Understanding and Treating Supralevator Fistula-in-Ano: MRI Analysis of 51 Cases and a Review of Literature

BACKGROUND: Supralevator fistulas are highly complex. The delineation of the supralevator fistula has become accurate because of MRI. OBJECTIVE: The aim of the study was to analyze the pathophysiology and treatment of different types of supralevator fistulas. DESIGN: This was a prospective study. SETTINGS: The study was conducted at a specialized fistula treatment center in North India. PATIENTS: All of the patients with fistula-in-ano who presented in the outpatient department were assessed with a physical examination and MRI scan. The patients in whom the supralevator extension was confirmed on MRI were included in the study. MAIN OUTCOME MEASURES: The MRI scans of patients included in the study were analyzed in detail to assess the types of supralevator fistulas and other characteristics of these fistulas. The patients who were operated on were followed for cure rate and deterioration in incontinence. RESULTS: Of 702 patients with fistula-in-ano who were analyzed by MRI over a period of 3 years, 51 patients with supralevator fistula-in-ano were identified. The mean age was 44.3 ± 12.1 years and the male:female ratio was 16:1. The incidence of supralevator fistulas was 7.26% (51 of 702). In supralevator fistulas, the supralevator extension (upper part) was found to be in the intersphincteric plane in all of the patients. This upper part could be successfully managed by laying it open through the transanal route. The infralevator (lower) part could be of 3 types: intersphincteric (n = 13), low transsphincteric (n = 3), or high transsphincteric (n = 35). The lower part could be managed conventionally. There were no extrasphincteric fistulas. An extensive review of the literature revealed only 2 studies (total fistulas = 16) in which supralevator fistula was studied. LIMITATIONS: This was a retrospective study. CONCLUSIONS: The upper supralevator extension in all of the supralevator fistulas is almost always in the intersphincteric plane. This upper part could be laid open through the transanal route. The lower infralevator part could be of 3 types, intersphincteric, low transsphincteric, or high transsphincteric, which could be managed conventionally. Thus, supralevator fistulas could be managed successfully and easily. See Video Abstract at https://ift.tt/2EPzEJG.

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