Axillary brachial plexus blockade for the reflex sympathetic dystrophy syndrome

The reflex sympathetic dystrophy syndrome (RSD) is a neurogenic pain syndrome that is characterized by pain, vasomotor and dystrohic changes and often motor impairments. Although the exact pathogenesis of RSD is unknown, for long the sympathetic nervous system was thought to play a dominant role and pharmacological and surgical sympathectomies have been a mainstay in treatment procedures. However, there is growing evidence of a pivotal role of C- and A delta-fibres in the aetiology of RSD. These fibres subserve a dual sensory-effector function. Besides the initiation of afferent impulses, they release neuropeptide mediators that cause a peripheral neurogenic inflammatory reaction and central neuroplastic reactions. Brachial plexus blockade (BPB) with local anaesthetic drugs interferes with the conduction of action potentials along both sympathetic efferents and the somatosensory C- and A delta-afferents and therefore seems a potential treatment modality in RSD. The aim of this study was to draw attention on this regional anaesthetic technique that is not commonly used in RSD. In this study six patients with severe RSD of an upper extremity in varying stages were treated with BPB in the multidisciplinary setting of an out-patient rehabilitation clinic with a follow-up of 12 to 21 months. The study was not placebo controlled. Three patients responded well. In these cases the treatment interval varied from 3 to 6 months, one case had RSD stage 1 and the two others stage 2. Three patients showed poor response. In one of these patients the initial effect was good but due to an infection at the insertion site of the catheter BPB had to be discontinued. The other two poor-responders had treatment intervals of 7 and 25 months and both had stage 3 RSD. We conclude that there is theoretical and clinical support to further evaluate the effect of BPB as a treatment modality in the early stages of RSD.