Aim: The aim of this study is to describe the diagnostic performance of magnetic resonance imaging in the management of supralevator abscess, regarding its origin, location, drainage route, subsequent treatment of the fistula, and long-term results.
Methods: A retrospective case series including thirteen consecutive patients with cryptoglandular supralevator abscess treated between 2001 and 2011 at a colorectal unit of a tertiary referral center. A magnetic resonance imaging was performed in all patients before surgical drainage, and its usefulness in assessing supralevator abscess origin was analyzed. Short- and long-term results after drainage were also evaluated.
Results: The final diagnosis of supralevator abscess and the location described in the magnetic resonance were confirmed intraoperatively in all patients. An ischiorectal origin was identified in nine patients, and perineal translevator drainage was performed placing a mushroom catheter through the ischiorectal or the postanal space. Four patients underwent secondary treatment of anal fistula: two rectal advancement flap and two non-cutting seton. In the other four patients, an intersphincteric origin was identified and transanal surgical drainage was performed placing a long-term mushroom catheter. Several weeks later, transanal unroofing of the residual cavity was performed and the fistula lay open to the anorectal lumen. In the long-term follow-up (median 61 months), only patients with supralevator abscess of ischiorectal origin in whom fistula was not subsequently treated presented a recurrence of the anal sepsis.
Conclusions: Magnetic resonance imaging seems essential to clarify the location of supralevator abscess, its origin, and choice of the right drainage route. Subsequent treatment of the fistula is necessary to avoid recurrence.