In vitro comparison of standard ultrasound and pneumatic lithotrites with a new combination intracorporeal lithotripsy device.

Objectives: A new combination intracorporeal lithotripter (Lithoclast Ultra) has been developed that incorporates the beneficial effects of pneumatic lithotripsy (rapid stone fragmentation) and ultrasound lithotripsy (rapid fragment removal). An in vitro study was performed to assess the efficiency of stone fragmentation and clearance of this new combination intracorporeal lithotripter compared with currently available ultrasound and pneumatic units.

Methods: Pneumatic and ultrasound lithotrites, along with the combination pneumatic/ultrasound unit, were used through a rigid 27F nephroscope to fragment and remove phantom stones made of BegoForm. The mean fragment removal times and stone fragment sizes for the standard ultrasound and pneumatic devices were compared with the combination unit to determine the completeness and efficiency of stone fragmentation and removal.

Results: The average time for stone clearance using the pneumatic and ultrasound devices was 23.8 and 12.9 minutes, respectively. The combination pneumatic/ultrasound unit was significantly more efficient, requiring only 7.4 minutes to completely fragment and clear all stone material (P <0.002). In addition, the average size of the 15 largest fragments removed was significantly less with the combination device than with the pneumatic and ultrasound lithotrites (1.67 mm versus 9.07 mm and 3.67 mm, respectively, P <0.00001).

Conclusions: The combination of pneumatic and ultrasound capabilities in a newly developed lithotrite exhibited a significantly enhanced ability to fragment and clear phantom stones compared with standard ultrasound or pneumatic devices alone. These preliminary studies suggest that this combination pneumatic/ultrasound lithotripter may be an ideal device for the expeditious removal of large-volume renal or bladder calculi. Additional studies are warranted to better assess the capabilities of this new device in treating human stones of various compositions and its safety, as well as the optimal power and frequency settings.