Triad of Trouble: CT Findings to Help Diagnose Internal Hernia Post-Gastric Bypass

Nicole A Kissane, MD, Garry Choy, MD, Denis W Gee, MD, Matthew M Hutter, MD MPH, David W Rattner, MD, Janey S Pratt, MD. Department of Surgery, Massachusetts General Hospital

INTRODUCTION: Abdominal pain after gastric bypass is a common complaint and etiology can be difficult to identify. While some causes are non life-threatening, others such as internal hernias may be surgical emergencies even when a CT scan is initially read as normal.

METHODS and PROCEDURES: Since 2003, our institution performed 1,262 laparoscopic retrocolic gastric bypass procedures (LGBP). Five patients recently presented with abdominal pain, nausea, and vomiting after LGBP. Each had a postoperative history of significant rapid weight loss (4 of the 5 patients lost an average of 71% excess body weight at 6 months, and 102% at one year) and normal laboratory studies. CT scans were initially read as normal in 3 of 5 patients. All patients underwent diagnostic laparoscopy and were found to have massive small bowel herniation through their transverse mesocolon with complete disruption of the initial mesocolic closure. The herniated small bowel was viable and easily reduced in every patient.

RESULTS: CT scans were retrospectively reviewed and all 5 patients were found to have the same findings. The CT findings suggestive of massive transmesocolic small bowel herniation after retrocolic gastric bypass were: (1) retroperitoneal displacement of transverse colon relative to the small bowel; (2) tethering of the SMA arcade with angulation lateral and cephalad; (3) bunching of small bowel loops in the left upper quadrant adjacent to gastric pouch and remnant.

CONCLUSIONS: The above triad of CT findings, although potentially a normal postoperative finding in antecolic gastric bypass, are suggestive of massive transmesocolic small bowel herniation when identified in retrocolic gastric bypass patients. Post-gastric bypass patients with these CT findings, persistent abdominal pain of unclear etiology, and rapid postsurgical weight loss should be considered for prompt diagnostic laparoscopy.