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Procedure: Sympathetic Nerve Block


What is a Sympathetic Nerve Block?

It is an injection of local anesthetic in the “sympathetic nerve chain” - the nerves which are a part of the Autonomic Nervous System. The nerves are located on the front surface of the spinal column and control blood flow, temperature regulation and other bodily functions that the patient have no control over.  Sometimes these nerves can malfunction and cause pain


What is the purpose of it?

The injection blocks the sympathetic nerves. This may in turn reduces pain, swelling, color, and sweating changes in the lower extremity and may improve mobility. It is done as a part of treatment for Reflex Sympathetic Dystrophy (RSD), Sympathetic Maintained Pain, Complex Regional Pain Syndrome, and Herpes Zoster (shingles).


How long does the injection take?

The actual injection only takes a few minutes, but plan to be in the office for one to two hours.  This allows for the patient’s pre-op and recovery time as well.  The patient’s driver must remain in the building during the procedure.


What is actually injected?

The injection consists of a local anesthetic (like lidocaine and bupivacaine). Epinephrine (adrenaline) may be added to prolong the effects of the injection.


Will the injection hurt?

The procedure involves inserting a needle through the skin and deeper tissue (like a tetanus shot). While there is some discomfort involved, the skin and deeper tissues are numbed with a local anesthetic using a very thin needle prior to inserting the actual block needle. Some of the patients also receive intravenous sedation and analgesic, which makes the procedure easy to tolerate.


Will I be “Put Out” for this procedure?

No. This procedure is done under local anesthesia. .  If the patient does not feel comfortable with just the numbing medication, Coastal Bend Pain Management can give the option of intravenous sedation.  The amount of sedation given generally depends upon the patient’s tolerance.


How is the injection performed?

The procedure is done with the patient lying on their stomach for pain in the legs OR on the back for pain in the arms. The patients may be monitored with an EKG, blood pressure cuff, and blood oxygen monitoring device. The area to be injected is cleaned with antiseptic solution and then the injection is performed.


What should I expect after the injection?

Immediately after the injection, the patient’s extremities may feel heavier and possibly numb. Due to the local anesthetic injected during the procedure, patient might notice their pain may be gone or quite less. The patient may also feel sore for two to three days due to the mechanical process of needle insertion as well as initial irritation from the steroid itself.  Patient should start to notice pain relief within three to seven days.


What should I do after the procedure?

The patient should have a driver take them home. Coastal Bend Pain Management advises patients to take it easy for a day or two after the procedure. The patient should perform activities as tolerated by their bodies. Some patients may go for immediate physical therapy.


Can I go to work the next day?

Unless there are complications, the patient should be able to return to work the next day. The most common thing the patient may feel is soreness at the injection site.


How long does the effect of the medication last?

The local anesthetic wears off in a few hours. However, the blockade of sympathetic nerves may last for many hours. Usually, the duration of relief gets longer after each injection.


How many injections do I need to have?

If the patient responds to the first injection, they 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.


Will the Sympathetic Nerve Block help me?

It is very difficult to predict if the injection(s) will indeed help the patient or not. Patients who present early during their illness tend to respond better than those who have this treatment after about six months of symptoms. Patients in the advanced stages of disease may not respond adequately.


What are the risks and side effects?

This procedure is safe. However, with any procedure there are risks, side effects, and possibility of complications. The most common side effect is pain-which is temporary. The other risks involve bleeding, infection, spinal block, epidural block, and injection into blood vessels and surrounding organs. Fortunately, the serious side effects and complications are uncommon.


Who should not have this injection?

If the patient is allergic to any of the medication being injected, if they are on a blood thinning medication (e.g. Coumadin, Plavix), or if they have an active infection going on near the injection site, you should not have the injection.

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