[Transformation and evidence-based progress of diagnosis and treatment mode for complex anal fistula]

Complex anal fistula remains a particularly challenging clinical condition, the primary difficulty in its management lies in the risk of damage to the anal sphincters, which is associated with a high incidence of treatment failure, recurrence and impairment of anal function, potentially leading to varying degrees of fecal incontinence in severe cases. Currently, there is no established gold-standard for the treatment of complex anal fistula, and efforts to identify effective therapeutic approaches continue. With advancements in medical science, the diagnosis and management of complex anal fistula have gradually transitioned from empirical medicine to evidence-based medicine, with continuous emergence of new theories and clinical evidence. This article reviews the relevant literature and systematically summarizes recent evidence-based medical findings on complex anal fistula, explores the driving factors in the evolution of diagnostic and therapeutic paradigms, and analyzes current clinical controversies and focal points. Furthermore,it elaborates on evidence-based diagnosis and treatment strategies, including preoperative precise assessment and selection of surgical techniques, with the aim of providing clinical practical guidance and promoting the advancement of diagnostic and therapeutic standards for complex anal fistula.