Complex regional pain syndrome type 1. Some treatments assessed versus placebo, limited efficacy

Abstract

(1) Complex regional pain syndrome type 1 generally occurs after trauma and usually affects a limb; (2) How is complex regional pain syndrome type 1 diagnosed? What is its natural course? How safe and effective are available treatments? To answer these questions, we reviewed the literature using the standard Prescrire methodology; (3) Diagnosis is mainly based on clinical features, including pain disproportionate to the initial trauma, associated with cutaneous vasomotor, trophic and sweating disorders; (4) Some clinical signs call for additional examinations to help rule out another vascular, neurological, infectious or rheumatic disorder. Radiological evidence of bone demineralisation supports the diagnosis, but radiography, magnetic resonance imaging (MRI) and scintigraphy generally contribute little to the diagnosis of complex regional pain syndrome; (5) Some patients recover spontaneously after a few weeks, while others develop chronic pain or even severe disability after a period of years; (6) The results of small placebo-controlled trials suggest that corticosteroids are effective during the initial phase of this syndrome; (7) A very high oral dose of alendronic acid provided sustained pain relief in a randomised trial. Other studies suggest that bisphosphonates have some impact. The adverse effects of alendronic acid given at such high doses are poorly known; (8) Calcitonin, antiepileptics, antidepressants and opiates have no proven efficacy; (9) Transcutaneous neurostimulation is rapidly effective and safe, but its efficacy also diminishes rapidly. Therefore, the sessions have to take place at increasingly shorter intervals. (10) Spinal neurostimulation with implanted electrodes has been assessed in a comparative trial in 54 patients. Some efficacy was observed, but one-third of patients had complications requiring further surgery; (11) Various substances have been given intravenously with the goal of achieving regional anaesthesia, but none was found to have any tangible efficacy; (12) Sympathectomy has a negative risk-benefit balance; (13) Non-drug approaches such as physiotherapy, relaxation and biofeedback seem to help some patients, with little risk of adverse effects. These methods have not been comparatively evaluated; (14) In practice, there is no truly effective treatment for complex regional pain syndrome. The few beneficial treatments have not been directly compared with one another. The advantages and disadvantages of the various treatment options must be discussed with each patient.