Prospective study of the effects of postanal repair in neurogenic faecal incontinence

The most important factor associated with a good result in the surgical treatment of neurogenic faecal incontinence by postanal repair is considered to be restoration of the obtuse anorectal angle. Sixteen patients (14F:2M; median age 59 years) with neurogenic faecal incontinence confirmed by a raised fibre density in the external anal sphincter underwent postanal repair. Pre- and postoperative manometric assessment was performed in 16 and radiological assessment in 12. Normal ranges for these parameters were established in age and sex matched control subjects. Continence was improved in 14 (88 per cent) patients, 6 (38 per cent) of whom regained normal continence, at a minimum of 15 months follow-up. A successful outcome was associated with no significant change in basal (pre-operative 35 (10-85) cmH2O, postoperative 44 (12-105) cmH2O; n.s.) or voluntary (pre-operative 43 (5-150) cmH2O, postoperative 32 (12-180) cmH2O; n.s.) components of anal canal pressure. There was a small but significant increase in sphincter length (pre-operative 2 (0-3) cm, postoperative 2.5 (0-3.5) cm; P less than 0.01). There was no significant change in the anorectal angle at rest (pre-operative 96 (90-110) degrees, postoperative 107 (79-118) degrees; n.s.) in the patients in whom continence was restored and five of these patients had resting anorectal angles within the normal range (75-94 degrees). Thus postanal repair need not be restricted to patients with widening of the anorectal angle since its beneficial effects do not appear to be related to reduction of this angle.