Prevalence of anal sphincter defects revealed by sonography in 335 incontinent patients and 115 continent patients

OBJECTIVE. The aim of this study was to compare the prevalence of anal sphincter defects on anal sonography of incontinent and continent patients. SUBJECTS AND METHODS. Four hundred sixty-eight consecutive subjects who underwent anal sonography were studied. The prevalence of anal sphincter defects was calculated in 335 incontinent patients, 115 continent patients, and 18 asymptomatic female volunteers. All subjects answered a questionnaire about childbirth and proctologic surgery. RESULTS. The prevalence of anal sphincter defects revealed on sonography was 65% in the 335 incontinent patients. The prevalence of anal sphincter defects in incontinent patients was 88% in patients with a history of childbirth and proctologic surgery and 62% with childbirth alone. The prevalence of anal sphincter defects revealed on sonography was 43% in continent patients and 22% in asymptomatic volunteers. The prevalence of anal sphincter defects in continent patients with a history of childbirth and proctologic surgery was 92% and was 41% with childbirth alone, We found no difference in the prevalence of sphincter defects according to the age and sex of patients. CONCLUSION. Anal sonography can be used to identify sphincter defects in approximately two thirds of incontinent patients. Prevalence is greater in patients with a history of proctologic surgery. Because of the presence of sphincter defects in continent patients and in asymptomatic volunteers, caution should be used in attributing incontinence to anal sphincter defects alone.