F72Visualization of anal sphincter disruptions with transperineal three‐dimensional ultrasound following vaginal delivery in primiparous women

Abstract

ObjectiveTo visualize the anal sphincter disruptions following vaginal delivery in primiparous women using 3D ultrasound to correlate damage to obstetrical factors.MethodsWe have studied prospectively 150 consecutive primiparous women. Axial and sagittal images of the anal sphincter were performed 48 h after vaginal delivery using a 7.5‐MHz convex transducer placed on the perineum (Voluson 530 D Kretz) and repeated in the 30 women with anal sphincter disruption at a median of six months post natally. Obstetrical characteristics were analysed in all cases.ResultsAnal sphincter defect and its location were detected in 30 women (20%). None of the 24 women (16%) who underwent cesarean section had a sphincter disruption even in the 10 women delivered by cesarean section in labor. Head circumference, birth weight, maternal age, the duration of each stage of labor and the duration of active pushing were not significantly related to anal sphincter disruptions after vaginal delivery. Instrumental delivery, epidural analgesia and posterolateral episiotomy were associated with a sphincter defect but the only single independent factor related to the development of sphincter defects was instrumental delivery. The 3D sonography revealed sphincter injuries in 70% of the cases in the forceps delivery group (7 of 10), 13.3% of the cases in the vacuum delivery group (2 of 15) and 9.9% of the cases in the normal vaginal delivery group (10 of 101). 12 women (8%) had anal incontinence of faecal urgency when studied two months after vaginal delivery. The anal function was not altered after cesarean section.ConclusionsTransperineal 3D ultrasound of the anal sphincter is a reliable method for evaluating the anal sphincter. It is quickly performed and well tolerated by patients. Besides forceps delivery, commonly measured delivery variables are not useful predictors of latent anal sphincter injury.