In vitro evaluation of the Lithoclast Ultra Vario combination lithotrite

Jonathan N. VonDerHaar, James A. McAteer, James C. Williams, James E. Lingeman

Research output: Contribution to journalArticle

4 Scopus citations


Rigid intracorporeal lithotrites can be invaluable in the removal of large stone burdens during percuta neous nephrolithotomy. One such device, the Lithoclast Ultra Vario (LUV) has an outer ultrasound probe and inner pneumatic-ballistic probe. The ballistic probe can be advanced or retracted and run at 1-12 Hz. Since it can be difficult to predict optimal settings with any new device, we asked if in vitro testing could give insight into how best to operate this lithotrite. We tested the LUV under hands-free conditions that simulate treatment of fixed stones and freely movable stones. A fixed-stone test system measured the time to penetrate a gypsum model stone placed atop the probe and a movable-stone system determined time for comminution of a stone within a confined space. In addi tion, the time to evacuate 2-mm stone particles was mea sured. For hands-on testing, model stones were placed in a plastic dish submerged in water and the time to comminu tion was measured. Penetration time of fixed stones was faster with the ballistic probe extended 2.5 mm than when retracted (5.30 ± 0.85 vs. 8.75 ± 1.07 s, p < 0.0001). Com minution of free stones was faster with the ballistic probe retracted than when it was extended 1 mm or 2.5 mm (9.7 ± 0.9, 13.8 ± 1.3, 23.7 ± 3.2 s, p < 0.0001). In hands-on testing, extending the ballistic probe substantially reduced the efficiency of comminution (36.7 ± 6.4 vs. 131.3 ± 15.3 s, p < 0.0001). Clearance of fragments was considerably faster when the pneumatic-ballistic rate was 12 Hz com pared to 1Hz (12.3 ± 1.1 vs. 28.3 ± 2.2 s, p < 0.0001). These in vitro findings suggest ways to take advantage of the positive features while minimizing potential limitations of this lithotrite. Extending the ballistic probe is an advan tage when the stone is immobile, as would be the case in treating a large stone that can be isolated against the wall of the pelvicalyceal system, but is a distinct disadvantage - due to retropulsion - when the stone is free to move. Operation of the LUV at fast ballistic rate significantly improved its ability to aspirate stone fragments.

Original languageEnglish (US)
Pages (from-to)485-489
Number of pages5
JournalUrological Research
Issue number6
StatePublished - Dec 1 2010


  • In vitro testing
  • Intracorporeal lithotripsy
  • Kidney stones
  • Lithotrite

ASJC Scopus subject areas

  • Urology

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