SIEMENS EXTRACORPOREAL LITHORIPTER

Article:

Extracorporeal shock wave lithotripsy: A technique for shattering a kidney stone or gallstone with a shock wave that is produced outside the body. Anesthesia may be necessary to control the pain, depending on the size and density of the stone and on the energy of the shock wave needed to break.
The first lithotripter for the treatment of human kidney stones, the HM1 (Human Model 1, Dornier, Germany; now Dornier MedTech America, Inc., Kennesaw, GA, USA), was introduced in 1980 by Chaussy et al. [1]. This is a classical example of a ‘spin-off’ from a military development, as in this case observations from the Dornier Star Fighter programme were translated into the development of this innovative medical device.
The first serial lithotripter, the Dornier HM3, became so successful that ESWL quickly replaced open stone surgery and became the first-line option for most stones in the upper urinary tract [3], and until the present, despite all the advances in percutaneous nephrolithotomy (PCNL) and transurethral stone treatment (ureteroscopy) , still more than half of all stones worldwide are treated using ESWL.
The current third- and fourth-generation machines are versatile, user-friendly and safe. Usually in a day-case setting, procedures are conducted under analgesia or sedo-analgesia .
One drawback remains: Despite all technical advances, the stone-free rates of the reference machine, the Dornier HM3, have never been reached again .
Thirty years after its introduction, extracorporeal shockwave lithotripsy (ESWL) is still first-line treatment for more than half of all urinary tract stones, but machines and treatment strategies have significantly developed over time. In this review, we summarise the latest knowledge about the clinically important aspects of ESWL.
Methods
We searched PubMed to identify relevant reports and the latest European Association of Urology guidelines, and standard urological textbooks were consulted.
Results
New technical developments include: Twin-head and tandem-pulse shock-wave generators; wide-focus, low-pressure systems; optimised coupling; and automated location and acoustic tracking systems. Indications have been refined, making possible the identification of patients in whom ESWL treatment is likely to fail. By lowering the shock-wave rate, improving coupling, applying abdominal compression, power ‘ramping’ and postoperative medical expulsion therapy, treatment protocols have been optimised.
The efficacy of ESWL lies in its ability to pulverize calculi in vivo into smaller fragments, which the body can then expulse spontaneously. Shockwaves are generated and then focused onto a point within the body. The shockwaves propagate through the body with negligible dissipation of energy (and therefore damage) owing to the minimal difference in density of the soft tissues. At the stone-fluid interface, the relatively large difference in density, coupled with the concentration of multiple shockwaves in a small area, produces a large dissipation of energy.
Conclusions
Promising new technical developments are under development, with the potential to increase the stone-free rate after ESWL. For optimal results, the refined indications need to be respected and optimised treatment protocols should be applied.