Treatment of complex perianal fistulas with fistula laser closure : Application of the IDEAL 2A framework

Fistula laser closure (FiLaC) is a minimally invasive treatment option for perianal fistulas with acceptable healing rates. We report implementation and include short-term results in line with the IDEAL (Idea, Development, Exploration, Assessment, Long-term study) 2A framework in patients with complex fistulas and previous surgical repair attempts.

Prospective audit data from 56 consecutive patients with perianal fistulas treated between June 2024 and January 2025. The FiLaC procedure included cleaning the fistula tract, application of approximately 100 J/cm fistula length and closing of the internal opening with a stitch. All patients refused more invasive operations and/or were not suitable for advanced repair.

Patients were diagnosed with fistulas after a median of 34.5 months (interquartile range, IQR 13.8-54.2 months), with a median of 3 months (IQR 1.8-4.0 months) following previous fistula-related surgery. Most patients had cryptoglandular fistulas (80.4%) while 19.6% had inflammatory bowel disease-related fistulas. Most fistulas were transsphincteric (69.6%), and only 32.1% of patients were seton-free before the procedure. During the first postprocedural outpatient visit at 7.9 weeks (median; IQR 6.4-10.9 weeks), clinical healing was evident in 14 (24.1%) cases, and 23 (39.7%) patients reported relevant symptomatic improvement. A total of 21 patients (36.2%) did not report any improvement, 3 patients (5.2%) experienced a postoperative complication, with 1 (1.7%) requiring a return to theatre due to an abscess. After a median of 10.4 months, the "seton-free rate" was 67.9%, This represents a relevant improvement to 32.1% before FiLaC.

The use of FiLaC is a safe, sphincter-preserving treatment for complex perianal fistulas and was associated with a marked increase in the seton-free rate. While complete fistula healing rates were lower than previously reported, FiLaC remains an option for patients with complex disease.