patient direct injections of vitamin B12. Iron-deficiency anemia can occur as the stomach normally converts iron into its absorbable form. Another side effect is the loss of ghrelin production, which has been shown to be compensated after a while. Lastly, this procedure is post-operatively associated with decreased bone density and higher incidence of bone fractures. This may be due to the importance of gastric acid in calcium absorption. Post-operatively, up to 70% of patients undergoing total gastrectomy develop complications such as dumping syndrome and reflux esophagitis. A meta-analysis of 25 studies found that construction of a "pouch", which serves as a "stomach substitute", reduced the incidence of dumping syndrome and reflux esophagitis by 73% and 63% respectively, and led to improvements in quality-of-life, nutritional outcomes, and body mass index. After Bilroth II surgery, a small amount of residual gastric tissue may remain in the duodenum. The alkaline environment causes the retained gastric tissue to produce acid, which may result in ulcers in a rare complication known as retained antrum syndrome. All patients lose weight after gastrectomy, although the extent of weight loss is dependent on the extent of surgery (total gastrectomy vs partial gastrectomy) and the pre-operative BMI. Maximum weight loss occurs by 12 months and many patients regain weight afterwards. History The first successful gastrectomy was performed by Theodor Billroth in 1881 for cancer of the stomach. Historically, gastrectomies were used to treat peptic ulcers. These are now usually treated with antibiotics, as it was recognized that they are usually due to Helicobacter pylori infection or chemical imbalances in the gastric juices. In the past a gastrectomy for peptic ulcer disease was often accompanied by a vagotomy, to reduce acid production. This problem is now managed with proton pump inhibitors. See also Finsterer-Hofmeister operation List of surgeries by type Roux-en-Y Sleeve gastrectomy References Digestive system surgery