Radial Shock Wave Devices Generate Cavitation

Nikolaus B M Császár; Nicholas B Angstman; Stefan Milz; Christoph M Sprecher; Philippe Kobel; Mohamed Farhat; John P Furia; Christoph Schmitz

doi:10.1371/journal.pone.0140541

Radial Shock Wave Devices Generate Cavitation

PLoS One. 2015 Oct 28;10(10):e0140541. doi: 10.1371/journal.pone.0140541. eCollection 2015.

Authors

Nikolaus B M Császár¹, Nicholas B Angstman¹, Stefan Milz¹, Christoph M Sprecher², Philippe Kobel³, Mohamed Farhat³, John P Furia⁴, Christoph Schmitz¹

Affiliations

¹ Extracorporeal Shock Wave Research Unit, Department of Anatomy II, Ludwig-Maximilians-University of Munich, Munich, Germany.
² AO Research Institute Davos, Davos, Switzerland.
³ Hydraulic Machines Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
⁴ SUN Orthopaedic Group, Lewisburg, Pennsylvania, United States of America.

Abstract

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.

Methods and findings: 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.

Clinical relevance: 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.

MeSH terms

Animals
Caenorhabditis elegans / physiology*
Fiber Optic Technology
High-Energy Shock Waves*
Locomotion / radiation effects
Pressure
Sound
Time Factors
X-Ray Film

Grants and funding

JPF was employed by SUN Orthopaedic Group during this study and received funding in the form of salary. Dr. Furia is paid for clinical work, not for any research activities. Accordingly, neither SUN Orthopaedic Group nor any other organization/institution have had any role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.