Horseshoe Abscess as a Rare Complication After Transanal Hemorrhoid Dearterialization With Mucopexy: A Case Report.

Transanal hemorrhoidal dearterialization (THD) is a minimally invasive procedure that has gained popularity as a treatment for symptomatic hemorrhoids. It involves ligating the arterial blood supply to the hemorrhoidal plexus. Compared to conventional ligation or resection, THD is associated with less postoperative bleeding and pain, allowing for same-day surgery discharge. Horseshoe abscess is a rare but known complication of anorectal surgery, characterized by an abscess that extends around the anal canal, often involving the ischiorectal fossa and adjacent structures. Although horseshoe abscesses have been reported after various anorectal surgeries, including hemorrhoidectomy, their occurrence following THD has not been well-documented in the literature. A 72-year-old male underwent THD for rectal prolapse with internal hemorrhoids and presented to the hospital on postoperative day 6 with severe rectal pain. A computed tomography (CT) scan revealed a large complex horseshoe perirectal abscess with fluid and air and significant rectal wall thickening. A rectal examination under anesthesia confirmed the presence of purulent drainage from the anus, and surgical drainage of the abscess was performed. The patient received antibiotics and analgesics and experienced a favorable recovery. The exact pathophysiology of a horseshoe abscess following THD remains unclear, and the incidence and risk factors associated with this complication are not well-established. Moreover, there has yet to be a consensus on the optimal management of horseshoe abscesses after THD, whether through surgical or medical approaches. This case emphasizes the importance of considering horseshoe abscess as a potential complication of THD and highlights the need for further research to understand better its incidence, risk factors, and optimal management strategies.