Background: Sphincter of Oddi manometry as performed at ERCP is the most accepted method to evaluate for sphincter of Oddi dysfunction. To fully assess for sphincter of Oddi dysfunction, both the pancreatic and the bile ducts must be evaluated. We assessed the frequency of pancreatic and biliary sphincter abnormalities in a large series of patients.
Methods: A total of 593 patients underwent manometry of the biliary and pancreatic ducts at one endoscopic retrograde cholangiopancreatography session. Basal sphincter pressure greater than or equal to 40 mm Hg was considered abnormal. Phasic waves were not evaluated. Manometric abnormalities were correlated with the clinical presentation as categorized using a modified Geenen/Hogan classification.
Results: Of 360 patients with intact sphincters, 18.9% had abnormal pancreatic sphincter basal pressure alone, 11.4% had abnormal biliary basal sphincter pressure alone, and in 31.4% the basal pressure was abnormal for both sphincters; thus, 60.1% of the patients had sphincter dysfunction. The frequency of sphincter of Oddi dysfunction did not differ whether typed by biliary or pancreatic criteria: approximately 65% type II and 59% type III. Of patients without pancreatitis, 55.9% had an abnormal basal sphincter pressure, whereas sphincter dysfunction was present in 72.3% of those with idiopathic pancreatitis and 53.9% of patients with chronic pancreatitis. Of patients with an ablated biliary sphincter, 45.9% had abnormal basal pancreatic sphincter pressure and only 0.6% had an abnormal biliary sphincter pressure alone. Abnormal pressure in both sphincters was found in 9.3%.
Conclusion: If both portions of the sphincter of Oddi are studied simultaneously, abnormalities are found very commonly (55% to 72%). Assessment of both sides of the sphincter is necessary. Classifying patients according to both pancreatic and biliary sphincter segments is cumbersome, and may be replaced by an overall type. Using this modified classification, the frequency of sphincter of Oddi dysfunction is similar in both type II and type III patients (59% to 67%).