A Cochrane review included 6 trials involving 588 women comparing end-to-end repair and overlap repair. There was heterogeneity in the outcome measures, time points and reported results. Meta-analyses showed that there was no difference in perineal pain (RR 0.08, 95% CI 0.00 to 1.45, 1 trial, n=52), dyspareunia (RR 0.77, 95% CI 0.48 to 1.24, 2 trials, n=151) and flatus incontinence (RR 1.14, 95% CI 0.58 to 2.23, three trials, n= 256). However, it showed a statistically significant lower incidence of faecal urgency (RR 0.12, 95% CI 0.02 to 0.86, one trial, 52 women), and lower anal incontinence score (standardised mean difference (SMD) -0.70, 95% CI -1.26 to -0.14, one trial, 52 women) in the overlap group. Overlap technique was associated with a lower risk of deterioration of anal incontinence symptoms over 12 months (RR 0.26, 95% CI 0.09 to 0.79, 1 trial, n=41). There was no difference in quality of life. At 36 months follow-up, there was no difference in flatus incontinence (average RR 1.12, 95% CI 0.63 to 1.99, one trial, 68 women) or faecal incontinence (average RR 1.01, 95% CI 0.34 to 2.98, one trial, 68 women).
Comment: More research evidence is needed in order to confirm or refute these findings.