Frequently Asked Questions
What are the signs and symptoms of SOD?
SOD is a disorder that involves the circular muscle surrounding the drainage hole (duct) through which bile and pancreatic juices flow from the liver and pancreas into the duodenum (small intestine). Some patients who have had their gall bladder removed (cholecystectomy) develop increased pressure in the sphincter muscle. This causes back up of bile and/or pancreatic juices which may result in attacks of abdominal pain. Many patients suspected to have SOD are referred to specialty centers for examination by a gastroenterologist (GI) physician who specializes in this area.
What tests and treatments are available for SOD?
In patients with “post-cholecystectomy pain” the first task is to make sure that there are no obvious causes, such as bile duct stones or pancreatitis. Thus it is usual to run blood tests for the liver and pancreas, and to scan the abdomen. Ultrasound scans give some information, but dedicated CT scanning is better. Even more information can be obtained from MRCP (a special type of MR scan that shows the biliary and pancreatic ducts), and from EUS (endoscopic ultrasound scanning). If these are negative, SOD becomes a possibility. It can only be proven by doing an ERCP, with sphincter manometry (described in more detail below). This carries risks, and is done only in special centers. Medical treatment to relieve spasm may help, so should be tried before considering ERCP.
What is an ERCP, manometry and sphincterotomy?
ERCP (Endoscopic retrograde cholangio-pancreatography) is a standard
(non-research) procedure commonly used to diagnose problems in the
liver, gallbladder, bile ducts, and pancreas, including SOD. ERCP
combines the use of x rays and an endoscope, which is a long, flexible,
lighted tube. Through the endoscope, physicians can see the lining of
the stomach and duodenum, and find the sphincter opening. The doctor can
inject dyes into the biliary and pancreas ducts so they can be seen on x
rays. During ERCP, the doctor can also measure the pressure (squeeze) of
the sphincter muscle. This is called sphincter of Oddi manometry (SOM).
Patients with abnormal SOM pressure results are usually treated at the
same time by cutting the sphincter muscle (sphincterotomy), so that it
cannot go into spasm, in the hope of preventing further attacks of pain.
As part of the procedure, a small plastic drainage tube (stent) is
usually placed (temporarily) to improve drainage and to reduce the risk
of complications.
What is the purpose of the study?
The main reason for doing this study is to understand better how to recognize and treat SOD. At present, experts rely on the ERCP test with manometry, but there are two problems. Firstly, it does carry a significant risk of causing pancreatitis, and, secondly, the results of the manometry testing are not completely accurate in deciding which patients will respond to the sphincterotomy treatment. In addition, there are actually 2 sphincters (biliary and pancreatic), and the study will show which should be treated (or both).
Why the need for randomized treatment, and “blinding”
Choosing from different treatments by random draw is the most scientific way to test which is the most effective. And to be sure that the assessment of results is completely accurate and unbiased, it is important that neither the patient nor the assessor knows which method has been used.
What if the patients doesn’t feel better during the study?
At any time they can ask to be reassessed at the treating center, and undergo standard treatments