A perianal abscess does not necessarily form an anal fistula after drainage surgery. Most perianal abscesses and fistulas are formed by the same principles, mainly secondary to sinusitis. Inflammation of the anal sinus, mainly by Escherichia coli, leads to inflammation of the subcutaneous tissue around the anus, the development of masses and the possible formation of abscesses. In some patients, after healing through abscess incision and drainage, the internal opening of the anal sinus, potentially the internal opening, will heal on its own and no anal fistula will be formed in this case. However, in some patients, after the abscess is healed by incision and drainage, the internal opening does not heal, and in this case an anal fistula may be formed. The overall incidence is not known, but is relatively low in clinical practice. Most fistulas occur when a perianal abscess breaks down on its own and is not changed and treated in the hospital. Most perianal abscesses heal if incision and drainage are performed in the hospital and the medication is actively changed.