A 35-year-old man with ulcerative colitis underwent an ileal pouch–anal anastomosis. Eight weeks after surgery, contrast enema and pouchoscopy demonstrate a normal pouch and a patent anastomosis. No leakage from the pouch was noted on radiography. He underwent an uneventful ileostomy takedown. He initially did well but 6 weeks postoperatively he presents with pelvic pain, fevers, and increased pouch output. Computed tomography of the abdomen and pelvis reveals a pelvic abscess high in the pelvis with a normal pouch–anal anastomosis. An image-guided percutaneous drain is placed and the patient is treated with antibiotics. A sinogram 6 weeks later demonstrates a persistent fistula to the pouch. What is the appropriate management for this patient?