Purpose: The present study was undertaken to evaluate anal endosonographic results of the transverse and longitudinal extent of internal anal sphincter division after closed lateral subcutaneous sphincterotomy and its relationship to outcome with respect to anal fissure recurrence and postoperative anal incontinence.
Methods: Ten patients selected for symptomatic anal fissure recurrence (mean follow-up, 10.9 months) and 41 asymptomatic control patients (mean follow-up, 15.5 months) were reviewed by anal endosonography after closed lateral subcutaneous sphincterotomy. Clinical evaluation was focused on anal fissure recurrence and postoperative anal incontinence. The anal endosonographic study involves serial radial images of the distal, proximal, and midanal canal.
Results: In 32 patients in whom a complete internal sphincter defect was identified, 31 (75.6 percent) were from the control group and only 1 patient (10 percent) was from the recurrence group (P < 0.001). In 19 patients, an incomplete internal sphincter defect was identified; 10 (24.4 percent) were from the control group (residual median size, 1.8 mm; contralateral, 2.5 mm) and 9 patients (90 percent) were from the recurrence group (P = 0.001; residual median size, 1.4 mm; contralateral, 2.2 mm). Ten patients (19.6 percent) were incontinent for gas and three patients (5.9 percent) for liquid feces, without significant differences between groups.
Conclusions: Anal endosonography is a useful method for evaluating the anatomic effectiveness of closed lateral subcutaneous sphincterotomy. An incomplete sphincterotomy is associated with significant symptomatic anal fissure recurrence.