Cabo, Jackson J S

Purpose: To compare stone clearance, stone-free status, and complications between patients undergoing ureteroscopy for renal stones using either Flexible and Navigable Ureteral Access Sheath (FANS) or the CVAC 2.0 system. Materials and Methods: A prospective study was completed on patients undergoing flexible ureteroscopy for renal stones at a single institution from March 2024 to December 2024. Subject demographics, intra-op data, volumetric and single-dimension stone clearance on non-contrast CT, and complications were compared. Stone-free rates (SFRs) using standardized cutoffs were compared. Pearson correlation analysis was performed to assess the relationship between preoperative stone volume and postoperative stone burden. Subanalysis was performed for patients with preoperative stone burden >1.5 cm. Results: A total of 123 cases (CVAC 2.0-36, FANS-87) were included, with 64 eligible for volumetric analysis. Preoperative stone volume was larger in the CVAC group vs FANS (1075 mm 3 vs 397 mm 3 ; p < 0.001). Absolute stone clearance was greater in the CVAC group (1016 mm 3 vs 392 mm 3 ; p < 0.001), whereas residual stone volume (4.1 mm 3 vs 15.0 mm 3 ; p = 0.55) and SFRs (90% vs 81%; p = 0.48) were similar. In individuals with >1.5 cm preoperative stone burden, relative stone clearance was greater with CVAC 2.0 (98.9% vs 95.1%; p = 0.026). Pearson correlation analysis revealed positive linear relationship between preoperative stone volume and residual stone volume for FANS, but not for CVAC 2.0. Conclusions: In this comparative study of FANS and CVAC 2.0, over 95% stone clearance was observed in both groups despite large initial stone burdens. In contrast to FANS, residual stone volumes with CVAC 2.0 did not increase significantly with increasing preoperative stone volumes.