Anal Resting Pressures at Manometry Correlate with the Fecal Incontinence Severity Index and with Presence of Sphincter Defects on Ultrasound

INTRODUCTION: We describe the relationship between anorectal manometry, fecal incontinence severity, and findings at endoanal ultrasound. METHODS: A total of 351 women completed the Fecal Incontinence Severity Index, underwent anorectal manometry, and endoanal ultrasound. Severity index and manometry pressures in 203 women with intact sphincters on ultrasound were compared with pressures in 148 women with sphincter defects. Relationships between resting and squeeze pressures, severity index, and size of sphincter defects were evaluated. RESULTS: Mean severity index in patients with and without sphincter defect was 35.7 vs. 36.7 (not significant). Worsening index correlated with worsening mean and maximum resting pressure (P < 0.0001). Differences were observed in mean and maximum resting pressure between the patients with and without sphincter defects (26.6 vs. 37.2, P < 0.0001; 39.4 vs. 51.7, P < 0.001). Resting pressures correlated with the sizes of defect (P < 0.0001). CONCLUSIONS: Patients with and without sphincter defects had similar severity scores, but patients with defects had a significant decrease in resting pressures. Patients with larger sphincter defects had lower severity scores and resting pressures. Until a manometry cutoff can be set to discriminate between absence and presence of defects, both manometry and ultrasound should be offered to patients with history of anal trauma.