and which can be painful and unsightly. The risk of abdominal-wall hernia is markedly decreased in laparoscopic surgery. Bowel obstruction Abdominal surgery always results in some scarring of the bowel, called adhesions. A hernia, either internal or through the abdominal wall, may also result. When the bowel becomes trapped by adhesions or a hernia, it may become kinked and obstructed, sometimes many years after the original procedure. An operation is usually necessary to correct this problem. Complications of gastric bypass Anastomotic leakage An anastomosis is a surgical connection between the stomach and bowel, or between two parts of the bowel. The surgeon attempts to create a water-tight connection by connecting the two organs with either staples or sutures, either of which actually makes a hole in the bowel wall. The surgeon will rely on the body's natural healing abilities and its ability to create a seal, like a self-sealing tire, to succeed with the surgery. If that seal fails to form for any reason, fluid from within the gastrointestinal tract can leak into the sterile abdominal cavity and give rise to infection and abscess formation. Leakage of an anastomosis can occur in about 2% of Roux-en-Y gastric bypass and less than 1% in mini gastric bypass. Leaks usually occur at the stomach-intestine connection (gastro-jejunostomy). Anastomotic stricture As the anastomosis heals, it forms scar tissue, which naturally tends to shrink ("contract") over time, making the opening smaller. This is called a "stricture". Usually, the passage of food through an anastomosis will keep it stretched open, but if the inflammation and healing process outpaces the stretching process, scarring may make the opening so small that even liquids can no longer pass through it. The solution is a procedure called gastro endoscopy, and stretching of the connection by inflating a balloon inside it. Sometimes this manipulation may have to be performed more than once to achieve lasting correction. Anastomotic ulcer Ulceration of the anastomosis occurs in 1–16% of patients. Possible causes of such ulcers are: Restricted blood supply to the anastomosis (compared to the blood supply available to the original stomach) Anastomosis tension Gastric acid The bacteria Helicobacter pylori Smoking Use of non-steroidal anti-inflammatory drugs This condition can be treated with: Proton pump inhibitors, e.g. esomeprazole A cytoprotectant and acid buffering agent, e.g. sucralfate Temporary restriction of the consumption of solid foods Dumping syndrome Normally, the pyloric valve at the lower end of