Sphincter of Oddi disorder: what is the clinical issue?

Sphincter of Oddi disorder (SOD) is a functional disorder of the sphincter of Oddi (SO) and is pathophysiologically equivalent to functional gastrointestinal disorder (FGID) of the digestive tract. SOD is important as a cause of biliary pain of unknown origin and idiopathic acute recurrent pancreatitis; however, the concept of SOD has not generally spread in the same way as FGID. SOD is diagnosed using ROME III criteria which were revised in 2006 to reduce the number of unnecessary and potentially risky procedures. Many cases of SOD still need SO manometry (SOM) which is performed during endoscopic retrograde cholangiopancreatography (ERCP). It is problematic that SOD patients, who already have a high risk of post-ERCP pancreatitis, require SOM for a definitive diagnosis. SOM is an invasive examination that is accompanied by a high risk of post-procedure pancreatitis and can be performed only at a limited number of institutions because of technical difficulties. In the treatment of SOD, the effectiveness of the drugs is uncertain, and the role of drug therapy in the management of SOD has not yet been established. In recent years, endoscopic sphincterotomy (EST) has been recognized as standard treatment for SOD; however, the effect of EST is not yet clear. The development of less invasive diagnostic techniques is desirable in the future. Furthermore, patient eligibility criteria for EST and the long-term prognosis after EST should be clarified.