Sympathetic Nerve Blocks for Complex Regional Pain Syndrome (CRPS)
What is complex regional pain syndrome (CRPS)?
Complex regional pain syndrome (CRPS), is a type of chronic pain condition. It typically occurs after an injury and usually affects one limb (arm or leg) or extremity (hand or foot). Symptoms include pain, swelling, and changes in skin temperature and color of the affected area.
Although complex regional pain syndrome is not yet completely understood, it is believed that CRPS develops when the central or peripheral nervous system is damaged or malfunctions. It may also be caused by an immune system response.
What is the sympathetic nervous system?
The sympathetic nervous system is one part of the autonomic nervous system, which is part of the peripheral nervous system. The sympathetic nervous system controls involuntary bodily functions such as heart rate, narrowing and widening of blood vessels, body temperature, digestion, sexual arousal, blood pressure, pupil dilation, and breathing.
What is a sympathetic nerve block for CRPS?
Complex regional pain syndrome is thought to involve sympathetic nerve damage or dysfunction, which causes pain, swelling, and changes in skin temperature and color of the affected area.
During a sympathetic nerve block, a local anesthetic, or pain reliever, is injected into a thick network of sympathetic nerves (a ganglion) located just outside the spine. The injection “blocks” the sympathetic nerves within the ganglion. The targeted location of a sympathetic block depends on the area affected by CRPS: either an upper limb/extremity or lower limb/ extremity. If an upper limb/extremity is affected, the injection is given in the stellate ganglion located in the lower neck region. If a lower limb/extremity is affected, the injection is given in a lumbar ganglion located in the lower back. Pain relief generally occurs within 30 minutes of the injection.
Sympathetic nerve blocks are a first-line treatment option for CRPS. However, they do not work in all cases, and their pain-relieving effects may decline over time. For individuals who do experience pain relief, the relief can last for weeks or months. Sympathetic nerve blocks are commonly given 1‒2 times per week. Approximately 4‒5 blocks are required to achieve maximum results.