A facet joint injection involves administering a steroid medication and local anesthetic agent into facet joints in the back to help relieve chronic spinal pain due to conditions affecting these joints. The facet joints are a set of joints located between the articulating processes of two adjacent spinal bones (vertebrae) and therefore these bones. Nerve roots that come out of the spinal cord pass through these joints to get to the arms, legs, and other parts of the body.
The function of these facet joints is to:
- Allow mobility of the vertebrae
- Limit and guide movement of spinal segments such as excessive rotation and flexion
The function of the facet joints can be disrupted by the following issues:
- Dislocation
- Degeneration
- Injury/trauma causing instability
- Osteoarthritis
- Fractures
- Surgery
These issues cause the facet joints to become swollen which results in pain that limits the mobility of the affected individual. If the swelling of a facet joint is severe enough, the inflamed tissue can compress on the nerve passing through it causing symptoms such as numbness of the anatomy it supplies sensation to.
Technique
The facet joint injection procedure includes the following steps:
- Since it’s a minimally invasive procedure, the patient may only receive a local anesthetic to numb the skin where the needle will be inserted and this may sting for a few seconds. In some cases, light sedation may have to be administered intravenously.
- Imaging guidance in the form of fluoroscopy is used to help guide the needle into the facet joint.
- A small amount of contrast dye is then injected to confirm that the needle is indeed in the correct place.
- The combined mentioned medications will then be injected into the joint and the contrast dye will also confirm that this has been administered in the correct area.
Efficacy
In an observational study that was done to look at the facet joint injection success rate, it was discovered that this procedure offers good short-term relief for pain caused by pathology affecting these joints.1
Although the data on the efficacy of facet joint injections is limited, of that which is available the following observations were made:
- Injections in facet joints of the lumbar region of the back resulted in an initial relief of symptoms for one to four weeks in 42 to 92 percent of affected patients.
- Long-term relief of more than three months varied between 18 and 62 percent of these participants.
Therefore, the conclusion that was made was that there was moderate evidence of short-term relief and limited evidence of long-term relief of chronic neck and lower back pain when performing facet joint injections.
Safety
Facet joints injections are simple and safe procedures.
Complications may include an allergic reaction to the medication used, bleeding from the site of the injection, infection, worsening of symptoms, and nerve injury causing numbness or loss of power of the area innervated by the tissue. Initially there may be some pain after the procedure which can be managed by using anti-inflammatory medication and applying ice packs to the site of injection.
These are relatively rare complications though as the appropriate measures are followed to prevent these from occurring. Therefore, the benefit of the procedure outweighs the risks associated with it.
Reference
- Peh W. Image-guided facet joint injection. Biomedical Imaging and Intervention Journal. 2011;7(1):e4. doi:10.2349/biij.7.1.e4.