The clinical role of sympathetic blocks

Sympathetic blocks are widely employed in ischaemic rest pain, hyperhydrosis and abdominal pain due to cancer of the pancreas. There are divergent views on their use for the control of neuropathic pain. There is powerful evidence for the involvement of the sympathetic nervous system in the generation of pain after experimental nerve damage. This is not borne out in clinical practice, where there is equivocal evidence for the pain relieving effect of sympathetic blocks. This discrepancy may be due to the relatively short-term nature of experiments compared with clinical practice. Secondly, pain in patients may be multifactorial. Clinical permanent sympathetic blocks are best performed after a previous temporary tril block.