Manometric squeeze pressure difference parallels functional outcome after overlapping sphincter reconstruction

This study was designed to evaluate the effectiveness of overlapping anal sphincter reconstruction and to determine the manometric parameters that correlate with a successful functional outcome.

A retrospective review of patients who had undergone overlapping sphincter reconstruction for anal incontinence from 1988 to 1999 was undertaken. Only patients with preoperative and six-months-postoperative anal manometry were included in this study. Standard statistical tests were used to compare pre- and postoperative findings.

A total of 52 overlapping sphincter reconstructions were performed on 49 patients (46 females). The mean age was 44 (+/- standard error, 15.8; range, 20-81) years, with follow-up at six months. Forty-two patients had a history of complicated vaginal delivery (episiotomies, tears, forceps delivery); 36 patients had a history of anal or perineal surgery; and two patients had perianal Crohn's disease. Nine patients (17 percent) had undergone prior sphincter repair. Incontinence grade improved in 37 patients (71 percent), and complete continence returned in 21 patients (40 percent). The presence of a rectovaginal fistula, postoperative complications, previous sphincter repair, and increase in pudendal nerve terminal motor latency did not affect functional outcome (P = not significant). Patients older than 50 years had a better functional outcome than their younger counterparts after sphincter repair (P = 0.02). Although mean maximal squeeze pressure and mean anal sphincter length increased significantly after sphincter reconstruction (P = 0.0006 and 0.004, respectively), only squeeze pressure difference correlated with functional outcome (r = 0.37; P = 0.007).

Overlapping sphincter reconstruction improved anal function in the majority of patients. The most important factor in the return to normal sphincter function is an increase in squeeze pressure.