Correlation between sphincter of Oddi manometry and intraductal ultrasound morphology in patients with suspected sphincter of Oddi dysfunction

Endoscopic approach to the patient with motility disorders of the bile duct and sphincter of Oddi

Since its original description by Oddi in 1887, the sphincter of Oddi has been the subject of much study. Furthermore, the clinical syndrome of sphincter of Oddi dysfunction (SOD) and its therapy are controversial areas. Nevertheless, SOD is commonly diagnosed and treated by physicians. This article reviews the epidemiology, clinical manifestations, and current diagnostic and therapeutic modalities of SOD.

Is sphincter of Oddi manometry a risk factor for pancreatitis? A different view

Studies suggest a causal relationship between sphincter of Oddi manometry (SOM) and acute pancreatitis, presumably due to water instillation in the ductal system. In this article, critical analysis of the existing studies attributes the high risk of acute pancreatitis with SOM to "association due to confounding" rather than to "causation." This conclusion is based on two pieces of evidence: The first is lack of biologic plausibility: Biologic evidence is lacking to support the hypothesis that water instillation during SOM can induce acute pancreatitis. The second is confounding evidence: Manometric studies show considerable variation in the risk of post-procedure pancreatitis (4% to 30%), which suggests that other important factors besides SOM influence the adverse outcome. These studies did not control for other variables, which are well known to predispose to pancreatitis and therefore may act as confounding factors. Two studies that assessed the independent role of SOM in causation of acute pancreatitis showed that SOM is not an independent predictor of acute pancreatitis. It is the underlying disorder sphincter of Oddi dysfunction, and not the "SOM" procedure, that predisposes patients to post-procedure acute pancreatitis.

Normal sphincter of oddi motor function

With the introduction of endoscopic retrograde cholangiopancreatography (ERCP) manometry, the characteristics of sphincter of Oddi (SO) motor activity have been described. SO manometry is the only available method to measure SO motor activity directly and is usually performed at the time of ERCP. SO manometry is considered to be the gold standard for evaluating patients for sphincter dysfunction. This review reports the technique of SO manometry and normal values for SO manometry. SO motility is characterized by prominent phasic contractions superimposed on a tonic pressure. Elevated basal SO pressure is the most consistent and reliable criteria to diagnose SO dysfunction. Basal pressures obtained from the biliary sphincter are similar to the basal pressure obtained from the pancreatic sphincter. Abnormal SO manometric values are shown. Factors that influence SO pressures, and interpretation of SO manometric tracing are discussed. The most common and serious complication of SO manometry is post-manometry pancreatitis. In healthy volunteers with normal sphincter function, pancreatitis is almost never seen. However, in patients with SO dysfunction, the incidence of pancreatitis is high. The use of new nonperfused microtransducers may reduce this complication.

Diagnosing and treating Sphincter of Oddi dysfunction: a critical literature review and reevaluation

Sphincter of Oddi dysfunction is a pathologic syndrome, without considering etiology, physiopathology, or anatomic aspects of the condition. The clinical manifestations of the syndrome may be a consequence of an "organic stenosis" of the tract or a consequence of "abnormal motility" of the sphincter. Until some years ago, the gold standard technique for studying and treating this pathologic condition was endoscopic retrograde cholangiopancreatography. Two criteria for defining patients in the Milwaukee classification are related to this procedure. The Milwaukee classification was introduced to use clinical and radiologic criteria to define patients with Sphincter of Oddi dysfunction to choose the best treatment. Subsequently, great emphasis has been placed on manometry of the sphincter performed by endoscopic cannulation. The enormous increase of cholecystectomies by means of laparoscopic technique has increased the number of patients who return to their reference-surgeon with a post-cholecystectomy pain and possible Sphincter of Oddi dysfunction. The aim of this paper is to review the literature and to evaluate an up-to-date flow chart for diagnosing and treating the syndrome by using alternative diagnostic procedures that are less invasive than endoscopic retrograde cholangiopancreatography.

Innovative methods of biliary tract diagnosis: intraductal ultrasound and tissue acquisition

Tissue can be acquired from the bile and pancreatic duct with either brush cytology or biopsy forceps, often without the need for sphincterotomy. Although the diagnosis of malignancy with these sampling techniques is often specific, the sensitivity is limited, and a wide range of diagnostic accuracies has been reported. A combination of biopsy and brush cytology along with some newer techniques in the development stage may increase the sensitivity. Intraductal ultrasound is a newer technique offers the endoscopist the ability to image the bile and pancreatic duct wall, adjacent organs, and vascular structures with a high degree of detail. This visualization can be accomplished during the course of an ERCP or percutaneously under fluoroscopic guidance. Indications for the procedure include detection of choledocholithiasis, differentiation of benign and malignant ductal strictures, pancreaticobiliary tumor staging, and detection of various pancreatic tumors. Continued research into the design of the probes, which could improve durability and extend the depth of penetration, may promote more widespread use of this novel technology.