Primary sphincter repair: are the results of the operation good enough?

This study was designed to evaluate the clinical outcome of primary anal sphincter repair caused by obstetric tears and to analyze possible risk factors associated with sphincter rupture during vaginal delivery.

A total of 52 females with a third-degree or fourth-degree perineal laceration during vaginal delivery were examined. The symptoms of anal incontinence were obtained by a standard questionnaire. In addition to a clinical examination, endoanal ultrasound, anal manometry, and pudendal nerve terminal motor latency examinations were performed. A control group consisted of 51 primiparous females with no clinically detectable perineal laceration after vaginal delivery.

After primary sphincter repair, 31 females (61 percent) had symptoms of anal incontinence. Fecal incontinence occurred in 10 females (20 percent). According to Hardcastle and Parks' and Jorge and Wexner's classifications, the study group had more severe symptoms of anal incontinence than the control group (P<0.001 in both classification groups). In endoanal ultrasound examination, a persistent defect of the external anal sphincter was found in 39 females (75 percent) in the rupture group compared with 10 females (20 percent) in the control group (P<0.001). Anal sphincter pressures were significantly lower in the rupture group than in the control group. An abnormal presentation was the only risk factor for anal sphincter rupture during vaginal delivery.

After primary sphincter repair, persistent external anal sphincter defect and symptoms of anal incontinence are common in females who have had a primary sphincter repair after vaginal delivery. The means of improving the results of primary repair should be studied further.