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.