Update on Sphincter of Oddi Dysfunction: A Review.

Sphincter of Oddi dysfunction (SOD) encompasses a spectrum of clinical syndromes that are not fully understood, and various diagnostic and therapeutic methods have had varying results depending on the type of dysfunction. This review explored various mechanisms that might play a role in SOD and methods of diagnosis and management. It is important to rule out other causes of abdominal pain with laboratory testing, imaging studies, and endoscopic procedures. Medications that affect sphincter motility should be identified as well. Manometry is the gold standard for diagnosis but it is not always required. For example, patients with type I SOD may have symptomatic improvement with sphincterotomy without need for a diagnostic manometry. Hepatobiliary scintigraphy and fatty meal sonography may also have diagnostic utility. Sphincterotomy is not always effective for symptomatic improvement in type II and III SOD. Alternate therapies with calcium channel blockers and botulinum toxin have been studied and might be considered as options after discussing the risks and benefits with the patients.