Novel Hydrogel for Stone Fragment Control During Ureteroscopic Lithotripsy

Abstract

Surgical treatment of kidney stones commonly involves ureteroscopic lithotripsy with laser-assisted stone fragmentations. Particles that remain are considered “clinically insignificant” and are left behind, though these fragments are associated with downstream complications such as infection and stone reformation. The researchers aimed to develop a novel hydrogel that would prevent stone retropulsion intraoperatively and facilitate complete fragment removal. A novel inversely thermosensitive gel was developed which would theoretically stay solid to surround kidney stone, suspend stone fragments and would become liquid for gel removal. The aim of this study was to better understand the gel delivery mechanism considering its unique thermal properties. It was hypothesized that due to the gel’s thermal properties, an active cooling method, i.e. an intracatheter cooled guide wire, would be necessary to maintain gel fluidity to reach the intended destination. The researchers designed an experiment to test gel delivery through a 5 French, 70 cm long catheter surrounded by body temperature water with and without a cooled guide wire. We found there was no significant difference between both trial groups, indicating the gel does not require an active cooling method and can be administered directly. The lack of easy-to-use and cost-effective commercially available options to effectively reduce residual stone fragments presents a path for clinical adoption of the proposed hydrogel. Future trials will look into the fluid mechanics of gel administration and potential clinical outcomes such as stone free rates and rates of complications.