Diagnosis of transmesocolic internal hernia as a complication of retrocolic gastric bypass: CT imaging criteria.

OBJECTIVE: The purpose of this study was to define the CT findings of surgically proven transmesocolic internal hernia after laparoscopic gastric bypass. CONCLUSION: Use of four CT signs should give radiologists a high degree of accuracy and confidence in recognizing internal hernia in patients who have undergone gastric bypass surgery.

Internal hernias after laparoscopic Roux-en-Y gastric bypass.

BACKGROUND: Laparoscopic gastric bypass (Lap-RYGB) is an increasingly common procedure performed for severe obesity. Internal hernias are a potential problem associated with Lap-RYGB, and little is known about the clinical presentation and the diagnostic accuracy of this potentially serious complication. METHODS: A retrospective review of 1,000 retrocolic Lap-RYGB was performed to identify those who developed postoperative internal hernias. Clinical symptoms, radiologic characteristics, and operative outcomes were analyzed to determine clinical and radiologic diagnostic accuracy (including computed tomography [CT] scan and upper gastrointestinal imaging). Subsequent independent review was performed to match operative intervention with radiologic imaging and interpretation. Operative outcomes, including the hernia closure technique, hospital length of stay, and mortality were obtained. RESULTS: Of 1,000 Lap-RYGB procedures, 45 internal hernias were identified (4.5%) in 43 patients. Hernia location included transverse colon mesentery (n = 43, 95%) or Petersen's defect (n = 2, 5%). The most common clinical symptoms included intermittent, postprandial abdominal pain, and/or nausea vomiting (86%), although 20% had no abdominal tenderness. Initial radiologic imaging studies were diagnostic in 64%, although subsequent review of all imaging studies showed diagnostic abnormalities in 97%. CT findings suggestive of internal hernia include small bowel loops in the left upper quadrant and evidence of small bowel mesentery traversing the transverse colon mesentery. All patients with internal hernias underwent operative repair (98% performed laparoscopic). One patient had a negative laparoscopy, although the preoperative CT suggested an internal hernia was present. The mean time to intervention for an internal hernia repair was 225 days (range 2 to 490), whereas hospital length of stay was 1.2 days (range 1 to 4). No deaths were noted. CONCLUSIONS: Internal hernias after retrocolic lap-RYGB are associated with vague abdominal complaints and limited radiologic imaging results. A high index of clinical suspicion should be used in this patient population, and surgeon review of radiology imaging studies should be performed. Prompt surgical intervention is successful and can commonly be performed laparoscopically.