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

Area of Science:

• Urology
• Medical Devices
• Nephrolithiasis Management

Background:

• Kidney stone management often involves fragment removal after lithotripsy.
• Current methods like direct in-scope suction (DISS) have limitations in efficiency.
• Novel aspiration systems aim to improve fragment clearance.

Purpose of the Study:

• To evaluate the aspiration efficiency and fragment evacuation performance of the second-generation CVAC system.
• To compare CVAC against direct in-scope suction (DISS) devices.
• To assess clearance rates and time to clearance for different fragment sizes.

Main Methods:

• Synthetic stones (Begostone) were categorized into five size groups (63 µm-3.3 mm).
• The CVAC catheter (7 Fr) was tested against two DISS ureteroscopes (Pusen 3.6 Fr and 5.1 Fr).
• Standardized trials used controlled irrigation (160 mmHg) and suction (155 mmHg), measuring aspiration efficiency, clearance success within 180 s, time to clearance, and clogging incidence.

Main Results:

• CVAC exhibited significantly higher aspiration efficiency across all fragment sizes (p < 0.01), up to 41x greater than DISS.
• Complete clearance within 180 s was achieved in 100% of CVAC trials for smaller fragments (Groups 1-4) and 25% for the largest (Group 5).
• DISS devices failed consistently for medium to large fragments (Groups 3-5); CVAC demonstrated faster clearance (median 49 s) and maintained function during clogs.

Conclusions:

• The CVAC system significantly outperformed DISS in aspiration efficiency, clearance rates, and time to clearance.
• The dual-channel simultaneous irrigation-aspiration design of CVAC offers advantages over DISS.
• Further in vivo studies are recommended to validate these ex vivo findings.