Case presentation
A 25-year- old heterosexual African man was admitted as an emergency
following a gun-shot to the abdomen and another to the pelvis. He was
resuscitated in the emergency unit with intravenous fluids and underwent
an urgent laparotomy. The findings included multiple perforations of the
small bowel requiring small bowel resection. The entry site of the
second bullet was in the left iliac fossa but caused no pelvic injury.
The exit point was through the perineum for which he sustained perineal
injury affecting the external anal sphincters (figure 1). On digital
examination, there was no loss of rectal or anal mucosa. He had normal
rectal and anal sensation but loss of anal tone on squeeze and loss of
active anal control. He had a high Cleveland clinic incontinence score
of 18/20 i.e., solids (always) 4, liquids (always) 4, flatus (sometimes)
2, use of pad (always) 4, lifestyle alteration (always) 4. He recovered
from his abdominal surgery but continued to have severe urge
incontinence. On examination following referral, there was mild faecal
soiling, the anal canal was scarred at 3 and 9 o’clock from the mid anal
canal extending posteriorly. This was associated with a palpable defect
in the posterior external anal sphincter complex. There was palpable
fibrous tissue adjoining the underlying separated ends of the posterior
anal sphincter complex (Figure 1). Clinically, a diagnosis of 50%
posterior anal sphincter complex damage (grade 3b) was made. He
consented for a repair but without a defunctioning stoma. Routine blood
tests were normal. The patient received no mechanical bowel preparation
and following a spinal anaesthesia he was placed in the lithotomy
position. The first step entailed the excision of all the secondary
epithelium and underlying scar tissue surrounding the margins of the
anus from the midline and extending posteriorly. This created a large
wound which was essential to allow exposure of the disrupted muscle ends
for opposition without tension (Figure 2). The next step involved
mobilizing the normal mucosa of the anal canal and lower rectum by
dissecting it about 1 cm free from the muscle wall. This would later
allow mucosal reconstruction without tension. The third and difficult
step was sorting the disrupted muscle ends without cleaning off all the
fibrous tissue which will aid holding the sutures. No attempt was made
to identify separately the internal and external sphincters. It was
necessary to dissect on the lateral surface of the sphincter for a short
distance to free fibrous tissue that may be tethering the muscles and
allow repair without tension, but not extensively which may damage the
laterally placed neurovascular bundle. Posteriorly, the insertion of all
the muscles attached to the coccyx are divided to allow the posterior
limb of the sphincter to be lifted forwards without tension. This leaves
a cavity between the coccyx and the rectum. Horizontal mattress sutures
with absorbable 2.0 vicryl were used in the overlapping repair of the
remnant external anal sphincter but tied lightly to avoid muscle
necrosis (Figure 3). The anal tone on palpation following the repair was
satisfactory. The perineal skin was closed in an inverted “Y” (Figure
4) and a compression dressing applied. He was administered three
perioperative doses of antibiotics (ceftriaxone and metronidazole) and
allowed an elemental diet for 2 weeks. His bowels moved the following
day with no urge incontinence and an excellent Cleveland clinic
incontinence score of 1/20 i.e., solids (never) 0, liquids (never) 0,
flatus (rarely) 1, use of pad (never) 0, lifestyle alteration (never) 0.
He had no faecal incontinence at six months, and long-term follow-up was
planned.