PURPOSE:This study was designed to evaluate long‐term results and quality‐of‐life outcomes after the muscle‐filling procedure for posterior transsphincteric fistulas.METHODS:A questionnaire was mailed to 207 patients who had been treated by the muscle‐filling procedure for posterior transsphincteric fistulas with cryptoglandular origin at the Social Health Insurance Hospital during a ten‐year period. One hundred fifty‐one patients who returned their questionnaires were included in this retrospective study. Information regarding fistula recurrence, time required for wound healing, postoperative incontinence, overall satisfaction with the procedure, and quality‐of‐life data were surveyed from the returned questionnaires.RESULTS:One hundred fifty‐one patients (140 males) with a mean age of 48 (range, 17‐75) years were analyzed. The mean follow‐up was 70 (range, 12‐131) months. Fistulas recurred in seven patients (4.6 percent). Fifty‐eight patients (38 percent) healed within 3 months, and 52 (34 percent) healed within 6 months. Eighty‐four patients (56 percent) reported some reduction in their sense of sphincter‐tightening ability after surgery. Seventy‐eight patients (52 percent) reported some degree of incontinence. One hundred thirty‐three patients (88 percent) were satisfied or very satisfied with their outcomes. Of the 18 patients (12 percent) who reported unsatisfactory or very unsatisfactory results, 7 experienced recurrence. Thirty‐seven patients (25 percent) indicated one or more lifestyle alterations, including social activities (11 percent), travel (12 percent), sports (5 percent), diet (4 percent), housework (1 percent), or sexual activities (1 percent), because of incontinence after surgery. Eighteen patients (12 percent) had more than one restriction in their quality‐of‐life parameters.CONCLUSION:The muscle‐filling procedure is a viable option in the treatment of transsphincteric fistulas, with a favorable recurrence rate and an overall patient satisfaction rate above 88 percent.