Botulinum Toxin and the Sphincter of Oddi

Abstract

Sphincter of Oddi (SO) dysfunction can be physical or functional. Physical dysfunction is referred to as SO stenosis, papillary stenosis, or ampullary stenosis and is most commonly due to post-inflammatory fibrosis thought to be secondary to the passage of small gallstones. Symptoms may be biliary and/or pancreatic, and diagnosis is based on the demonstration of a localized SO stricture or its back pressure effects. Endoscopic sphincterotomy is associated with a >90% cure rate (Bistritz and Bain 2006). Physiological dysfunction of the SO is referred to as SO dysfunction or, more accurately, SO hypertension (SOH). In the resting phase, the SO contracts and relaxes up to seven times per minute. SOH is defined by SO manometry, and the critical measurement has been shown to be the relaxation (basal) pressure exhibited by the resting SO. An abnormal SO pressure profile is said to exist when the SO relaxation pressure is >40 mm Hg. SOH has been associated clinically with acalculus biliary pain, postcholecystectomy right upper quadrant abdominal pain, postprandial pancreatic pain and idiopathic recurrent acute pancreatitis (Sherman and Lehman 2001). Updated (Rome III) diagnostic criteria, investigative algorithms and suggestions regarding management were published in 2006 (Behar et al. 2006).