Anal fistula, complex, persistent

This code signifies a complex anal fistula that has not resolved despite treatment or has recurred. It represents an abnormal, epithelialized tract connecting the anal canal or rectum to the perianal skin, characterized by multiple tracts, involvement of significant portions of the external anal sphincter, or association with other conditions like Crohn's disease.

Assign this code when documentation clearly indicates a diagnosis of a complex anal fistula that is persistent or recurrent. This typically applies to patients who have undergone previous interventions without complete resolution, or whose fistula exhibits features making it inherently difficult to treat. Supporting documentation should detail the complexity (e.g., high, transsphincteric, multiple openings) and the persistent nature.

• Ensure the physician's documentation explicitly states "complex" and "persistent" or provides details that unequivocally support these descriptors.
• Distinguish from simple anal fistulas (K60.31x) which are typically low and superficial.
• Consider sequencing this code with an underlying condition, such as Crohn's disease (K50.-), if it is the etiology of the fistula.