A series of seton techniques involving "top-down therapy" for patients with Crohn's disease who initially presented with perianal fistulas.

Objectives: We determined the outcomes of seton treatment through a series of techniques using biological agents (BIOs) in 18 patients with Crohn's disease (CD) who initially presented with perianal fistulas.

Methods: The patients underwent seton drainage using three seton types: a Penrose tube for fistulas with massive purulent discharge, a vessel loop for a small amount of discharge, and a rubber band for unproductive fistulas. If the distal end of the fistula extended more than 4 cm from the anal orifice, the skin and subcutaneous tissue were dissected along the outer edge of the anal sphincter to divide the fistulous tract into two portions. One seton encircled the sphincter from the primary opening throughout the anal canal (medial seton), and the other was inserted through the distal tract outside the sphincter (lateral seton). A BIO was then introduced immediately. When discharge ceased, the Penrose tube or vessel loop was replaced sequentially with a rubber band, which was tied fittingly and subsequently removed in medial to lateral order.

Results: The mean interval between fistula onset and CD diagnosis was 2.1 years, and that between CD diagnosis and introduction of BIOs was 0.5 years. The mean follow-up duration was 4 years. The BIOs currently used were infliximab in 10 patients, adalimumab in 7, and ustekinumab in 1. The overall success rate was 94.4%, including unproductive fistulas in 10 (55.6%) patients and fistula disappearance in 7 (38.9%).

Conclusions: Our seton drainage techniques via the "top-down" approach represent a promising avenue for treating perianal fistulas in patients with CD.