Colangioscopy

Endoscopic endoscopic cholangiopancreatography (CPER) is currently the procedure of choice for the diagnosis and treatment of multiple bilio-pancreatic diseases. Although this technique has proven successful in many clinical situations, it remains limited by the fact that the endoscopist is able to visualize structures indirectly, only by fluoroscopy [1]. This indirect visualization may be particularly restrictive in patients with large gallstones or in the case of biliary strictures whose etiology is unclear [2]. In addition, other technical resources such as brush cytology and radio-guided biopsies are limited by a low sensitivity for the detection of malignant lesions [3]. Direct oral visualization of the bile duct has been available since the 1970s, but only recently has technology improved enough to highlight diagnostic and therapeutic benefits when classical procedures are insufficient. There are currently three systems available for cholangioscopy, including the single-operator, dual-operator procedure, and direct cholangioscopy. Significant technological advances are noted for all of these types, each with particular advantages, such as ease of use, better image quality, or other diagnostic options, such as narrow band imaging. Single operator cholangioscopy (CSO) is the cholangioscopic technique characterized by the greatest accessibility and spread.

The diagnostic indications for cholangioscopy are:
– evaluation of strictures
– direct visualization of undetected stones by standard cholangiography
– biopsy collection by direct viewing
– evaluation of the source of hemobilia

Therapeutic indications for cholangioscopy are:
– lithotripsy of stones by laser or electrohydraulic method
– catheterization with the guide wire under direct visual control
– radiofrequency ablation of bile duct tumors [1]

Recent studies have shown the benefit of using CSO in patients with difficult gallstones. Calculations can be considered difficult when they are larger (> 15 mm), impacted, located in difficult locations (eg in the area of ​​strictures) or if they are present in large numbers [4]. Stones impacted in the cystic duct or intrahepatic bile ducts, or wall adhesions, may be difficult to visualize on the standard cholangiogram and may remain undetected. In these circumstances, direct visualization of the calculation by CSO can ensure greater therapeutic success (possibly removing it by placing the guidewire). Patients with recurrent angiocolitis, significant dilation of the bile ducts, and unusual presentation of gallstones may also benefit from CSO [5]. In addition to the benefits of direct visualization of a calculus, CSO also allows other treatment options, such as laser or electrohydraulic lithotripsy. Previous methods available for fragmentation of difficult stones have included extracorporeal lithotripsy or CPER-guided laser lithotripsy. These techniques have been limited by the lack of direct visualization of the stone and the reliance on indirect fluoroscopy to guide laser placement. With the help of the cholangioscope, difficult calculations are fully visualized, allowing precise laser aiming for successful fragmentation. A 2018 study evaluated the use of SpyGlass DS (produced by Boston Scientific) in patients with difficult biliary stones. The results were studied in 407 patients from several centers who underwent CSO with electrohydraulic or laser lithotripsy. Technical success was defined as complete removal of stones and was seen in 97.3% of patients. In addition, 77.4% of patients required a single CSO session to achieve complete ductal clearance. Subsequent analysis showed that difficult anatomy was a significant predictor of failure [6]. In general, CSO has proven to be a safe and effective alternative to surgery.

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Abbreviations:
CPER – retrograde endoscopic cholangioscopy
CSO – cholangioscopy with a single operator

References:

1. Michael Yodice, Joseph Choma, and Micheal Tadros, The Expansion of Cholangioscopy: Established and Investigational Uses of SpyGlass in Biliary and Pancreatic Disorders, Diagnostics (Basel). 2020 Mar; 10 (3): 132.
2. Chen K.Y., Pleskow D.K. SpyGlass single-operator peroral cholangiopancreatoscopy system for the diagnosis and therapy of bile-duct disorders: A clinical feasibility study (with video) Gastrointest. Endosc. 2007; 65: 832-841
3. Navaneethan U., Njei B., Lourdusamy V., Konjeti R., Vargo J.J., Parsi M.A. Comparative effectiveness of biliary brush cytology and intraductal biopsy for detection of malignant biliary strictures: A systematic review and meta-analysis. Gastrointest. Endosc. 2015; 81: 168–176.
4. Yan S., Tejaswi S. Clinical impact of digital cholangioscopy in management of indeterminate biliary strictures and complex biliary stones: A single-center study. Ther. Adv. Gastrointest. Endosc. 2019;12:2631774519853160
5. Averbukh L.D., Miller D., Birk J.W., Tadros M. The utility of single operator cholangioscope (Spyglass) to diagnose and treat radiographically negative biliary stones: A case series and review. J. Dig. Dis. 2019;20:262–266.
6. Brewer Gutierrez O.I., Bekkali N.L.H., Raijman I., Sturgess R., Sejpal D.V., Aridi H.D., Sherman S., Shah R.J., Kwon R.S., Buxbaum J.L., et al. Efficacy and Safety of Digital Single-Operator Cholangioscopy for Difficult Biliary Stones. Clin. Gastroenterol. Hepatol. 2018;16:918–926 e1. doi: 10.1016/j.cgh.2017.10.017