Response to Botox Has a High Predictive Value for the Outcome of Endoscopic Sphincterotomy for Post-Cholecystectomy Biliary Pain Due to Sphincter of Oddi Spasm

Abstract

Introduction: Muscle spasm of the sphincter of Oddi (SO) can cause post-cholecystectomy biliary pain. Sphincter of Oddi hypertension is classically diagnosed using endoscopic sphincter of Oddi manometry (EBM). This procedure is associated with a high incidence of pancreatitis and does not accurately define the patients whose symptoms are due to SO spasm. Botulinum toxin (Botox) injected into the SO muscle will relax the sphincter for 2 to 3 months. Aim: To study whether relief of pain following Botox injection predicts the outcome of endoscopic biliary sphincterotomy in post-cholecystectomy biliary pain due to sphincter of Oddi hypertension. Methods: Over a 3 year period, 91 patients underwent 4 injections of 25 units each of Botox into their SO muscle at duodenoscopy. Results: Sixty three (55 females) of these 91 patients were referred with post-cholecystectomy biliary pain and no physical abnormality of the biliary tree. Thirty five of these 63 patients underwent EBM prior to Botox treatment. Forty seven of the 63 patients (75%) experienced temporary relief from their pain following Botox treatment. Forty six of these 47 patients have undergone endoscopic biliary sphincterotomy with relief of pain in 43 patients (93%). All 21 patients (100%) with positive EBM and relief of pain following Botox achieved pain relief following endoscopic biliary sphincterotomy compared with a 90% response for those patients who did not undergo EBM prior to Botox treatment. This compares with a 75% pain relief rate when endoscopic biliary sphincterotomy was based on EBM results alone. Conclusion: Botox relaxation of the SO is a highly sensitive indicator of the response to endoscopic biliary sphincterotomy in patients likely to have post-cholecystectomy biliary pain from sphincter of Oddi hypertension.