A 56-year-old patient with a BMI of 41 is transferred to your hospital after undergoing emergent sigmoid colectomy with colostomy for perforated diverticulitis. On postoperative day 3 she is found to have sloughed the distal portion of the ostomy due to necrosis and retraction of the stoma (see figure below). Bedside evaluation demonstrates ischemia that extends proximal to the fascia. The patient is currently hemodynamically stable. Computed tomography angiogram of the abdomen and pelvis demonstrates patency of the celiac and superior mesenteric arteries and no visualization of the the inferior mesenteric artery. What is the best next step in management?