Complex Regional Pain Syndrome: Past, Present & Future

Complex Regional Pain Syndrome (CRPS) is a chronic neuropathic pain disorder that involves one or more extremities with dystrophic changes of the skin, muscle, or bone. CRPS is characterised by constant regional neuropathic pain that does not follow the usual dermatomal distribution or nerve territory. In addition to neuropathic pain, patients suffer from sensory loss, autonomic dysfunction, vasculature changes and motor dysfunction in the region affected. As a debilitating disease with an unclear pathophysiology, patients suffering from this disorder often do not get the adequate level of care or treatment. Until recently, many clinicians believed CRPS was a purely psychiatric ailment and was lumped together with conditions such as conversion disorder. Recent strides in the understanding of responses in both the nervous system and body to trauma has allowed researchers and clinicians to elucidate possible pathophysiology components for this disorder, as well as to better understand the CRPS patient. Currently, CRPS is viewed to be a multiple component disorder activated by the dysfunction of multiple systems. This includes local injury response, inflammatory response, central and peripheral nervous sensitisation, abnormal vasculature changes and psychiatric components. Herein, not only are the pathophysiological mechanisms synthesised from current and past research discussed, but also the available pharmaceutical, interventional, and rehabilitative treatment modalities are reviewed in detail. From the neurophysiology of physical therapy and psychiatric interventions, to concepts in acupuncture, to evidence regarding peripheral and central nerve blocks and implantable devices, and to mechanisms involving supraspinal interventions used to directly manipulate brain circuitry, CPRS treatment options are examined in detail. Furthermore, as evidenced by the diverse and multimodal array of available and emerging treatment modalities, it is clear that CRPS management requires a truly interdisciplinary approach, highlighting this book as a central reference for multiple often-disconnected specialties. Furthermore, the mechanisms of action in each intervention strategy, current evidence base, and gaps in knowledge for management of CRPS are explored with special emphasis on avenues for future research. CRPS is a pain syndrome that has seen an explosion of research in recent decades, due in part to the fairly recent development of internationally formalised diagnostic criteria. However, many questions remain; while some continue to build an evidence base for efficacy and safety of current therapies, others are delving into new pharmaceutical options, experimental therapies, and molecular-level strategies focused on epigenetic manipulation. Moreover, this plethora of emerging CRPS research will surely maintain this syndrome in the forefront of medical research and scientific discovery for the next several decades.