|Performed to treat CRPS I and II, phantom limb pain and to improve blood flow (e.g. Raynaud's disease and intra-arterial injection of thiopentone).
The underlying mechanism is unknown but may involve abnormal linkage between mechanoreceptors and sympathetic neurones. Recent evidence suggests that efficacy is questionable.
Sympathetic ganglia may be blocked at three levels:
Cervicothoracic ganglia (stellate ganglion block)
Coeliac plexus (coeliac plexus block)
Lumbar ganglia (lumbar sympathetic block)
Blockade may be short term (local anaesthetics) or permanent (phenol or alcohol).
This is a neurolytic agent used for nerve blocks. It is believed to spare large myelinated nerve fibres while damaging unmyelinated C pain fibres by protein denaturation.
Hyperbaric 5% solution in glycerin is used for subarachnoid neurolysis of nerve roots; 0.5-2.0 ml has an effect for up to 14 weeks.
6-7% solution in water is used for sympathetic nerve blocks.