Long-term results of lateral internal sphincterotomy for chronic anal fissure with particular reference to incidence of fecal incontinence

PURPOSE: Lateral internal sphincterotomy is the procedure of choice for chronic anal fissure because it relieves symptoms and heals the fissure in nearly all patients. However, there is evidence that fecal incontinence complicates lateral internal sphincterotomy. The aim of this study was to examine the outcome of lateral internal sphincterotomy in terms of fissure healing and incidence of fecal incontinence. METHODS: Between 1984 and 1996, 585 patients underwent lateral internal sphincterotomy and were surveyed by questionnaire. Eighty-three percent (487/585) responded. The mean follow-up was 72 (range, 6-145) months. RESULTS: Fissures had healed by a median of three weeks after surgery in 96 percent of patients. Recurrent fissures occurred in 8 percent. Two thirds of the recurrent fissures healed on conservative management alone. Ninety-eight percent of patients were satisfied with the outcome of surgery, but some degree of fecal incontinence occurred in fully 45 percent of patients at some time in the postoperative period. Incontinence occurred in 53.4 percent of women and 33.3 percent of men (P < 0.05). Incontinence to flatus, mild soiling, and gross incontinence occurred in 31, 39, and 23 percent of patients, respectively. However, by the time of survey (a mean of > 5 years after lateral internal sphincterotomy) 6 percent reported incontinence to flatus, 8 percent had minor fecal soiling, and 1 percent experienced loss of solid stool. Importantly, only 3 percent of patients stated that incontinence had ever affected their quality of life. CONCLUSION: Although lateral internal sphincterotomy heals and relieves symptoms of chronic anal fissure in nearly all patients (96 percent), incontinence occurs frequently. Most episodes of incontinence are indeed minor and transient, but in a small subgroup, incontinence seems to be permanent.