What is a Sympathetic Nerve Block?
A sympathetic nerve block is a medical procedure aimed at diagnosing or treating pain that is maintained by the sympathetic nervous system. This part of the nervous system controls various involuntary body functions, including blood flow, digestion, and sweating, and can sometimes contribute to pain syndromes, particularly those involving the limbs or abdomen. The procedure involves the injection of an anesthetic near the sympathetic nerve chain, which runs along the spine, to temporarily block the transmission of pain signals to the brain.
Sympathetic nerve blocks can target different levels of the spine, depending on the location of the pain. For example, a stellate ganglion block targets the sympathetic nerves of the head, neck, upper chest, and arms, while a lumbar sympathetic block is used for pain in the lower limbs. These blocks are used to treat conditions such as complex regional pain syndrome (CRPS), peripheral neuropathy, and certain types of chronic abdominal pain. By blocking the sympathetic nerves, the procedure can reduce pain, swelling, and improve blood flow in the affected area, providing significant relief and helping to assess the role of the sympathetic nervous system in the patient's pain condition.
What are the benefits and risks of a Sympathetic Nerve Block?
The following are a brief list of the benefits and risks of a sympathetic nerve block:
Benefits
- Pain Relief: The primary benefit is significant reduction in pain, especially for conditions like Complex Regional Pain Syndrome (CRPS), certain neuropathic pain disorders, and pain from peripheral vascular disease.
- Improved Function: By alleviating pain, patients often experience improved mobility and function in the affected limb or area.
- Diagnostic Information: Performing a sympathetic nerve block can help in diagnosing the source of pain by determining if the sympathetic nervous system is contributing to the pain.
- Reduction in Sympathetic Nervous System Symptoms: For conditions associated with overactivity of the sympathetic nervous system (such as swelling, discoloration, and abnormal sweating), the block can provide symptomatic relief.
- Minimally Invasive: Compared to surgical interventions, sympathetic nerve blocks are minimally invasive and have a quick recovery time.
Risks
- Infection: As with any procedure that penetrates the skin, there is a risk of infection at the injection site.
- Bleeding: There is a risk of bleeding, especially for patients on blood thinners.
- Temporary Side Effects: Patients may experience temporary side effects such as hoarseness, difficulty swallowing, or drooping of the eyelid (Horner’s syndrome) due to the block's effect on nearby nerves.
- Nerve Damage: Although rare, there is a risk of damage to the nerves near the injection site.
- Blood Pressure Changes: The block may cause temporary changes in blood pressure, usually a decrease, due to its effect on the sympathetic nervous system.
- Lung Puncture: For certain blocks, like the stellate ganglion block, there is a small risk of accidentally puncturing the lung (pneumothorax).
- Allergic Reactions: There is a potential for allergic reactions to the medications used during the block.
We have performed many successful sympathetic nerve blocks for our patients. Schedule a pain management consultaiton to determine whether a sympathetic nerve block is appropriate to meet your pain treatment goals.
Who is a good candidate for a Sympathetic Nerve Block?
A good candidate for a sympathetic nerve block typically includes individuals suffering from pain conditions that are believed to be associated with the sympathetic nervous system. These conditions often involve a component of neuropathic pain or dysregulation of the sympathetic nervous system. Key criteria and conditions that may make someone a suitable candidate include:
- Complex Regional Pain Syndrome (CRPS): Individuals with CRPS, a condition characterized by severe, chronic pain often accompanied by swelling, changes in skin color, and abnormal sweating, may benefit significantly from sympathetic nerve blocks.
- Peripheral Neuropathy: Patients experiencing neuropathic pain, especially when it's associated with diabetes or other systemic diseases, might find relief through this procedure.
- Vascular Insufficiency Pain: Those suffering from pain due to peripheral vascular disease, which affects blood circulation, could see improvements with a sympathetic nerve block.
- Phantom Limb Pain: Individuals experiencing pain in a limb that has been amputated may find a sympathetic nerve block helpful in managing their symptoms.
- Hyperhidrosis: Excessive sweating (hyperhidrosis) that's resistant to other treatments might also be managed with sympathetic blocks.
- Postherpetic Neuralgia: Patients with lingering pain after a shingles outbreak (postherpetic neuralgia) may benefit from a block if the pain is sympathetically maintained.
Candidates should have a clear diagnosis and typically have tried other, less invasive forms of pain management without sufficient relief. Additionally, good candidates are those without contraindications to the procedure, such as certain medication allergies or infections at the proposed injection site. A thorough evaluation by a pain management specialist, including a detailed medical history and possibly diagnostic blocks, is essential to determine if a sympathetic nerve block is appropriate and likely to provide benefit.
How is a Sympathetic Nerve Block performed?
We perform sympathetic nerve blocks in our pain clincs on an outpatient setting. Here's a general overview of how the procedure is typically performed:
- Preparation: The patient is positioned in a way that allows the physician easy access to the injection site. This position varies depending on which sympathetic nerve chain is being targeted (e.g., lumbar sympathetic block for leg pain or stellate ganglion block for arm pain). Vital signs are monitored, and the skin over the injection site is cleaned and sterilized.
- Imaging Guidance: Fluoroscopy (a type of real-time X-ray) or ultrasound is commonly used to guide the needle placement. This imaging helps the physician visualize the anatomy and ensure accurate placement of the needle near the sympathetic nerves.
- Anesthetic Administration: Once the needle is correctly positioned, a local anesthetic is injected to numb the area. This step may be followed by the injection of a steroid medication to reduce inflammation and prolong pain relief.
- Observation: After the medication is administered, the needle is carefully removed, and the injection site is bandaged. The patient is then observed for a short period to monitor for any immediate reactions or complications. The effectiveness of the block and any side effects, such as weakness or numbness in the affected limb, are also assessed.
- Post-Procedure Care: Patients are typically advised to rest for the remainder of the day and may need someone to drive them home. Instructions are given regarding how to care for the injection site and signs of complications to watch for. Pain relief from the block can be immediate for some patients, but the full effect may take several days to manifest.
The entire procedure usually takes less than an hour. Patients are encouraged to track their pain levels and any side effects experienced following the block, as this information is valuable for assessing the effectiveness of the procedure and planning future treatment.