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

Complex regional pain syndrome (CRPS) remains a poorly understood chronic pain disorder. Little data has been published assessing the epidemiology of CRPS (and reflex sympathetic dystrophy, RSD). This study assessed epidemiological 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-imposed immobilization of the CRPS limb was assessed, as was physical examination evidence of myofascial dysfunction. This study found that these patients 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 both prior to and during pain clinic treatment. The mean duration of CRPS symptoms prior to pain center evaluation was 30 months. Seventeen percent had a lawsuit and 54% had a worker compensation claim related to the CRPS. Fifty-one patients received a bone scan, but only 53% of which were interpreted as consistent with the diagnosis of RSD/CRPS. Forty-seven percent had a history of physician-imposed immobilization, and 56% had a myofascial component present at evaluation. The duration of CRPS symptoms and the involvement 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 many failed therapies. The data also suggest the lack of utility of a diagnostic bone scan and highlight the prominence of myofascial dysfunction in a majority of CRPS patients.