PERINEAL BODY MEASUREMENT IMPROVES EVALUATION OF ANTERIOR SPHINCTER LESIONS DURING ENDOANAL ULTRASONOGRAPHY

Endoanal ultrasonography has become an important tool in the evaluatio n of patients with anal incontinence. However, the extent of anterior defects is sometimes difficult to quantitate during endoanal ultrasono graphy. PURPOSE: This study was designed to evaluate perineal body mea surement during endoanal ultrasonography in assessing patients with ob stetric anal sphincter injuries. METHODS: Forty-two patients with anal incontinence because of obstetric sphincter injuries and 13 asymptoma tic subjects were investigated with endoanal ultrasonography. Sphincte r muscle thickness, sphincter defects, and perineal body were measured . Perineal body measurement was performed by inserting a finger, held gently against the posterior vaginal wall, into the vagina and measuri ng the distance between the inner surface of the internal sphincter an d the ultrasonographic reflection of the finger. RESULTS: Ah patients had anterior sphincter lesions of varying extent. Mean size of interna l sphincter lesions was 146 degrees, and mean size of external sphinct er lesions was 107 degrees (P < 0.001). Perineal body measurement was performed without difficulty in all patients and subjects. Perineal bo dy measurement (mean standard deviation) was 6 +/- 2 mm in patients an d 12 +/- 3 mm in asymptomatic subjects (P < 0.001). Ninety-three perce nt of patients had perineal body measurement less than or equal to 10 mm, and 70 percent of asymptomatic subjects had perineal body measurem ent >10 mm. Digital delineation of the perineal body during endoanal u ltrasonography improved the visualization of sphincter lesions in 74 p ercent of patients. CONCLUSIONS: Digital delineation of the perineal b ody during endoanal ultrasonography improved the visualization of sphi ncter lesions in the majority of patients. Perineal body measurement i s performed without difficulty and is a good predictor of anterior sph incter lesions. Use of this technique improves visualization of sphinc ter lesions.