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Drainage Seton Versus External Anal SphincterSparing Seton After Rerouting of the Fistula Tract in the Treatment of Complex Anal Fistula

A Randomized Controlled Trial

Omar, Waleed M.B.B.Ch., M.D.; Alqasaby, Abdallah M.B.B.Ch.; Abdelnaby, Mahmoud M.B.B.Ch., M.D.; Youssef, Mohamed M.B.B.Ch., M.D.; Shalaby, Mostafa M.B.B.Ch., M.D.; Anwar Abdel-Razik, Mohamed M.D.; Emile, Sameh Hany M.B.B.Ch., M.D.

Diseases of the Colon & Rectum: August 2019 - Volume 62 - Issue 8 - p 980–987
doi: 10.1097/DCR.0000000000001416
Original Contributions: Anorectal
Denotes Associated Video Abstract
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BACKGROUND: Complex anal fistula is one of the challenging anorectal conditions. Several treatments have been proposed for complex anal fistula, yet none proved to be ideal.

OBJECTIVE: This randomized trial aimed to assess the efficacy of external anal sphinctersparing seton in comparison with the conventional drainage seton in the treatment of complex anal fistula.

DESIGN: This was a prospective, randomized, single-blind controlled study.

SETTINGS: The study was conducted at the Colorectal Surgery Unit of Mansoura University Hospitals.

PATIENTS: Adult patients of both sexes with complex anal fistula were recruited and evaluated with MRI before surgery.

INTERVENTIONS: Patients were randomly divided into 2 groups; group 1 was treated with conventional drainage seton and group 2 was treated with external anal sphinctersparing seton using a rerouting technique.

MAIN OUTCOME MEASURES: The duration of healing, incidence of recurrence or persistence, postoperative pain, and complications including fecal incontinence were measured.

RESULTS: Sixty patients (56 men) with a mean age of 43 years were included. Mean operation time in group 1 was significantly shorter than group 2 (29.8 ± 4.3 vs 43.8 ± 4.5 min; p < 0.0001). The mean pain score at 24 hours in group 1 was 8.1 ± 1.6 versus 5.3 ± 1.3 in group 2 (p < 0.0001). Five patients (17%) in group 1 experienced complications versus 2 (7%) in group 2. All of the patients in group 1 required a second-stage fistulotomy versus 2 patients (7%) in group 2 (p < 0.0001). Time to complete healing in group 1 was significantly (p < 0.0001) longer than group 2 (103 ± 47 vs 46 ± 18 d). Four patients (13%) in group 1 and 1 patient (3%) in group 2 experienced persistence or recurrence of anal fistula (p = 0.35).

LIMITATIONS: This was a single-center study with relatively small numbers in each group.

CONCLUSIONS: Patients treated with external anal sphinctersparing seton after rerouting of the fistula tract achieved quicker healing and less postoperative pain than those with conventional drainage seton. Postoperative complication and recurrence rates were comparable in both groups. See Video Abstract at

TRIAL REGISTRATION: identifier: NCT03636997 (

Colorectal Surgery Unit, Department of General Surgery, Mansoura University Hospitals, Mansoura University, Dakahliya, Egypt

Funding/Support: None reported.

Financial Disclosure: None reported.

Correspondence: Sameh Emile, M.D., Department General Surgery, Mansoura, University Hospitals, Mansoura University, 60 El-Gomhouria St, 35516 Mansoura, Dakahliya, Egypt. E-mail:

© 2019 The American Society of Colon and Rectal Surgeons