Imbrication of the external anal sphincter may yield similar functional results as overlapping repair in selected patients

Abstract

Overlapping external anal sphincter repair is the preferred procedure for incontinent patients with functional yet anatomically disrupted anterior external anal sphincter. When incomplete disruption, thinning or technically difficult mobilization of the external anal sphincter occurs, imbrication without division may be the more feasible surgical option. The aim of the study was to assess retrospectively the indications for external anal sphincter imbrication in patients who underwent either overlapping external anal sphincter repair or external anal sphincter imbrication, and to compare the success rates. Patients who had external anal sphincter repair and follow up of at least 3 months were studied. Fecal incontinence was measured using the validated Wexner fecal Incontinence Scoring system (0 = perfect continence, 20 = complete incontinence); postoperative scores 0-10 were interpreted as successful, and scores of 11-20 as failures. A total of 131 females who had anal sphincter repair between 1988 and 2000 were analysed. One hundred and twenty-one patients had overlapping external anal sphincter repair (group I), and 10 had external anal sphincter imbrication (group II). Indications for external anal sphincter imbrication were attenuation of the external anal sphincter without overt defect (n = 5), partial disruption of external anal sphincter with muscle fibres bridging the scar (n = 2), thick bulk of scar between the muscle edges (n = 2), and wide lateral retraction of the muscle edges (n = 1). There were no statistically significant differences between the groups relative to preoperative incontinence score (16.5 vs 16.5, P = 0.99), pudendal nerve terminal motor latency assessment (left 9.6%vs 0.0%, P = 0.19; right 13.4%vs 11.1%, P = 0.84), and extent of electromyography pathology (61%vs 47%, P = 0.30). The patients in group I were younger than those in group II (mean age 50.8 years vs. 61.7 years, respectively; P = 0.052) and the length of follow-up was significantly longer (32.3 months vs 14.3 months, respectively; P < 0.0001). Both procedures had similar success rates (59.5%vs 60%; P = 0.98). Imbrication of the external anal sphincter may yield similar results as overlapping external anal sphincter repair in patients with incomplete external anal sphincter disruptions, external anal sphincter attenuation, and in patients presenting with wide lateral retraction of the muscle edges.