Neurogenic temporomandibular joint dislocation treated ... - SOMICS

Neurogenic temporomandibular joint dislocation treated with
botulinum toxin: report of 4 cases
Olga Vázquez Bouso, MD, a Gabriel Forteza González, MD, PhD, b Jens Mommsen, MD, DDS, a
Víctor Gumbao Grau, MD, a Javier Rodríguez Fernández, MD, a and Mario Mateos Micas, MD, a
Tarragona, Spain
DEPARTMENT OF ORAL AND MAXILLOFACIAL SURGERY, UNIVERSITY HOSPITAL JOAN XXIII
Many patients suffer recurrent episodes of temporomandibular joint (TMJ) dislocation due to an excess of
muscle contraction or spasticity in the depressor muscles of the jaw. The manual repositioning using the Nelaton
maneuver is the first treatment. Occasionally, it may be necessary to use sedation or general anesthesia to achieve the
desired muscle relaxation. In case of recurrence, surgical treatment is indicated. One nonsurgical method of treatment
is the local infiltration of botulinum toxin type A. We present 4 cases of recurrent TMJ dislocation in patients suffering
from conditions of neurologic origin, with considerable motor deterioration, treated with local infiltration of botulinum
toxin type A. In conclusion, the injection of botulinum toxin type A is an effective method in cases of neurogenic TMJ
dislocation, with low morbididty and side effects, improving patients’ quality of life. (Oral Surg Oral Med Oral Pathol
Oral Radiol Endod 2010;109:e33-e37)
The anterior dislocation of the temporomandibular joint
(TMJ) is by far the most frequent form. It occurs when
one or both mandibular condyles are displaced in front of
the temporal eminence. It may be reducible when it returns
spontaneously to the glenoid cavity, or nonreducible
when 1 or 2 condyles remain dislocated. In this position,
the mouth remains open due to the action of the elevator
muscles with or without lateral deviation, depending on
whether the dislocation is unilateral or bilateral.
Dislocation of the TMJ is generally of unknown origin,
with several theories put forward to explain its onset.
Some disorders of collagen metabolism, such as ligamentous
hyperlaxity and Ehler-Danlos syndrome might be
related. However, there is a group of patients who suffer
recurrent episodes of TMJ dislocation due to an excess of
muscle contraction-spasticity in the muscles depressing
the lower jaw. These patients are frequently associated
with severe disorders of the central nervous system, with
motor and cognitive deterioration, thus contraindicating
surgery under general anesthesia. Daelen defined these
cases of TMJ dislocation as neurogenic, 1 to distinguish
them from traumatic injuries. Some degenerative neurologic
disorders are accompanied by repeated bouts of TMJ
dislocation, such as Parkinson disease or multiple sclero-
a
Attending, Maxillofacial Surgical Department, Joan XXIII Hospital,
Tarragona, Spain.
b
Chairman, Maxillofacial Surgery Department, Joan XXIII Hospital,
Tarragona, Spain.
Received for publication Oct 1, 2009; accepted for publication Oct
21, 2009.
1079-2104/$ - see front matter
© 2010 Published by Mosby, Inc.
doi:10.1016/j.tripleo.2009.10.046
sis, as well as posttraumatic cerebral palsy, particularly
those occurring with spasticity and orofacial or oromandibular
dystonia.
The treatment of acute episodes, in the case of nonreducible
TMJ dislocation, consists of the manual repositioning
using the Nélaton maneuver. 2 Occasionally,
in cases of inveterate TMJ dislocation, it may be necessary
to use sedation and even general anesthesia to
achieve the desired muscle relaxation. 3
In cases of recurrence, surgical treatment is indicated
using various techniques. These are basically divided
into 2 groups:
1) Eminectomy (Myrhaug technique). 4
2) Interposition techniques (redirecting the tendon of
the temporal muscle, alloplastic or bone graft, dislocation
fracture of the zygomatic arch). 5-8
One nonsurgical method of treatment that has been
described is the injection of sclerosing substances in the
area adjacent to the joint, including arthroscopic techniques.
9
In those patients suffering neurogenic TMJ dislocation,
the reiteration of the dislocation produces local
pain and severe eating difficulties. This, together with
the inconvenience of repeated visits to emergency centers,
causes anxiety in patients and their relatives. In
these cases, TMJ dislocation occurs through a loss of
coordination of the muscles in the jaw and hypertonia
of the muscles depressing the lower jaw.
.The use of local treatment with botulinum toxin type A
might be effective in such patients. The toxin produces
temporary denervation on the muscles depressing the
lower jaw, thus preventing excessive displacement of the
e33

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e34 Vázquez Bouso et al. March 2010
condyle when opening. Botulinum toxin type A is indicated
for the treatment of a focal dystonias, 10,11 and it is
effective to treat episodes with excess of muscular activity.
We decided to use botulinum toxin type A to treat 4
cases of recurrent TMJ dislocation of neurologic origin
after approval by the ethics committee and authorization
of each case by the Ministry of Health.
CASE REPORTS
We present 4 cases of recurrent TMJ dislocation in patients
suffering from conditions of neurologic origin treated with
local infiltration of botulinum toxin type A.
Case 1
A 26-year-old male who suffered severe head and brain
trauma in 2003 as the result of a traffic accident. After the
accident, he presented multiple foci of brain contusions, with
subarachnoid bleeding in the third and lateral ventricles, the
right thalamus, and the right occipital cortex. These injuries
led to the presence of chronic subdural haematomas. He also
suffered diaphyseal fracture of the right humerus, right shutter
ring, right acetabulum, and sacrum.
The clinical consequence of these injuries was the onset of
right-side hemiparesia, predominantly brachial, as well as
movement dystonia, particularly marked in the orofacial
sphere, and widespread spasticity. The most striking manifestation
was the presence of recurrent episodes of temporomandibular
dislocation when eating, yawning, or speaking,
with a strong tendency to relapse and requiring multiple
treatments (simple manual reduction under sedation, temporary
intermaxillary fixation under general anesthesia) over the
course of 2 years.
For this reason, after obtaining the family’s written consent,
he was injected in September 2007 with 25 UI botulinum
toxin type A (Botox; Allergan, Irvine, Calif), under
electrical control (Botox Injection Amplifier) in each of the
external pterygoid muscles. The technique used in this patient
was that described by Daelen et al. 12 With the patient in a
sitting position, the location of the sigmoid notch and the
condyle of the jaw were determined on either side by palpation.
Next, the needle 13 connected to the electrical amplifier
was inserted 1 cm in front of the condyle, obliquely backwards,
down, and in. When the patient was asked to open his
mouth, slight movements were made with the needle to capture
the signal corresponding to the contraction of the external
pterygoid muscle. Then, after aspiration, the contents of the
syringe were injected. No side effects were noted during
administration or in the subsequent interval. Approximately
10 days after the treatment, the episodes of TMJ dislocation
ceased. This allowed the patient to significantly improve in
independence to carry out physiologic functions and in his
ability to communicate (Fig. 1).
In October 2008, he was treated again, after reappearance
of the TMJ dislocation. Forty UI of botulinum toxin type A
(Botox) was injected into both external pterygoid muscles and
10 UI into the anterior faces of both digastric muscles. After
1 week had elapsed, moderate dysphagia appeared, accompanied
by oropharyngeal candidiasis, probably secondary. He
Fig. 1. Electrical amplifier and needles for injection.
was treated with a soft diet and Nystatin mouthwash, and the
condition disappeared in 2 weeks. Once more, the episodes of
TMJ dislocation disappeared, and he remained in remission
for 10 months to the time of writing.
All of these treatments were administered on an outpatient
basis.
Case 2
A 72-year-old female patient, diagnosed as having Alzheimer
and Parkinson diseases, had severe intellectual impairment
and widespread spasticity. Since May 2008, she had
presented repeated bouts of inveterate TMJ dislocation associated
with eating, yawning, and even sleeping, leading her to
be repeatedly taken to our hospital’s Emergency Unit for its
reduction, on occasions under general anesthesia, in view of
the associated spasticity that hindered simple manual reduction,
even under sedation.
In January 2009, after obtaining the family’s consent, the
patient was subjected to general anesthesia in the operating
theater by means of nasotracheal intubation.
No systemic muscle relaxants were used. With the assistance
of the electrical amplifier, per the technique described
by Moore and Wood, 13 the mandibular opening reflex was
explored by striking the chin with a reflex hammer (Fig. 2).
The capture of the amplified electrical signal produced by this
reflex allowed the localization of the infiltration point. Twentyfive
units of Botox was injected into both external pterygoid
muscles (Fig. 3). No immediate or late-onset side effects were
observed. The patient was discharged the next day.
Over the next 7 months, the patient did not present any
episode of TMJ dislocation. The patient’s quality of life and
autonomy notably improved during this period, according to
the testimony of her relatives.
Case 3
A 88-year-old woman presented to us for recurrent bilateral
TMJ dislocation that had started several months before
the initial referral. She had diagnosed Alzheimer and Parkinson
diseases with widespread spasticity.
In February 2009, after obtaining the family’s written
consent, she was subjected to sedation in the operating the-

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Volume 109, Number 3 Vázquez Bouso et al. e35
Fig. 2. Localization of the infiltration point with electrical
amplifier as per the technique described by Moore.
Fig. 3. Botulinum toxin type A injection by electrical amplifier.
ater. We injected 25 UI Botox into both external pterygoid
muscles.
Over the next 6 months, the patient did not present any
episode of TMJ dislocation.
Case 4
A 23-year-old male suffering from Steinert disease (myotonic
dystrophy) began to develop recurring episodes of TMJ
dislocation in October 2007. The dislocation occurred while
performing minimal movements of mouth opening, including,
e.g., daily dental hygiene. He frequently had to use our
emergency department for reduction, making his normal life
impossible.
In March 2009, after giving written consent, he was treated
by injection of 25 UI Botox into each lateral pterygoid muscle
under local anesthesia. The muscle was localized using the
Plexygon 7501.31 nerve stimulator (Vygon) connected to a
injection needle (Locoplex 17°, 23 gauge, 35 mm; Vygon).
Fig. 4. Nerve stimulator and needle for injection.
Applying a stimulation of 1 mA, frequency 2 Hz, 300 �s, it
was assumed that the tip of the needle penetrated the muscle
when a rhythmic movement of the mandible occurred in
synchronicity with the stimulation (Fig. 4).
No side effects were noted. The patient presented with a
TMJ dislocation episode 5 months after treatment, and a new
dose of Botox was administered.
DISCUSSION
Botulinum toxin type A is a double-chain protein,
150 kD in weight, produced by Clostridium botulinum,
an anaerobic bacterium responsible for botulism. It
prevents the release of acetylcholine into the synaptic
cleft, temporarily blocking neuromuscular transmission.
14 It acts selectively on the peripheral cholinergic
nerve endings 15 to produce muscle relaxation, diminished
compression of the muscle vessels, and occasionally
a reduction in the concentration of excitatory neuropeptides.
16
Botulinum toxin type A was first indicated for the
treatment of strabismus in patients �12 years old,
blepharospasm, hemifacial spasm, and associated focal
dystonias. Later, new indications were approved, such
as cervical dystonia (for the reduction of signs and
symptoms of spasmodic torticollis), dynamic equine
foot deformity caused by spasticity in children �2
years old with cerebral palsy, arm spasticity in patients
who have suffered a cerebrovascular accident, 11 and,
recently, axillary hyperhidrosis.
In the literature, there is an increasing number of
reports on the applications of botulinum toxin for the
treatment of disorders of the TMJ. Bakke et al. 17 described
its use in severe clicking of the TMJ associated
with anterior disc displacement, with good results.
The treatment with botulinum toxin type A is contraindicated
in the case of hypersensitivity to any of the

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e36 Vázquez Bouso et al. March 2010
components in its formulation and when there are widespread
disorders of muscle activity; e.g., it should not
be used in patients with myasthenia gravis or Eaton
Lambert syndrome, when aminoglycoside antibiotics or
spectinomycin are or will be administered, or when
there is inflammation or infection at the injection site. 18
In 1997, Moore and Wood 13 and subsequently
Daelen 12 described the treatment of TMJ dislocation
with botulinum toxin in patients affected by recurrent
TMJ dislocation and neurologic disorders. The technique
used by the authors is based on the work of Brin
et al., 19 who first described the injection of botulinum
toxin type A into the external pterygoid muscles under
electromyographic control for the treatment of oromandibular
dystonia.
In the present cases, it is reasonable to assume that
during injection there is a certain diffusion of botulinum
toxin into the pterygoid space, affecting not only
the lateral but also the medial pterygoid muscle. The
denervation of the medial pterygoid muscle is compensated
by other masticatory muscles, such as the masseter
or the temporal muscles. The denervation of the
lateral pterygoid muscle is not compensated, thus preventing
movements of the condyle that lead to dislocation.
In 1998, Daelen described 5 cases of neurogenic
TMJ dislocation treated with botulinum toxin, with
scant undesirable effects. 20 Only 1 of our cases presented
some side effects: the appearance of transitory
dysphagia, probably due to the toxin spreading from the
anterior fasces of the digastric muscles. From the perspective
of our current experience, we do not consider
it to be necessary to administer the drug in this location,
because there is no need for it and because of the
possible onset of dysphagia. Other injection techniques
include intraoral route with electromyografic guide, as
described by Martínez-Pérez and García Ruiz-Espiga. 21
Case 2 presented particularly difficult characteristics,
in view of the impossibility of injecting the toxin into
the patient while conscious, owing to a lack of cooperation
resulting from the underlying disorder. For this reason, we
used the technique described by Moore and Wood in
1997, 13 which allows the medication to be administered in
a controlled fashion under general anesthesia. However,
the outcome in this case was the most satisfactory, as
indicated by the improvement in the patient’s quality of
life. The greatest difficulty lies in not using systemic
muscle relaxant drugs and in observing the mouth opening
reflex, which can easily be confused with the mouth
closure reflex (masseter reflex). Probably, at present, the
most effective technique is the use of the nerve stimulator,
as is described in case 4.
The doses used (between 25 and 40 UI) depend on
the type of drug (Botox in this series), because the other
preparation available on the market, Dysport, is �4
times less active than Botox, 22 although there is no
fixed dose relationship. In view of the scarcity of literature
on the subject, there are no references about the
dose per individual or the titration of botulinum toxin
type A. Therefore, the doses used in this series can be
considered to be valid, although, as mentioned above,
they depend on the preparation used and different formulations
are not interchangeable.
The irrelevance of side effects, together with the
dramatic results on these patients’ quality of life, makes
TMJ dislocation treatment with botulinum toxin type A
an extraordinarily useful resource as an alternative to
well tried surgical techniques that are difficult to apply
in patients with sever neurologic disorders. Moreover,
the etiology of TMJ dislocation in these cases is confirmed
by the efficacy of botulinum toxin type A. There
is no limit on the number of doses if a minimum
interval of 3 months is respected between applications.
Respecting this time interval minimizes the formation
of neutralizing anti–botulinum toxin type A antibodies,
thus maintaining its efficacy without limit of time.
In conclusion, the injection of botulinum toxin type
A in the external pterygoid muscles under instrument
control is an effective method in cases of neurogenic
TMJ dislocation, with scant morbidity and side effects,
improving patients’ quality of life and their interaction
with their surroundings.
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Reprint requests:
Olga Vázquez Bouso, MD
Department of Oral and Maxillofacial Surgery
University Hospital Joan XXIII
C/ Dr.Mallafré Guasch n°4
43007 Tarragona
Spain
vbolga@hotmail.com