Pain relief in sports medicine by radial extracorporeal shock wave therapy: An update on the current understanding

Radial extracorporeal shock wave treatment (RSWT) has become a well-established treatment opportunity for several diseases of the musculoskeletal system that play also a major role in sports medicine, such as chronic plantar fasciitis and chronic Achilles tendinopathy (Am J Sports Med 2007;35:374-383; 2008;36:2100-2109; 2009;37:463-470; J Bone Joint Surg Am 2008;90:52-61). Consequently, RSWT has become recognized recently by several top sports teams all over the world as an efficient tool to legally optimize performance of athletes and help them recover from sports injuries as fast as possible. To further develop RSWT in sports medicine it remains important to learn more about how extracorporeal shockwaves exerts its pain relieving action on the muscoloskeletal system. In this regard a recent hypothesis claims that extracorporeal shock waves act on the body’s pain memory when used for the treatment of chronic, painful conditions, i.e., without underlying anatomical disorders (Urol Res 2008;36:327-334). On the other hand, a wealth of data exist in the literature indicating that analgesia induced by extracorporeal shock waves is mediated mainly by the reduction of substance P in the target tissue (Clin Orthop 2003;406:237-245) in conjunction with reduced synthesis of this molecule in dorsal root ganglia cells (Brain Res 2008;1207:96-101) as well as by selective destruction of unmyelinated nerve fibers within the focal zone of extracorporeal shockwaves (Neuroscience 2008;155:138-144). This paper will provide an update on the current understanding of pain relief by RSWT, based on the principles of molecular cell biology.