MONTREAL — Endoanal ultrasound performed immediately postpartum can identify clinically occult anal sphincter defects, which are linked to an increased risk of anal incontinence, according to a British study.
“This technology can improve our prediction of incontinence and has the potential to be used to target postnatal follow-up to women at increased risk,” said Philip Toozs-Hobson, M.D., a consultant gynecologist at Birmingham (England) Women's Hospital.
Speaking at the annual meeting of the International Continence Society, Dr. Toozs-Hobson outlined his study, which compared findings from endoanal ultrasounds performed immediately after delivery in 198 women with anal incontinence. Questionnaires were administered at 6 weeks postpartum.
Clinical evidence of anal sphincter damage had been ruled out in all women after clinical examination by two separate assessors.
While 60% of study participants had intact external and internal anal sphincters seen on endoanal ultrasound, and 30% had an isolated external anal sphincter defect only, the remaining 10% of participants had either defects in both sphincters or such profound distortion of the sphincters that the anatomy was not interpretable.
Among this latter group, 30% of the women reported anal incontinence symptoms at 6 weeks postpartum—which was threefold the rate of the rest of the study participants.
“A severely abnormal endoanal ultrasound scan immediately postpartum increases the risk of anal incontinence three times when compared [with] women with a normal ultrasound or an isolated [external anal sphincter] defect,” Dr. Toozs-Hobson concluded.
He said the clinical absence of ultrasound-detected anal sphincter damage “confirms the concept of occult anal sphincter damage” and could prove very important on a medico-legal level in showing that anal sphincter may not have been “missed” by obstetricians but may be “genuinely occult.”
Endoanal detection of defects also could predict which women should be followed closely for symptoms of incontinence, he said.
Although participants in Dr. Toozs-Hobson's study were not managed any differently based on their endoanal ultrasound results (all had clinically intact sphincters), another recent study altered management when endoanal ultrasound revealed a defect (Obstet. Gynecol. 2005;106:6–13).
“We showed that it is very possible for any resident to be trained to diagnose these clinically occult defects by ultrasound, and that managing these defects definitely improved the outcome,” said Dr. med. Daniel Faltin, one of the authors of that study, who was present in the audience. Dr. Faltin is director of the Dianuro perineology center and consultant in obstetrics and gynecology at the Hôpitaux Universitaires in Geneva.
Dr. Faltin's study randomized 752 primiparous women to clinical and endoanal ultrasonographic examination of the anal sphincter immediately postpartum (experimental group), or clinical examination alone (control group).
In the control group, clinically detected anal sphincter tears were repaired. In the experimental group, when anal sphincter defects were detected, the anal sphincter was surgically exposed and examined, and repairs were made when a tear was identified.
The authors reported a benefit in adding endoanal ultrasonography to the standard clinical exam. At 3 months postpartum, severe incontinence was reported by 3.3% of women in the repair group, compared with 8.7% of women in the control group.
The benefit persisted at 1 year, reported the authors, with severe incontinence reported by 3.2% of the intervention group, compared with 6.7% of the control group.
But the chairman of the session, Abdul H. Sultan, M.D., questioned the value of postpartum endoanal ultrasound, dismissing the idea of occult defects as “more of a myth than anything else.”
“You can pick these defects up clinically if you are properly trained,” he said in an interview. “If you can see what you're looking for, that is the best way forward—all you need to do is improve your clinical skills.”
Dr. Sultan, who is a consultant obstetrician and gynecologist at Mayday University Hospital in Croydon, England, runs courses on the clinical recognition and repair of obstetrical anal sphincter defects.
“Even if you see a defect on ultrasound, you've still got to find it clinically. Otherwise, you cannot repair it,” he said.
Dr. Sultan pointed out that in the Faltin study, five women had an anal sphincter tear diagnosed by ultrasonography that could not be confirmed during surgical exploration of the perineum. Of these women, one reported severe incontinence at 3 months and 1 year postpartum.