Botulinum toxin injection after biliary sphincterotomy

Endoscopic biliary sphincterotomy in patients with sphincter of Oddi dysfunction (SOD) is associated with a high risk of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP), which may be secondary to residual pancreatic sphincter hypertension. It was hypothesized that botulinum toxin injection could be used to reduce pancreatic sphincter hypertension temporarily in SOD patients after biliary sphincterotomy, thereby reducing the rate of procedure-induced pancreatitis.

All patients undergoing ERCP with manometry due to a suspected biliary SOD were asked to participate in the study. Patients with elevated basal sphincter pressures were randomly assigned to receive either botulinum toxin or a sham saline injection after biliary sphincterotomy. Fifty units of botulinum toxin were delivered via a sclerotherapy needle in the form of two 25-U injections of 0.25 ml each into the pancreatic sphincter. In patients in the sham arm, 0.50 ml of saline was injected into the duodenal lumen.

Between 12 February 1999 and 29 November 2000, a total of 98 patients were referred for ERCP with manometry; 86 consented to participate in the study, and 26 had elevated baseline pressures and underwent random assignment. Twelve received botulinum toxin injection and 14 were randomly assigned to receive the sham injection. A total of six patients in the sham group (43 %) developed procedure-induced pancreatitis, compared with three patients in the botulinum toxin group (25 %; P = 0.34).

Biliary sphincterotomy in patients with sphincter of Oddi dysfunction without pancreatic protection is risky and should no longer be carried out. This study demonstrates that botulinum toxin injection into the residual pancreatic sphincter after biliary sphincterotomy is technically feasible and safe, showing a trend toward a reduced post-ERCP pancreatitis rate in patients with sphincter of Oddi dysfunction. Further studies will need to confirm the validity of these experimental results before this technique can be used routinely.