Description

A woman in her 50s, with a history of complex perineal fistula disease managed by seton drainage, presented with rectal dyschezia and narrow stools. An anal inspection showed no secondary abscess and well-drained fistulas by Prolene threads. Digital rectal examination, anoscopy and rigid proctoscopy revealed a circumferential low rectal stenosis, suggestive of inflammatory scarring. The patient was tested HIV negative and the fistula tract swab culture came back negative for perianal tuberculosis. A complete colonoscopy was consequently ordered, which showed no evidence of malignancy or inflammatory bowel disease, as confirmed by endoscopic biopsies. Preoperative pelvis MRI allowed the diagnosis of an idiopathic high transsphincteric fistula-in-ano resulting in a cranial extrasphincteric tract with an annular supralevator extension, causing rectal stenosis (figures 1 and 2). A partial fistulectomy with a mucosal advancement flap was performed in this case, in order to defunction the primary orifice.1 The stenosis was treated by concomitant Hegar dilatation to 24 mm. A Penrose drain was left in the extrasphincteric space and removed 10 days later. The postoperative period was uneventful, with effective improvement of the dyschezia symptoms and no fistula recurrence. Due to the persistence of a subclinical fibrous stenosis at two postoperative months, the patient was instructed to perform self-mechanical rectal dilatation. Our approach was effective to manage this complex high fistula-in-ano and allowed us to avoid defunctioning stoma or proctectomy.

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Figure 1

Annular supralevator extension of a transsphincteric posterior fistula, shown on a turbo spin echo T2-weighted MRI sequence.

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Figure 2

Supralevator fistula can develop both in the intersphincteric (A) or extrasphincteric planes (B), with the latter potentially derived - as in our case - from the cranial extension of a transsphincteric fistula (C). Adapted by NC from ‘Human anus’ by Jordi March i Nogué,2 used under CC BY-SA 3.0 licence and with the permission of the author.