The outcome of complex regional pain syndrome type 1: a systematic review.

UNLABELLED: The purpose of this systematic review was to examine the outcome of complex regional pain syndrome (CRPS) type 1. We searched MEDLINE, Embase, and PsycINFO for relevant studies and included 18 studies, with 3,991 participants, in this review. The following data were extracted: study details, measurement tools used, and rates or severity scores for the symptoms/signs of CRPS at baseline and follow-up, or in groups of patients with different disease durations. A quality assessment revealed significant limitations in the literature, with many studies using different diagnostic criteria. The 3 prospective studies demonstrated that for many patients, symptoms improve markedly within 6 to 13 months of onset. The 12 retrospective studies had highly heterogeneous findings, documenting lasting impairments in many patients. The 3 cross-sectional studies showed that rates of pain and sensory symptoms were highest among those with the longest duration of CRPS. Additionally, most studies showed that motor symptoms (stiffness and weakness) were the most likely to persist whereas sudomotor and vasomotor symptoms were the most likely to improve. Overall, this suggests that some CRPS patients make a good early recovery whereas others develop lasting pain and disability. As yet little is known about the prognostic factors that might differentiate between these groups. PERSPECTIVE: We found evidence that many CRPS patients recover within 6 to 13 months, but a significant number experience some lasting symptoms, and some experience chronic pain and disability. The quality of the evidence was poor. Future research should examine the factors associated with recovery and identify those at risk of poor outcomes.