Located at the back of the spine, one to each side, the facet joints are overlooked compared with the charismatic disc. The facet joints are a synovial joint—covered in an articular capsule and containing a lubricating joint fluid. The functions of these small but important joints are to:
- bear load,
- allow motion,
- and limit excessive motion.
The facet joints in the low back bear up to one-third of the compressive load. They are a source of pain when injured.
Symptoms Facet Joint Pain
Facet joint pain has a number of symptoms:
- Localized pain: a dull ache is present in the lower back. This pain might be tender to touch.
- Referred pain: the nerves overlying and within the facet joint can refer pain to the buttocks, hips, thighs, or knees. This type of pain is often described as a dull ache.
- Sciatic pain: the facet joints are located directly behind the nerve roots. If swollen or crusty with bone growth, the facet joint may damage the nerve root and trigger shooting leg pain.
- Stiffness: as with other arthritic conditions, prolonged activity or stresses to the joint will cause a lingering stiffness which is usually relieved gradually with walking.
- Instability: the facet joints might click, grind, pop and buckle with the loss of joint laxity.
Causes of Facet Joint Pain
The stressful postures, motions, and loads for the facet joint are:
- Extension bending
- Shear forces
- Direct trauma
However, the most common cause of facet joint arthritis is none of the above. It’s actually a prior disc injury. The reason is this:
When a disc injury occurs, the disc may lose stiffness. The reduced stiffness means that the disc is bearing less than its fair share of the compressive load. This extra burden falls to the poor facet joints, which are small and ill-equipped for the task.
Over the years, the increased pressure on the facet joints at the same level of a weakened disc wear down. The following changes might arise:
- Cartilage injury
- Cartilage degeneration
- Cysts — a type of internal blister
- Swelling of nearby ligaments (ligamentum flavum)
- Bone overgrowth (hypertrophy)
This degenerative cascade explains why the 30-year-old with an acute disc bulge becomes the 60-year-old with facet arthritis, to go along with his degenerated disc.
Diagnosis of Lumbar Facet Joint Injury
The facet joint is stressed with extension, twisting, and lateral bending. Not coincidentally, a facet load test combines these three forces together. Performed properly, the absence of pain on a facet loading test virtually excludes the presence of facet region pain. (The presence of pain, however, is not necessarily specific without additional testing.)
Shear loads can injure the facet joint as well, which help restrict shear slippage. In a healthy spine with a functional disc, the facet joints are generally safe during tasks with compression. A notable exception is if a high compression load occurs while the spine is extended. This posture will migrate stresses directly into the facet joint and neural arch.
One example of this injury is a professional athlete who had, during a celebration, jumped feet first into a shallow swimming pool when his spine in a long extended posture.
Facet joint injury can be seen on spinal imaging:
- X-rays can show bone spurs within a facet joint. This is not the best way to see facet joint injuries.
- MRI scans provide the best overall view. It can show bone, cartilage, and soft tissue changes, such as cysts.
- CT scans provide the best visualization of bone changes. It is usually not needed if an MRI has been performed.
Steroid injections into the facet joint or adjacent to it is another diagnostic test. An impressive response to the injection—significant pain relief—is a sign that your pains arises from the facet region.
Treatment of Facet Joint Injury
The treatment of lumbar facet joint injury depends on the type of condition.
Pain medication should be used sparingly for facet joint pain and back pain. Keep in mind that these medications do not help your condition heal. The medications will not:
- Reduce the days missed from work for back pain
- Reduce your future need for pain medications
- Reduce your risk of needing a spine injection or for surgery.
That said, the conventional medical practice will usually prescribe Tylenol, NSAIDs, and—if the pain is severe—opioids.
Cannabidiol (CBD) products are safer for pain relief than these standard medications. The level of effectiveness varies for each patient but can be profound for some.
Therapy for facet injuries should focus on lumbar stabilization and avoidance of triggering extension, rotational, shear, and compressive forces.
Exercises that might be appropriate include:
- The McGill Big 3
- Standing bird dog
- Wall plank
- Side wall plank
- Bench push-up
- And TRX pulls.
For a symptomatic facet region cyst, an interventional drainage can be curative. The cysts may, however, grow back.
For facet cartilage, bone inflammation, and arthritis, a facet joint injection with steroid and a numbing agent can calm the inflammation and pain temporarily.
Facet hypertrophy that is relentless compressing a nerve root might need surgical decompression. A facetectomy can relieve the space behind the affected nerve room. This procedure is usually performed in addition to a discectomy—removal of disc material—and laminectomy—removal of part of the neural arch.
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