Clinical Usefulness of Digital Single-operator Cholangioscopy(SpyGlass™) for Post-liver Transplant Anastomotic Stricture

Liver transplantation (LT) is an essential treatment for end-stage liver disease. Although clinical outcomes of LT recipients have markedly improved, anastomotic biliary strictures (ABS) are still occurred in 10-40% of post-LT patients. In the Korea, living donor LT (LDLT) is the more common than deceased donor LT (DDLT). When LDLT is performed, the right lobe graft is usually used, and the right anterior and posterior segmental bile ducts (RASD/RPSD) of the graft are reconstructed by the duct-to-duct anastomosis method to the common hepatic duct of the recipient. When ABS occurs in LDLT recipients, the stricture site is often very tight and twisted. So, conventional endoscopic procedure is challenging and success rate of ERCP for ABS is still unsatisfactory (about 60%). Furthermore, approach to the RPSD is more intricate than that to RASD because the duct opening is located deeper in a posterior aspect. Therefore, despite being able to benefit the patient, bilateral drainage (both RASD and RPSD) is considered to be more difficult and unilateral drainage of RASD is mainly performed. In 2015, high-resolution cholangioscopy (SpyGlass™) was introduced. The system enables direct visualization of the bile and pancreatic ducts strictures. The 3rd Generation SpyScope DS II Access \& Delivery Catheter introduced in 2018, features increased resolution and adjusted lighting to provide physicians with an even better view of the biliary and pancreatic ducts. To date, only several retrospective studies have evaluated the efficacy of SpyGlass for guidewire placement across the ABS and to the best of our knowledge only one prospective study is ongoing (ClinicalTrials.gov NCT #03205072). In that study ABS in both LDLT and DDLT patients are enrolled. Private communications with the Sponsor of this study, however, have reported that only approximately 10% of the cases are LDLT cases. In addition, there is no reported paper about the usefulness of Spyglass for bilateral drainage an