Anal Fistula: From Diagnosis and Classification to Surgical Management

Abstract

In this chapter, we discuss the classification and diagnosis of anal fistulas and the surgical approaches for fistula repair. According to the Parks classification, there are four main fistula types based on the location of the fistula tract in relation to the external sphincter: intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric. One of the conventional repair techniques for low transsphincteric fistulas involves cutting open the tract by lay open fistulotomy. Control of a complex fistula tract with a draining seton is used as the first of a two-stage repair or as definitive therapy in patients with contraindications to repair such as concomitant fecal incontinence or active Crohn’s disease. Sphincter-preserving techniques for high transsphincteric fistulas include ligation of the intersphincteric fistula tract (LIFT) and endorectal or anodermal advancement flap with largely equivalent expected results. Biologic adjuncts such as platelet-rich plasma (PRP), acellular matrix (AM) material, and mesenchymal stem cells (MSC) represent a promising area for possibly augmenting healing of complex fistulas. Additional novel treatment techniques being developed for complex fistulas including Video-Assisted Anal Fistula Treatment (VAAFT), Fistula Tract Laser Closure (FiLaC), and Over the Scope Clip (OTSC) are also described.