Steerable Ureteroscopic Renal Evacuation (SURE) for Large Renal Stones: A Multi-Institutional Center Study

Background: The results of a recent pilot study suggest that steerable ureteroscopic renal evacuation (SURE) is safe and more effective in stone removal than basketing following laser lithotripsy. The objective of this retrospective study was to further assess the safety and efficacy of SURE using the CVAC® Aspiration System (Calyxo, Inc., Pleasanton, CA) in patients with large stone burdens. Materials and Methods: Patients with a baseline stone burden of ≥10 mm who underwent SURE were identified. Subject demographics, secondary procedures, complications, and stone clearance (defined as percent baseline volume reduction) were evaluated. Subanalyses were performed to explore patients identified as high risk for percutaneous nephrolithotomy (PCNL) because (1) they were on anticoagulation or antiplatelet therapy at the time of procedure or (2) they had limited mobility due to neurologic conditions. Results: Identified patients (N = 43) had a mean preoperative stone burden of 29 ± 12 mm and mean stone volume of 3092 ± 5002 mm3. Approximately one-half of patients (n = 24, 55.8%) had CT imaging at follow-up, and of those, 8 (33.3%) had no residual stones, 22 (91.7%) had >90% stone clearance, 23 (95.8%) had >80% stone clearance, and 24 (100%) had >60% stone clearance. Stone clearance based on baseline stone burden varied between 93.8% and 98.9%. At baseline, 21 patients were anticipated to require staged ureteroscopy; however, only two of those (9.5%) needed secondary procedures. High-risk patients (n = 22) were on anticoagulation or antiplatelet therapy (n = 12) or had neurologic conditions (n = 10). Stone clearance was 97% among patients in the anticoagulated cohort with postoperative CT imaging and 83% in the neurologic condition cohort. There were no device-related complications and no postoperative admissions. Conclusions: The CVAC Aspiration System is safe and effective for treating large stone burdens, including in high-risk patients, and may decrease the need for PCNL or secondary procedures. ClinicalTrials.gov Identifier: NCT04519294.