Epidemiology of complex regional pain syndrome: a retrospective chart review of 134 patients

Complex regional pain syndrome (CRPS) remains a poorly understood chronic p ain disorder. Little data has been published assessing the epidemiology of CRPS (and reflex sympathetic dystrophy, RSD). This study assessed epidemiol ogical variables in 134 CRPS patients evaluated at a tertiary chronic pain clinic in the US, including demographic, health care utilization and legal/ workman's compensation measures. In addition, the frequency of physician-im posed immobilization of the CRPS limb was assessed, as was physical examina tion evidence of myofascial dysfunction. This study found that these patien ts had seen on average 4.8 different physicians before referral to the pain center and had received an average of five different kinds of treatments b oth prior to and during pain clinic treatment. The mean duration of CRPS sy mptoms prior to pain center evaluation was 30 months. Seventeen percent had a lawsuit and 54% had a worker compensation claim related to the CRPS. Fif ty-one patients received a bone scan, but only 53% of which were interprete d as consistent with the diagnosis of RSD/CRPS. Forty-seven percent had a h istory of physician-imposed immobilization, and 56% had a myofascial compon ent present at evaluation. The duration of CRPS symptoms and the involvemen t of the upper extremity was significantly associated with the presence of myofascial dysfunction. Thus, this study found that most CRPS patients are referred to a pain specialty clinic after several years of symptoms and man y failed therapies. The data also suggest the lack of utility of a diagnost ic bone scan and highlight the prominence of myofascial dysfunction in a ma jority of CRPS patients. (C) 1999 International Association for the Study o f Pain. Published by Elsevier Science B.V.