Complications of sphincter of Oddi manometry: Biliary-like pain versus acute pancreatitis

Objective. Although acute pancreatitis is the most significant complication of sphincter of Oddi manometry (SOM), acute biliary-like abdominal pain - similar or identical to the patient's usual recurrent acute episodes of pain and not fulfilling clinical criteria for acute pancreatitis - can also be provoked by SOM. The aim of the article is to determine and compare the relative frequency of occurrence of, and risk factors for, post-manometry biliary-like abdominal pain and post-manometry pancreatitis. Material and methods. The clinical and laboratory features, the manometric recordings from the sphincter of Oddi, and the immediate post-manometry outcomes, were examined in 234 consecutive patients undergoing sphincter of Oddi manometry at our Unit. Results. Post-manometry pancreatitis occurred in 9% of patients, and was associated with two risk factors on multivariate analysis: a history of post-ERCP pancreatitis (odds ratio [OR] 5.9) and a raised basal sphincter pressure (≥40 mmHg) at SOM (OR 3.5). An increased sphincter phasic wave frequency (≥7/ min) at SOM was identified as a significant (p <0.05) risk factor on univariate testing only. Post-manometry biliary-like pain occurred in 12% of patients, and was associated with 3 different risk factors on multivariate analysis: age below 50 years (OR 4.6); less than a 2-year history of recurrent abdominal pain (OR 3.0); and ERCP and/or ES carried out during the SOM procedure (OR 9.3). Conclusions. Provocation of biliary-like pain following SOM, without clinical evidence of pancreatitis, occurs at least as frequently as post-manometry acute pancreatitis. In contrast to post-manometry pancreatitis, post-manometry biliary-like pain occurs more often in younger patients with a shorter duration of symptoms and does not appear related to the manometric features of the sphincter documented at SOM; we propose that this clinical entity may reflect the presence of bile duct or duodenal hypersensitivity/ hyperalgesia.