The aim of a Nerve Root Injection injection is to help pinpoint which nerve, if any, is causing your back or leg pain so that your doctor can plan the appropriate treatment.
The injection consists of a combination of local anaesthetic and a steroid which are injected around one of the nerves in your back. The local anaesthetic will numb the nerve immediately, the steroid will give long-term pain relief and reduce inflammation. You will generally feel the effects of the steroid for about three days after the injection.
A nerve root block or TFI numbs your nerve root temporarily. If your pain decreases after the treatment, the nerve blocked by the injection is the most likely cause of your pain. If your pain stays the same, then that nerve is most likely not the cause of your pain. A nerve root block can help with pain but it is not a permanent cure.
During the procedure
As with many spinal injections, nerve root injections are best performed using fluoroscopy (live X-ray) for guidance to properly target and place the needle (and to help avoid nerve injury or other injury).
The injection procedure includes the following steps:
- The patient lies face down on an X-ray table and the skin over the area to be treated is well cleaned.
- The physician numbs a small area of skin with an anaesthetic (a numbing medicine). This may sting for a few seconds.
- The physician uses X-ray guidance (fluoroscopy) to direct a very small needle into the correct place. Several drops of contrast dye are then injected to confirm that the medicine is in the right area only goes into the joint.
- A small mixture of anaesthetic and anti-inflammatory medication (cortisone) is then slowly injected around the nerve root.
The injection itself only takes a few minutes, but the entire procedure usually takes between fifteen and thirty minutes thirty and sixty minutes. After the procedure, the patient typically rests in the waiting area on the table for twenty to thirty minutes, and then is asked to move the area of usual discomfort to try to provoke the usual pain. Patients may or may not obtain pain relief in the first few hours after the injection, depending upon whether or not the nerve root which was injected are the main source of the patient’s pain. On occasion, the patient may feel numb or experience a slightly weak or odd feeling in the upper back or legs for a few hours after the injection. On the day of the injection, patients are advised to avoid driving and avoid doing any strenuous activities.
The patient should record the levels of pain relief during the next week in a pain diary. Tracking the level of pain is helpful to clearly inform the treating physician of the injection results and in planning future tests and/or treatment, as needed.
You will need to make an appointment for this examination and will also need to arrange a driver. You may eat and drink as you wish before and after the procedure.
Please advise our receptionists if you take any blood thinning medication or medication to prevent stroke. These usually need to be stopped seven days prior to your injection. It is very important that we are advised of any medication that you are currently taking, including antibiotics, when you make your appointment with us. In some cases you may be require a blood test before the procedure. You will be asked to sign a consent form prior to the procedure.
After the procedure
On the day of the injection, patients are advised to avoid doing any strenuous activities, unless instructed by their doctor. The patient should not drive the day of the injection unless approved by the treating physician. If sedation was used, the patient should not drive for 24 hours after the procedure. Patients may notice a slight increase in pain lasting for several days as the numbing medicine wears off and before the cortisone starts to take effect. If the area is uncomfortable in the first two to three days after the injection, carefully applying ice or a cold pack to the general area of the injection site will typically provide pain relief.
If the nerve root that was treated is the source of the pain, the patient may begin to notice pain relief starting two to five days after the injection. If no improvement occurs within ten days after the injection, then the patient is unlikely to gain any pain relief from the injection and further diagnostic tests may be needed to accurately diagnose the patient’s pain.
Patients may continue to take their regular pain medicine after the procedure, with the exception of limiting pain medicine within the first four to six hours after the injection so that the diagnostic information obtained is accurate. Patients may be referred for physical therapy or manual therapy after the injection while the numbing medicine is effective and/or over the next several weeks while the cortisone is working.
On the day after the procedure, patients may return to their regular activities. When the pain has improved, it is advisable to start regular exercise and activities in moderation. Even if the pain relief is significant, it is still important to increase activities gradually over one to two weeks to avoid recurrence of pain.
If the first block procedure is effective in alleviating the patient’s back pain, it is often considered reasonable for the procedure to be repeated up to three times per year if needed. However, if the first nerve root injection does not relieve the patient’s pain then the injection should not be repeated.
Potential Risks and Complications
As with all invasive medical procedures, there are potential risks and complications associated with nerve root injections. However, in general the risk is low, and complications are rare. Potential risks and or complications that may occur from a nerve root injection include:
- Allergic reaction. Usually an allergy to X-ray contrast or steroid; rarely to local anaesthetic
- A rare complication, bleeding is more common for patients with underlying bleeding disorders.
- Minor infections occur in less than 1% to 2% of all injections. Severe infections are rare, occurring in 0.1% to 0.01% of injections.
- Worsening of pain symptoms
- Discomfort at the point of the injection
- Nerve or spinal cord damage or paralysis. While this is extremely rare, damage could possibly occur from direct trauma from the needle, or secondarily from infection, bleeding resulting in compression, or injection into an artery-causing blockage.