Radial Shock Wave Devices Generate Cavitation.
BACKGROUND
Conflicting reports in the literature have raised the question whether radial extracorporeal shock wave therapy (rESWT) devices and vibrating massage devices have similar energy signatures and, hence, cause similar bioeffects in treated tissues.


RESULTS
We used laser fiber optic probe hydrophone (FOPH) measurements, high-speed imaging and x-ray film analysis to compare fundamental elements of the energy signatures of two rESWT devices (Swiss DolorClast; Electro Medical Systems, Nyon, Switzerland; D-Actor 200; Storz Medical, Tägerwillen, Switzerland) and a vibrating massage device (Vibracare; G5/General Physiotherapy, Inc., Earth City, MO, USA). To assert potential bioeffects of these treatment modalities we investigated the influence of rESWT and vibrating massage devices on locomotion ability of Caenorhabditis elegans (C. elegans) worms.


RESULTS
FOPH measurements demonstrated that both rESWT devices generated acoustic waves with comparable pressure and energy flux density. Furthermore, both rESWT devices generated cavitation as evidenced by high-speed imaging and caused mechanical damage on the surface of x-ray film. The vibrating massage device did not show any of these characteristics. Moreover, locomotion ability of C. elegans was statistically significantly impaired after exposure to radial extracorporeal shock waves but was unaffected after exposure of worms to the vibrating massage device.


CONCLUSIONS
The results of the present study indicate that both energy signature and bioeffects of rESWT devices are fundamentally different from those of vibrating massage devices.


CONCLUSIONS
Prior ESWT studies have shown that tissues treated with sufficient quantities of acoustic sound waves undergo cavitation build-up, mechanotransduction, and ultimately, a biological alteration that "kick-starts" the healing response. Due to their different treatment indications and contra-indications rESWT devices cannot be equated to vibrating massage devices and should be used with due caution in clinical practice.
Extracorporeal Shock Wave Research Unit, Department of Anatomy II, Ludwig-Maximilians-University of Munich, Munich, Germany.
Nikolaus B M
NB
Császár
Extracorporeal Shock Wave Research Unit, Department of Anatomy II, Ludwig-Maximilians-University of Munich, Munich, Germany.
Nicholas B
NB
Angstman
Extracorporeal Shock Wave Research Unit, Department of Anatomy II, Ludwig-Maximilians-University of Munich, Munich, Germany.
Stefan
S
Milz
AO Research Institute Davos, Davos, Switzerland.
Christoph M
CM
Sprecher
Hydraulic Machines Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
Philippe
P
Kobel
Hydraulic Machines Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
Mohamed
M
Farhat
SUN Orthopaedic Group, Lewisburg, Pennsylvania, United States of America.
John P
JP
Furia
Extracorporeal Shock Wave Research Unit, Department of Anatomy II, Ludwig-Maximilians-University of Munich, Munich, Germany.
Christoph
C
Schmitz
D000818:Animals; D017173:Caenorhabditis elegans / Q000502:physiology*; D005336:Fiber Optic Technology; D019220:High-Energy Shock Waves; D008124:Locomotion / Q000528:radiation effects; D011312:Pressure; D013016:Sound; D013997:Time Factors; D014962:X-Ray Film