The treatment of fistula-in-ano is difficult and there are a variety of treatment options. To approach fistula repair in a systematic manner, the anatomy must be accurately understood; Parks provides a useful anatomic classification (1). In addition, in a separate paper, he described patients who have fistulas whose treatment place them at higher risk of developing impairment of continence (2)—the term “complex” fistula is based on a modification of Parks classification (3).

Complex fistulas are defined as those that traverse >30% of the external sphincter (high transsphincteric, suprasphincteric, and extrasphincteric fistulas according to Parks (2)), are anterior in a female, have multiple tracks, are recurrent, in patients with pre-existing continence issues, irradiation, or Crohn’s (3).

Historically, approaches to these fistulas were quite varied. Lay-open fistulotomy, while successful, results in incontinence due to destruction of significant portions of the sphincter complex. Sphincter-sparing approaches such as advancement flaps and core-out fistulectomies were morbid and have varying success. Current methods to treat these fistulas include the fistula plug, fibrin glue, cutting seton, and advancement flaps with varying rates of success and impact on continence (4,5,6,7,8,9). There is no consensus on the best approach to this difficult problem (3).