Spondylolisthesis is a condition of spinal instability, in which one
vertebra slips forward over the vertebra below. Isthmic spondylolisthesis,
the most common form of this condition, is caused by a bony defect (or
fracture) in an area of the pars interarticularis, an area located
in the roof (laminae) of the vertebral structure. This bony defect occurs
in approximately 4% of the population, and results from a genetic failure
of bone formation. The condition most commonly affects the fourth and
fifth lumbar vertebrae (L4 and L5) and the first sacral vertebra (S1).
It is interesting to note that the condition is not always painful.
Slip of L5 vertebra on sacrum
Symptoms of Isthmic Spondylolisthesis
Symptoms of isthmic spondylolisthesis may include the following:
- Pain in the low back, thighs, and/or legs especially after
exercise that radiates into the buttocks
- Muscle spasms
- Leg pain or weakness
- Tight hamstring muscles
- Irregular gait
Some people are symptom free and only discover the disorder when seeing
a doctor for another health problem. In severe cases, the condition
may cause swayback and a protruding abdomen, a shortened torso, and
a waddling gait.
What Causes Isthmic Spondylolisthesis?
Isthmic spondylolisthesis can be the result of a genetic failure of
bone formation in the spinal vertebrae. Usually physical stresses to the
spine then break down the weak or insufficiently formed vertebral components.
Repeated heavy lifting, stooping, or twisting can cause small fractures
to occur in the vertebral structure and lead to the slippage of one vertebra
over another. Weightlifters, football players, and gymnasts often suffer
from this disorder due to the considerable stress placed on their spines.
How is Isthmic Spondylolisthesis Diagnosed?
To make an accurate diagnosis, the physicians at CCSI will conduct a
careful and rigorous diagnostic process, including:
- Medical history. We will talk to you about your symptoms, how severe
they are, and what treatments you have already tried.
- Physical examination. You will be carefully examined by one of our
spine specialists for limitations of movement, problems with balance,
and pain. During this exam, we will also look for loss of reflexes in
the extremities, muscle weakness, loss of sensation or other signs of
- Diagnostic tests. Generally, we start with plain x-rays, which allow
us to rule out other problems such as tumors and infections. We may also
use a CT scan or MRI to confirm the diagnosis. In some patients we may
need a myelogram. This is a test that involves the use of a liquid dye
that is injected into the spinal column to show the degree of nerve compression
and slippage between involved vertebrae.
X-Ray showing lumbar spondylolisthesis
Treatment of Isthmic Spondylolisthesis
There are several methods used to "grade" the degree of slippage ranging
from mild to most severe. Your surgeon will discuss with you the extent
of your spondylolisthesis and how the severity indicates the type of treatment
that is needed.
In general, the physicians at CCSI use the Meyerding Grading System
for classifying slips. This is a relatively easy to understand system.
Slips are graded on the basis of the percentage that one vertebral body
has slipped forward over the vertebral body below. Thus a Grade I slip
indicates that 1-24% of the vertebral body has slipped forward over the
body below. Grade II indicates a 25-49% slip. Grade III indicates a 50-74%
slip and Grade IV indicates a 75%-99% slip. If the body completely slips
off the body below it is classified as a Grade V slip, known as spondyloptosis.
Your physician will consider the degree of slip, and such factors as
intractable pain and neurological symptoms, when deciding on the most
suitable treatment. As a general guideline, the more severe slips (especially
Grades III and above) are most likely to require surgical intervention.
For most cases of isthmic spondylolisthesis (especially Grades I and
II), treatment consists of temporary bed rest, restriction of the activities
that caused the onset of symptoms, pain/ anti-inflammatory medications,
steroid-anesthetic injections, physical therapy and/or spinal bracing.
Surgery is rarely needed unless the case is severe (usually Grade III
or above), neurological damage has occurred, the pain is disabling, or
all non-operative treatment options have failed.
The most common surgical procedure used to treat spondylolisthesis is
called a laminectomy and fusion. In this procedure, the spinal canal is
widened by removing or trimming the laminae (roof) of the vertebrae. This
is done to create more space for the nerves and relieve pressure on the
spinal cord. The surgeon may also need to remove all or part of the vertebral
disc (discectomy) and then also fuse vertebrae together. If fusion is
done, various devices (like screws or interbody cages) may be implanted
to enhance fusion and to support the unstable spine.
Post-operative X-ray showing corrective implants
Prevention is Key
While it may not be possible to prevent all spine problems, there are
things you can do to help keep your spine healthy. The most important
prevention method is to avoid or limit those work or recreational activities
that cause considerable stress to your spine.
At CCSI we will work closely with you in establishing healthy lifestyle
habits that can help keep your back healthy. For example, losing weight,
starting a regular exercise regimen, not smoking, and learning proper
body mechanics can all help reduce the risk of further back problems.