Ultrasound Blocks for the Anterior Abdominal Wall

94 | Ultrasound Blocks for the Anterior Abdominal Wall
such as inguinal repair or orchidopexy that do not include bowel
exposure. In three children from 6 to 14 years of age, subserosal
hematomas of the colon and small bowel have been reported
following an IIB under general anesthesia respectively for
spermatic vein ligation, appendicectomy and left inguinal hernia
(Johr 1999, Frigon 2006, Amory 2003).
In one case, small bowel hematoma required resection of a
bowel loop. The recovery was uneventful and the child was
discharged on day 8 (Amory 2003). Subcutaneous local
hematoma at the puncture site has been also reported (Erez
2002).
Liver trauma has been also described after a TAPB (Farooq
2008, O’Donnell 2009, Lancaster 2010). In one case the liver was
enlarged and reached the right iliac crest. Hepatomegaly or
splenomegaly with the liver or spleen margin reaching the iliac
crest may be a risk factor for puncture (Farooq 2008, O'Donnell
2009). It would be prudent to palpate the edge of the liver and
spleen before performing the procedure, and this is particularly
important in patients of small stature.
Failure to recognize the “pops” may result in needle
advancement deeper than the TAM and into the peritoneal
cavity (O’Donnell 2009).
Aspiration prior to injection and image check for vascular
structures reduces the risk of direct intravascular
administration of the anesthetic agent (Figure 13.2).
In order to reduce the risk of puncturing intra-abdominal
structures, some authors strongly suggest the routine use of
ultrasonography (Weintraud 2008, Fredrickson 2008). Needle tip
and correct tissue visualization is advocated in all cases
(Lancaster 2010). Moreover, an in-plane approach may allow
easier visualization of the muscle layers and needle tip position.