A Pilot Clinical Trial of Sympathetic Blockade With Botulinum Toxin Type A to Treat Complex Regional Pain Syndrome (CRPS): a Randomized, Double-Blind, Controlled, Crossover Trial.

Lumbar sympathetic blocks are part of the standard of care for treating patients with sympathetically-maintained pain (e.g. in complex regional pain syndrome or reflex sympathetic dystrophy- RSD). In these patients lower extremity pain can be reduced or abolished temporarily by blocking sympathetic nerves by doing a lumbar sympathetic block. Patients who respond only transiently to sympathetic blocks often choose between potentially dangerous lumbar sympathetic block with neurolytic agents, surgical sympathectomy, continued severe refractory debilitating pain or other risky invasive surgical procedures such as spinal cord electrical stimulation.. It is hypothesized that Botulinum Toxin Type A (BTA) injected in a lumbar sympathetic block can provide extended sympathetic blockade and thus pain relief. This pilot study aims to see if BTA can be used safely in lower extremity sympathetic blocks, and might be useful in providing prolonged pain relief.