Elsevier

Urology

Volume 83, Issue 4, April 2014, Pages 726-731
Urology

Endourology and Stones
In Vitro Comparisons of Retropulsion and Fragmentation Efficacy of 2 Cordless, Handheld Pneumatic and Electromechanical Lithotripsy Devices

https://doi.org/10.1016/j.urology.2013.11.008Get rights and content

Objective

To compare, in vitro, probe velocity/displacement, retropulsion, and fragmentation capacity of the cordless electromechanical (LithoBreaker) (hard vs soft probe guide) and pneumatic (StoneBreaker).

Materials and Methods

Probe velocities/displacements were measured using high-speed resolution camera (100.000 frames/s). The lithotripsy probes were projected through a 7.5F ureteroscope against a nonfrangible led ball placed in a 15F horizontally mounted silicone tube immersed in water bath as an in vitro ureter model. Retropulsion is considered as displacement distance of led ball. Fragmentation efficiency was quantified as number of shots required to break Bego-stone phantoms (hard [15:3] and soft [15:6], average size 7.5 × 5.5 mm) placed on metal mesh into <3-mm fragments. Mean and standard deviation of repetitive measurements were statistically analyzed.

Results

StoneBreaker yielded higher probe velocity (22 ± 1.9 m/s) compared with LithoBreaker with hard (14.2 ± 0.5 m/s) and soft (11.5 ± 0.5 m/s) probe. Maximum probe displacement for StoneBreaker was 1.04 mm vs 0.9 mm and 1.1 mm (hard vs soft LithoBreaker-probe, respectively). Retropulsion using 1-mm probes showed no statistical differences. Using harder 2-mm probe decreased Lithobreaker retropulsion significantly compared with Stonebreaker. The amount of shots (1-mm probe) to fragment soft Bego stones was significantly higher for LithoBreaker with soft (mean 31.5 ± 11.31) and hard (mean 21.5 ± 5.29) probe guide vs StoneBreaker (mean 11.2 ± 2.65). Fragmentation efficiency for hard Bego stones showed similar statistically significant outcome. Comparison of the 2 probe guides showed higher velocity linked to harder-probe that improved LithoBreaker fragmentation performance and reduce propulsion.

Conclusion

Both examined lithotripters are effective in cracking stone phantoms with relatively low pulse number. They produce comparable retropulsions. Fragmentation improved substantially using LithoBreaker with hard probe guide. More tests are required to assess differences in stone clearance time.

Section snippets

Materials and Methods

The used devices and their probes are shown in the Supplementary Figure 1A,B.

Results

The technical characters of both devices are listed in Table 1.

Comment

Despite recent advances in instruments (eg flexible endoscopes), stone fragmentation devices (eg laser technology), and stone retrieval devices, the stone-free rate remains a constant challenge after minimally invasive stone surgeries especially for upper tract calculi. A success rate of 91% was reported.13, 14, 15, 16 As mentioned before, up to 50% of patients with residual stone fragments after endoscopic stone removal (ureteroscopy or percutaneous nephrolithotomy) develop stone-related

Conclusion

The mechanic impact EMS LithoBreaker and the pneumatic Cook LMA StoneBreaker are comparably effective in stone disintegration. Both produced comparable amounts of retropulsion. The amount of single shots for fragmentation of stone phantoms was significantly higher for the LithoBreaker compared with the StoneBreaker irrespective of the probe size and probe guide used. Fragmentation characteristics of mechanic impact lithotripters improve with the hardness of the probe guide used.

Acknowledgment

The authors thank EMS company for their support and supplying the equipment for the current examinations. They also thank Mr. Wolfgang Merkle for his technical support.

References (21)

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Cited by (0)

Wael Y Khoder and Markus J Bader shared senior authorship.

Financial Disclosure: M.J.B. and N.H. were partially sponsored by Electric Medical Systems as speakers in international congress. The remaining authors declare that they have no relevant financial interests.

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