title: In-vitro assessment of a new portable ballistic lithotripter with percutaneous and ureteroscopic models.
abstract: OBJECTIVE
  The EMS Swiss LithoBreaker is a new, portable, electrokinetic lithotripter. We compared its tip velocity and displacement characteristics with a handheld, pneumatic lithotripter LMA StoneBreaker.™ We also evaluated fragmentation efficiency using in vitro models of percutaneous and ureteroscopic stone fragmentation.
  
  
  METHODS
  Displacement and velocity profiles were measured for 1-mm and 2-mm probes using a laser beam aimed at a photo detector. For the percutaneous model, 2-mm probes fragmented 10-mm spherical BegoStone phantoms until the fragments passed through a 4-mm mesh sieve. The ureteroscopic model used 1-mm probes and compared the pneumatic and electrokinetic devices to a 200-μm holmium laser fiber. Cylindrical (4-mm diameter, 4-mm length) BegoStone phantoms were placed into silicone tubing to simulate the ureter; fragmented stones passed through a narrowing in the tubing.
  
  
  RESULTS
  For both 1-mm and 2-mm probes, the electrokinetic device had significantly higher tip displacement and slower tip velocity, P<0.01. In the percutaneous model, the electrokinetic device needed an average of 484 impulses over 430 seconds to fragment one BegoStone, while the pneumatic device needed 29 impulses over 122 seconds to fragment one stone. Both clearance times and number of impulses needed for percutaneous stone clearance were significantly different at P<0.01. Ureteroscopically, the mean clearance time was 97 seconds for the electrokinetic lithotripter, 145 seconds for the pneumatic lithotripter, and 304 seconds for the laser. Comparing the pneumatic device with the electrokinetic device ureteroscopically, there was no significant difference in clearance time, P=0.55. Both the pneumatic and electrokinetic lithotripters, however, demonstrated decreased clearance times compared with the laser, P=0.027.
  
  
  CONCLUSIONS
  The portable electrokinetic lithotripter may be better suited for ureteroscopy instead of percutaneous nephrolithotomy. It appears to be comparable to the portable pneumatic device in the ureter. Further clinical studies are needed to confirm these findings in vivo.
authors.affiliation: Department of Surgery, Division of Urology, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: Agnes J
authors.initials: AJ
authors.lastname: Wang
authors.forename: Gregory T
authors.initials: GT
authors.lastname: Baldwin
authors.forename: James C
authors.initials: JC
authors.lastname: Gabriel
authors.forename: F Hadley
authors.initials: FH
authors.lastname: Cocks
authors.forename: Zachariah G
authors.initials: ZG
authors.lastname: Goldsmith
authors.forename: Muhammad W
authors.initials: MW
authors.lastname: Iqbal
authors.forename: Gaston M
authors.initials: GM
authors.lastname: Astroza
authors.forename: W Neal
authors.initials: WN
authors.lastname: Simmons
authors.forename: Pei
authors.initials: P
authors.lastname: Zhong
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Preminger
authors.forename: Michael Eric
authors.initials: ME
authors.lastname: Lipkin
mesh_terms: D007669:Kidney Calculi / Q000601:surgery; D008096:Lithotripsy / Q000295:instrumentation*; D009403:Nephrostomy, Percutaneous / Q000295:instrumentation*; D019047:Phantoms, Imaging; D018666:Ureteroscopy / Q000295:instrumentation*