Vagotomy — the surgical cutting of the vagus nerve — was once one of the most commonly performed abdominal operations in the world. For decades it was the primary treatment for peptic ulcer disease, and millions of patients underwent the procedure before proton pump inhibitors made it largely obsolete. The history of vagotomy teaches us more about vagus nerve function than almost any other medical intervention, because surgeons systematically documented what happens when different portions of the nerve are severed.
Why Surgeons Cut the Vagus Nerve
Before the discovery of Helicobacter pylori and the development of acid-suppressing drugs, peptic ulcers were a major cause of morbidity and death. The vagus nerve drives gastric acid secretion through two mechanisms: the cephalic phase (brain-to-stomach signalling triggered by the sight, smell, or thought of food) and direct stimulation of parietal cells and gastrin-releasing G cells in the stomach. Cutting the vagus nerve eliminates the neural component of acid secretion, reducing acid output by approximately 50%.
The first successful vagotomy for ulcer disease was performed by Lester Dragstedt at the University of Chicago in 1943. By the 1960s and 1970s, vagotomy combined with a drainage procedure (pyloroplasty or gastrojejunostomy) had become the standard surgical treatment for duodenal ulcers worldwide.
Types of Vagotomy
Truncal Vagotomy
Truncal vagotomy involves cutting both vagal trunks (anterior and posterior) at the level of the oesophageal hiatus, where the vagus nerve enters the abdomen. This is the most complete form of vagotomy, eliminating vagal input to the stomach, liver, pancreas, small intestine, and proximal colon.
While effective at reducing acid secretion, truncal vagotomy also eliminates vagal control of gastric motility. Because the vagus nerve coordinates the relaxation of the pylorus (the valve between the stomach and duodenum), truncal vagotomy causes gastric stasis — the stomach cannot empty normally. This is why truncal vagotomy was almost always combined with a drainage procedure to allow the stomach to empty mechanically.
Selective Vagotomy
Selective vagotomy preserves the hepatic and coeliac branches of the vagus nerve while cutting only the gastric branches. This eliminates vagal acid stimulation while maintaining vagal innervation to the liver, pancreas, and intestines. Selective vagotomy still disrupts gastric motility and typically requires a drainage procedure.
Highly Selective Vagotomy (Proximal Gastric Vagotomy)
Highly selective vagotomy (HSV), also called proximal gastric vagotomy or parietal cell vagotomy, preserves the nerves of Latarjet — the vagal branches that control the antral pump and pyloric relaxation — while cutting only the branches to the acid-producing body and fundus of the stomach. This reduces acid secretion without impairing gastric emptying, eliminating the need for a drainage procedure.
HSV was the most physiologically elegant form of vagotomy and produced the fewest side effects. However, it had a higher ulcer recurrence rate (10-15% over 10 years versus 2-5% for truncal vagotomy) because it did not completely eliminate vagal acid drive.
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Post-Vagotomy Syndrome
The consequences of vagotomy provided the clearest demonstration of what the vagus nerve does in the gastrointestinal tract.
Dumping Syndrome
Early dumping syndrome occurs within 30 minutes of eating, when hyperosmolar stomach contents rush into the small intestine due to impaired pyloric control. This draws fluid into the intestinal lumen, causing abdominal cramping, diarrhoea, bloating, nausea, and vasomotor symptoms (flushing, dizziness, tachycardia). Late dumping occurs 1-3 hours after eating, when rapid carbohydrate absorption triggers an excessive insulin response, producing reactive hypoglycaemia. Dumping syndrome affected 20-40% of patients after truncal vagotomy with drainage.
Post-Vagotomy Diarrhoea
Approximately 5-10% of truncal vagotomy patients developed chronic diarrhoea, sometimes severe and debilitating. The mechanism involves loss of vagal regulation of intestinal transit time, bile acid malabsorption due to denervation of the gallbladder and biliary system, and altered gut microbiome composition. In about 1% of patients, the diarrhoea was severe enough to be disabling.
Altered Appetite and Weight Changes
Vagotomy disrupts the normal hunger-satiety cycle mediated by vagal afferent signalling. Patients commonly reported reduced appetite, early satiety, and unintended weight loss in the months following surgery. The vagus nerve carries ghrelin, CCK, and GLP-1 signals from the gut to the brain, and severing this pathway fundamentally changes the neural regulation of eating behaviour.
Gallstone Formation
Truncal vagotomy increases the risk of gallstone formation because the vagus nerve regulates gallbladder contraction. Denervation of the gallbladder leads to impaired bile emptying and biliary stasis, creating conditions favourable for stone formation.
The Vagotomy-Parkinson’s Connection
One of the most unexpected findings from vagotomy research came from epidemiological studies examining long-term outcomes. In 2015, Svensson and colleagues published a study in Annals of Neurology using Danish national registry data covering over 15,000 vagotomised patients followed for more than 20 years. They found that patients who had undergone truncal vagotomy had a significantly lower risk of developing Parkinson’s disease compared to the general population and compared to patients who had undergone selective vagotomy.
This finding supported the Braak hypothesis — the proposal that Parkinson’s disease may begin in the gut, where misfolded alpha-synuclein protein originates in enteric neurons and spreads retrogradely up the vagus nerve to the brainstem and then to the substantia nigra. If truncal vagotomy severs this pathway, it could block the progression of alpha-synuclein from the gut to the brain.
A 2017 study by Liu and colleagues in Neurology, using Swedish national registry data, confirmed the association: full truncal vagotomy was associated with reduced Parkinson’s risk, while selective vagotomy (which preserves some vagal pathways) was not. The protective effect became apparent only after 5 or more years of follow-up, consistent with the hypothesis that alpha-synuclein spread is a slow process.
This research does not suggest vagotomy as a Parkinson’s prevention strategy — the side effects of the procedure far outweigh any potential benefit. But it provides compelling epidemiological support for the gut-origin theory of Parkinson’s disease and identifies the vagus nerve as a critical conduit in neurodegenerative disease.
Modern Context: Why Vagotomy Is Rare Today
The discovery of H. pylori by Barry Marshall and Robin Warren in the 1980s, combined with the development of proton pump inhibitors (omeprazole, lansoprazole, and others), eliminated the need for surgical acid reduction in most ulcer patients. Vagotomy rates declined dramatically from the 1990s onward, and the procedure is now performed only in rare situations: failed medical therapy, complications of ulcer disease (perforation or haemorrhage not controlled endoscopically), and occasionally as part of surgery for morbid obesity (laparoscopic truncal vagotomy has been studied as a weight-loss adjunct, though it is not a standard bariatric procedure).
The legacy of vagotomy, however, remains essential to vagus nerve science. The millions of patients who underwent the procedure and the decades of follow-up data they generated produced the most detailed understanding of vagal gastrointestinal function available — knowledge that now informs modern research on gut-brain signalling, appetite regulation, and neurodegenerative disease.
The vagus nerve connects the gut and the brain in ways that surgical history has made remarkably clear. My Vagus Nerve & Me tells the full story. Get My Vagus Nerve & Me eBook.
