現在使用可能な経口胆道鏡の種類と特徴

Currently available peroral cholangioscopies and their features

要旨

経口胆道鏡には，十二指腸鏡（親スコープ） の鉗子チャネルから内視鏡（子スコープ）を挿入する親子式の経口胆道鏡（POCS），細径内視鏡を経乳頭的に直接胆管内へ挿入する経口直接胆道鏡（PDCS）の2種類がある。PDCSは挿入技術や専用機器の発展が不十分であり，普及には至っておらず，近年開発が進んでいるのは挿入技術が確立されている親子式POCSである。親子式POCSは，近年，複数のメーカーから特性の異なる機種が登場し，症例に応じた選択が可能となった。加えて，生検鉗子，結石に対するEHLやHo-YAGレーザーによる破砕装置，さらには採石用のバスケットなどの処置具も改良が進み，診断・治療の精度と安全性の向上が期待されている。各機器には画質，操作性，挿入性などに特徴があり，スペック上の数値だけでは判断できない微妙な使用感の差も存在する。高価な装置であり，導入に際しては各施設でのおもな使用目的や運用体制を十分に考慮し，実際に製品を試用したうえで適切な機種を選定することが重要である。

　There are two types of peroral cholangioscopy: the “mother-baby” system (POCS), where a cholangioscope is inserted through the working channel of a duodenoscope, and peroral direct cholangioscopy (PDCS), in which an ultra-slim endoscope is directly advanced into the bile duct via the papilla. Due to limited development of insertion techniques and dedicated devices, PDCS has not been widely adopted, and recent innovations have focused primarily on the mother-baby system, whose insertion method is well established. Various POCS models with differing features have recently become available from several manufacturers, expanding the options available for case-specific selection. In addition to the scopes themselves, accessory tools such as biopsy forceps, electrohydraulic lithotripsy (EHL) and holmium: YAG (Ho-YAG) laser lithotripters, and stone retrieval baskets have also undergone technical improvements. These advances are expected to enhance both the diagnostic and therapeutic performance of POCS. The systems differ in image resolution, maneuverability, and ease of insertion, and there are subtle differences in usability that cannot be assessed by specifications alone. As these devices are expensive, it is important for institutions to carefully evaluate their clinical needs and operational environment. Ideally, product selection should be based not only on technical data but also on direct hands-on experience with the devices.