When should sympathetic blocks be considered for treatment of neuropathic pain?
Sympathetic blocks such as the classic stellate ganglion block and lumbar sympathetic block (depending on affected region) should be considered when CRPS or sympathetic involvement in pain is suspected. CRPS, types 1 and 2, may have significant sympathetic involvement. Aside from typical neuropathic pain description and allodynia, vasomotor instability, swelling, hair and nail changes, and temperature changes can indicate sympathetic system dysfunction. Traditionally sympathetic blocks have had both diagnostic and therapeutic roles in management of sympathetically maintained pain, despite the fact that there is weak evidence to support its role in diagnosis.