Internal hernia following Roux-en-Y gastric bypass surgery for morbid obesity: evaluation of radiographic findings at small-bowel examination.

PURPOSE To characterize features of internal hernia (IH) at small-bowel follow-through (SBFT) following Roux-en-Y gastric bypass procedure (RYGBP) for morbid obesity. MATERIALS AND METHODS The institutional review board approved this HIPAA-compliant retrospective study; informed consent was waived. Radiologic database review revealed 1655 SBFT studies over 6 years in 1282 patients after RYGBP. IH was suggested on 24 studies in 23 patients. Studies were analyzed for atypical bowel configuration, change in bowel or suture position, and obstruction. Chart review was performed to determine clinical course, treatment, and outcome. Studies from a control group of 21 RYGBP patients were similarly analyzed. Statistical comparison was performed with the Fisher exact test. RESULTS Clinical and/or surgical evidence of IH was found following 21 SBFT studies in 20 of 1282 patients (1.6%). Atypical bowel configuration with clustered small bowel was identified on all studies. Cluster location was lateral to descending colon (n = 10), left upper quadrant (n = 6), left upper and mid abdomen (n = 3), right midabdomen (n = 2), under the gastric pouch (n = 1), and right lower quadrant (n = 1). For two studies, two locations of clustered bowel were identified. Change in jejunojejunal suture position occurred in all cases with radiopaque suture (n = 15). Other signs of IH included displaced colon (n = 19), visible entrance and exit limbs into the hernia (n = 17), stasis in clustered bowel (n = 16), densely matted bowel (n = 12), and a straight left lateral border of clustered bowel (n = 10). Partial obstruction occurred in 16 patients. Findings of atypical bowel configuration, clustered bowel, and staple line change were significant when compared with the control. CONCLUSION IH following RYGBP is a rare but potentially fatal complication. Radiologists must be aware of this complication and its diagnostic features at SBFT.