Ureteroscopic Aspiration Dynamics and Stone Fragment Evacuation: In Vitro Comparison of the Second-generation CVAC System and Direct In-scope Suction.

OBJECTIVE

To compare the aspiration efficiency and fragment evacuation performance of the second-generation CVAC aspiration system with direct in-scope suction (DISS) devices.

METHODS

Synthetic stones (Begostone) were sieved into 5 size groups (63 µm-3.3 mm). The CVAC catheter (7 Fr lumen) was tested against 2 DISS ureteroscopes (Pusen 3.6 Fr and 5.1 Fr). Standardized trials were performed using a Thermedx irrigation system (160 mmHg) and Neptune suction (155 mmHg). Endpoints included aspiration efficiency (g/min), clearance success within 180 seconds, time to clearance (Kaplan-Meier analysis), and clogging incidence.

RESULTS

CVAC achieved significantly higher aspiration efficiency than DISS across all fragment sizes (P <.01), with rates up to 41× greater (group 4 vs Pusen 3.6 Fr). Complete clearance within 180 seconds was achieved in 100% of CVAC trials for groups 1-4 and in 25% of group 5 runs, whereas both Pusen devices failed consistently in groups 3-5. Kaplan-Meier analysis confirmed faster and more complete clearance with CVAC (median 49 seconds, 95% confidence interval [CI]: 44-90 seconds), while neither the Pusen device reached median clearance. Cox modeling showed the probability of clearance with Pusen devices was <25% that of CVAC. Only CVAC maintained partial or complete clearance when clogs occurred.

CONCLUSION

The CVAC system outperformed DISS in aspiration efficiency, clearance rates, and time to clearance across multiple fragment sizes. These findings highlight the advantages of a dual-channel simultaneous irrigation-aspiration design compared to DISS systems. Further ex vivo and clinical studies are warranted to confirm these results in vivo.