Gaertner WB, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula. Dis Colon Rectum. 2022 Aug 1;65(8):964-985. Full-text for Emory users.

Patients with acute anorectal abscess should be treated promptly with incision and drainage. Grade of recommendation: strong recommendation based on low-quality evidence, 1C.

“Abscesses that cross the midline (ie, horseshoe) can be challenging to manage. These abscesses most often involve the deep postanal space and extend laterally into the ischiorectal spaces. [40,71] Under these circumstances, primary lay-open fistulotomy should typically be avoided because these fistulas tend to be transsphincteric. The Hanley procedure, a technique that drains the deep postanal space and uses counter incisions to address the ischiorectal spaces, is effective in the setting of a horseshoe abscess, [71] although it may negatively impact anal sphincter function. [40,71] A modified Hanley technique using a posterior midline partial sphincterotomy to unroof the postanal space plus seton placement has a high rate of abscess resolution and has been reported to better preserve anorectal function compared to other operative interventions. [40,72,73]” (p. 969)

“After drainage, abscesses may recur in up to 44% of patients, most often within 1 year of initial treatment. [2,10,70] Inadequate drainage, the presence of loculations or a horseshoe-type abscess, and not performing a primary fistulotomy are risk factors for recurrent abscess (primary fistulotomy is further addressed in recommendation no. 4). [10,71,72]” (p. 969)