Biological effects of shock waves

Abstract

Summary.Extracorporeal shock wave lithotripsy has become established worldwide as the method of choice for the treatment of nephrolithiasis and ureterolithiasis over the last 10 years. Although initial studies showed no damaging effects of the shock waves on organs and tissues, numerous recent reports have presented evidence for severe acute effects and chronic complications after shock wave treatment. The pathophysiological effects on kidneys and the histopathological effects on organs or tissues in man and animal, and also the effects on ceils in culture and tumors are sumarized. Suspended and immobilized cell cultures were used to characterize and quantify the efficacy of shock wave. Extended applications of shock waves and possible modifications to shock wave generators are discussed.A reproducible generation of shock waves in fluids was first reported by Eisenmenger [31,32], who described an electromagnetic arrangement using a flat solenoid and a metal membrane. About 20 years later, underwater sparkgap-induced shock waves were used for kidney stone disintegration [17], a procedure that has become clinical routine [30]. In the meantime, the third generation of lithotripters has been developed (Siemens Lithostar Plus, Dornier Compact, Storz Modulith). Most of them are equipped with electromagnetic shock-wave emitters (EMSE), but piezo-electric shock-wave sources (Piezolith 2500, Diasonics) with similar properties for stone fragmentation are also in clinical use. However, all commercially available shock-wave generators (spark gap, electromagnetic, piezo-electric) produce side effects that accompany stone disintegration in patients. Furthermore, their biological effects are described as injuries to organs or tissues in vivo that have been exposed to the focal area of shock waves and as damage to cells in culture that have been treated with shock waves. * Dedicated to Prof. Dr. Wolfgang Eisenmenger on the occasion of his 60th birthday Side effectsIn kidney-or gallstone treatment with shock waves, side effects are equivocally classified and certainly depend not only on the number and energy of the applied shock waves but also on the disposition of the patients. Petechial bleeding of the skin that can be observed macroscopically has been found in about 10% of patients [29]. Varying degrees of subcapsular fluid collection and hemorrhage have been detected using different methods [4,37,71].Most of the damage typically caused by shock-wave treatments is routinely observed and is not considered to represent severe pathological change, but the occurrence of perirenal hematoma has increased significantly in patients with pre-existing or poorly controllable hypertension [47]. Physiological tests have revealed only minor, transient reductions of renal plasma flow in the treated kidney [45,82] and no clinically relevant changes in blood chemistry [17]. Furthermore, cytoplasmic enzymes have been reported to be only transiently released into the blood and urine of shock-wave-treated patients [46]. Kishimoto et al. [46] ha...

On the Destruction of Cancer Cells Using Laser-Induced Shock-Waves: A Review on Experiments and Multiscale Computer Simulations

“…37 The physical mechanisms related to the cavitation phenomenon that cause both stone destruction and tissue damage are very complex, not well understood and hardly experimentally controllable. 35,[37][38][39] The fact that ESWL can cause tissue damage, inspired experiments that applied lithotripter induced shockwaves to tumors in vivo. While several first studies in animal models did not show any impact of shock waves on tumor growth, 36 some results seemed encouraging, for example a delayed tumor growth in mice 40 and even complete remission of dorsal skin tumors in hamsters.…”

“…Most striking for a possible shock wave based tumor therapy was a study on different normal and malignant cell lines, which showed no selective effect. 38 When the energy deposited by the lithotripter is reduced below the lethal value, it is possible to permeabilize the cells without killing them. [42][43][44][45][46] In this way, molecules present in the surrounding medium can diffuse into the cells.…”

Finite element modeling of acoustic wave propagation and energy deposition in bone during extracorporeal shock wave treatment

“…In some cases, as SW-induced cavitation fields deviate far from the intended treatment region, undesired damage might be caused in bone and/or surrounding tissues because of unforeseen acoustic energy deposition. 17,24 Therefore, the strain energy distribution should be taken seriously in SW treatments.…”

“…17 Therefore, better physical understandings of SW propagation characteristics and energy deposition during ESWT processes may be a prerequisite for standardizing treatment dosage, optimizing future protocols, and even providing guidance to manufacturers regarding machine designs.…”

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“…It has been hypothesized that cavitation near the application site may have been the cause. 6 The peak pressure amplitude of radial shockwave generators used for extracorporeal shockwave therapy (ESWT, lithotripsy) is approximately 20 times higher than the output of chiropractic instruments. 3 In addition, ESWT generally requires between 1,000 and 4,000 impulses per treatment while the Activator devices are limited to just one impulse per treatment site.…”