Evaluation of obstetric anal injuries

Abstract

Intrapartum damage to the anal sphincter is an important factor in fecal incontinence. Obstetric anal sphincter injuries (OASIS) vary from 1 to 18% of vaginal deliveries, including instrumental deliveries. The severity of anal sphincter injuries vary from superficial lacerations to deep injuries that can extend to the epithelium. Obstetric anal sphincter injuries are associated with both short-term complications (heavy bleeding, difficulties in recovery, increased incidence of infections, increased perineal pain) and long-term complications (rectovaginal fistulae or facal incontinence). A significant number of these anal sphincter injuries can be detected promptly after a good clinical examination, but still that does not exclude the possibility of these women suffering long-term complications. What is more when some of these so called ‘occult tears’ go undetected further increase the morbidity of the woman. Sonography of the perineum and the anal sphincter appears to offer a better diagnosis and detection of these injuries after vaginal delivery, which allows a timely and better treatment with less complications, with endoanal sonography offering the best detection rates so far.