Repair techniques for obstetric anal sphincter injuries: a randomized controlled trial

To compare one-year outcomes of primary overlap versus end-to-end repair of the external anal sphincter after acute obstetric anal sphincter injury.
Women who sustained third-degree (3b = greater than 50% external anal sphincter thickness, 3c = internal sphincter injury) or fourth-degree (including anorectal epithelium) perineal tears were randomly allocated to either immediate primary overlap or end-to-end repair. They were prospectively followed up for 12 months postrepair with serial questionnaires. The primary outcome was fecal incontinence at 12 months. Secondary outcomes were fecal urgency, flatus incontinence, perineal pain, dyspareunia, quality of life, and improvement of anal incontinence symptoms.
Thirty-two women were randomized to each group. At 12 months, 24% (6/25) in the end-to-end and none in the overlap group reported fecal incontinence (P = .009, relative risk [RR] 0.07, 95% confidence interval [CI] 0.00-1.21, number needed to treat 4.2). Fecal urgency at 12 months was reported by 32% (8/25) in the end-to-end and 3.7% (1/27) in the overlap group (P = .02, RR 0.12, 95% CI 0.02-0.86, number needed to treat 3.6). There were no significant differences in dyspareunia and quality of life between the groups. At 12 months, 20% (5/25) reported perineal pain in the end-to-end and none in the overlap group (P = .04, RR 0.08, 95% CI 0.00-1.45, number needed to treat 5). During 12 months, 16% (4/25) in the end-to-end and none in the overlap group reported deterioration of defecatory symptoms (P = .01).
Primary overlap repair of the external anal sphincter is associated with a significantly lower incidence of fecal incontinence, urgency, and perineal pain. When symptoms do develop, they appear to remain unchanged or deteriorate in the end-to-end group but improve in the overlap group.