Diode Laser Closure for Cryptoglandular Anal Fistula: A Single-Centre Retrospective Experience

Background Laser closure of cryptoglandular anal fistula is a sphincter-preserving method with variable success rates across the literature, and the optimal preconditioning of the tract before laser treatment remains undefined. We are reporting here our experience with diode laser closure carried out as part of a systematically staged approach. Methods This was a retrospective, descriptive and analytical study, carried out at a single centre and involved 33 patients who were treated in succession from January 2023 to December 2024, with follow-up lasting until August 2026. The laser closure was conducted using a radial fibre with a wavelength of 1470 nm in continuous mode at a power of 10 W, with the fibre being retracted at a speed of 1 mm/s (i.e., 100 J/cm of tract), and without closing the internal opening. In all cases except four patients, preparatory measures, such as seton drainage, abscess drainage or partial opening of the accessory tracts, were carried out before the laser closure. Healing, persistence and recurrence were considered as separate outcomes. Kaplan-Meier estimates were used together with the log-rank test, Fisher's exact test and Mann-Whitney U test. Results In 31 out of 33 patients (93.9%), primary healing was achieved, with the median time to healing being 20 weeks. Of these 31 patients who were healed, eight (25.8%) experienced a recurrence - all except one occurring between 9 and 13 months after healing. Sustained healing was found in 23 of 33 patients (69.7%) at a median follow-up of 24 months. None of the patients developed any degree of faecal incontinence. Recurrence was found to be more common in patients with high fistulas than patients with low fistulas (46.2% vs 11.1%; odds ratio 6.86, 95% confidence interval 1.10-42.76; p = 0.043; log-rank p = 0.029). The period between the preparatory procedure and laser closure was shorter in those patients who had a recurrence (median 5.0 vs 12.0 months; p = 0.048), and no recurrences occurred in patients whose tract had been drained for more than eight months. Conclusions In the case of a staged approach, laser closure resulted in a high rate of immediate sealing without causing any impairment of continence, and failures occurred in the form of late recurrence rather than persistence. Both the height of the fistula and the duration of drainage before laser closure were associated with recurrence in exploratory analyses. These preliminary findings need to be confirmed by prospective studies and suggest that follow-up should continue well past the first postoperative year.