The sympathetic nervous system may be involved in specific pain syndromes. These include complex regional pain syndrome (formerly called reflex sympathetic dystrophy or RSD), atypical facial pain and microvascular ischemia. Local anesthetic injected around the sympathetic ganglia in the cervical or lumbar spine may diagnose sympathetic involvement in painful conditions of the head/neck/upper extremities and the lower extremities, respectively.
These procedures require the use of X-ray in order to provide accurate needle placement and treatment of potential side-effects. The patient is evaluated immediately after such injections in order to determine the effect of the local anesthetic. For certain conditions, repeated sympathetic nerve blocks combined with aggressive physical therapy can result in symptom resolution. For recalcitrant conditions, long-term block of the sympathetic nervous system can be obtained by radiofrequency neuroablation or spinal cord stimulation.