Suspected Sphincter of Oddi Dysfunction Type II: Empirical Biliary Sphincterotomy or Manometry-Guided Therapy?

Background and Study Aims: Sphincter of Oddi manometry is considered to be the gold standard for diagnosing sphincter of Oddi dysfunction (SOD). Elevated basal sphincter pressures are found in about half of the patients with findings consistent with biliary type II SOD, and most of these patients will symptomatically improve after endoscopic sphincterotomy. Since manometric sphincter evaluation is not widely available, a decision analysis was used to compare the overall costs and outcomes of manometry-directed therapy with ”empirical” sphincterotomy in patients with suspected biliary type II SOD.
Patients and Methods: A decision analysis model was constructed using a software program. In a hypothetical cohort of 100 patients with suspected type II SOD, the following strategies were evaluated: a) endoscopic retrograde cholangiopancreatography (ERCP) with manometry followed by biliary sphincterotomy only if an elevated sphincter of Oddi basal pressure was found; and b) ”empirical” biliary sphincterotomy without manometry. Data on the probability of an elevated sphincter of Oddi basal pressure at the time of ERCP in patients with suspected biliary SOD type II, the proportion of patients who improved after biliary sphincterotomy (with and without elevated basal pressures), the proportion of patients who improved without biliary sphincterotomy, complications, and death were obtained from the literature and from our center. The procedural and hospitalization costs represented the average Medicare reimbursement at our institution. The expected overall costs and numbers of patients improving with each strategy were compared.
Results: The strategy of ERCP with manometry resulted in total costs of $ 2790 per patient, whereas a strategy of ”empirical” biliary sphincterotomy resulted in total costs of $ 2244. In a cohort of 100 patients with suspected SOD, 55 % of patients would be expected to improve if manometry were performed, compared to 60 % of patients improving with ”empirical” biliary sphincterotomy. Univariate sensitivity analyses demonstrated that ”empirical” biliary sphincterotomy continued to be a cost-saving strategy in comparison with ERCP with manometry as long as the probability of spontaneous improvement in patients with ”normal” manometry was less than 41 %, the probability of complications associated with manometry was greater than 6 %, and the probability of complications due to biliary sphincterotomy was less than 19 %.
Conclusions: For patients with suspected biliary SOD type II, empirical biliary sphincterotomy performed by experienced endoscopists appears to be cost-saving in comparison with a strategy based on the results of manometry.

References

• 1 Hogan W J, Geenen J E. Biliary dyskinesia.  Endoscopy. 1988;  20 (Suppl 1) 179-183
• 2 Geenen J E, Hogan W J, Dodds W J. et al . The efficacy of endoscopic sphincterotomy after cholecystectomy in patients with sphincter-of-Oddi dysfunction.  N Engl J Med. 1989;  320 82-87
• 3 Toouli J, Craig A. Sphincter of Oddi function and dysfunction.  Can J Gastroenterol. 2000;  14 411-419
• 4 Eversman D, Fogel E L, Rusche M. et al . Frequency of abnormal pancreatic and biliary sphincter manometry compared with clinical suspicion of sphincter of Oddi dysfunction.  Gastrointest Endosc. 1999;  50 637-641
• 5 Sherman S, Troiano F P, Hawes R H. et al . Frequency of abnormal sphincter of Oddi manometry compared with the clinical suspicion of sphincter of Oddi dysfunction.  Am J Gastroenterol. 1991;  86 586-590
• 6 Botoman V A, Kozarek R A, Novell L A. et al . Long-term outcome after endoscopic sphincterotomy in patients with biliary colic and suspected sphincter of Oddi dysfunction.  Gastrointest Endosc. 1994;  40 165-170
• 7 Fogel E L, Eversman D, Jamidar P. et al . Sphincter of Oddi dysfunction: pancreaticobiliary sphincterotomy with pancreatic stent placement has a lower rate of pancreatitis than biliary sphincterotomy alone.  Endoscopy. 2002;  34 280-285
• 8 Linder J D, Klapow J C, Geels W. et al . Long term follow-up of patients undergoing sphincter of Oddi manometry (SOM) and sphincterotomy (S): evidence for a chronic pain disorder.  Gastrointest Endosc. 2001;  53 AB 3327
• 9 Tarnasky P R, Palesch Y Y, Cunningham J T. et al . Pancreatic stenting prevents pancreatitis after biliary sphincterotomy in patients with sphincter of Oddi dysfunction.  Gastroenterology. 1998;  115 1518-1524
• 10 Freeman M L, Nelson D B, Sherman S. et al . Complications of endoscopic biliary sphincterotomy.  N Engl J Med. 1996;  335 909-918
• 11 Freeman M L, DiSario J A, Nelson D B. et al . Risk factors for post-ERCP pancreatitis: a prospective, multicenter study.  Gastrointestinal Endosc. 2001;  54 425-434
• 12 Sox H C, Blatt M A, Higgins M C, Marton K I (eds). Expected value decision making. Boston, MA; Butterworth-Heinemann 1988: 147-166
• 13 Linder J D, Geels W, Wilcox C M. Pancreatic endotherapy as a risk factor for endoscopic retrograde cholangiopancreatography (ERCP)-related complications.  Gastrointest Endosc. 2001;  53 AB 3350
• 14 Toouli J, Roberts-Thomson I C, Kellow J. et al . Manometry based randomized trial of endoscopic sphincterotomy for sphincter of Oddi dysfunction.  Gut. 2000;  46 98-102