Obstetric Anal Sphincter Injury Ten Years After: Subjective and Objective Long Term Effects

Objective: To establish the long term effects of obstetric anal sphincter rupture.

Design: Prospective observational study.

Setting: University hospital in Sweden.

Population: Eighty-two women from a prospective study from 1990 to compare anorectal function after third degree tear.

Methods: Women completed a structured questionnaire, underwent a clinical examination and anorectal manometry, endoanal ultrasound (EAUSG) with perineal body measurement.

Main Outcome Measures: Symptoms of anal incontinence, sexual symptoms, anal manometry scores and evidence of sphincter damage on EAUSG.

Results: Five women had undergone secondary repair and three were lost to follow up. Fifty-one women (80%) completed the questionnaire. Twenty-six out of 46 (57%) of the original study group and 6/28 (20%) of the original controls were examined. Incontinence to flatus and liquid stool was more severe in the study group than in controls. Flatus incontinence was significantly more pronounced among women with subsequent vaginal deliveries. Mean maximal anal squeeze pressures were 69 mmHg in the partial rupture group and 42 mmHg in the complete rupture group (P= 0.04). Study group women with signs of internal sphincter injury reported more pronounced faecal incontinence and had lower anal resting pressures (24 mmHg) than those with intact internal sphincters (40 mmHg) (P= 0.01). Perineal body thickness of less than 10 mm was associated with incontinence for flatus and liquid stools, less lubrication during sex and lower anal squeeze pressures (58 mmHg vs 89 mmHg, P= 0.04).

Conclusions: Subjective and objective anal function after anal sphincter injury deteriorates further over time and with subsequent vaginal deliveries. Thin perineal body and internal sphincter injury seem to be important for continence and anal pressure.