A 64-year-old supermarket manager had an elective operation for duodenal ulcer disease. He has not returned to work because he has diarrhea with more than 20 bowel movements per day. Medication has been ineffective. The exact details of his operation cannot be ascertained. What operation was most likely performed?

Although a milder type of diarrhea is not uncommon after gastrectomy, fulminant diarrhea may be a problem after vagotomy (it is one of the many complications collectively referred to as post vagotomy syndromes). The exact mechanism is not known. It occurs in 1-2% of patients following truncal vagotomy and is less likely to be found after selective or highly selective vagotomy.