A lumbar sympathetic block is an injection in the middle of the lower back, toward the left or right side. The “lumbar sympathetic nerves” are a small bundle of nerves that carries “sympathetic” nerve signals from the lower extremities. In some instances, certain injuries to the lower extremities can cause a burning, unusual pain called complex regional pain syndrome or reflex sympathetic dystrophy. Injecting a small amount of local anesthetic on the lumbar sympathetic nerves can identify whether or not this pain is carried by the sympathetic nervous system.
A lumbar sympathetic block is performed to block the sympathetic nerves that go to the leg on the same side as the injection. This may in turn reduce pain, swelling, color, sweating and other unusual changes in the lower extremity and may improve mobility. It is done as a part of the treatment of Reflex Sympathetic Dystrophy (RSD), Sympathetic Maintained Pain, Complex Regional Pain Syndrome and Herpes Zoster (shingles) involving the legs. Certain patients with neuropathy or peripheral vascular disease may also benefit from lumbar sympathetic blocks.
Another indication for lumbar sympathetic blockade includes phantom limb pain, a phenomenon in which pain is perceived from a limb that is no longer present. Case studies have found lumbar sympathetic blocks to be safe and effective for the alleviation of phantom limb pain. Additionally, lumbar sympathetic blocks may be used for management of neuropathic pain in special instances. There are case studies demonstrating improvement in pain, function, and quality of life after lumbar sympathetic block in patients with postherpetic neuralgia secondary to zoster.
The local anesthetic wears off in a few hours. However, the blockade of sympathetic nerves may last for many more hours. Usually, the duration of relief gets longer after each injection. If you respond to the first injection, you will be recommended for repeat injections. Usually, a series of such injections is needed to treat the problem. Some may need only 2 to 4 and some may need more than 10. The response to such injections varies from patient to patient.
The actual injection takes from ten to thirty minutes. Pain management nerve block injection consists of a local anesthetic. In occasion, epinephrine, clonidine or a steroid medication may be added to prolong the effects of the lumbar sympathetic block.
Overall, the lumbar sympathetic block is a safe and effective procedure that can be used to alleviate sympathetic nerve pain in the appropriate patient population. This includes people with vascular insufficiency of the lower extremities, complex regional pain syndrome, phantom limb pain, postherpetic neuralgia, and other neuropathic pain syndromes that are refractory to medical management. You are able to return to your work the next day.