Sphincter of Oddi dysfunction refers to abnormal function of the sphincter muscle at the end of the bile and pancreatic ducts, the tubes that drain the liver and pancreas into the small intestine through a small nipple-like opening called the papilla.
The sphincter is a circular band of muscle tissue that controls the release of bile and pancreatic juices though an opening in the papilla into the intestine. Abnormal function of the sphincter prevents normal flow of bile or pancreatic juices into the intestine.
Sphincter of Oddi dysfunction may cause episodic upper abdominal pain and even pancreatitis (see separate discussion under pancreatic disorders).
The diagnosis is considered in patients with typical pain and abnormally elevated liver enzymes in the absence of gallstones or other causes of bile duct obstruction. The diagnosis should also be considered in patients with repeated and unexplained episodes of pancreatitis.
The diagnosis can be confirmed by Endoscopic Retrograde Cholangiopancreatography (ERCP). After the patient is deeply sedated, the physician passes a flexible tube (endoscope) through the mouth, esophagus and stomach and into the beginning of the small intestine called the duodenum. At this location the bile duct drains into the intestine through a small nipple-like opening called the papilla. A plastic tube called a catheter is then passed through the scope, into the papilla and up into the bile duct. The pressure within the sphincter can be assessed. An elevated sphincter pressure is suggestive of sphincter dysfunction.
Treatment consists of cutting the sphincter muscle (sphincterotomy) during ERCP using a thin wire attached to a catheter. ERCP and sphincterotomy are associated with a significant risk of a complication called pancreatitis when performed on patients with Sphincter of Oddi dysfunction or in patients suspected to have the condition.