[Internal Hernia Following Laparoscopic Roux-Y Gastric Bypass - a Challenge not only for the General Surgeon]

The frequency of bariatric operations has increased in Germany. Primary operations are usually performed at specialised centres. However, late complications may develop months or even years after the operation, and every general and visceral surgeon may be confronted with them, regardless of the size and specialisation of their clinics. The laparoscopic Roux-Y gastric bypass is the most frequently performed bariatric operation worldwide. During this procedure, the alimentary loop is lifted up in front of the colon to form a pouch, which creates a mesenteric space, also called the Petersen space, dorsal to the alimentary loop and below the transverse colon. Both here and around the mesenteric space of the Roux anastomosis, an internal hernia may develop, i.e. the small intestine can twist on its own axis. Abdominal discomfort due to intestinal obstruction is unspecific, but very pronounced. Clinically, patients either present with an acute abdomen or with intermittent unspecific abdominal pain with nausea, and rarely also with vomiting. Clinical examinations and lab chemistry tests usually do not reveal any indicative findings. In cases of doubt, therefore, contrast-enhanced computed tomography of the abdomen is the diagnostic imaging procedure of choice. A diagnostic laparoscopy should be performed in every patient with a clinical suspicion of an internal hernia, even if the CT scan is unremarkable. This should be done by a surgeon who is well-versed in laparoscopy and experienced in bariatric surgery, since classification of the intestinal loops is very difficult without knowledge of the hernial orifices. First, an inframesocolic view is obtained with the transverse colon being lifted. From here, the open Petersen space offers a direct view of the ligament of Treitz from the right side. If small intestine is found to the right of the ligament, there is a Petersen hernia. After the inframesocolic view, the gastroenterostomy should be located and the alimentary loop should be followed in distal direction towards the jejunojejunostomy, where the second possible space may be found. Once both spaces have been located and a hernia has been reduced as appropriate, the spaces should be closed with non-absorbable suture.