Description & Causes
Facet joints are the small knuckle sized joints along the posterior aspect of the spinal column. Each vertebral level has two facet joints; one on the left and one on the right. Facet joints normally function to guide movement of the spine and contribute to its weight bearing (approximately 80% of body weight goes through the vertebral body and disc with the remainder being taken via the facet joints).
Facet joint pain may develop in a number of ways. Direct trauma, such as a fall onto the back, may damage the articular surface (cartilage) with the joints, or problems may develop more slowly due to mal-postural and biomechanical imbalances. For example, in the neck facet joint, loading is associated with an excessive forward head posture, which causes excessive cervical lordosis (arch) in the middle neck. Similarly excessive, an inward curve in the lower back disproportionately loads the facet joints thus predisposing it to increased wear and tear. Excessive arching of the lower back can be the result of
- Weak abdominal muscles.
- Tight back muscles.
- An excessive anterior tilt of the pelvis due to tight hip flexors.
- An excessive anterior tilt of the pelvis due to internal rotation of the legs, which in turn may be due to excessive foot pronation.
- Leg length discrepency and scoliosis, which may place more strain on facet joints on one side of the body.
- Disc degeneration, which may cause loss of disc height thus increasing weight bearing through the facet joints and, unless the core muscles are adequately strong enough, any associated slackening of the spinal ligaments may lead to micro-instability, causing shearing movements and further wear and tear on the facet joints (and disc).
Once the facet joints become painful and inflamed, this tends to cause local muscle guarding, tension and fibrosis. This then causes further compression of the facet joints and stiffness, restricting normal movement. Since facet joints are “synovial joints” (just like the hip and knee), the health of the articular cartilage within the joint requires appropriate lubrication of the joint surfaces with synovial fluid, which is promoted by proper movement of the joint. Therefore stiffness in a facet joint can, especially if accompanied by joint shearing due to segmental micro-instability, predispose it to arthritis.
Symptoms
Facet joint surfaces approximate when the spine extends, therefore a characteristic of facet joint pain is pain that is aggravated by backward bending movements and relieved by bending forwards. The articulation of facet joints during walking may also aggravate symptoms.
Acute “Facet Lock” may occur when micromovements lead to jamming of a single facet joint and the lipping of the flap of cartilage (meniscoid) with it. Characteristic signs are a sharp localised pain, stabbing in quality, just off centre of the spine, with the pain tending to limit even the slightest movement.
Facet joint hypertrophy is a common finding with increasing age and may be symptom free (asymptomatic) for many years. However, when symptomatic, the pain tends to cause a chronic, deep, nagging pain slighty to the side of the spine. In the lower back, pain may be also be referred to the upper leg or buttock and in the neck, with neck pain possibly accompanied by referred pain to the upper arm or shoulder area.
Treatment
Facet lock symptoms will usually improve by resting for a week or so but spinal manipulation is usually very successful, providing near instant relief and may be needed to unjam the joint to fully restore movement and joint alignment.
Chronic facet joint pain may improve with careful bespoke management, as used in our clinics, to redress the individual causative factors, such as:
- Corrective postural and core muscle strengthening.
- The use of orthotics and heel lifts to address adverse foot biomechanics and leg length discrepency.
- Facet joint pain secondary to disc degeneration, which may respond to a course of IDD Spinal Decompression Therapy.
- Dry needling to the deep paraspinal muscles and facet joint surfaces in order to reduce trigger point irritability, promote blood flow and reduced fibrosis. (NB: This is usually a different approach to that used in Traditional Chinese Acupuncture; the paraspinal muscles in the lower back are usually at least 1.5 inches thick, therefore anything less than 50mm acupuncture needles will usually not go in deep enough to have the desired effect).
- Stretching, deep massage and spinal mobilisation to reduce stiffness and improved range of movement (especially into flexion).
Occasionally, additional and slightly more invasive therapeutic intervention is required. We would encourage patients to seek x-ray guided facet joint therapeutic injections from a pain doctor or interventional radiologist in this regard. If any benefit is achieved, then this can be repeated, but often with diminishing returns. However, the facet joint is thereby shown to be causal of the symptoms and therefore the patient is a candidate for Facet Joint Nerve Rhysolysis (or Radio Frequency Denervation). This technique uses tissue electrical impedance to precisely locate the nerves from the facet joints and then radiofrequency energy is used to ablate (divide) them with longer lasting benefits.
In severe cases that do not respond to physical therapy or injection therapy, spinal surgery is the next appropriate step.