Preventing migration of stones during fragmentation with thermosensitive polymer

Area of Science:

• Urology
• Biomaterials Science
• Nephrology

Background:

• Minimizing stone migration during lithotripsy is crucial for treatment efficacy.
• Current methods for stone stabilization present limitations.
• Thermosensitive polymers offer potential for targeted in-situ applications.

Purpose of the Study:

• To evaluate a thermosensitive polymer for stabilizing stones during extracorporeal (SWL) and intracorporeal lithotripsy.
• To assess the polymer's efficacy in preventing ureteral stone migration in vivo.
• To determine the safety and biocompatibility of the polymer in the ureteral environment.

Main Methods:

• Phantom stones (calcium oxalate, plaster of Paris) were subjected to SWL in polymer gel versus saline.
• In vivo studies utilized electrohydraulic lithotripsy on ureteral stones in swine, with polymer instillation.
• Renal function was assessed post-procedure by comparing urine collections from treated and contralateral ureters.

Main Results:

• The polymer did not improve stone fragmentation with SWL.
• In vivo, the polymer effectively prevented ureteral stone migration.
• No significant differences in renal function parameters were observed between treated and control sides.
• The polymer was easily removed from the ureter using cold saline.

Conclusions:

• Thermosensitive polymer instillation proximal to ureteral stones effectively prevents migration during lithotripsy.
• The polymer demonstrates a favorable safety profile, being non-traumatic to the ureter.
• This approach presents a promising adjunct for managing ureteral stones during lithotripsy procedures.