A pilot clinical study of developing an External Assist Targeting Device for rapid and precise renal calyx access during percutaneous nephrolithotomy

OBJECTIVE: To design a device to increase the accuracy of the targeting process and reduce the radiation exposure to both the patients and the medical staff. METHODS: We analyzed the inherent problem and designed the External Assist Targeting Device (EATD) to assist in the alignment of needle targeting on the desired renal calyx under fluoroscopic guidance. The EATD was designed to allow rapid and precise access to calyces at all angles, with a simple two-step puncture protocol developed for puncturing a target renal calyx. We then tested the device in a pilot human trial with four patients. RESULTS: In experiments with phantom models, the time for successful targeting was reduced by 31% using the device. The mean fluoroscopic time was reduced by 40%. In initial human trial, the puncture time was shortened by 66% and the radiation dose was decreased by 65% compared to free-hand technique. No complication was observed during the trial. CONCLUSION: The EATD was found to be cost effective, portable, simple to set up, and safe to operate for assisting in the percutaneous nephrolithotomy procedures. Our preliminary tests showed high degree of accuracy in gaining precise access to a targeted renal calyx with much shorter time and lesser radiation dose. The EATD also has the potential to be used to access other organs with precision under fluoroscopic guidance.