Paper 44: Anal Sphincter Injury in Women With and Without Pelvic Floor Disorders: A Case-Control Study

Abstract

OBJECTIVES: A high rate of anal incontinence (AI) and anal sphincter injury (ASI) was previously reported in a cohort of women with pelvic floor disorders.1 The aim of this study was to compare the prevalence of AI and ASI in women with pelvic organ prolapse (POP) and/or urinary incontinence (UI) (cases) versus a group of normal controls. METHODS: Ninety healthy controls (Stage 0 or 1 POP and no UI) and 100 women with pelvic floor disorders (≥ Stage II POP and/or UI) completed the Rockwood-Thompson fecal incontinence severity index questionnaire (FISI). The FISI is a validated severity index whose score (0–61) is generated based on the frequency of incontinence of gas, mucus, liquid, or solid stool. Prolapse was recorded using the ICS's Pelvic Organ Prolapse Quantification system (POP-Q). All women underwent endoanal ultrasonography using a 7-MHz transducer and a 360-degree rotating probe and the internal and external anal sphincters were reported as intact versus disrupted. Chi-square, student t-test, and logistic regression were used for statistical analysis and odds ratios, means, medians and standard deviations were reported as appropriate. RESULTS: Cases differed from controls in the following categories: Mean age (57 versus 53, P=0.05), race (77% versus 58% white, 21% versus 41% black, P=0.02), history of operative vaginal delivery (46% versus 32%, P=0.04) and highest mean infant birth weight (3650 g versus 3470 g, P=0.03). Women with pelvic floor disorders were significantly more likely to report AI (54% versus 18%, OR 5.4, 95% CI 2.8–10,6, P<0.001) and had higher mean FISI scores (22.3 ± 13 versus 12.7 ± 6.3, P=0.006) than controls. Cases also had higher rates of ASI on ultrasound than controls (51% versus 30%, P=0.007). Defects of the internal anal sphincter only, external anal sphincter only, or both were found in 1%, 30%, and 21% of cases versus 3%, 16%, and 11% of controls, respectively. The presence of AI was significantly associated with ASI in women with pelvic floor disorders (OR=38.3, 95% CI 12–120, P<0.001) and controls (OR=5.9, 95% CI 3–11, P=0.002). Operative vaginal delivery was significantly associated with AI in cases (OR 3.6, CI 1.6–8.8, P=0.002) but not controls (OR 1.8, CI 0.6–5.6, P=0.3). A logistic regression model that controlled for age, race, BMI, parity, highest infant birthweight, and history of operative vaginal delivery did not reveal any other risk factors for AI. CONCLUSION: In this study, women with pelvic floor disorders had significantly higher rates of anal incontinence and anatomic anal sphincter injury than a group of healthy controls. A strong correlation existed between anal incontinence and anal sphincter disruption in both groups.