PURPOSE:Most surgical texts describe the length of division of the internal sphincter during closed lateral sphincterotomy as “to just above the dentate line,” resulting in significant rates of incontinence. This study reviews our experience using a “tailored” lateral sphincterotomy by selecting the height of sphincter to be divided with the aim of preserving more sphincter.METHODS:From 1976 to March 1996, the files of 440 patients who had sphincterotomies were reviewed by an independent research assistant. After exclusions, a residual group of 352 patients had undergone tailored left lateral sphincterotomy for chronic anal fissure that had failed conservative treatment or for acute anal fissure requiring surgical intervention.RESULTS:A total of 287 patients from the group who had tailored left lateral sphincterotomy returned for review (81.5 percent). Of these, four complained of imperfect control of flatus (1.4 percent), one of minor staining (0.35 percent), and two of urgency (0.7 percent). None had incontinence of feces or leakage of stool. Five patients had repeat sphincterotomies, four for recurrence and one for a persistent fissure.CONCLUSION:The technique of tailored lateral sphincterotomy is safe, effective, and preserves more anal sphincter. It might be argued that a controlled trial comparing tailored sphincterotomy with the standard height of incision (with preprocedure and postprocedure manometry) should be performed, but the clinically significant reduction in incontinence rates using the tailored approach would seem to support its use.