Obstetric sphincter tears and anal incontinence: an observational follow-up study.
BACKGROUND
Persistent defects after primary sphincter repair and occult sphincter tears are common after vaginal deliveries. Anal incontinence may be associated with these morphological defects.


METHODS
Forty-six primiparous women were evaluated with ultrasonography, manometry and electrophysiology. Twenty-four women had undergone primary repair of obstetric sphincter tears (sphincter group), 16 women had no clinical sphincter tear but developed anal incontinence postpartum (symptom group), and six were delivered by elective cesarean section (cesarean group).


RESULTS
In the sphincter group, 50% had anal incontinence at follow-up. At ultrasonography, 70% had injuries anteriorly in the midanal canal. At manometry, 4% had decreased resting pressure and 50% decreased squeeze pressure. At electrophysiology, 19% had pathologic pudendal latency and 25% pathologic fiber density. In the symptom group, 44% had injuries anteriorly in the midanal canal at ultrasonography. At manometry, all women had normal resting pressure and 19% had a decreased squeeze pressure. At electrophysiology, 46% had pathologic pudendal latency and 29% pathologic fiber density. In the cesarean group, 33% had mild anal incontinence at follow-up. Ultrasonography and manometry were normal in all women. At electrophysiology, 33% had pathologic pudendal latency and 17% pathologic fiber density.


CONCLUSIONS
Anal sphincter injuries at childbirth are often inadequately diagnosed and primary repair frequently results in persisting defects in the anal sphincter. Anatomic injuries to the anal sphincter play an important role in the development of anal incontinence after delivery, but a significant proportion of symptomatic women also demonstrate neurologic impairment at electrophysiologic testing.
Zetterström
Jan
J
Department of Obstetrics and Gynecology, Danderyd Hospital, Sweden. jan.zetterstrom@kids.ki.se
López
Annika
A
Holmström
Bo
B
Nilsson
Bengt Y
BY
Tisell
Ake
A
Anzén
Bo
B
Mellgren
Anders
A
D000328:Adult; D001003:Anal Canal / Q000000981:diagnostic imaging / Q000293:injuries* / Q000294:innervation / Q000502:physiology; D036861:Delivery, Obstetric / Q000009:adverse effects*; D004594:Electrophysiology; D005242:Fecal Incontinence / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008365:Manometry; D010298:Parity; D011247:Pregnancy; D011446:Prospective Studies; D011644:Puerperal Disorders / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D014463:Ultrasonography