Vagal Nerve Transection During Pouch Formation in Laparoscopic Roux-Y-Gastric Bypass for Technical Simplification

Laparoscopic Roux-Y gastric bypass procedure (RYGBP) is one of the most effective and reliable bariatric procedures that is available to treat morbidly obese patients with excellent long-term results. Bariatric surgery and especially the RYGBP have been shown to significantly reduce comorbidities such as diabetes, sleep apnea, degenerative arthritis, hyperlipidemia, metabolic syndrome, and cardiovascular diseases (1–3). Since the amount of morbidly obese patients is still increasing all over the world, various weight loss procedures are performed in rising numbers. Interestingly, the precise mechanism for weight loss after gastric bypass has not been fully understood. It is clear that RYGPB has both, restrictive and some sort of malabsorptive components due to the creation of a small gastric pouch with a narrow outlet and the bypassing of the stomach, duodenum, and variable length of the jejunum. Technical operative details and changed postoperative hormonal influence may contribute to the effect of pure restriction after RYGBP and reduce postoperative hunger. The interrelationship between the integrity of the vagal nerve and changing levels of ghrelin, a hormone that is mainly produced in the fundus of the stomach and with increased levels before meals, also remains unclear. In a rat study (4) it has been proposed that preservation of the vagal nerve during gastric bypass might play an important role for the mechanism that induces weight loss and food intake. However, the precise role can only be presumed. Other animal studies suggest that vagotomy results in low ghrelin levels even during the fasting state without the ability to rise to higher levels (5, 6). In humans, vagotomy may result in postoperative bowel problems such as diarrhea, bloating, and dumping as we have learned from antireflux surgery (7, 8). This may be due to the fact that vagal activity is thought to be responsible for the release of ghrelin from mucosal cells of the gastric fundus (9, 10). After gastric and esophageal surgery, hunger may therefore be decreased due to a lack of vagal nerve stimulation. It is interesting that in humans, atropine blockage of the vagal nerve reduces ghrelin plasma levels, while exogenous compensatory ghrelin is unable to induce hunger in patients after vagotomy. This may be due to the interrupted afferent vagal signaling.

Abstract

Laparoscopic Roux-Y gastric bypass is one of the most often performed procedures to treat morbid obesity. During the procedure, the vagal nerve is tempted to be preserved by most surgeons due to the fear of postoperative side effects such as dumping, diarrhea, and abdominal pain. To keep postoperative morbidity and mortality low it is mandatory to simplify the operative procedure and to avoid leakage at the anastomosis. Division of the minor omentum including the anterior branch of the vagal nerve allows a better view to create the small gastric pouch in primary bypass procedures. In revisional surgery, an anastomosis close to the esophagus including total vagotomy may be necessary to allow an uncomplicated postoperative course. So far the available data does not report significant differences after gastric bypass with and without vagotomy, respectively.

Keywords

vagal nerve, bariatric surgery, gastric bypass, technique