Cavitation bubbles generated by the D-Actor 200 and the Swiss DolorClast devices.

<p>The panels show the frames with the highest number of labeled pixels (from the corresponding high-speed imaging film sequences described in the main text) generated by the D-Actor 200 (A-D) operated at 3 bar and 1 Hz (A), 3 bar and 15 Hz (B), (maximum) 5 bar and 1 Hz (C), and 5 bar and 15 Hz (D), as well as with the Swiss DolorClast (E-H) operated at 3 bar and 1 Hz (E), 3 bar and 15 Hz (F), (maximum) 4 bar and 1 Hz (G), and 4 bar and 15 Hz (H). The scale bar represents 5 mm.</p

Devices investigated in the present study and their working principles.

<p>(A) Working principle of radial extracorporeal shock wave therapy (rESWT) devices. Compressed air (1) is used to fire a projectile (2) within a guiding tube (3) that strikes a metal applicator (4) placed on the patient’s skin. The projectile generates stress waves in the applicator that transmit pressure waves (5) non-invasively into tissue. Note that both the Swiss DolorClast (B) and the D-Actor 200 (C) share this construction principle. (B) “Radial” handpiece of the Swiss DolorClast (EMS) with the 15-mm applicator. (C) Handpiece of the D-Actor 200 (Storz Medical) with the 15-mm applicator. (D) Vibracare (G5/General Physiotherapy). The arrow indicates the direction of view into the chamber of the Vibracare head that was opened in (E); the asterisk indicates the backside of the chamber. (E) Working principle of the Vibracare. A flywheel mass (6) rotates around a vertical axis (7) within a chamber (asterisk).</p

Absence of cavitation bubbles when investigating the Vibracare device with high speed imaging.

<p>The arrows point to the surface of the moving head of the device in frames of the high-speed imaging experiments, showing minimum (A) and maximum (B) deflection of the device’s head.</p

Exposure of <i>C</i>. <i>elegans</i> worms to radial shock waves and the movements of the Vibracare head.

<p>In (A) the “Radial” handpiece of the Swiss DolorClast (Electro Medical Systems) with the 6-mm applicator was lowered from above into one U-bottom well of a 96-well plate containing <i>C</i>. <i>elegans</i> worms either in S-Medium or PVA (see main text). A fluorinated rubber O-ring (green) was used to seal the U-bottom well. In (B) a 96-well plate containing <i>C</i>. <i>elegans</i> worms, sealed with parafilm and closed with its lid, was fixed with adhesive tape onto the upwards facing massaging head of the Vibracare (G5/General Physiotherapy).</p

Damage of the surface of x-ray film caused by pressure waves generated by the D-Actor 200 and the Swiss DolorClast devices.

<p>The figures show the surface of x-ray film after exposure to 10,000 pressure waves generated by the D-Actor 200 (A) and the Swiss DolorClast (B) at maximum energy settings (i.e., 5 bar for the D-Actor 200 and 4 bar for the Swiss DolorClast). The asterisk in (A) indicates a hole in the x-ray film. The Vibracare device operated at maximum energy settings (50 cycles per second) had no detectable impact on x-ray film (C). The scale bars represent 500 μm.</p

Pressure waves and cavitation bubbles generated by the D-Actor 200 and the Swiss DolorClast devices.

<p>Representative frames of the high-speed imaging experiments described in the main text, showing pressure waves (arrows) emitted from the applicators of the D-Actor 200 operated at (maximum) 5 bar air pressure (on the left) and the Swiss DolorClast operated at (maximum) 4 bar air pressure (on the right). The panels show five consecutive frames each 3.33 μs apart, plus a subsequent frame that was captured 120 μs after the first frame. Asterisks indicate the tip of the applicators lowered from above into the top section of the camera’s field-of-view. Note that the first cavitation bubbles were already detected at 10 μs after occurrence of the pressure wave (arrowheads in frames “+10 μs”). The scale bar represents 5 mm.</p

Pressure as a function of time generated by the D-Actor 200 and the Swiss DolorClast devices.

<p>The panels show the pressure as a function of time generated by the D-Actor 200 operated at 3 bar (A,E,I,M) and (maximum) 5 bar (B,F,J,N) as well as with the Swiss DolorClast operated at 3 bar (C,G,K,O) and (maximum) 4 bar (D,H,L,P). Measurements were performed five times each; the data shown here represent the measurements (one out of five repetitions) that resulted in the highest positive pressure each. Measurements were performed with a laser hydrophone at a distance of 1 mm (A-D), 5 mm (E-H), 10 mm (I-L) and 20 mm (M-P) to the applicator.</p

Influence of radial shock waves and the movements of the Vibracare head on <i>C</i>. <i>elegans</i> locomotion ability.

<p>The upper panel shows mean and standard error of the mean (SEM) of the speed of locomotion of the following groups of <i>C</i>. <i>elegans</i>: C-S, control worms in S-medium; SW-S, exposure of worms to 500 impulses of radial shock waves (rESW) in S-medium; MA-S, exposure of worms to the movements of the Vibracare head in S-medium; C-PVA, control worms in polyvinyl alcohol (PVA); SW-PVA, exposure of worms to 500 impulses of rESW in PVA; MA-PVA, exposure of worms to the movements of the Vibracare head in PVA. The lower panel shows the percentages of worms paralyzed (red bars) and not paralyzed (green bars) of the same groups of <i>C</i>. <i>elegans</i>. The numbers in red above the bars in the upper panel indicate the numbers of worms per group. ***, p < 0.001 (results of Dunn's multiple comparison test).</p

Results of the quantitative analysis of the high-speed imaging experiments.

<p>Number of detected pixels as a function of time in the high-speed imaging experiments described in the main text, obtained for the D-Actor 200 (A-D) operated at 3 bar and 1 Hz (A), 3 bar and 15 Hz (B), (maximum) 5 bar and 1 Hz (C), and 5 bar and 15 Hz (D), as well as with the Swiss DolorClast (E-H) operated at 3 bar and 1 Hz (E), 3 bar and 15 Hz (F), (maximum) 4 bar and 1 Hz (G), and 4 bar and 15 Hz (H).</p

Experimental set-up of the 50 Hz MF exposure of the present study.

<p>Details are provided in the main text.</p