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  • PRACTICAL GASTROENTEROLOGY APRIL 2009 15

    INTRODUCTION

    T his profile summarizes the technical aspects andthe preliminary literature related to the use of theSpyGlass Direct Visualization System. Thisnovel technology provides the endoscopist with adirect intraluminal view of the biliary duct system.Consequently, lesions within the biliary tract can bebiopsied under direct vision. It also allows for theapplication of therapeutic devices such as electrohy-draulic lithotripsy (EHL) and holmium laser to frag-ment stones. This technology has utility when imaginglimitations of conventional endoscopic retrogradecholangiopancreatography (ERCP) are encountered. Italso appears to have overcome many of the limitationsof earlier generation choledochoscopes.

    HISTORICAL PERSPECTIVE For the better part of forty years, biliary duct evaluationvia cholangioscopy, in one form or another, has been inuse by gastroenterologists. The techniques and technol-ogy through which this has been possible have beenunder significant scrutiny and constant refinement fromits onset. The evolution of peroral cholangioscopy(POCS) is impressive, and has been well documented.

    The earliest attempts at visualizing biliaryanatomy with fiberscopes were only a glimpse of whatwas to come. Roughly thirty years after the first intra-operative cholangioscopy, the mother-baby scopewas introduced. Initially a lengthy procedure requiringtwo specially trained endoscopists, POCS cases oftenlasted upwards of two hours. In addition, the earlyscopes were large, cumbersome and fragile. Oftentheir specially designed optical fibers would breakfrom the movement of the duodenoscope alone. Also,the first steering apparatuses were bidirectional asopposed to the four-quadrant steering of standardendoscopes. The initial working channels were some-times less than adequate for biopsy forceps.

    I Spy Biliary and Pancreatic Ducts:The SpyGlass Single-Operator PeroralCholangiopancreatoscopy System

    ENDOSCOPY: OPENING NEW EYES, SERIES #1

    Andrew K. Roorda, M.D., Fellow, Section of DigestiveDiseases; Justin T. Kupec, M.D., Fellow, Section ofDigestive Diseases; Uma Sundaram, M.D., Chief,Section of Digestive Diseases; Department of Medi-cine, West Virginia University School of Medicine,Morgantown, WV.

    Andrew K. Roorda Justin T. Kupec Uma Sundaram

  • PRACTICAL GASTROENTEROLOGY APRIL 200916

    The evolution of miniscopes came next. Thesesmaller scopes were more apt to access the commonbile duct (CBD) without papillotomy, and, as technol-ogy allowed the scopes to get smaller, the workingchannels became more useful in therapeutic situations.While not yet perfect (e.g. no separate working chan-nels), the option to move away from the mother-babyscope was present, and it was now possible to pass theminiscopes through the duodenoscope (duodenoscopeassisted cholangiopancreatoscopyDACP). As moretechnology went into the miniscopes, their size becamesmaller, their resolution sharper and their therapeuticapplications broader. Great strides have been madefrom the first miniscope to the advent of the SpyGlassperoral cholangiopancreatoscopy system, not the leastof which are separate working and irrigation channelsas well as four-way maneuvering (13).

    ERCP has been a proven means of evaluating andtreating a myriad of biliary pathologies. It remains thegold standard for CBD stone removal, therapeuticsphincterotomy and biliary stent placement (for benignor malignant strictures), but often the pathology inquestion during ERCP needs further imaging beyondfluoroscopy. Direct evaluation of the biliary tree nowallows optically guided biopsies, real-time video ofquestionable lesions and a view of previously seenstrictures with the chance of determining whether theyare benign or malignant.

    SPYGLASS DIRECT VISUALIZATION SYSTEMIn May of 2007, Boston Scientific introduced the SpyGlass Direct Visualization System. The goal of thesystem was to overcome the limitations of prior chole-dochoscopes and simplify peroral cholangioscopy.

    Theoretically, at least, direct optical visualizationof biliary ducts has advantages. As discussed above,standard ERCP allows a radiographic view of theducts; however, interpretation and extrapolation arerequired. Radiologic imaging during ERCP may beinsufficient to make a correct diagnosis. As gastroen-terologists, we are trained to recognize, diagnose andtreat diseases with direct real time visualization ofpathology; SpyGlass now allows those trained in theprocedure to do just that. Further, the ability to biopsy

    ENDOSCOPY: OPENING NEW EYES

    I Spy Biliary and Pancreatic Ducts

    (continued on page 19)

    Practical Points

    Easier to use than previous generation choledocho-scopes with added benefit of single user and improvedvisibility with irrigation channel

    First-generation device with expected refinements infuture generation technology

    Expands diagnostic and therapeutic applications whereERCP has fallen short, both peroral and percutaneous

    May avoid unnecessary surgery if indeterminate stric-tures on previous ERCP subsequently diagnosed asbenign with SpyGlass

    Variation in success among reported studies may be afunction of varying skill level of biliary endoscopist

    Utility for foreign body removal Potential for extraluminal applications

    Figure 1. SpyGlass mounted on duodenoscope. (Boston Scientific)

  • within the biliary system, with direct view of a lesion,is now afforded with the SpyGlass System.

    Major components of the system (Figure 1)include the SpyGlass fiber optic probe, SpyScope

    access and delivery catheter and the SpyBite biopsyforceps. A single-use, single-operator device, theSpyScope catheter consists of four lumens; a) a 1.2mm accessory channel, through which the SpyBite

    forceps can pass, b) two irrigation channels and c) anoptic channel. This 10 Fr catheter allows four-quadrant

    biliary viewing due to a tip that has four-way steeringcapabilities. The total length of the Access and Deliv-ery Catheter is 230 cm and is stabilized by the endo-scopist with its placement just below the operatingchannel of the duodenoscope. The SpyGlass fiberoptic probe, a multiple-use device, is a fragile 231cm long catheter with an outer diameter of 0.77 mmwhich easily passes through the SpyScope Catheter.As both a transmitter of light (6,000 pixels) and intra-ductal images, its angle of viewing is 70. The SpyBite forceps are single-use, similar to thecatheter, and have a central spike that minimizes the loss of small biopsies. Used in conjunction with thefiber optic probe, direct visualization of the biopsy siteis now possible.

    The SpyGlass system is compatible with EHL andholmium laser, for stone fragmentation. EHL uses theprinciple of high pressure shock waves generated byhigh voltage discharge and laser treatment offersanother therapeutic alternative to EHL (4,5). Thisallows direct visualization of two proven methods ofablation for stones that may not be amenable toremoval by conventional therapies (i.e. stones toolarge to pass after sphincterotomy).

    CLINICAL ASSESSMENT PRIOR TO SPYGLASS PROCEDUREWhile no standard patient protocol or evaluation hasbeen advocated prior to performing SpyGlass, generalguidelines are useful and are outlined here. The currenttrend has been toward performing ERCP and SpyGlassunder general anesthesia and therefore each patientshould have a routine laboratory evaluation. Thisincludes at minimum a complete blood count (CBC), achemistry panel (electrolytes, BUN, creatinine) and acoagulation panel (PT, PTT), no more than 14 dayspreceding the surgery. On arrival to the endoscopysuite or operating room (OR), the patient should havea full history and physical (H&P) performed, or atleast an H&P update if a full H&P has been per-formed within the past 30 days. Vital signs, whichshould be continuously monitored by anesthesia forthe duration of the procedure, should include a pulse-oximetry reading, blood pressure, pulse, respiratoryrate, as well as temperature.

    PRACTICAL GASTROENTEROLOGY APRIL 2009 19

    ENDOSCOPY: OPENING NEW EYES, SERIES #1

    I Spy Biliary and Pancreatic Ducts

    (continued from page 16)

    Table 1Diagnostic and Therapeutic applications of SpyGlassSingle-Operator Peroral Cholangiopancreatoscopy System

    Diagnostic Biopsy stricture under direct visualization (indetermi-

    nate stricture, dominant stricture in primary sclerosingcholangitis)

    Evaluate fixed filling defect noted on prior radiologicstudy

    Differentiation of intraductal mass (benign vs. malignant)

    Precision mapping of intraductal tumor prior to resection

    Collection of significant fluid sample for cytology Evaluate intraductal mucinous neoplasms under

    direct vision Evaluate choledochal cyst under direct vision Evaluate post liver-transplant ductal ischemia under

    direct vision Evaluate intraductal spread of ampullary adenoma

    under direct vision Evaluate for infection (CMV, fungal infection) using

    direct vision and tissue sampling

    Therapeutic Choledocholithiasis (EHL, laser lithotripsy, argon

    plasma coagulation) Photodynamic therapy Nd-YAG laser ablation Cystic duct stent placement Foreign body removal Extraluminal applications Placement of stent through post liver transplant

    tight stricture

  • PRACTICAL GASTROENTEROLOGY APRIL 200920

    Confirmation of the indication(s) for performingthe procedure is also warranted. Routinely, transami-nases (AST, ALT), alkaline phosphatase (Alk P), biliru-bin and other markers of hepatic function (dysfunction)are obtained and reviewed prior to initiation of the pro-cedure. Imaging, usually via one or more separatemodalities, should also be reviewed as often they indi-cate when SpyGlass direct visualization is warranted. Aright upper-