A 48-year-old man with a history of ulcerative colitis (UC) underwent the closure of a diverting ileostomy following an open restorative proctocolectomy with the creation of a J-pouch. Three weeks following stoma closure, he develops enteric drainage from his midline surgical-site, and computed tomography (CT) demonstrates a fistula tract from the tip of the J pouch. This drainage persists after an additional 4 weeks of observation. What is the most appropriate next step in management for this patient?