FAQs on Lumbar Sympathetic Block in Colorado


A lumbar sympathetic nerve block involves injecting a nerve bundle of the lower back with medication. This procedure is used to diagnose and treat back pain disorders that cause symptoms involving the lower extremities, which are sustained by the sympathetic nervous system.

What is the sympathetic nervous system (SNS)?

The SNS is the network of nerves that are linked to numerous neuropathic pain syndromes. The role of the SNS in the transmission of pain signals involves the nerves that are associated with adaptive physical reactions. The SNS constricts blood vessels and controls sweating. To block these nerves, the doctor uses an anesthetic, neurolytic agent, or radiofrequency energy.

What conditions are treated using the lumbar sympathetic nerve block?

Injury or irritation to the sympathetic nerves can affect the feet and lower extremities. This causes a condition called complex regional pain syndrome. The main symptoms of CRPS include burning intense pain of the lower extremities. Another condition treated is sympathetically maintained pain (SMP), or pain that is facilitated by the SNS activity. SMP is often provoked by stimuli that are not necessarily painful.

What symptoms are relieved using the lumbar sympathetic block?

Allodynia (pain from slight touch) and hyperalgesia (severe irritation and pain) are symptoms associated to the SNS. The lumbar sympathetic block is used to treat these symptoms. Low-threshold sensory fibers are activated and excite neurons in the spinal cord that typically do not respond to such stimuli. When sympathetic pain goes untreated, it often becomes chronic and irreversible.

Does the lumbar sympathetic block hurt?

The doctor will first numb the back skin and deeper tissues with a local anesthetic, such as bupivacaine or lidocaine. A corticosteroid is often injected onto the nerves along with the local anesthetic. Other agents used include the analgesic ketamine, which has an adjuvant effect, as well as guanethidine, which decreases SNS hormone and catecholamine release.

How do I prepare for the lumbar sympathetic nerve block?

You will first meet with the pain specialist who evaluates your condition. After reviewing your medical history, conducting an exam, and doing some diagnostic tests, the doctor schedules your procedure. He will review the risks and benefits, and have you sign a consent form. Because increased bleeding can occur, you must hold any agent that thins the blood for a few days before your procedure. Arrange to have someone drive you home, do not eat or drink six hours before your appointment, and leave all valuables at home.

How is the lumbar sympathetic block done?

The Colorado pain doctor uses fluoroscopy (real-time x-ray) to visualize the area being injected. Live images on a monitor allow the doctor to position the needle close to the nerves. After you are positioned face-down on the procedure table, a nurse administers a sedative. One your back has been cleansed with an antimicrobial solution, the area is numbed with an anesthetic. The procedure needle is inserted, medications are instilled, and the needle is then removed. A small bandage will be secured to the site afterwards.

Does the lumbar sympathetic nerve block work?

Many clinical trials have proven the efficacy of the lumbar sympathetic nerve block. In a Japanese study, nerve blocks were found to decrease the pain intensity and lower opioid consumption without any serious side effects. A recent randomized controlled study found that this block was more effective than placebo, and patients had remarkable pain reduction after the procedure. The block was also found useful for treating the pain of abdominal and pelvic cancer. Additionally, the lumbar sympathetic nerve block using a neurolytic agent was found to produce long-term pain relief in patients with interstitial cystitis.


Doi K, Saito Y, Nikai T, et al. (2001). Lumbar sympathetic block for pain relief in two patients with interstitial cystitis. Reg Anesth Pain Med, 26(3), 271-273.