Prospective study of the influence of parity and operative technique on the outcome of primary anal sphincter repair following obstetrical injury

Objective: To determine the influence of parity and method of primary anal sphincter repair on outcome following obstetrical third degree perineal tear. Study design: Prospective study of 154 women after primary repair following third degree tear conducted over 2 years. Postpartum evaluation included a continence questionnaire, anal manometry and endoanal ultrasound. Results: Third degree tears occurred in 1.6% primiparae and 0.6% multiparae during the study period; in 42/112 (38%) primiparae and 10/42 (24%) multiparae, these tears occurred at instrumental deliveries. Mean birthweight (3.8+/-0.43 kg) was similar in both groups, but prolonged latent second stage of labour (P=0.003), use of epidural analgesia (P<0.0001) and episiotomy extension (P<0.0001) occurred more often in primiparae. Both methods of sphincter repair (approximation or overlap) were performed with comparable frequency, irrespective of parity. At 3 months postpartum, 53% patients noticed some alteration in faecal continence, Anal manometry results were not influenced by parity, symptoms or technique of repair. 33% of patients had ultrasound evidence of a persistent large (>1 quadrant) anal sphincter defect. Conclusion: Outcome of anal sphincter repair was not influenced by parity or mode of repair. Despite good symptomatic outcomes, ultrasound evidence of significant anal sphincter injury was found in one-third of patients. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.