Prospective controlled ex vivo observational study on changes in elasticity of ureteral stents following clinical use

Ureteral stents significantly impair health-related quality of life. Advances in stent material, particularly in polyurethane compositions, may mitigate adverse effects. This study evaluated ex vivo changes in the elasticity of ureteral stents made from a novel thermoplastic polyurethane composite (HybridPRO Technology by Urotech) compared to a control stent.

In this prospective controlled ex vivo observational study, 97 patients undergoing ureteroscopy received one of two types of tethered 7 Fr, 28 cm ureteral stents. Eleven patients underwent bilateral procedures, yielding a total of 108 stents (54 per group). Group 1 received a polyurethane stent with HybridPRO Technology and group 2 received a polyurethane stent without HybridPRO Technology. After removal, stents were measured at the patient's bedside using a hanging apparatus with a predetermined 400 g load. In vitro (room temperature) and ex vivo elongations were recorded, and the net difference was calculated.

In vitro measurements showed a median elongation of 4 mm (IQR: 4-4) in group 1 vs 2 mm (IQR: 2-2) in group 2. Ex vivo, group 1 elongated significantly more (median, 12 mm; IQR: 11-13) compared to group 2 (median: 5 mm; IQR: 4-6; p <0.001). The net difference was larger in group 1 (median: 10 mm; IQR, 9-11) compared to group 2 (median: 3 mm; IQR: 2-4; p <0.001).

Ureteral stents incorporating HybridPRO Technology demonstrated significantly greater elongation under standardized load after use compared to a control stent. These findings indicate material changes ex vivo; however, the clinical implications regarding comfort or quality of life remain to be determined in future studies.