There seem to be no controlled studies demonstrating efficacy of neurolytic sympathetic blocks. Possible side effects, ranging from trivial to devastating, are of even greater importance with these more permanent procedures—painful sequelae may include phe-
nol or alcohol neuritis and postsympathectomy pain (sympathalgia), which can also occur after surgical sympathectomy.
The involvement of the sympathetic nervous system in causalgia and reflex sympathetic dystrophy, which for ms the rationale for treatment by sympathetic interruption, has been questioned, and the issues discussed here raise further questions. Contrary to predictions from experimental data, interrupting the sympathetic nervous system in practice seems futile for obtaining long term relief of pain in many if not most of these patients. How to identify the minority of patients whose pain might respond to these procedures is the next task, but fresh approaches to management are also required.
G D Schott Consultant neurologist
Interrupting the sympathetic outflow in causalgia and reflex sympathetic dystrophy - A futile procedure for many patients
The National Hospital for Neurology and Neurosurgery, London
1998;316;789-790 BMJ