Internal seton for supralevator sepsis: An effective technique for complex fistulae.

Abstract

BACKGROUND The majority of supralevator sepsis results from superior extension within the intersphincteric plane (Fig 1). The basis of management of these patients is drainage of sepsis and subsequent definitive repair. Drainage of supralevator sepsis is challenging, as achieving sustained drainage of this anatomical space can be difficult. Drainage techniques include: Insertion of internal latex mushroom drainage catheters. This is first step management in our institution (Fig 2). External drainage with mushroom catheters through the perirectal skin. Incision over the abscess with drainage into the anal canal combined with partial internal sphincterotomy. Definitive management options for supralevator fistula include: specialty procedures such as flap repairs long term internal mushroom catheter placement, or long term management with external setons or drains. Management of supralevator fistula with internal setons has not previously been described. We present a novel technique to insert an internal seton into supralevator fistula-in-ano as a definitive management option. SURGICAL TECHNIQUE Patients are placed in lithotomy. Skin preparation used, and antibiotics administered at the discretion of the operating surgeon. Using a Hill-Ferguson anal retractor, the site of supralevator extension is identified via examination under anaesthetic (EUA). A gently curved Lockhart-Mummery probe is used to intubate the tract through the opening at the dentate line. The index finger of the surgeon’s non-operating hand is placed the rectum. The probe is guided to the apex of the tract and the index finger palpates the tip of the probe through the rectal wall for proximity. The probe is then perforated back into the anorectal lumen through the rectal wall (Fig 3). An 0 silk tie is then tied to the tip of the probe, and the probe withdrawn to advance the tie through the tract and back through the opening at the dentate line. The silk tie is then tied to the end of a silastic seton, which is guided into the tract by withdrawing the other end of the tie. A further 0 silk tie is then used to secure the seton with the two ends of the silastic seton lying parallel (Fig 4). SURGICAL TECHNIQUE Patients are placed in lithotomy. Skin preparation used, and antibiotics administered at the discretion of the operating surgeon. Using a Hill-Ferguson anal retractor, the site of supralevator extension is identified via examination under anaesthetic (EUA). A gently curved Lockhart-Mummery probe is used to intubate the tract through the opening at the dentate line. The index finger of the surgeon’s non-operating hand is placed the rectum. The probe is guided to the apex of the tract and the index finger palpates the tip of the probe through the rectal wall for proximity. The probe is then perforated back into the anorectal lumen through the rectal wall (Fig 3). An 0 silk tie is then tied to the tip of the probe, and the probe withdrawn to advance the tie through the tract and back through the opening at the dentate line. The silk tie is then tied to the end of a silastic seton, which is guided into the tract by withdrawing the other end of the tie. A further 0 silk tie is then used to secure the seton with the two ends of the silastic seton lying parallel (Fig 4). PROCTOTOMY The authors acknowledge there may be reluctance by colorectal surgeons to perforate the rectum. Internal drainage however is logical due to the proximity of the abscess cavity and fistula tract to the rectal wall. Precedence to healing of a sinus by internal drainage exists, such as in the use of Endosponge for anastomotic leak(8). In addition, we believe it is preferable to external drainage, which requires perforation through the pelvic floor and creation of complex fistula. IN PRACTICE This simple and cost effective technique of internal seton for definitive management of supralevator fistula has been used in our institutions since 2000 in a range of Chron’s and cryptoglandular fistula patients. To date, no significant intraoperative or post-operative complications related to this technique have been noted. Internal seton drainage is an effective, sphincter preserving, low morbidity procedure for definitive management of supralevator sepsis in selected cases.