How Lithotripsy Works
The first lithotripsy shockwave Unit set up in Queensland was in Brisbane at Holy Spirit hospital, Wickham terrace, in October 1990 and was the first machine used to treat kidney stones in the State, treating patients from all over QLD including Townsville, Cairns, Rockhampton , Gold Coast, & Toowoomba.
The original machine from the early 1980’s was called the HM1 Or Human model 1 and comprised a huge water bath, the Dornier MFL 5000 replaced the need for using a water bath and used a very large spark plug and water cushion for delivery. We now use an electromagnetic coil which is even more efficient.
The Dornier Epos Ultra then followed and was specifically designed for use in orthopaedic conditions with a much shorter focal length to the kidney machine to enable exact focusing on very small tendons.
ESWT works using acoustic waves of high pressure amplitudes with high rise times of a few nanoseconds and a frequency spectrum ranging from the audible to the far ultrasonic level.
Shockwaves result from intense changes in pressure such as explosion, supersonic aircraft, or lightning. These intense changes in pressure produce strong waves of compression and tensile forces that can travel through any elastic medium such as water, or certain solid substances.
There are several ways to generate shockwaves. Our machines either use an electromagnetic coil/lens combination to generate the shockwave or a pneumatic delivery using pulse triggering system with a projectile/applicator combination.
Soundwaves do not travel well through air. Shockwaves can be produced over a broad energy range from low to high energy so you can again tailor your treatment for different conditions.
FOCUSED Shockwaves are released from 60-240 shocks/min and from 0 .01mj energy to 0.5 mj energy per shockwave.
RADIAL shockwaves are produced with a pressure of between 1 and 4 Bar.
The therapy head is either coupled to the patients body via a water cushion or using oil/gel for transfer of energy from the hand piece, and coupling is also done via gel.
The EMSE (Electromagnetic Shockwave Emitter) works on a similar principal to a loud speaker. A capacitor is charged to high voltage of several kilovolts. After charging this energy is available for a high-energy discharge of short duration.
The unit also consists of a coil opposite a highly conductive metallic layer. The two will be magnetically repulsed due to the current pulse through the system, produced after discharge. The metallic layer deflects towards the wave propagating medium (water) causing a shockwave in the water. The intensity of which is proportional to the current pulse and is propagated with the speed of sound. At a distance at the end of its path in the water a plane shock wave results. This is then focused using a convex acoustic lens to produce great and steep pressure amplitudes over a limited volume to the area of inflammation.