EP115 - Transanal intersphincterotomy (TROPIS) for complex perianal abscess

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Purpose/Background: Complex perianal abscess is an extensive abscess, usually involved both the intersphincteric space and ischiorectal fossa, or spread as transphincteric and horseshoes’ patern. Surgical drainage is the cornerstone of initial treatment. The principal of surgery is an adequate incision to facilitate efficient drainage while meticulously preserving the anal sphincter complex. However, 50%-80% of abscess develops into fistula subsequently after drainage, even higher for complex one. As a result, patient has to undergo at less another surgerical intervention and sufer from prolonged healing times and wound dressing, even an elevated risk of anal incontinence. The ongoing pursuit of a surgical technique that minimizes both pain and the incidence of fistula associated with perianal abscesses has long been a primary aspiration of anorectal practitioners. Transanal intersphincterotomy (TROPIS) is reported effecacy in treating complex anal fistula with minimal injury of anal sphincter. The application on abscess is not well studied. In this paper, we introduce a transanal intersphincterotomy (TROPIS) as an innovative approach for the management of complex perianal abscess.

Methods/Interventions: In the assessment of patients with perianal abscess, the following procedures were implemented: clinical examination, routine laboratory tests, digital rectal examination, colonoscopy when deemed necessary, magnetic resonance imaging (MRI), and anal rectal manometry. Prior to surgery, patients underwent an enema procedure and was administered intravenous antibiotics. The surgical procedure was performed under lumbar epidural anesthesia with the patient in the prone-knife position. The internal opening was identified by MRI, or by pressing the abscess from anal verge, or by injecting a low dose of methylene blue from the small incision of abscess. The surgical procedure involved 1. incision outside the external sphincter complex for draining the lateral pus, followed by the removal of corrupt and necrotic tissue within the purulent cavity; 2. incision in the internal opening and internal sphincter confirmed previously; 3. repairment by 8 stitches surture of transphincteric defect when the defect is large. In case of horseshoes abscess, drainage was achieved via incision confined in the posterior intersphincteric space and reached to the dentate line, even through extension were found cranially.

Results/Outcomes: This study encompassed a total of 11 patients, all of whom underwent a transanal intersphincterotomy (TROPIS) procedure. 9 patients were all healed within 2 months. 1 pateint were confirmed Crohn’s diease with unhealed wound. 1 pateint were experienced delayed healing. Over a period of 6 months, with a median follow-up duration of 7.3 months, 10 patients, representing 90.9% of the cohort, achieved complete healing. 2 were repaired intraoperatively without suture detachment. Notably, the postoperative anal incontinence scores were found to be within the normal range.

Conclusion/Discussion: This methodology effectively treated complex perianal abscess with a promising cure rate, accompanied by maintenance of satisfactory anal function. We recommend the conduct of larger, prospective studies with longer-term follow-up to solidify and reinforce these observations.