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Low back pain complaints are the leading cause of disability globally.
Even though it’s common, determining the specific tissues causing the pain is challenging.
This is because any structure in the low back that receives innervation could be a potential source of pain.
Literature has shown that between 15% and 40% of patients presenting with low back pain will have lumbar facet syndrome (1).
Before we jump right into what these causes are and how chiropractors can help, let’s talk about what a facet joint is and how it’s best diagnosed.
The Anatomy, Physiology, and Biomechanics of Lumbar Facets
The spine is made up of 24 vertebral bones, and between all these bones are joints.
Each functional segment between vertebral bones in the lumbar spine has three joints: the intervertebral joint and two facet (or zygapophyseal) joints.
Many chiropractors are familiar with the Kirkaldy-Willis model, which proposes a functional relationship between these three joints regarding degeneration.
If you need to refresh your memory, we recommend watching this brief video
Facet joints in the lumbar spine are oriented to allow flexion and extension but limit lateral bending and rotation of the lumbar functional segments.
Lumbar facet syndrome is a painful inflammation of the lumbar spine’s posterior structures, which various irritants can cause.
The lumbar facet joints have been called “J-shaped,” allowing for this forward to backward motion.
Anatomically, facet joints in the lumbar spine account for a significant portion of weight-bearing in the lumbar spine.
Facet joints receive innervation from medial branches of the posterior primary rami, which span several functional segments.
This means there is overlap in the innervation between the inferior and superior facets for each segment.
Due to this overlap, it is theorized that this causes the pain experienced from facet syndrome to be localized and one-sided (i.e., left vs. right).
Causes of Compression
Facet syndrome occurs when there is compression of one of the nerves which supply a facet joint.
Compression can occur from three primary causes.
Facet degeneration typically begins from a nonspecific synovial reaction triggered by trauma, aging, or several other causes.
Degeneration of the underlying hyaline cartilage, which covers the facets and inflammation in the joint capsule causing expansion can lead to a host of painful symptoms.
This can cause narrowing of the surrounding structures like the lateral canal and uncomfortable compression on the nerve.
Osteophytes are extra bony growths that can occur anywhere in the skeletal system.
When osteophytes form on facet joints, it can cause disruptions in the biomechanics of the joint and lead to further compression on the nerves of the functional segment.
When synovial joints move normally, the fibrous cap of the meniscoid separating them can become trapped between the articular surfaces and cause significant discomfort.
Diagnosing Lumbar Facet Syndrome
Diagnosing facet syndrome and distinguishing it from other causes of low back pain like a herniated disc or nerve root irritation is often a more complicated task than it would seem.
Chiropractic clinicians should first aim to determine symptoms that may indicate more serious pathology.
Following conservative care, providers should establish if any congenital anomalies exist like facet tropism.
In this common anomaly, there is a change in the direction of orientation of the facets.
While facet tropism may alter the biomechanics at a segmental level, there is no evidence to demonstrate that it causes a higher incidence of low back pain in those with a confirmed diagnosis.
- A “classic” presentation of facet syndrome is usually described by the patient as local to one side of the low back, beginning after a miscalculated simple movement.
- Patients may also recall standing up too quickly from being bent over to pick something up or completing an activity like gardening.
- They may also complain of pain in the lower extremities, including the hip, buttock, or thigh but not below the knee.
It is also important for chiropractic clinicians to remember that patients with low back pain and a history of trauma may have more signs of facet joint degeneration on radiographs, but this does not appear to be associated with pain or disability levels.
Chiropractic evaluation of facet joints can include compression or stretching maneuvers.
In a supine patient, flexing the heel toward the buttocks can increase the lordosis and load the facets with indirect compressive pressure.
Another maneuver is Kemp’s Test which assesses extension and can be completed seated or standing.
To perform this seated, a chiropractor can passively extend and rotate the lumbar spinal segments to either side to identify whether local or radiating pain is replicated.
Local discomfort indicates a facet origin.
When performing this test standing, it is essential to note that it involves the patient’s active participation.
This can cause less anatomically specific results because muscle pain or cramping may be unrelated to the intended reproduced compressive force.
There is typically a cluster of findings that can help delineate lumbar facet syndrome versus a disc herniation or nerve root irritation through a patient’s intake, medical history, and physical examination.
In summary, for facet syndrome, these findings include…
- Absence of neurologic deficits.
- Absence of nerve root tension sign/tests.
- Localized pain with Kemp’s maneuver.
- Pain, when reproduced with straight leg raise (SLR), does not extend below the knee.
Lumbar Facet Syndrome Treatment
Now that we understand the anatomy, physiology, biomechanics, and diagnosis of facet syndrome – let’s talk treatment strategies!
Facet-related pain is thought to be very responsive to chiropractic manipulative therapies (spinal adjustments).
This is believed to be primarily due to an increased gapping of facet joints following side-posture spinal adjusting.
Research even shows this effect through magnetic resonance imaging! (2).
While this mechanism is still formally unknown, two primary theories exist.
The first theory suggests that a spinal adjustment in the lumbar spine releases an entrapped meniscoid, restoring proper biomechanical movement to the area and reducing associated pain.
The second theory proposes that an improvement in the functioning of large-fiber input nerves produces modifications in the pain reflex, causing reductions in associated muscle spasms and reflex-mediated pain.
Neither of these is proven in research, but we think that there is likely a combination of both of these suggested theories – and patients with lumbar facet syndrome see significant relief with spinal adjustments.
Other treatment methods to consider include taking the time to educate your patient about how to prevent flare-ups in painful symptoms from lumbar facet syndrome through lifestyle modifications and adjusting any activities of daily living that may cause discomfort.
Many chiropractors also pair spinal adjustments with prescriptive exercises for the abdominal and core muscles and stretches for the paraspinal muscles to address the low back’s strength and flexibility.