National observational study about the surgical treatment of anal fistula with laser (the FISTULASER study)

Ablation of anal fistula tract using a radial laser-emitting probe is a sphincter-preserving technique.

The objective of investigating the safety and efficacy of laser treatment for complex anal fistula.

This was a prospective and observational analysis of the long-term outcomes of 172 patients who underwent laser ablation of the fistula tract.

This was a multicentre, single-arm study, involving 20 Spanish centres.

Patients with cryptoglandular anal fistulas with an external orifice, high intersphincteric fistula or low intersphincteric fistula with faecal incontinence, transsphincteric fistula and suprasphincteric fistula.

A probe housing a 12-watt laser emitting at a wavelength of 1470 nm and an energy level of 100 joule/cm was used.

Complete treatment success was defined as the closure of the external opening and the absence of fistula drainage, with closure of the fistula tract confirmed by clinical evaluation. Partial success was defined as the external opening remaining open but without drainage. Surgical complications, including continence disorders, were also assessed. Patients were evaluated at 1, 3, 6, and 12 months after surgery.

A total of 172 patients underwent laser ablation of the fistula tract with a median age of 51 (43-61) years. The majority of them were men (62,8%). A total of 133 patients (77.32%) were followed up for a minimum of 12 months. The number of patients with complete healing was 59 (44.3%) and partial healing was observed in seven (5.26%). Healing (clinical and radiological) was not achieved in 67 patients (50.37%). Nine reported adverse events. None of the patients experienced permanent anal incontinence.

It is the loss to follow-up of up to 20% of patients, as many patients do not tolerate waiting within a strict visit schedule.

Laser ablation of the fistula tract is a sphincter-preserving procedure with an acceptable long-term success rate.