Use of endoanal ultrasound as complimentary evaluation for detection of anal sphincter injury after vaginal birth

Abstract

Purpose Anal sphincter injury after delivery is the main factor in the pathogenesis of fecal incontinence. Clinical obvious and specific injury to anal canal sphincter is seen in 3% of vaginal deliveries. There are many women who do not have a clear and specific laceration but they are damaged by sphincter muscles of anal canal. The purpose of the present study is to investigate the frequency of occult anal sphincter injury after vaginal delivery by Endo-anal sonography. Methods Fifty women with first pregnancy were assessed at 27–33 weeks of pregnancy, and at 6 weeks and 6 months after vaginal delivery by questionnaire, examination and Endo-anal sonography. Women age, duration of delivery, the effect of epidural anesthesia, episiotomy and birth weight were studied and Endo-anal sonography results were recorded. Anal manometry was performed for all mothers before delivery and 5 ones with sphincter injury at 6 months and 3 years after delivery. Results Five (10%) patients, with mean age 29.4 ± 6.5 years, mean neonatal weight of 3874 ± 287, and mean duration of delivery 11.6 ± 1.51 h, had signs of sphincter injury in Endo-anal sonography. The injury was persisted at six months after delivery. Also, significant differences were seen between anal manometry before delivery and 6 months and 3 years after delivery (p = 0.006 for mean squeezing pressure) in the five mothers. Conclusion Endo-anal sonography might be a good screening tool for early detection of postpartum anal sphincter damages. However, further prospective cost benefit studies should be performed to propose it as a standard of care.