Phase I trial of a temporary ureteral drainage stent

The temporary ureteral drainage stent (TUDS; Boston Scientific/Microvasive, Natick, MA) is a biodegradable device that is designed to maintain patency for 48 hours with gradual softening and spontaneous expulsion thereafter. We evaluated the durability, patency, and safety of TUDS in a Phase I clinical trial. Eighteen stone patients requiring sequential percutaneous nephrolithotomies (PNL) for complex stone disease underwent antegrade TUDS placement following initial percutaneous treatment. Nineteen devices were placed in 21 attempts, with one patient undergoing bilateral TUDS placement. Day 2 nephrostograms were performed to allow assessment of stent status and to demonstrate antegrade flow. Stents were removed at the time of the secondary PNL (day 2 or 3). No complications occurred during TUDS placement. On day 2, 1 stent had passed into the bladder. Eleven stents were completely intact, with seven others partially intact. Day 2 ureteral patency was demonstrated in all 19 stented ureters. Eighteen TUDS were removed completely during the secondary PNL with one incident of partial retention. All stent material had passed out of the body in all patients by 1 month. No adverse events were attributable to the TUDS. The TUDS appears to facilitate ureteral drainage for at least 48 hours after placement. Although occasional stent tail detachments were noted, these did not interfere with device function. The safety profile of TUDS was favorable, with no complications attributable to the device itself. A larger prospective clinical study in patients receiving TUDS placed retrograde after uncomplicated ureteroscopic manipulation appears appropriate on the basis of these initial findings.