The usefulness of SpyGlass™ choledochoscopy in the diagnosis and treatment of biliary disorders.

Peroral choledochoscopy was first described in the 1970s, but the use of earlier generation choledochoscopes was significantly limited by complex equipment setup and fragility resulting in high repair costs. In late 2006, the SpyGlass Direct Visualization System (Boston Scientific Corp, Natick, MA, USA) was introduced to the market. It is a single-operator cholangioscopy platform and improves upon many shortcomings of the dual-operator systems. Currently, the two main indications for its use are evaluation of indeterminate biliary strictures and lithotripsy for difficult-to-remove biliary stones. Recently published prospective data reconfirm that the overall success rates for adequate tissue sampling and bile duct stone clearance are around 90 %, with an acceptable safety profile. The sensitivity for detecting cancer in intrinsic biliary strictures (e.g., cholangiocarcinoma) is superior to that of standard ERCP sampling modalities, but a limited yield has been noted when sampling extrinsic malignant biliary strictures (e.g., pancreatic cancer). The two main limitations of the SpyGlass system are image quality that is impeded by the use of fiberoptic technology and a relatively small accessory channel providing passage only for dedicated miniaccessories. Nevertheless, the SpyGlass platform has made single-operator cholangioscopy feasible and refined the technique in a number of important ways. This innovation has significantly expanded our diagnostic and therapeutic ERCP armamentarium. An upgraded digital imaging version is currently in development.