medicine

Peripheral Nerve Blocks, Rhizotomy, and Sympathectomy

Peripheral nerve blocks with alcohol or anesthetics have been attempted for pain localized to the facet, although without success. Peripheral blocks with anesthetics can, however, be safely attempted in all cases. Abolition of incoming afferent signals sometimes can secure temporary relief, whereas repeated or prolonged blocks can reduce the temporary relief to the painful patient.
Peripheral neurectomy and rhizotomy have also been used in some cases of facial pain. Trigeminal rhizotomy has been ineffective in relieving pain caused by bulbopontine vascular lesions or syringobulbia. Results of sympathectomy and sympathetic blocks are highly variable, and relief is generally not long lasting. Sympathetic blockade has been used, especially when there is hyperpathy, but it is only
rarely helpful. In some patients, spinal block can relieve central pain; for this reason, relief of pain by spinal block has been explained on the basis of blocking normal peripheral input to the damaged central neuraxis, which would eliminate the activation of dysfunctional central circuits.