Endosonographic assessment of the anal sphincter after surgical reconstruction

Patients with anal incontinence attributable to trauma are usually treated by sphincter reconstruction. Failures because of incomplete reconstruction may possibly be detected by anal endosonography which gives detailed information on the anal sphincter muscles. The aim of this study was to describe the endosonographic findings in patients after sphincter reconstruction.

Ten female patients who had undergone surgical sphincter reconstruction using an overlapping technique because of anal incontinence were studied with anal endosonography a median of six months after surgery. Five patients were fully continent, three were incontinent for flatus, and two patients were still incontinent for solid stool at the time of this study. Eight patients had also been studied with endosonography before surgery, and, in these patients, we compared the initial sonograms with the follow-up sonograms. The angular extent of the endosonographic defects in the external sphincter before and after reconstruction was measured in degrees and compared with the outcome of surgery.

After reconstruction, continuity of the external anal sphincter was completely restored at all levels in four patients, one of whom still had anal incontinence. Continuity was partially restored in three patients: two were fully continent, while one patient, previously incontinent for stool, was incontinent for flatus. In three patients the continuity was restored at one level but a persisting defect was found at a different level. In two of these patients the grade of incontinence was unchanged. Three patients also had defects in the internal anal sphincter.

After surgical sphincter reconstruction for anal incontinence, we found sphincteric defects in six patients, including four of five patients who still had some degree of incontinence. Thus, endosonography may be used for postoperative assessment and may explain the unsatisfactory results of surgery in some patients. We recommend that endosonography be also performed preoperatively, whereby the effect of the operation on the size of the sphincteric defect can be assessed.