You are prohibited from using or uploading content you accessed through this website into external applications, bots, software, or websites, including those using artificial intelligence technologies and infrastructure, including deep learning, machine learning and large language models and generative AI.


We developed innovations in shock wave lithotripsy (SWL) technology.

Materials and Methods:

Two technical upgrades were implemented in an original unmodified HM-3 lithotriptor (Dornier Medical Systems, Inc., Kennesaw, Georgia). First, a single unit ellipsoidal reflector insert was used to modify the profile of lithotriptor shock wave (LSW) to decrease the propensity of tissue injury in SWL. Second, a piezoelectric annular array (PEAA) generator (f = 230 kHz and F = 150 mm) was used to produce an auxiliary shock wave of approximately 13 MPa in peak pressure (at 4 kV output voltage) to intensify the collapse of LSW induced bubbles near the target stone for improved comminution efficiency.


Consistent rupture of a vessel phantom made of single cellulose hollow fiber (i.d. = 0.2 mm) was produced after 30 shocks by the original HM-3 reflector at 20 kV. In comparison no vessel rupture could be produced after 200 shocks using the upgraded reflector at 22 kV or the PEAA generator at 4 kV. Using cylindrical BegoStone phantoms (Bego USA, Smithfield, Rhode Island) stone comminution efficiencies (mean ± sd) after 1,500 shocks produced by the original and upgraded HM-3 reflectors, and the combined PEAA/upgraded HM-3 system, were 81.3% ± 3.5%, 90.1% ± 4.3% and 95.2% ± 3.3%, respectively (p <0.05).


Optimization of the pulse profile and sequence of LSW can significantly improve stone comminution while simultaneously decreasing the propensity of tissue injury during in vitro SWL. This novel concept and associated technologies may be used to upgrade other existing lithotriptors and to design new shock wave lithotriptors for improved performance and safety.


  • 1 : A survey of the acoustic output of commercial extracorporeal shock wave lithotripters. Ultrasound Med Biol1989; 15: 213. Google Scholar
  • 2 : Fracture mechanics model of stone comminution in ESWL and implications for tissue damage. Phys Med Biol2000; 45: 1923. Google Scholar
  • 3 : Acoustic cavitation generated by an extracorporeal shockwave lithotripter. Ultrasound Med Biol1987; 13: 69. Google Scholar
  • 4 : The role of stress waves and cavitation in stone comminution in shock wave lithotripsy. Ultrasound Med Biol2002; 28: 661. Google Scholar
  • 5 : In vitro study of the mechanical effects of shock-wave lithotripsy. Ultrasound Med Biol1997; 23: 1107. Google Scholar
  • 6 : Medical applications and bioeffects of extracorporeal shock waves. Shock Waves1994; 4: 55. Google Scholar
  • 7 : Dynamics of bubble oscillation in constrained media and mechanisms of vessel rupture in SWL. Ultrasound Med Biol2001; 27: 119. Crossref, MedlineGoogle Scholar
  • 8 : Kidney damage and renal functional changes are minimized by waveform control that suppresses cavitation in shock wave lithotripsy. J Urol2002; 168: 1556. LinkGoogle Scholar
  • 9 : Improvement of stone fragmentation during shock wave lithotripsy using a combined EH/PEAA shock-wave generator–in vitro experiments. Ultrasound Med Biol2000; 26: 457. Google Scholar
  • 10 : Dual-pulse lithotripter accelerates stone fragmentation and reduces cell lysis in vitro. Ultrasound Med Biol2003; 29: 1045. Google Scholar
  • 11 : Suppression of large intraluminal bubble expansion in shock wave lithotripsy without compromising stone comminution: methodology and in vitro experiments. J Acoust Soc Am2001; 110: 3283. Crossref, MedlineGoogle Scholar
  • 12 : Suppression of large intraluminal bubble expansion in shock wave lithotripsy without compromising stone comminution: refinement of reflector geometry. J Acoust Soc Am2003; 113: 586. Google Scholar
  • 13 Zhou, Y.F.: Optimization of pressure waveform, distribution and sequence in shock wave lithotripsy, Ph.D Dissertation, Duke University, Durham, North Carolina, 2003 Google Scholar
  • 14 : A dual passive cavitation detector for localized detection of lithotripsy-induced cavitation in vitro. J Acoust Soc Am2000; 107: 1745. Google Scholar
  • 15 : Extracorporeal Shock Wave Lithotripsy: New Aspects in the Treatment of Kidney Stone Disease. New York: Karger1982. Google Scholar
  • 16 : Inertial cavitation and associated acoustic emission produced during electrohydraulic shock wave lithotripsy. J Acoust Soc Am1997; 101: 2940. Google Scholar
  • 17 : Shockwave lithotripsy: anecdotes and insights. J Endourol2003; 17: 687. Google Scholar
  • 18 : Evaluation of synchronous twin pulse technique for shock wave lithotripsy: determination of optimal parameters for in vitro stone fragmentation. J Urol2003; 170: 2190. LinkGoogle Scholar
  • 19 : Dynamic photoelastic study of the transient stress field in solids during shock wave lithotripsy. J Acoust Soc Am2001; 109: 1226. Google Scholar
  • 20 : The effect of treatment strategy on stone comminution efficiency in shock wave lithotripsy. J Urol2004; 172: 349. LinkGoogle Scholar

From the Department of Mechanical Engineering and Materials Science (YZ, FHC, PZ), and Duke Comprehensive Kidney Stone Center, Division of Urology (GMP, PZ), Duke University, Durham, North Carolina