[Diagnosis and treatment of complex anal fistula:current status and prospects]

In recent years, although we have made significant progress in the precise diagnosis and treatment of anal fistula, we still lack a thorough and in-depth understanding about the mechanism of formation, development, nonunion and recurrence of complex anal fistula. As a result, there is still a high failure rate, recurrence rate and the risk of the fecal incontinence after treatment. There is hardly any consensus on whatever treatment options, and the various treatment also means no established standard treatment for complex anal fistula. According to recent relevant literatures and personal experience, discuss recent pathbreaking updates in the management of complex anal fistula, we systematically summarize and generalize some critical issues in the diagnosis and treatment of complex anal fistula, including the pathogenesis, reasonable classification criteria, preoperative evaluation and surgical procedure selection. At the same time, we envision the future development directions.