Why perform a selective nerve root block?
A selective nerve root block is a diagnostic procedure, which means that the procedure is being used to determine if a particular nerve is causing or contributing to your pain. In general, this procedure is not used to treat pain. A selective nerve root block is performed by injecting an anesthetic agent (like lidocaine or bupivacaine) around a specific nerve root and then assessing pain levels. These are the same medications that when used in dental procedures can make your mouth or face feel numb.
These medications will last for a number of hours before wearing off. Because the anesthetic is temporary, it is important for the patient to frequently reassess and document their pain and symptoms following the procedure. We provide a “pain journal” to facilitate this. This information allows us and our surgical colleagues to precisely determine the affected nerve root that needs to be treated or surgically decompressed.
How is the procedure performed?
A selective nerve root block is performed in the office. Your physician will use fluoroscopy (x-ray guidance) to identify bony landmarks and target the nerve that will be blocked. After numbing the skin, a spinal needle will be advanced next to the targeted spinal nerve.
When the needle is around the nerve, a syringe containing the anesthetic solution is connected to the needle. After making sure that the needle is not in a blood vessel or in the spinal fluid, the doctor slowly injects the medications.
You may briefly feel pins and needles in the arm or leg (depending on the site of injection). If the needle touches a bone you may feel a sharp local pain. You should tell your doctor about these feelings.
Following the injection, you will remain at the facility for a few minutes to recover. While recovering, you will be monitored for any adverse reactions to the procedure. Once you are feeling well enough to walk, you will be allowed to leave with your ride. You are expected to call or follow-up with your physician with your pain journal so we can assess your response to the injection. This will help him determine whether or not to perform another injection.
What are the risks of a selective nerve root block?
With any injection, interventional procedure, or operation there are risks. In the case of selective nerve root blocks, these risks are small and rare. Of the variety of potential side-effects and complications, most are related to the way the injection is given.
As with any procedure that breaks the skin, it is possible for bacteria to gain entry and cause an infection. The procedures are performed under sterile conditions, and the risk for this is very small.
It is also theoretically possible that a nerve could be damaged. During the procedure, the needle is inserted very slowly and visualized with fluoroscopy. If the lining around the nerve were touched, the patient may feel pain in the arm or leg. If this were to happen, the doctor would change the position of the needle to avoid any risk of damage to the nerve.
Certain other side-effects have been reported, related to the amount of anesthetic injected into the epidural space or to medications being injected into the spinal fluid. These side-effects, including irritation or damage to the nerves in the area of the injection, are extremely rare.
