CASE 13986 Published on 09.02.2017

Intermesenteric internal hernia after Roux-en-Y gastric bypass


Abdominal imaging

Case Type

Clinical Cases


Teiga, Eduardo; Radosevic, Aleksandar; Busto, Marcos; Bazán, Fernando

Hospital Universitario del Mar;
Passeig Maritim
08005 Barcelona, Spain;

55 years, male

Area of Interest Abdomen ; Imaging Technique CT
Clinical History
A 55-year-old patient who underwent a Roux-en-Y gastric bypass about 9 years before presented with acute abdominal pain and vomiting. Physical examination displayed upper abdominal guarding. X-ray showed an abnormal bowel gas pattern with hydro-air levels. Leukocyte count was of 12260/ul.
Imaging Findings
Abdominal X-ray showed hydro-air levels (Fig. 1). CT examination showed mesenterial root haziness and congestion with clustered small bowel loops noted tightly, contiguous to the distorted mesenterial fat in the left hypochondrium region (Fig. 2b). A swirling appearance of the mesentery (Whirl sign) was also noted (Fig 2c). Moreover, the “mushrooms sign” was visible, represented by the mesenteric root and involving small bowel loops displaced and stretched above and posterior to the distal jejunal anastomosis of the gastric bypass (Fig. 3e). Promptly, the patient underwent surgery and an internal intermesenteric hernia was confirmed. The patient was discharged a few days after surgery in good condition.
The use of bariatric surgery has grown steadily in response to the rising prevalence of obesity. Laparoscopic Roux-en-Y gastric bypass has become the most common bariatric procedure. In this operation, the stomach is stapled or divided to form a small pouch which empties into a Roux-en-Y limb of jejunum of varying length. The Roux limb may be brought up to the gastric pouch anterior (antecolic) or posterior (retrocolic) to the transverse colon. Any visible defects that might allow potential bowel herniation are routinely closed at surgery. [1] Owing to several technical differences in LRYGB (laparoscopic Roux-en-Y gastric bypass) surgery it is difficult to give detailed information about true incidence of IH (Internal Hernia). Differences in surgical techniques influence the incidence distribution of hernia location. Therefore, it cannot be defined if Petersen's or intermesenteric hernia is more common. IH after LRYGB typically occurs after significant weight loss. Loss of mesenteric fat leads to a widening of intermesenteric spaces. Rapid excess weight loss seems to increase the risk for hernia occurrence. [2]

The symptoms of internal hernia are nonspecific, making the diagnosis challenging. It requires a high index of suspicion. Most patients report a combination of postprandial abdominal pain, nausea, and emesis. There is no doubt that in persisting symptoms, also in cases with non-diagnostic imaging, an early diagnostic laparoscopy is mandatory [3]. If no bowel necrosis is present, hernia reduction should be attempted by laparoscopy [4]. It is of utmost importance that a surgeon with experience in bariatric surgery is involved.

Recent literature advocates the mesenteric swirl sign and SBO as the most sensitive and accurate signs of internal hernia after laparoscopic Roux-en-Y gastric bypass. Even minor degrees of swirl should be considered suspicious for internal hernia in this population. SMV beaking and SBO were shown to have the highest specificity [5]. CT findings are helpful in the overall management of complications after laparoscopic Roux-en-Y gastric bypass, but careful clinical correlation is paramount to avoid missed diagnoses that may be detrimental to the patient [1].

We would like to raise awareness to the following facts: internal hernia after laparoscopic Roux-en-Y gastric bypass surgery can arise in up to 10% and is a potential fatal complication; CT scan of internal hernia can be normal; and last but not least there's an increasing evidence that primary closure of mesenteric defects reduces the risk for internal hernia after LRYGB.
Differential Diagnosis List
Intermesenteric space hernia after Roux-en-Y gastric bypass
Petersen's internal hernia
Closed small bowel loop obstruction
Final Diagnosis
Intermesenteric space hernia after Roux-en-Y gastric bypass
Case information
DOI: 10.1594/EURORAD/CASE.13986
ISSN: 1563-4086