Transanal ultrasound and anorectal physiology findings affecting continence after sphincteroplasty

This study was undertaken to evaluate endosonographic and physiologic determinants of fecal continence after sphincteroplasty.

Sixteen female patients with severe fecal incontinence were treated with overlapping sphincteroplasty. Mean postoperative follow-up was 12 (range, 3-48) months. All patients underwent preoperative and postoperative transanal endosonography and anal manometry. Bilateral pudendal nerve terminal motor latency determinations were performed in each patient. A physiologic continence score was used to assess stool control.

Postoperatively, continence was worse, unchanged, and improved in one, five, and ten patients, respectively. An inverse correlation was noted between endosonographic sphincter discontinuity postoperatively, in degrees, and the change in fecal continence after overlapping sphincteroplasty (r = -0.51; P = 0.04). Postoperative increases in sphincter resting (r = 0.6; P = 0.02) and squeeze (r = 0.54; P = 0.03) pressures correlated with improved fecal continence. Mean pudendal nerve terminal motor latency (r = -0.34; P = 0.20) and changes in anal sphincter length at rest (r = 0.41; P = 0.11) and squeeze (r = 0.33; P = 0.20) after sphincteroplasty did not significantly correlate with the change in continence. Patients with intact endosonographic anatomy postoperatively and bilateral, unilateral, or no evidence of pudendal neuropathy had a mean change in continence score of 0.5, 1.8, and 2.2, respectively (P = 0.48).

Endosonography after sphincteroplasty can identify residual sphincter defects that are significant in terms of fecal continence. Restoration of anal canal resting and squeeze pressures was related to improved fecal control after overlapping sphincteroplasty. Mean pudendal nerve terminal motor latency was not significantly related to poor postoperative continence. A trend toward less improvement in fecal continence was noted with bilateral pudendal neuropathy.