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Interventional therapies have been commonly used in the treatment of reflex sympathetic dystrophy (RSD) even though there was little scientific evidence of their efficacy. The basic premise of most interventional treatments is the involvement of the sympathetic nervous system in RSD, a premise which has come under increasing scrutiny in the face of new evidence of more global involvement.

The role of interventional treatment in RSD is that of an adjunct therapy performed in order to provide pain relief to enable the patient to actively participate in functional rehabilitation. The decision to undergo interventional therapy should be considered carefully regarding the level of need, timing, and whether it will be more effective for pain relief than other therapies which had been undertaken and failed.

Interventional procedures include:

• Nerve block
• Sympathectomy
• Spinal Cord/Peripheral Nerve Stimulation
• Implantable Spinal Pumps

You can read more about various interventional procedures by clicking on the following link: http://www.ncbi.nlm.nih.gov/pubmed/16772798

Nerve Block

A nerve blockade is a procedure usually performed by a pain management specialist (anesthesiologist) and its objective is to interrupt the flow of pain signals along the sympathetic nerve in the region of RSD pain. If successful, the anesthetic temporarily blocks the local sympathetic nervous system and thus reduces or eliminates pain.

Based on clinical experience, some doctors recommend a nerve block in the presence of any of the following conditions:

• Burning pain
• Allodynia (pain in response to innocuous stimuli such as a feather touch or breeze on the limb)
• Temperature changes in the affected limb
• Color changes in the affected limb
• If pain is limiting functional rehabilitation early in the treatment process with physical therapy or occupational therapy despite medication

There are three types of nerve blocks - two that target the sympathetic nervous system and one that targets the local nerves in the affected limb. These include:

• Stellate ganglion block - the anesthetic is injected around the sympathetic nerves in the cervical spine area to interrupt pain signals to the upper body and arm.

• Lumbar sympathetic block - the anesthetic is injected around the sympathetic nerves in the lumbar region and targets interruption of nerve signals causing lower body/leg pain.

• Bier block - also called Intravenous Regional Anesthesia block (IVRA). With this procedure, blood is drained from the limb either by gravity (holding the limb up) or pressure. A blood pressure cuff is then inflated at the upper arm or leg and an anesthetic is injected intravenously into a blood vessel in the hand or foot. The inflated cuff prevents the anesthetic from flowing out of the limb and into the body. The patient may feel a burning sensation and numbness as the anesthetic diffuses from the blood vessels into nearby nerves. The procedure ends by slowly deflating the pressure cuff allowing the small amount of residual anesthetic to slowly flow out of the limb through the veins into the body where it is resorbed. The numbness eventually wears off. Pain relief is temporary and may last days, weeks, or months. When the effect wears off, the procedure can be repeated. The main complication of the Bier block is that if the pressure cuff is released too quickly, before a sufficient amount of anesthetic has been absorbed into the arm, too much anesthetic is introduced into the body and can reach toxic levels.