Overlapping Compared With End-to-End Repair of Third- and Fourth-Degree Obstetric Anal Sphincter Tears: A Randomized Controlled Trial

Abstract

The traditional procedure in obstetric practice used to repair external anal sphincter defects has been an end-to-end technique. Clinicians have been concerned, however, by reports of high rates of external anal sphincter defects and associated symptoms of anal incontinence with this technique. In a small retrospective study, another procedure, overlapping repair, lowered the rate of postoperative defects and improved anal function leading to suggestions that the traditional end-to-end surgical repair technique does not restore normal anatomy or function. As a result, some investigators believe that overlapping repair should replace the end-to-end technique as the standard of care. A Cochrane review of 3 randomized trials comparing the overlapping and end-to-end repair techniques reported no difference in flatal or fecal incontinence rates but a lower rate of fecal urgency and a lower anal incontinence scores in the overlapping group. Although these data suggest some advantage of the overlapping repair technique, the 3 trials were limited by deficiencies in design. Limitations included lack of reporting surgeon experience, inclusion of multiparous women and women with partial tears of the external anal sphincter, and lack of clarity in regard to interpreting outcome measures. This randomized controlled trial compared the use of overlapping repair and end-to-end repair of obstetric tears and investigated which of these procedures is associated with a higher rate of flatal incontinence. The study subjects—149 primiparous women who had sustained a complete third- or a fourth-degree tear of the perineum—were randomly assigned to overlapping (n = 74) or end-to-end (n = 75) external anal sphincter repair. The study was conducted at a tertiary care academic center between 2001 and 2007. All participants and follow-up assessment personnel were blinded as to the surgical procedure performed. At the 6-month follow-up, outcome measures examined included rates of flatal and fecal incontinence, rates of internal and external anal sphincter defects using ultrasonography, anal function using anal manometry, and quality-of-life scores. Compared with end-to-end repair, overlapping repair was associated with higher rates of flatal incontinence (61 % vs. 39%); the odds ratio was 2.44, with a 95% confidence interval of 1.2-5.0 (P = 0.015). The rate of fecal incontinence was also higher with overlapping repair (15% vs. 8%) but not statistically significant (P = 0.243). The difference between groups in rates of internal and external anal sphincter defects was not significant. The presence of a defect in both sphincter muscles was associated with a higher rate of fecal incontinence. There was no significant difference in anal sphincter function between the surgical groups. These findings indicate that overlapping repair of third- or fourth-degree obstetric anal sphincter tears is more likely to result in anal incontinence compared with the traditional end-to-end repair procedure. The investigators recommend use of the traditional end-to-end procedure for repair of these tears.