Unsuspected sphincter defects shown by anal endosonography after anorectal surgery. A prospective study.

PURPOSE

Anorectal surgery can lead to fecal soiling and incontinence. Whether surgery changes the anatomy and causes symptoms is unknown. Anatomic changes can be visualized by anal endosonography.

METHODS

We studied 50 patients after hemorrhoidectomy (24), fistulectomy (18), and internal sphincterotomy (8). Symptoms were assessed, and anal endosonography, anal manometry, mucosal electrosensitivity, and neurophysiologic tests were performed.

RESULTS

In 23 (46 percent) patients, a defect of the anal sphincter was found (13 patients had an internal sphincter defect, 1 had an external sphincter defect, and 9 had a combined sphincter defect), 3 after hemorrhoidectomy, 13 after fistulectomy, and 7 after internal sphincterotomy. Seven patients had symptoms, and they all had a sphincter defect. In the other 16 of 23 patients (70 percent), the sphincter defect did not produce symptoms. An internal sphincter defect lowered maximum basal pressure and shortened sphincter length.

CONCLUSION

Anal endosonography can reveal sphincter defects after anorectal surgery. Seventy percent of the patients in this group had no complaints; therefore, defects were unsuspected. This has clinical implications in the evaluation of patients with fecal incontinence.