The goal of treatment is to reduce sphincter of Oddi pressure, thereby improving drainage of biliary and pancreatic secretions into the duodenum. This may be accomplished through medical, endoscopic, or surgical therapy.
Medical therapy for sphincter of Oddi dysfunction is an attractive approach mainly because it is noninvasive (as compared with endoscopic or surgical therapy), thereby avoiding the occasionally severe complications of sphincterotomy. Because the sphincter of Oddi is composed of smooth muscle, it is reasonable to assume that drugs that relax smooth muscle may be effective in patients with sphincter of Oddi dyskinesia and not in patients with papillary stenosis. Agents such as calcium channel blockers and long-acting nitrates have been shown to reduce sphincter of Oddi basal pressure and improve symptoms. However, there are several drawbacks to medical therapy. First, side effects may be seen in up to one-third of patients. Second, a response rate of only about 75% is expected in patients with the spastic-type of sphincter of Oddi dysfunction. Third, medical therapy utilizing muscle-relaxing agents is not expected to be effective in the patient with papillary stenosis.
Surgical treatment consists of transduodenal sphincteroplasty with or without transampullary septectomy (Figures 13 and 14). This procedure has shown long-term benefit in follow-up at 1–2 years in uncontrolled trials.
|Figure 13. Surgical technique for transduodenal sphincteroplasty.|
|Figure 14. Surgical technique for transduodenal sphincteroplasty with transampullary septoplasty.|
There are no randomized trials comparing surgical sphincteroplasty with endoscopic sphincterotomy.
Endoscopic sphincterotomy is the current standard of therapy for sphincter of Oddi dysfunction (Figure 15, A-D). Controlled studies document the short-term and long-term efficacy of endoscopic sphincterotomy with relatively low morbidity and mortality rates. The presence of an elevated basal sphincter pressure appears to predict good benefit from sphincter ablating procedures. In appropriate situations, benefits of endoscopic sphincterotomy are greater than 90%, with good results in long-term follow-up. Because of the high complication rate of pancreatitis after endoscopic sphincterotomy for sphincter of Oddi dysfunction, prophylactic short-term pancreatic stenting is recommended, and often yields good results.
Other Endoscopic Therapy
|Figure 15. A,B,Technique for endoscopic sphincterotomy;C,D,stent placement in the pancreatic duct;A'-D',endoscopic views.(Click the blue letters to view the consecutive images)|
Endoscopic balloon dilation and stenting, in an attempt to preserve sphincter function, have not been found to be effective in reducing sphincter of Oddi pressure or symptoms. This technique is also associated with unacceptably high complication rates.
|Figure 16. Endoscopic technique for botulinum toxin(Botox) injection.|
Recent success has been reported using botulinum toxin (Botox) injections to reduce sphincter of Oddi pressure and to improve bile flow dynamics (Figure 16). This technique, pioneered at the Johns Hopkins Hospital, has shown promise both as a diagnostic and therapeutic modality. The mechanism of action of Botox occurs at the nerve endings within the sphincteric muscle. Botox inhibits the release of acetylcholine (a neurotransmitter), preventing the contraction of the muscle (Figure 17).
|Figure 17. Mechanism of action of botulinum toxin.|
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