Types of Peroral Cholangioscopy: How to Choose the Most Suitable Type of Cholangioscopy.

OPINION STATEMENT: A number of case studies have described the usefulness of peroral cholangioscopy for diagnosis and therapy, performed by visualizing the inner cavity of the bile duct. Currently available types of peroral cholangioscopy include peroral videocholangioscopy (POCS) using a mother-baby scope system (MBSS), direct peroral videocholangioscopy (D-POCS), and SpyGlass™ Direct Visualization System (SGDVS). POCS started with cholangioscopy using MBSS, requiring two skilled endoscopists using two endoscopic systems. On the other hand, D-POCS and SGDVS were developed as single-operator techniques. In MBSS, the videocholangioscope is inserted into the bile duct through the accessory channel of a conventional therapeutic duodenoscope. MBSS enables comparatively easy scope insertion into the bile duct and stable scope positioning. POCS using MBSS provides excellent images and can be coupled with an image-enhanced function system. However, it has a smaller accessory channel, limiting the devices that can be used. Additionally, scope fragility is serious problem. D-POCS using an ultraslim upper endoscope has been introduced to overcome the drawback of POCS using MBSS. D-POCS has a larger working channel and requires only one endoscopist. D-POCS allows a greater variety of procedures under excellent imaging even with an image-enhanced function system; however, scope insertion is still challenging. SGDVS is designed for single-operator use and is dedicated to procedural purposes. It comprises a reusable optical probe and disposable delivery catheter, which has four-way deflected steering and dedicated irrigation channels. These features lead to good maneuverability, although image quality is poor due to its optical probe system. All systems' features should be recognized and the appropriate system used depending on the need. Cholangioscopy has shown dramatic progress from diagnosis to therapy with high future growth potential.