Introduction to CRPS Special Issue

Abstract

The International Association for the Study of Pain (IASP) Special Interest Group on Pain and the Sympathetic Nervous System held a satellite symposium in Cardiff, Wales, ahead of the World Congress in August 2008. Papers presented at this symposium, now edited and updated, are published here. The problems facing the field of complex regional pain syndrome (CRPS) were addressed in general terms by Dr. Donald Manning, summarized below but not published here. Dr. Manning drew on his methodological experience and previewed his contributions to IMMPACT (Dworkin et al. Research design considerations for confirmatory chronic pain clinical trials: IMMPACT recommendations. Pain 2010;140:177–93). Manning pointed out that the state of CRPS research was plagued with methodological issues, with most published studies being inadequate in one or more areas: 1. Definition of CRPS itself has not necessarily been universally accepted. 2. Duration of CRPS (avoiding the terms “acute” and “chronic”) might affect both diagnostic criteria and therapeutic stratagems. 3. Average duration of treatment is usually short. 4. Studies have too few subjects. 5. Double-blind studies are rare, placebo controls are difficult, and statistical analytic methods are controversial. 6. Objective outcome measures are rarely, if ever, used. This results in practical difficulties for clinicians and patients in applying clinical trial data to management of CRPS: 1. How does the physician know which CRPS trial applies to the particular patient? 2. Does information from “acute” CRPS or animal models apply to “chronic” CRPS? 3. How can the clinician and patient assess the risk/cost/benefit of a treatment? 4. How can the clinician and patient assess the risk/cost/benefit of “doing nothing”? 5. Why do the “best” medical centers and research groups appear to have the highest placebo effects? 6. How are CRPS recurrences, relapses, and spread prevented? 7. What are realistic treatment/intervention goals for the individual patient? With these questions in mind, Dr. R. Norman Harden reviewed his studies on …