The extent of endosonographic anal sphincter defects after primary repair of obstetric sphincter tears increases over time and is related to anal incontinence

Objective To describe and classify endosonographic obstetric sphincter defects at 1 week, 3 months and 1 year after primary repair, and to relate the endosonographic results to anal sphincter pressure and to symptoms of anal incontinence over time. Methods Forty-one women who had suffered a third- or fourth-degree perineal tear at delivery underwent anal endosonography and anal manometry 1 week, 3 months and 1 year after primary suture of the tear. The extent of the endosonographic defects was described using defect scores ranging from 0 (no defect) to 16 (maximal defect), the score taking into account the location and the longitudinal and circumferential extent of the defect. The women answered a questionnaire with regard to bowel function 1 and 4 years after delivery, the degree of incontinence being expressed as a Wexner score. Results Some 90% (37/41) of the women had endosonographic defects at 1 week, 3 months and 1 year. The endosonographic defect scores increased significantly between the first and second examinations and then remained unchanged. At 1 year there was a negative correlation between endosonographic sphincter defect score and sphincter pressure. At 1 and 4 years, 54% (22/41) and 61% (25/41) of the women, respectively, had a Wexner score 1. There was a positive correlation between the endosonographic sphincter defect score at 1 week, 3 months and 1 year and the Wexner incontinence score at 1 and 4 years. The endosonographic sphincter defect score at 1 week was the variable that was most predictive of the Wexner score at 4 years (r = 0.48, P = 0.002). Conclusion The higher the endosonographic sphincter defect score after primary repair of an obstetric sphincter tear the lower the sphincter pressure and the higher the risk of anal incontinence.