Development of devices for EUS-guided biliary drainage

【Background】No specific devices for EUS-guided biliary drainage (EUS-BD) are currently available in Japan.【Methods】We designed and developed the devices which resolve the following two limitations in the current EUS-BD. 1) Because bile leak occurs during needle-tract dilation step, we developed a thinner delivery system with tapered tip, which prevents bile leak by skipping its step. 2) Because stent migration sometimes occurs, we developed a lasercut stent with hook structure at its end (Hook stent) for high anchoring effects. Using these devices, we performed phantom, animal and clinical studies.【Results】1) Preclinical stuides showed that 7Fr delivery system with a tee-shaped tip had less resistance force to advancement and lower rates of requiring needle-tract dilatation than the other ones. In a prospective multicenter study to evaluate the efficacy of EUS-guided choledochoduodenostomy using the thin delivery system, technical and clinical success rates were 95.0% and 100%, respectively. The delivery system was successfully inserted into the bile duct without a dilatation device in 31.6%, who had significantly shorter procedure times than those requiring dilatation device. 2) Preclinical experiments showed that Hook stents had significantly higher resistance force to migration than conventional stents with no adverse effects. We are currently conducting an investigator-initiated clinical trial to verify the efficacy of EUS-guided hepaticogastrostomy using Hook stent for its device approval of MHLW.   【Conclusion】We have developed specific devices for EUS-BD, with which we can perform EUS-BD more successfully with less adverse events.