Controlled lateral sphincterotomy for chronic anal fissure.

PURPOSE: This study assessed the usefulness of "controlled" lateral sphincterotomy for chronic anal fissures.

METHODS: Of 225 patients with chronic anal fissure, 110 underwent traditional sphincterotomy to the level of the dentate line, and 115 underwent controlled sphincterotomy in three steps according to the degree of anal stenosis. In Step 1, the internal sphincter was divided to the proximal level of the fissure. If the anal canal was still stenosed, the division was extended to the level of the dentate line in Step 2. Step 3 was a bilateral internal sphincterotomy. The anal stenosis was evaluated under anesthesia using a new conical calibrator scaled in 1-mm diameter increments. Forty adults without anorectal disease were examined as controls. In a telephone follow-up, 102 patients in the traditional sphincterotomy group and 106 patients in the controlled sphincterotomy group responded.

RESULTS: The normal group measured 34.6 +/- 1.4 mm (mean +/- standard deviation). Confounding effects of age, gender, body weight, and height were not significant. Based on the anal caliber measured in the normal group, anal stenosis is present with values of 31 mm and below (mean--2SD of the control value). Of 115 patients in the controlled sphincterotomy group, 90 (78 percent) underwent sphincterotomy below the level of the dentate line, 18 (16 percent) underwent sphincterotomy to the level of the dentate line, and 7 (6 percent) underwent bilateral sphincterotomy. None had incontinence of feces or leakage of stool. Ten of 102 patients (10 percent) in the traditional sphincterotomy group and 2 of 106 patients (2 percent) in the controlled sphincterotomy group complained of minor incontinence, such as gas incontinence, minor staining, or urgency (P = 0.017). There was one recurrence in the traditional sphincterotomy group.

CONCLUSION: Controlled lateral sphincterotomy could be a way of overcoming the risk of incontinence with lateral internal sphincterotomy for chronic anal fissure.