Influence of seton configuration, thickness, and laxity on patient comfort in chronic perianal fistula: a prospective comparative study

Purpose To determine how seton configuration, thickness, and laxity influence patient comfort and clinical outcomes in the management of chronic perianal fistulas. Methods A prospective single-center study was conducted involving 33 patients (53 setons). Both intraindividual paired (n = 20) and independent group analyses (n = 13) were performed. Setons were categorized by configuration (O-shaped vs. V-shaped), thickness (1.5 mm vs. 2.5 mm), and laxity (≤ 2 cm vs. > 2 cm from the anal verge). Patient-reported outcomes were assessed using structured questionnaires evaluating sitting discomfort, discharge, sexual impact, and fecal incontinence. Results O-shaped setons caused significantly less sitting discomfort than V-shaped ones (50.0% vs. 80.0%, p = 0.021). Excess laxity (> 2 cm) was associated with increased discharge (86.4% vs. 51.6%, p = 0.008), sexual impact (42.1% vs. 10.3%, p = 0.016), and fecal incontinence (66.7% vs. 10.0%, p = 0.041). Thicker setons (2.5 mm) showed a non-significant trend toward more pain (42.9% vs. 17.9%, p = 0.080). Conclusion Seton configuration and laxity significantly affect patient comfort. O-shaped setons and shorter laxity (≤ 2 cm) are preferable for reducing discomfort. These findings support evidence-based seton selection, although larger multicenter studies are needed to confirm these results.