Defects on endoanal ultrasound and anal incontinence after primary repair of fourth‐degree anal sphincter rupture: a study of the anal sphincter complex and puborectal muscle

Abstract

To perform three-dimensional endoanal ultrasound (EAUS) after primary repair of fourth-degree anal sphincter rupture (ASR) and correlate the sonographic defects with anal incontinence (AI); to measure the axial and sagittal thickness and angle of the puborectal muscle (PRM) as well as the length of the anal canal, and then correlate these measures with AI; and to assess the interobserver measurement agreement between an inexperienced and an experienced sonologist. EAUS was offered to 84 consecutive women, who were asked to answer a validated questionnaire after fourth-degree ASR. AI was graded according to the Wexner score and EAUS defects were graded according to the Starck score. Sixty-one women (73%) answered the questionnaire. The median (range) follow-up time was 5.1 (1.3-8.7) years. Thirty-three (54%) of these women underwent EAUS and were included in the study. There was no difference in the incontinence scores between women who underwent EAUS and those who did not. Eleven of the women who underwent EAUS (33%) were continent, 22 women (67%) had flatus incontinence at least once a month, of whom 12 also had incontinence for liquid stool and two had incontinence for solid stool. The median Wexner score was 2 (range, 0-12). Five of the patients (15%) had no ultrasound defects. All of the patients with Wexner scores > or = 4 had a Starck score of > or = 10. No association between ultrasound defects and AI was demonstrated, however, the angle of the PRM and parity were associated with Starck score. No clear association between the measurements of the PRM and AI was shown. The experienced observer detected more of the small defects than did the inexperienced observer. In a 1-9-year follow-up period after primary suture of fourth-degree ASR, the frequency of AI was high, at 67%. No clear association was seen between AI and sphincter defects detected on ultrasonography. There was an association between the angle of the PRM and the extent of ultrasound defects.