CURRENT STATUS OF CHOLANGIOSCOPY

Abstract

Cholangioscopy can provide endoscopic direct visualization of the biliary system. First described in 1970s, cholangisoscopy is categorized into peroral cholangioscopy (POCS) and percutaneous cholangioscopy (PTCS). Traditional POCS using a dedicated cholangioscope that advances through the accessory channel of the duodenal scope is called the mother-baby system. This procedure requires the presence of two experienced endoscopists because baby cholangioscopes have been shown to be fragile. Recently, single-operator cholangioscopy was introduced as the SpyGlass system. SpyGlass system is semi disposable, but the optical quality is low compared with videoscopes. More recently several endoscopists have reported the usefulness of single-operator peroral direct cholangioscopy (PDCS) using a conventional ultraslim endoscope. Compared with the mother-baby system, the advantages of PDCS are the high-resolution image and large-diameter working channel. On the other hand, the disadvantage is the difficulty to insert the ultraslim scope into the biliary system. However, the success rate can be improved using assistant devices such as guidewire, anchoring balloon, overtube duodenal balloon, and prototype cholangioscopy. PTCS is used for patients who are not able to tolerate POCS, but it is time consuming. Cholangioscopy is currently employed primarily for the characterization of indeterminate strictures. Narrow-band imaging, which displays images of the superficial mucosal surface, improves biliary tract disease diagnosis. Cholangioscopy-guided target biopsy can although increase diagnostic yields. In addition, cholangioscopy can provide an accurate diagnosis of intraepithelial tumors extending into biliary cancers. The main therapeutic indication of cholangioscopy is the management of difficult stones. Intraductal electrohydraulic lithotripsy or laser lithotripsy using cholangioscopy is an effective and safe procedure for the removal of bile duct stones. Furthermore, PDCS can be used to remove stones with a basket catheter. Several studies also reported the importance of cholangioscopy in palliative therapy for malignant jaundice, because of the ability to guide across difficult biliary strictures and to place selective biliary stents. In addition, PDCS using upper gastrointestinal (GI) endoscope or single/double balloon enteroscope is directly effective for diagnostic and therapeutic biliary diseases even in patients with altered GI anatomy. Since air embolism was reported as a fatal complication of cholangioscopy, use of CO2 and minimal air insufflation are required. In the future, with the development of new devices and endoscopes, cholangioscopy will be very useful in the diagnostic and therapeutic fields. This review will highlight the historical developments, the currently available cholangioscopic equipment and techniques, the indications and future perspectives of this procedure.