Frequency of sphincter of Oddi dysfunction in patients with previously normal sphincter of Oddi manometry studies

Background and study aims: Sphincter of Oddi manometry (SOM), performed at endoscopic retrograde cholangiopancreatography (ERCP), is the gold standard for diagnosing sphincter of Oddi dysfunction (SOD). The question remains as to whether the short-term manometric recordings reflect the 24-hour pathophysiology of the sphincter. The aim of this study was to determine the frequency of SOD in persistently symptomatic patients with previously normal SOM studies. Patients and methods: All patients who underwent ERCP for suspected SOD over a 13-year period (19942007) were considered for inclusion in the study. Patients with an intact papilla and a previously normal SOM who had a repeat ERCP for persistent symptoms formed the study group. SOM was performed in conventional retrograde fashion. Results: In all, 5352 patients without prior papillary intervention underwent SOM during the study period. A total of 1037 patients had normal SOM, and of these, 30 patients (27 female, mean age 40.1 years) underwent repeat ERCP for persistent symptoms. The median duration between the two ERCPs was 493.5 days (range 523538 days). In these 30 patients, SOD classification prior to the initial ERCP was: type I in one patient (not treated in 1994), type II in 17 patients, and type III in 12 patients. Of the 30 patients, 12 (40%) had normal SOM at repeat ERCP; SOD was diagnosed in 18/30 (60%) patients. Conclusions: A single SOM study may not represent the day-to-day physiology of the sphincter of Oddi; sphincter pathology may progress over time. One normal exam may not rule out SOD. A repeat ERCP with manometry may be warranted in a subset of patients with persistent debilitating symptoms and a high index of suspicion for SOD. Outcome data are needed to determine whether this approach justifies the potential risks of ERCP.