Methods of repair for obstetric anal sphincter injury

Anal sphincter injury during childbirth - obstetric anal sphincter injuries (OASIS) - is associated with significant maternal morbidity including perineal pain, dyspareunia and anal incontinence. Anal incontinence affects women psychologically and physically. Many do not seek medical attention because of embarrassment. The two recognised methods for the repair of damaged external anal sphincter (EAS): are end-to-end (approximation) repair and overlap repair.

To compare the effectiveness of overlap repair versus end-to-end repair following OASIS in reducing subsequent anal incontinence, perineal pain, dyspareunia and improving quality of life.

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 January 2006), MEDLINE (January 1966 to 31 January 2006), EMBASE (January 1974 to 31 January 2006), SciSearch (January 1974 to 31 January 2006) and conference proceedings of obstetrics and gynaecology, surgery and coloproctology.

Randomised controlled trials comparing different techniques of immediate primary repair of EAS following OASIS.

Trial quality was assessed independently by all authors.

Three eligible trials, of grade A quality, involving 279 women, were included. There was considerable heterogeneity in the outcome measures, time points and reported results. Meta-analyses showed that there was no statistically significant difference in perineal pain (relative risk (RR) 0.08, 95% confidence interval (CI) 0.00 to 1.45, one trial, 52 women), dyspareunia (RR 0.62, 95% CI 0.11 to 3.39, one trial, 52 women), flatus incontinence (RR 0.93, 95% CI 0.26 to 3.31, one trial, 52 women) and faecal incontinence (RR 0.07, 95% CI 0.00 to 1.21, one trial, 52 women) between the two repair techniques at 12 months but showed a statistically significantly lower incidence in faecal urgency (RR 0.12, 95% CI 0.02 to 0.86, one trial, 52 women) and lower anal incontinence score (weighted mean difference -1.70, 95% CI -3.03 to -0.37) in the overlap group. Overlap technique was also associated with a statistically significant lower risk of deterioration of anal incontinence symptoms over 12 months (RR 0.26, 95% CI 0.09 to 0.79, one trial, 41 women). There was no significant difference in quality of life.

The limited data available show that compared to immediate primary end-to-end repair of OASIS, early primary overlap repair appears to be associated with lower risks for faecal urgency and anal incontinence symptoms. As the experience of the surgeon is not addressed in the three studies reviewed, it woudl be inappropriate to recommend one type of repair in favour of another.