From the Guidelines
A sphincter of Oddi (SO) spasm is a condition where the sphincter of Oddi, a muscular valve that regulates the flow of bile and pancreatic juices into the duodenum, contracts abnormally, causing increased pressure in the common bile duct and potentially leading to biliary pain.
Key Characteristics of SO Spasm
- The sphincter of Oddi plays a crucial role in maintaining the pressure in the common bile duct higher than that in the duodenum or the gallbladder, as noted in the study by 1.
- The coordinated contraction of the gallbladder and simultaneous relaxation of the sphincter of Oddi allow for the controlled delivery of bile into the duodenum, as described in 1.
- Abnormal patterns of gallbladder contractions, including hypokinesia and dyskinesia, can lead to functional biliary pain, which may be related to SO spasm, as suggested in 1 and 1.
Diagnosis and Management
- Biliary manometry, which measures the pressure in the sphincter of Oddi, can be used to diagnose SO dysfunction, but it carries a significant risk of precipitating acute pancreatitis and should be performed only in specialist units, as warned in 1 and 1.
- Cholecystokinin-cholescintigraphy (CCK-CS) is a diagnostic test that can be used to evaluate gallbladder function and may be helpful in identifying patients with functional biliary pain, as discussed in 1 and 1.
- The use of a standardized CCK-CS protocol, as recommended in 1, can help improve the diagnosis and management of patients with suspected functional biliary pain and SO spasm.
From the Research
Definition of Sphincter of Oddi (SO) Spasm
- The sphincter of Oddi (SO) is a smooth muscle valve that regulates the flow of biliary and pancreatic secretions into the duodenum 2.
- SO dysfunction (SOD) is a broad term referring to numerous biliary, pancreatic, and hepatic disorders resulting from spasms, strictures, and relaxation of this valve at inappropriate times 2.
- 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 3.
Characteristics of SO Spasm
- SO spasm is characterized by an abnormal contraction of the sphincter of Oddi, which can cause pain and other symptoms 4.
- The spasm can be caused by various factors, including cholecystectomy, opiates, and alcohol 2.
- SO dysfunction can be subdivided into two groups: a stenotic pattern (raised sphincter basal pressure) and a dyskinetic pattern (paradoxical response to cholecystokinin injection, rapid contraction frequency, high percentage of retrograde contractions, or short periods of raised basal pressure) 4.
Diagnosis and Treatment of SO Spasm
- Diagnosis of SO dysfunction is best done by manometry, which can correctly stratify patient groups and determine therapy 5.
- Biliary scintigraphy is a noninvasive screening tool that has shown promise in diagnosing SO dysfunction 5.
- Treatment of SO dysfunction includes division of the sphincter, which is effective for patients with manometrically proven SO stenosis, and pharmacotherapy for other forms of SO dysfunction 5.
- Endoscopic sphincterotomy (EST) has been recognized as a standard treatment for SOD, but its effect is not yet clear and patient eligibility criteria for EST and long-term prognosis after EST need to be clarified 3.