Research Article|Articles in Press

Clinical evaluation of a novel drill dilator as the first-line tract dilation technique during EUS-guided biliary drainage by non-expert hands (with video)

Published:February 09, 2023DOI:
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      Background and aim

      In cases where tract dilation fails using the initially selected dilation device during EUS-guided hepaticogastrostomy (HGS), dilation should be re-attempted using another device. However, switching from one device to another during procedure is often associated with prolonged procedure time and deviation from the correct axis. Therefore, it is highly desired that the initial tract dilation succeeds on the first attempt. Recently, a novel drill dilator has become available in Japan. As there have been no previous studies comparing this novel device to others as an initial dilation device, here we report on the technical feasibility of this novel device for use during EUS-HGS, and compare it with a balloon catheter.


      This retrospective study included patients who underwent EUS-HGS using SEMS between October 2021 and October 2022. Excluded from the study were patients who underwent EUS-HGS using a plastic stent or stent deployment without tract dilation. The primary outcome in this study was the technical success rate of initial tract dilation using the drill dilator. This dilator has been available at our hospital since June 2022. Therefore, EUS-HGS was performed using this device as the primary dilation device from June 2022 to October 2022. As the control group, we corrected patients who underwent EUS-HGS using 4-mm balloon catheter as the primary dilation device from October 2021 to May 2022.


      A total of 49 patients were included, of whom 19 underwent EUS-HGS using the drill dilator and 30 underwent EUS-HGS using a balloon catheter. EUS-HGS using the drill dilator initially was performed mainly by non-expert hands (n=19), whereas only some in the balloon catheter group were performed by non-expert hands (n=2). Although the initial tract dilation was successful in all patients in the drill dilator group (19/19, 100%) and in 29/30 (97%) in the balloon catheter group, an additional tract dilation was needed in 73.7% (14/19) of the drill dilator group upon 8.5Fr stent delivery system insertion. On the other hand, the stent delivery system insertion was successful without an additional tract dilation in all patients of the balloon catheter group.


      The novel drill dilator might be useful as a dilation device, however, the balloon dilation technique should be selected first upon deploying a dedicated metal stent with an 8.5Fr stent delivery system.

      Key words


      EUS (endoscopic ultrasound), SEMS (self-expandable metal stent), EUS-BD (endoscopic ultrasound-guided biliary drainage), EUS-HGS (endoscopic ultrasound-hepaticogastrostomy), ERCP (endoscopic retrograde cholangiopancreatography)
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