|Facet Arthropathy: An Underdiagnosed
but Treatable Cause of Low Back Pain
What are the facet joints ?
The facet joints lie on the side of the spine closest to
the skin of your back. A pair of these joints can be
found at each of the 32 motion segments in the
human spine. These joints move with each bend or
twist of the body, working in conjunction with the
intervertebral disc to allow motion in the neck, trunk,
and lower back.
What function do the lumbar facet joints perform ?
These joints help to restrict and control the motion of
the spine. They help to guide and protect the
intervertebral discs as well. In the lower back
(lumbar spine) they help to constrain the amount of
twisting and also keep the segments of the spine
from slipping off of one another.
Why are the facet joints prone to disease ?
Because the facet joints constrain motion they are
subject to significant mechanical stress. The spine of
a physically active adult undergoes as many as one
million motions per year. This repetitive trauma
leads to cumulative wear and tear. The facet joints
allow movement between two surfaces covered with a
thin layer of cartilage, and an interposed fluid-like
sac helps to lubricate any motion, just like in the
knee. Microscopic injuries (tears and abrasions on
the cartilage) lead to an inflammatory process that
produces pain. This is a form of osteoarthritis just
like in the other joints of the body.
What are the symptoms of facet arthritis ?
Severe back pain is the most common complaint.
This can be associated with leg pain that is almost
undistinguishable from sciatica caused by a herniated
disc. In addition, the symptoms are typically worse
in the morning upon awakening and can be
aggravated by bending backwards (in extension).
Facet arthritis can occur in any part of the spine but
is most common in the lower back.
How is facet arthropathy diagnosed ?
Like most diseases, facet arthritis is primarily
diagnosed based upon the specific nature of the
patient's complaints. In addition a physical
examination is useful for eliminating other causes of
back pain. Imaging studies such as X-Rays, CT
scans, and MRI's can also show evidence of the
physical abnormalities in the facet joint. However,
the most specific test for this disease remains a
SPECT bone scan. This study involves the injection
of a minute amount of harmless radiotracer into the
bloodstream. The tracer then migrates to areas of
the body with excessive inflammation which can be
identified through photographs taken by a specialized
Why is facet disease underdiagnosed ?
There has been a tremendous emphasis on the
intervertebral disc as a cause of back pain. Most
patients are familiar with the concepts of herniated
discs or disc bulges. However, there has been a
general lack of understanding of facet disease in the
medical community. This has resulted in a situation
where many medical professionals fail to suspect that
a patient with back pain might have facet arthropathy.
How is facet arthritis treated ?
Facet arthritis is primarily treated like any other form
of osteoarthritis. Medications used to reduce
inflammation are the first line of treatment. This
includes non-steroidal anti-inflammatory medications
as well as oral steroids. Physical therapy to mobilize
and stretch the joints can also be utilized. For
severe cases a direct injection of anti-inflammatory
medications into the joint itself can be highly
effective. This is done with a small needle under X-
Ray or CT guidance and is quite distinct from an
epidural injection. These, injections, while highly
effective and diagnostic for the disease, provide a
limited period of relief. Thus, efforts are underway to
engineer facet replacement devices to treat patients
with refractory symptoms. In this manner the
disease will be treatable just like hip arthritis can be
cured with a total joint replacement.
|Coronal view CT scan showing
severe bilateral facet joint
degeneration at L4/5 with air
in the joints (red arrows)
|CT SPECT fusion scan showing
radioisotope uptake in both
facet joints (hot areas are
reflected by orange coloration)
|MRI scan showing asymmetry of
the facet joints with overgrowth
of one side associated with severe
arthritis (red circle)
|Side view (sagittal image) of a
SPECT bone scan showing facet
joint arthritis in the neck (red