Anal Fistula—Principles of Initial Management: Sepsis Control, Drainage, and Timing of Definitive Surgery

Abstract

Cryptoglandular anorectal abscess and fistula-in-ano represent a disease continuum and one of the most common benign anorectal disorders. Accurate estimation of incidence and prevalence remains difficult due to variable presentation and reporting. Prompt incision and drainage remain the cornerstone of abscess treatment. Aspiration alone is not recommended. External drainage is preferred for perianal and ischiorectal abscesses, while transrectal drainage is used for supralevator and submucosal collections to minimize iatrogenic fistula formation. Intersphincteric abscesses should be drained either transrectally or via an incision over the intersphincteric groove. Routine wound packing is not supported by randomized evidence, as it increases pain without reducing recurrence. Selective use of mushroom catheters or Penrose drains improves patient comfort and facilitates drainage of large cavities. Routine postoperative antibiotics do not prevent recurrent abscesses, but they may reduce subsequent fistula formation. Primary fistulotomy during abscess drainage is safe for low fistulas in selected patients with accurate anatomic assessment and good baseline continence, significantly lowering recurrence rates compared with drainage alone. High fistulas should not undergo fistulotomy. Draining setons are valuable for high or complex fistulas to control sepsis, prevent recurrent abscesses, and allow inflammation to subside before definitive repair. Cutting setons have largely fallen out of favor due to elevated incontinence risk. Definitive sphincter-preserving fistula repair should be delayed until acute inflammation resolves.