Low back pain is an extremely common condition, affecting up to 80% of the population at some point in their lives. It is one of the most common reasons for doctor’s visits across the country.The problem is that while many acute causes of neck and low back pain will resolve with conservative treatment like rest and ice or hot packs, far too many patients will move from acute to chronic neck and low back pain and require additional care to find relief.
In order to obtain relief your doctor must accurately diagnose the source of your pain and that is exactly where a medial branch nerve block comes in. sometimes it’s just referred to as just medial branch block. If performed in the neck it is called cervical medial branch block. In the low back it’s called lumbar medial branch block.
Medial Branch Nerve Block
The medial branch injection procedure includes the following steps:
- Commonly, the procedure is performed without any sedation, however, an IV line can be started if relaxation medicine is needed
- The patient lies face down on an procedure table, and the skin over the area to be tested is well cleansed
- The physician treats a small area of skin with a numbing medicine (anesthetic), which may sting for a few seconds
- The physician uses X-ray guidance (fluoroscopy) to direct a very small needle over the medial branch nerves
- A small amount of contrast dye is then injected to confirm that the medicine covers the medial branch nerve
- Following this confirmation, a small amount of numbing medicine (anesthetic) will then be slowly injected onto each targeted nerve.
The injection itself only takes a few minutes, but the entire procedure usually takes between 15 to 20 minutes.
- As with all invasive medical procedures, there are potential risks and complications associated with medial branch blocks. However, in general the risk is low and complications are rare.
Potential risks and/or complications that may occur from a medial branch injection include:
- Allergic reaction : The potential allergy is usually to the X-ray contrast solution and rarely to local anesthetic
- Bleeding : A rare complication, bleeding is more common for patients with underlying bleeding disorders
- Infection :Minor infections occur in less than 1% to 2% of all injections. Severe infections are rare, occurring in 0.01% to 0.1% of injections
- Worsening of pain symptoms
- Discomfort at the point of the injection
- Nerve or spinal cord damage or paralysis. While extremely rare, damage can occur from direct trauma from the needle, or secondarily from infection, bleeding resulting in compression, or injection into an artery causing blockage.
- Patients who are on a blood thinning medication (such as Plavix® or Coumadin®) should notify their treating provider and discuss whether or not to discontinue the medication prior to the injection.
- Patients with an active infection may not be able to have this procedure, and should discuss their specific situation with the treating physician.
- Patients should also let their doctor know of any allergies they have to medications, especially allergies to medications that may be used for the procedure.
- Patients may or may not obtain pain relief in the first few hours after the injection, depending upon whether or not the medial branch nerves targeted are the ones carrying signals for their pain. If the joint or joints being targeted are not causing the pain, a patient will not obtain relief from the medial branch nerve block.
- The patient will discuss with the doctor any immediate pain relief. Ideally, patients will also record the levels of pain relief during the next several hours in a pain diary. A pain diary is helpful to clearly inform the treating physician of the injection results and in planning future tests and/or treatment, as needed.
- Patients may continue to take their regular medications after the procedure, with the exception of limiting pain medicine within the first 4 to 6 hours after the injection so that the diagnostic information obtained is accurate.
- On occasion, patients may feel numb or have a slightly weak or odd feeling in their neck or back for a few hours after the injection.
Pain Relief Post-Injection
- The medial branch nerve block is designed to interrupt the pain signal being carried by the medial branch nerves supplying a specific facet joint. Because of this, patients may feel complete or partial pain relief during the first 4 to 6 hours after an injection. They may also feel no pain relief during this time (anesthetic phase).
- Depending on the amount of pain relief the patient has during the first 4 to 6 hours after the injection, the patient may be a candidate for a radiofrequency ablation procedure to try and provide longer term pain relief.
- Generally, a patient must report at least 80% improvement in their pain during the first 4 to 6 hours after the injection to be considered a candidate for radiofrequency ablation.
