The purpose of this study is to examine anal fistulae, with emphasis on a specific type called horseshoe fistula. Horseshoe fistulae are the rarest type of anal fistulae and can be challenging to treat. There is a paucity of data in the literature as to the treatment of such fistulae and the outcome of surgical intervention. This study is a retrospective review of all patients with anal fistula admitted to the Colorectal Surgery Service at Kaiser Permanente's Los Angeles Medical Center over the past five years. The purpose of this study will be to determine the demographics of patients with anal fistulae, presenting symptoms, length of symptoms, type of fistula, diagnostic modality, surgical intervention type, short and long term outcome, complications and reoccurrence rate. This retrospective review will entail review of outpatient and inpatient medical records, clinic visit summary and operative and diagnostic reports will be evaluated.