migration of a grass awn often is suspected in field dogs with pyothorax. 

Anaerobic bacteria and Nocardia asteroides are isolated most often from dogs with pyothorax. 

Pasteurella multocida and anaerobes are the most prevalent isolates in cats. 

Pleuritis and pyothorax frequently have an insidious course and presentation may be 

delayed. Moderate to severe respiratory distress usually is present. The patient also shows signs 

of systemic infection characterized by anorexia, weight loss, malaise, and fever. Physical and 

radiographic findings are those of pleural effusion. Inflammatory exudates typically exhibit a 

total protein greater than 3.0 gm/dl, a specific gravity greater than 1.018, and a total cell count 

greater than 30 X 10 3 cells/ul. Inflammatory exudates may be nonseptic or septic.Nonseptic 

exudates usually have a serofibrinous or serosanguineous appearance. Feline infectious 

peritonitis produces a nonseptic exudative pleural effusion that appears yellow, translucent, and 

viscous on gross examination. Total protein values will approach serum levels ranging from 4 to 

8 gm/dl. Electrophoresis will reveal an elevated gamma globulin fraction. The predominant cell 

types present in nonseptic exudates are nondegenerative neutrophils and macrophages. Total cell 

counts are generally not high, ranging from 5 to 15 X 10 3 cells/ul. Septic exudates are

characteristic of pyothorax. The fluid is viscous, opaque, and varies in color from white or 

yellow to green or red. The fluid may clot or exhibit fibrinous debris, and often produces a foul 

odor. Cell counts range from 30 to 200 X10 3 cells/ul, although accurate cell counts are difficult 

due to extensive cellular degeneration. Degenerate neutrophils predominate and bacteria are 

often visualized. Gram stains may give an early indication of the types of bacteria present. Fluid 

should be cultured for aerobic and anaerobic bacteria. Macrophages and plasma cells increase as 

an exudative process becomes longstanding. 

Treatment of pyothorax must be prompt and aggressive. The prognosis is guarded but not 

hopeless. The initial goal of therapy is to relieve respiratory embarrassment by thoracocentesis, 

preferably under minimal restraint with the patient sternal or standing. Supportive care with 

intravenous fluids is necessary to correct dehydration, acid-base and electrolyte imbalance. 

Systemic antibiotic therapy should be initiated immediately, and then adjusted based on culture 

and sensitivity results if necessary. Success in culturing anaerobic bacteria is dependent on 

sample handling. Samples must be submitted in a capped syringe within one hour or in 

appropriate transport media within 24 hours. Due to the high incidence of anaerobic infections, 

antibiotics with an anaerobic spectrum should be started upon diagnosis of pyothorax and 

continued throughout the course of disease. Many animals with pyothorax will have bacteremia 

or septicemia so intravenous antibiotics are indicated in the initial treatment period. Oral 

antibiotic therapy should be continued for at least four to six weeks after diagnosis. Once the 

patient is stable, a thoracostomy tube should be placed utilizing local anesthesia and sedation. 

Bilateral thoracostomy tubes often will be necessary. After complete evacuation of the pleural 

space, pleural lavage is initiated. The pleural space should be lavaged twice daily with 

approximately 20 ml/kg of warmed 0.9% saline or Ringer’s solution. The lavage fluid should be 

instilled slowly and discontinued if respiratory distress occurs. The lavage fluid should remain 

in the pleural space for one hour if respiratory distress does not occur. Approximately 25% of 

the initial lavage volume will be absorbed by the patient. Efficacy of treatment is monitored by 

clinical findings, thoracic radiographs, and cytology of the pleural effusion. Most animals with 

successful treatment will have a decrease in fever and improvement in general attitude within the 

first 48 hours. Cytology of pleural fluid can be used to assess the response to therapy. 

Neutrophils, both total number and percentage of degenerate cells, and bacteria should gradually 

subside over three to five days. The combination of thoracostomy tube, pleural lavage, and 

antibiotic therapy have been reported to resolve 50 to 60% of cases of pyothorax in small 

animals. 

Lack of significant clinical improvement within 48 to 72 hours or radiographic 

demonstration of undrained encapsulated fluid are indications to surgically explore the thoracic 

cavity. Radiographic evidence of lung lobe consolidation and pneumothorax suggest the 

possibility of a ruptured pulmonary abscess and is a relative indication for surgery. Exploratory 

thoracotomy should be undertaken by medium sternotomy which gives access to both 

hemithoraces. Adhesions and loculated pockets of fluid should be broken down carefully during 

surgery. Mediastinectomy often is necessary since the ventral mediastinum is invariably 

thickened and filled with small abscesses (Figure 8.1). The pericardium also may require 

excision if it is thickened and abscessed. Consolidated lung lobes which cannot be inflated

should be excised by partial or complete lobectomy. Large lung lacerations created by adhesion 

breakdown must be repaired or the damaged tissue excised. Before closure, the thoracic cavity is 

vigorously lavaged with copious amounts of warm isotonic crystalloid solution. Closed pleural 

lavage should be continued postoperatively for at least two to three days. The probability of 

success with surgical management of refractory pyothorax is better for dogs than for cats. 

Constrictive pleuritis is a serious sequela to longstanding pyothorax that is suggested by an 

inability to re-expand the lungs following resolution of the pyothorax. If the constriction is 

diffuse, then surgical decortication of the fibrous peel from the visceral pleura is necessary 

(Figure 8.2). Decortication in small animals is a difficult surgical procedure, but it can be 

successfully accomplished with careful technique. The procedure often results in numerous 

pulmonary lacerations that should be treated with continuous pleural drainage postoperatively. 

Decortication should be attempted as soon as possible after it is recognized. 

CHYLOTHORAX 

Chylothorax results when chyle from the cisterna chyli-thoracic duct system gains access 

to the pleural space. In the dog, the caudal thoracic duct courses dorsal and to the right of the 

aorta, lateral to the intercostal arteries, and ventral to the azygos vein. The duct crosses to the left 

side of the aorta ventral to the body of the fifth thoracic vertebra and continues cranioventral 

across the left side of the esophagus to empty at the junction of the left jugular vein and cranial 

vena cava. Although this description of the thoracic duct is considered "normal", few dogs 

exhibit this pattern without some variation. Variations included multiple collaterals of the caudal 

and middle portions of the duct, and double duct systems. In the cat, the caudal thoracic duct 

typically courses dorsal and to left of the aorta. 

The etiology of chylothorax is poorly understood in the dog and cat. The incidence of 

chylothorax in Afghan is inordinately high, but it is unknown if this predisposition is hereditary. 

Trauma is an often cited cause of chylothorax in dogs and cats. Thoracic duct rupture might 

result from blunt or penetrating injuries, traumatic diaphragmatic herniation , thoracic surgery, or 

severe coughing or vomiting episodes. Recent evidence suggests that traumatic rupture of the 

thoracic duct may be an uncommon cause of chylothorax in animals. The role that obstruction of 

the thoracic duct plays in the development of chylothorax is unclear. Experimental obstruction of 

the thoracic duct alone rarely results in chylothorax, but ligation of the cranial vena cava 

produces lymphangiectasia of the thoracic duct and a high incidence (> 50%) of chylothorax in 

dogs and cats. It is speculated that lymphangiectasia may allow extravasation of chyle through 

the lymphatic vessel wall. Malignancies or thrombosis that occludes the cranial vena cava might 

induce chylothorax by such a mechanism. Elevations in systemic venous pressure secondary to 

congestive heart failure likely explain why chylothorax occurs with cardiomyopathy, tricuspid 

dysplasia, and heartworm disease. Lymphangiectasia of unknown origin has been demonstrated 

in dogs and cats with spontaneous chylothorax. 

Debilitation associated with chylothorax is caused primarily by loss of chyle from the body 

after pleural drainage is instituted. Water and electrolyte losses can be sufficient to cause 

dehydration and electrolyte imbalance. Loss of lipid and protein can lead to protein-calorie 

malnutrition and hypoproteinemia. Malnutrition is compounded by the loss of fat soluble

vitamins. Immunocompetence becomes impaired due to loss of antibodies, lymphopenia, and 

malnutrition. 

Diagnosis of chylothorax is based on recognition of characteristic clinical and radiographic 

findings of pleural effusion and by demonstration of chyle on fluid analysis. Chylous effusions 

are typically opaque and milky white to yellow in color. Chyle retains its milky appearance upon 

standing and may form a creamy top layer. Physicochemical properties of chylous effusions are 

similar to obstructive transudates since lymph composes a large portion of thoracic duct chyle. 

Total protein ranges from 3 to 5 gm/dl. Cytological examination reveals a predominance of small 

and large lymphocytes. Chronic chylous effusions will show increased neutrophils, 

macrophages, and mesothelial cells. Total cell counts generally do not exceed 20 X 10 3 cells/ul. 

Chylomicrons within an effusion confirms its chylous nature. Chylomicrons can be visualized on 

direct smears or with supravital stains such as Sudan III or IV. The presence of chylomicrons is 

most reliably confirmed by determination of triglyceride levels in the serum and fluid. Chylous 

fluids typically show triglyceride levels that are 12 to 100 times greater than levels measured in 

the serum. Cholesterol levels in chylous effusions are not elevated when values are compared to 

values from serum. Anorectic animals with chylous effusion may have greatly reduced levels of 

chylomicrons. Pleural fluid from such animals may easily be mistaken for a modified transudate 

or obstructive effusion. Feeding a fatty meal is often necessary to demonstrate the chylous nature 

of a pleural effusion in these animals.Pleural effusions high in cholesterol or lecithin-globulin 

complexes appear grossly similar to chylous effusions, but are due to degenerating cells 

associated with chronic inflammatory or malignant processes. These effusions are termed 

pseudochylous effusions. Pseudochylous effusions will be low in triglycerides and may have a 

high cholesterol level. 

Once chylothorax is diagnosed, an attempt to determine its cause should be undertaken. 

Owners should be questioned regarding the possibility of recent trauma. Thoracic radiographs 

taken after complete pleural drainage should be evaluated for the presence of masses particularly 

in the cranial mediastinum. Echocardiography and ultrasound examination of the mediastinum 

also can be undertaken. Animals with chylothorax should be evaluated for dirofilariasis using 

microfilaria concentration techniques or serum adult antigen detection tests, or both. Cytologic 

examination of the chylous effusion for the presence of neoplastic cells helps rule out neoplasia. 

Often, a cause for chylothorax is not found and the clinician is left with a diagnosis of idiopathic 

chylothorax. Direct lymphangiography may provide information on the etiology of idiopathic 

chylothorax (i.e rupture versus lymphangiectasia), but generally is of academic interest only 

since it usually does not change the therapeutic plan. 

Treatment of chylothorax may be medical or surgical. Medical management is directed at 

draining the pleural space and reducing the formation of chyle. Pleural drainage is indicated to 

relieve respiratory distress and may either be intermittent or continuous. Low-fat diets decrease 

the triglyceride content of chyle, but there is no evidence that the volume of chyle is similarly 

decreased. Animals with chylothorax should receive aggressive nutritional support and be 

supplemented with fat soluble vitamins. 

Surgical management of chylothorax involves ligation of the caudal thoracic duct. The 

rationale for ligation of the thoracic duct is based on formation of lymphaticovenous

anastomoses that divert chyle flow away from the thoracic duct system. Absolute indications for 

surgical intervention are not established in animals. The following indications for surgery are 

suggested: 1) failure to significantly diminish the flow of chyle after 5 to 10 days of medical 

management, 2) losses of chyle exceeding 20 ml/kg/day over a five day period, or 3) proteincalorie 

malnutrition and hypoproteinemia. Transthoracic ligation of the thoracic duct is 

accomplished through a right ninth or tenth intercostal thoracotomy in the dog. Failure to ligate 

all collateral branches of the caudal thoracic duct is thought to be a most common cause of 

operative failure. For this reason, en bloc ligation of all structures in the caudal mediastinum 

dorsal to the aorta is recommended. Intraoperative lymphangiograms performed to ensure 

complete ligation of the thoracic duct have been advocated, however this approach substantially 

increases operative time and requires facilities for taking intraoperative radiographs. The success 

rate for surgical management of chylothorax alone is generally less than 60%. Combined 

mechanical pleural pleurodesis and thoracic duct ligation, both performed via median 

sternotomy, is currently undergoing clinical evaluation and shows early promise for improving 

the success of surgery. 

Despite vigorous attempts at medical and surgical management, a significant number of 

animals with chylothorax will fail to respond to therapy. Pleuroperitoneal shunting and chemical 

pleurodesis have been advocated as palliative treatments for refractory chylothorax. Chronic 

chylothorax can cause a constrictive pleuritis that may require decortication. 

HEMOTHORAX 

The most common cause of hemothorax is trauma, either accidental and surgical. 

Coagulopathies including thrombocytopenia or warfarin toxicity also can manifest with 

hemothorax as a primary finding. Neoplasia or parasites, e.g. Spirocerca lupi and Dirofilaria 

immitus, can cause rupture of thoracic vessels and spontaneous hemothorax. 

Diagnosis of hemothorax is based on demonstration of blood in the pleural space. 

Specific gravity, total protein, total cell counts, and cytologic findings of hemorrhagic effusions 

are similar to values in the peripheral blood. The myeloid-erythroid ratio is approximately 1 to 

100, similar to peripheral blood. Hemorrhagic effusions generally will have a hemoglobin level 

of at least 25% of the blood level, whereas serosanguineous effusions rarely have hemoglobin 

values exceeding 1 gm/dl. Hemorrhage within the pleural space generally does not clot due to 

mechanical defibrination and activation of fibrinolytic mechanisms. Clotting also is impaired by 

the disappearance of platelets within eight hours following hemorrhage. 

Diagnostic evaluation of coagulation parameters is indicated in animals with hemothorax, 

especially in the absence of obvious trauma. A platelet count and activated clotting time should 

be performed. If a platelet count and activated clotting time are normal but coagulopathy is still 

suspected, a mucosal bleeding time should be performed to assess platelet function particularly 

in breeds that commonly have von Willebrand’s disease. A citrated blood sample should be 

collected before blood transfusion, centrifuged immediately, and frozen for future assessment of 

specific factor deficiencies if needed. 

Hemothorax is a common injury associated with thoracic trauma. Hemorrhage can 

originate from internal structures such as the heart, great vessels, or lungs, or from laceration of

intercostal or internal thoracic arteries. Treatment of hemothorax depends on the volume and 

flow of hemorrhage in the pleural space. Dogs are capable of complete resorption of their blood 

volume from the pleural space within 90 hours. Therefore, mild hemothorax that does not induce 

significant respiratory distress should be managed conservatively to allow resorption of pleural 

blood. Occasionally, pleural hemorrhage is sufficient to require pleural drainage for relief of 

respiratory embarrassment. Animals with substantial blood loss from the pleural space may 

require blood transfusion in addition to crystalloid volume replacement to maintain an adequate 

packed cell volume. Autotransfusion of autogenous blood removed by pleural drainage provides 

a readily available source of compatible blood in patients with severe hemothorax. Blood can be 

collected directly into a standard blood collection bag and returned to the patient by standard 

gravitational infusion. Blood collected into 60 ml syringes should be anticoagulated with citrate 

phosphate dextrose (CPD) or of anticoagulant citrate dextrose (ACD) (8 to 10 ml/100 ml blood). 

Autogenous blood should be administered with a standard blood administration set. Filtration of 

autotransfused blood with a micropore filter has been recommended to remove microthrombi. 

However, due to the expense of these filters and a lack of observed problems when they are not 

used, standard blood filtration is usually used in animals. Potential problems associated with 

autotransfusion include microembolization, hemolysis, and coagulopathy. Despite these 

problems, autotransfusion is a practical and lifesaving procedure for animals with severe 

hemothorax. Rarely pleural hemorrhage will be such that pleural drainage and autotransfusion 

cannot keep ahead of accumulation. In this case, exploratory thoracotomy is indicated in an 

attempt to repair the site of hemorrhage. Exploratory thoracotomy should be undertaken by a 

median sternotomy approach. If exploratory surgery for severe hemothorax is undertaken, the 

surgical team should be prepared for intraoperative collection of blood for autotranfusion. 

Occasionally, chronic hemothorax can organize to form a fibrous pleural peel that may require 

decortication. Decortication is ideally performed within five weeks of hemothorax before 

fibrous infiltration of the visceral pleura has occurred. 

NEOPLASTIC EFFUSION 

Pleural effusion can result from primary or metastatic neoplasia involving the thoracic 

cavity. Lymphosarcoma, pulmonary carcinoma, metastatic carcinomas, and hemangiosarcomas 

have all been reported to cause neoplastic effusions. Mesotheliomas are rare in all species, but 

are associated with pleural effusion when present. 

Neoplastic effusions are suspected when physical, radiographic, and laboratory findings 

suggest the presence of a thoracic neoplasm. Neoplastic effusions may have either a exudative or 

transudative fluid pattern and are identified by the presence of neoplastic cells on cytological 

examination. Thymic lymphosarcoma is the most common cause of neoplastic effusions in cats. 

Neoplastic lymphocytes are usually prolymphocytes or lymphoblasts. These cells are large, 

variable in size, and have intensely basophilic cytoplasm and multiple nucleoli. Metastatic 

carcinomas and occasionally sarcomas will produce neoplastic effusions. Differentiation of 

neoplastic cells from reactive mesothelial cells is difficult even for experienced cytologists. 

Therefore, care must be used in diagnosing neoplasia on cytologic examination alone. Cytologic 

findings should be correlated with other clinical findings. A punch biopsy of the pleura is 

indicated when pleural neoplasia such a mesothelioma is suspected.

Treatment of a neoplastic pleural effusion is directed at the causative neoplasm. The 

prognosis for animals with neoplastic effusions is poor with the exception of effusions associated 

with lymphosarcoma. Intermittent pleural drainage gives temporary relief from respiratory 

distress. Intracavitary chemotherapy or radionucleotides have been used in the management of 

neoplastic effusions in dogs. Pleurodesis also may be considered for palliation of neoplastic 

effusions.

PATENT DUCTUS ARTERIOSUS 




Congenital heart defects are the most common indication for considering cardiac 

surgery in small animals. Congenital heart defects result in pathophysiologic alterations 

that can lead to progressive heart failure, sudden death, or severe hypoxemia. For most of 

the congenital heart defects more than one surgical option is available. The options 

depend on the nature and the severity of the defect, and financial constraints. The 

surgical options are either a closed heart or an open-heart technique. Closed heart 

techniques provide most of the time a palliative treatment for the defect while open 

technique will provide more a curative treatment. 

Patent Ductus Arteriosus (PDA) is the most common congenital heart defect seen in 

dogs. It is also present in cats. Poodles Shelties, German Shepherds, Collies, Pekinese 

and Welsh Corgies are the most common breed presented for PDA. Females are over 

represented. 

Ductus arteriosus establishes a communication between the pulmonary circulation and 

the systemic circulation in the fetus. The lungs in the fetus are non-functional and the 

pulmonary circulation is a high pressure system. Oxygenated blood coming from the 

placenta can bypass the lung and perfused the fetus. Ductus arteriosus physiologically 

closed at birth when the lungs expand and the pulmonary artery resistance drops. 

Prostaglandins are involved in the closure of the ductus. The ductus arteriosus is 

anatomically closed at 2 weeks. 

Patent ductus arteriosus induces a left to right shunt, which results in volume overload 

of the left heart. Volume overload of the left atrium and ventricle results in left 

ventricular dilation and hypertrophy. During diastole, pressure in the aorta drops very 

low because the blood shunts into the low pressure system of the pulmonary circulation. 

Cardiac output is maintained by augmentation of stroke volume with fluid retention. 

Progressive left ventricular dilation induces a mitral regurgitation with a more severe 

volume overload of the left ventricle. If untreated the dogs will develop left-sided 

congestive heart failure with pulmonary edema. Atrial fibrillation can develop later. 

Dogs with PDA can also develop pulmonary hypertension a reverse flow can occur in the 

PDA when pulmonary pressures are superior to systemic pressures. This condition 

occurs rarely. It induces cyanosis. 

Diagnosis 

Dogs with PDA will present a continuous murmur over the left heart base and a strong 

femoral pulse. A palpable cardiac thrill often is present. The murmur is usually first 

heard during a vaccination visit. Dogs with severe dilation and advance mitral

egurgitation are presented with signs of congestive heart failure: difficulty breathing, 

cough and exercise intolerant. A separate holosystolic heart base murmur might be heard 

when the mitral regurgitation is severe. Dogs with a reverse PDA will be presented for 

exercise intolerance, and hind leg weakness. The patient is cyanotic. The cyanosis is 

more pronounced in the caudal half of the animal. The femoral pulse is usually normal. 

No cardiac murmur is present especially if polycythemia is present. 

Thoracic radiographs show left atrial and ventricular enlargement, enlargement of the 

pulmonary circulation, and a dilation of the descending aorta. Pulmonary edema can be 

visible in the patient in early congestive heart failure. 

Echocardiography confirms the left ventricular and atrial dilation. Myocardial function 

is usually normal. Ejection fraction is reduced when congestive heart failure develops. 

The mitral regurgitation can be evaluated with Doppler echocardiography. Turbulences 

are visible in the pulmonary artery with color Doppler echocardiography. The pulmonic 

stenosis or insufficiency is not present. Sometimes the ductus arteriosus can be 

visualized on the echocardiography. 

Surgical treatment 

Surgical correction of a left to right PDA is accomplished by ligation or occlusion of 

the ductus arteriosus. If the patient is presented with pulmonary edema it should be 

treated with furosemide for 24 to 48 hours prior to surgery. Surgical treatment is a cure 

for this congenital heart defect. If the ductus is not occluded the animal will dye of 

congestive heart failure at 1 or 2 years old. Some animal will develop pulmonary 

hypertension at a younger age if they have a predisposition. 

Surgical technique for ligation 

The animal is placed in right lateral recumbency after induction of general anesthesia. 

The left side of the thoracic cavity from the cranial point of the shoulder to the last rib is 

prepared with aseptic technique for surgery. 

A left 4 th intercostal thoracotomy is performed to access the PDA. After incision of the 

skin and the latissimus dorsi caudal to the scapula, the 4 th intercostal space is identified. 

The serratus ventralis and scalenus muscles are dissected and separated. The intercostal 

muscles are incised and the pleura space entered. The left cranial lung lobe is retracted 

caudally with sponges. A Finochietto retractor is used to retract the ribs. The vagus and 

the phrenic nerves are identified. The patent ductus arteriosus is located medially to the 

vagus nerve. 

The dissection of the PDA is performed with a right-angled forceps. The dissection 

starts with the caudal part of the ductus. The cranial part is then dissected with the rightangled 

forceps. Sharp dissection with Metzembaum scissors is required to detach the 

pericardium from the ascending aorta. The right-angled forceps is dissecting between the 

ascending aorta, the pulmonary artery and the ductus. The forceps should be directed

caudally with a 45 degree angle to avoid the major blood vessels. After dissection of the 

PDA, 2 silk sutures are placed around the ductus. The suture the closest to the aorta is 

tied first. 

Rupture of the PDA could happen during the dissection of the medial wall or ligation 

of the ductus. Small ruptures can be controlled by tamponnade. Bleeding may worsen 

with further dissection is attempted. More severe bleeding requires clamping of the 

ductus on each side of the tear. Mattress sutures with Teflon pledgets can then be placed 

across the ductus to control the hemorrhage. The ductus can be divided first then closed 

with mattress sutures. Both stumps of the ductus are oversewn with a simple continuous. 

Prior to closure of the thoracic cavity a thoracostomy drain is placed. The thoracic 

cavity is closed in a routine fashion. Ribs are approximated with simple interrupted 

suture. The serratus ventralis muscle and scalenous muscles are closed with a simple 

continuous suture pattern (3-0 monofilament absorbable suture). The latissimus dorsi 

muscle is closed with a simple continuous pattern with 3-0 monofilament absorbable 

suture. The subcutaneous tissue is closed with a simple continuous suture pattern with a 

3-0 braided absorbable suture. Skin is closed with a simple continuous suture pattern 

with 4-0 nylon. 

The chest drain is maintained for 24 hours after surgery. If the thoracic cavity does not 

produce any fluid or air after 4 hours the drain might be removed then. The animals are 

maintained under fentanyl for 24 hours (2 to microgm/kg/hr IV). 

Surgical technique fo occlusion 

Interventional cardiology is now commonly used to successfully occlude the PDA. 

With vascular access either through the femoral artery or vein a occlusion device is 

delivered in the PDA under visualization with fluoroscopy. 

Dogs and cats with a PDA successfully ligated have an excellent long term outcome. 

Even if mitral valve is present at the time of surgery it is not affecting the long term 

prognosis more likely because the mitral regain competency after reverse remodeling of 

the left ventricle after surgery.


www.ammvepe.com.mx

MEMORIAS AMMVEPE CURSO CIRUGIA TEJIDOS BLANDOS 2014

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