LASER FiLaC™ (FISTULA LASER CLOSURE) : First-line Treatment of Complex Anal Fistulas

Complex anal fistula is a fistula whose treatment with fistulotomy would expose the patient to an excessive risk of post-operative continence disorders. It is a challenge in proctological surgery because of the complexity of its therapeutic management in relation to the recurrences' frequency and the need to preserve sphincter function. Indeed, management is mainly based on fistulotomy techniques, but the latter expose patients to a significant alteration of their continence (less than 10% incontinence for simple fistulas but 30-50% for complex fistulas). In addition, these fistulas' management is constraining for patients due to the need for multiple interventions, long-term post-operative care and repeated discontinuation of activity. Sphincteral saving techniques have therefore developed over the last three decades and have enriched the therapeutic panel of complex fistulas. They aim to block fistula pathways without risking altering sphincter function. In addition, their surgical consequences are often simple. However, they are associated with a greater risk of failure than after fistulotomy and sometimes disappointing to the point that some of these techniques have been gradually abandoned (biological glue and plug for example). Among these sphincteral saving techniques, the investigators know the advancement flap, the injection of biological glue, plug's installation, the LIFT (Ligation of Inter sphincteric Fistula Tract), the clip's use but also, more recently a laser treatment, FiLaC™ (for Fistula Laser Closure), knowing that the idea was not new since the ND-YAG3 and CO24.5 lasers were already used in the treatment of anal fistulas, about twenty years ago, in experimental studies. This technique consists of radiating 360° laser energy radially into the fistula path to "burn" it and causing thermal destruction by coagulation of the fistula wall ans granulation tissue2. It can bo offered to any type of fistula at risk on continence, including horseshoe ext