Spondylolisthesis-Isthmic

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Isthmic spondylolisthesis is a spinal condition in which one vertebra slips forward over the vertebra below.  It is caused by a defect, or fracture, of the pars interarticularis; a bone connecting the upper and lower facet joints.  The defect may be congenital and a fracture can be caused by the accumulative affects of spinal stress.  Sometimes isthmic spondylolisthesis affects young athletes.

*Isthmic spondylolisthesis most often occurs at L5-S1, the fifth lumbar vertebra and first sacral segment.

Symptoms

Although isthmic spondylolisthesis can cause spinal instability, not all patients find the condition painful. Symptoms of isthmic spondylolisthesis may include:

• Low back pain
• Sciatica
• Muscle spasms
• Leg weakness
• Tight hamstring muscles
• Irregular gait or limp

Causes

Isthmic spondylolisthesis may result from failure of bone to form properly.  Accumulated physical stresses to the spine may cause weak or insufficiently formed vertebral structures (i.e., pars interarticularis) to break.  Repeated heavy lifting, stooping over, or twisting may cause small fractures to occur and lead to a vertebral slip.  Weightlifters, football players, and gymnasts may suffer from this disorder because of considerable spinal stress.

Video: Spondyloisthesis
Click below to view a video from our library about this condition.

Diagnosis

Isthmic spondylolisthesis must be diagnosed by an expert physician.

• Medical history

The doctor asks you about symptoms, their severity, treatments you have already tried.

• Physical examination

The physician examines you for limitations of movement, balance problems, and pain. He tests your reflexes, and evaluates muscle weakness, loss of sensation, and other signs of neurologic problems.

• Diagnostic tests

Most doctors start with x-rays.  Isthmic spondylolisthesis may be seen on a lateral (side) lumbar x-ray.  If necessary, a CT scan or MRI may be ordered to see the spine’s tissues in greater detail.

Classification of Isthmic Spondylolisthesis

Information from your medical file and imaging studies is used to grade the degree of vertebral slippage from mild to severe.  The grade of your spondylolisthesis is explained to you along with what it means.

Doctors use the Meyerding Grading System to classify the degree of vertebral slippage.  This system is easy to understand. Slips are graded on the basis of the percentage that one vertebral body has slipped forward over the vertebral body below.

• Grade I:  1-24%
• Grade II: 25-49%  
• Grade III: 50-74%
• Grade IV: 75%-99% slip.
• Grade V: Complete slip (100%), known as spondyloptosis

When considering treatment, the degree of slip is taken into account as well as your pain and neurological symptoms (if any).  Most cases of isthmic spondylolisthesis are Grade I or II. In general,  the more severe the slip (Grades III and above), the more  likely a surgical intervention will be required.

Non-operative Treatment

Most cases of isthmic spondylolisthesis are treated without surgery.
 

• Short-term bed rest
• Activity restriction
• Over-the-counter or prescription pain medication
• Anti-inflammatory medication
• Muscle relaxants
• Oral steroids
• Steroid injections
• Physical therapy
• Bracing

Isthmic spondylolisthesis can be progressive.  This means the spondylolisthesis worsens with time. This is why it is important to follow-up with your doctor to monitor your treatment progress and spondylolisthesis.

Surgery

If isthmic spondylolisthesis progresses or causes neurologic problems, such as incontinence, surgery may be recommended.  Spinal instrumentation (i.e., rods, screws) and fusion (bone graft) are common procedures performed to stop slip progression and stabilize the spine. There are different types of instrumentation, bone graft and graft products, as well as procedures (some minimally invasive) to surgically treat isthmic spondylolisthesis. The surgeon will explain surgical options if you are an appropriate candidate, along with associated risks and benefits.

Conclusion

Isthmic spondylolisthesis is a serious condition but it is one that can be safely and effectively treated. Many patients are able to recover fully and enjoy healthy, pain-free, and active lifestyles. There are many treatment options for isthmic spondylolisthesis but not all people are candidates for every treatment. An expert in spinal conditions should diagnose the condition and can then provide advice as to the best treatment options for an individual case.