Innovative ideas to disintegrate kidney stones noninvasively by using underwater shock waves appeared during the seventies and resulted in a technique that revolutionized the management of urolithiasis: extracorporeal shock wave lithotripsy (SWL). After the first clinical treatment, many companies worldwide developed clinical devices, the number of successfully treated patients increased exponentially and SWL of other stones, such as gallbladder stones, pancreatic concrements and stones of the salivary glands was included. Scientists from various specialties joined their efforts to better understand the phenomena involved and to help improving clinical outcomes. Even today, innovations to enhance stone fragmentation and reduce tissue damage are constantly sought.
During the early days of SWL few researchers believed that shock waves could have clinical uses different from comminution of the various types of calculi that may be formed in the human body. Nowadays there is no doubt that research on many biomedical applications of shock waves has a promising future.
Shock waves were introduced into the treatment of various diseases of the musculoskeletal system because of an incidental observation of osteoblastic response during animal studies. Nowadays they are used to treat chronic and painful conditions, particularly those where connective tissues attach to bone, such as plantar fasciitis, Achilles tendonitis and tennis elbow. Surprisingly, shock waves promote bone healing and may be used to treat non-healing fractures. Impressive results in the management of wounds, osteonecrosis and myocardial revascularization have also been reported. Different theories to explain pain relief mechanisms after shock wave therapy were proposed. Free radicals in the neighborhood of cell membranes and shock wave-induced neovascularization and hyperstimulation analgesia occurring as a consequence of a cascade of molecular events are believed to be involved.
Furthermore, special pressure profiles have shown to induce necroses in tumors and to delay the growth of tumors in vivo. New technologies using shock waves for drug release and needleless vaccine delivery, as well as shock wave-mediated particle delivery in gene therapy are other promising research topics. The discovery that shock waves can genetically transform bacteria and filamentous fungi will play an important role in the textile, food, paper and pharmaceutical industry by producing essential proteins, metabolites and compounds. It may also improve the production of valuable phenotypes of fungi and reduce several industrial production costs.
This presentation will give an overview on the broad and exciting field of biomedical applications of shock waves and focus on the most important physical phenomena involved. Some cutting edge research topics will also be discussed briefly.
