An Overview of Spondylolisthesis

Spinal Vertebral Bone and Intervertebral Disc
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Spondylolisthesis is a condition in which a vertebra slips out of its normal position. One spinal bone slides either forward or back, usually forward, relative to the bone beneath it.

Spondylolisthesis may be a cause of, and is often considered to be a form of, spinal instability.

Symptoms

There are two main types of spondylolisthesis, including:

  • Isthmic spondylolisthesis: This type occurs as the result of spondylolysis, a condition that leads to small stress fractures (breaks) in the vertebrae. In some cases, the fractures weaken the bone so much that it slips out of place.
  • Degenerative spondylolisthesis: Degenerative spondylolisthesis is related to changes that occur in the spine as we age. For one thing, the discs start to dry up and become brittle. As this occurs they shrink and may bulge. Degenerative changes that affect the disc may give rise to spinal arthritis. Another common condition in degenerative spondylolisthesis is spinal stenosis, in which the bones may narrow and put pressure on the spinal cord.

In many cases, patients do not have any obvious symptoms. The condition may not even be discovered until an X-ray is taken for an unrelated injury or condition.

When there are symptoms, they include leg pain and lower back pain; numbness and electrical sensations are also possible. You may find these disappear when you bend forward or sit, and get worse when you stand or walk. This is because sitting and bending opens up the space where nerves are located, thereby relieving pressure.

Causes

Children involved in sports such as gymnastics, football and diving tend to be at a higher risk for isthmic spondylolisthesis. These sports require repeated spinal hyperextension (bending backwards), which can weaken the pars interarticularis, L5-S1, the fifth lumbar vertebra and first segment of the sacrum. This leads to spondylolysis, the precursor to the slippage of the vertebra that is characteristic of spondylolisthesis. Slippage occurs in about 30% of patients with spondylolysis. 

Another theory is that genetics plays a role in the development of the pars defects and spondylolisthesis. Certain racial groups, such as Inuit Eskimos, have a much greater overall incidence (approximately 40%) of spondylolysis, suggesting inherent genetic weakness of the pars.

Degenerative spondylolisthesis tends to mainly occur in non-athletic adults after the age of 40. Older age, female gender, larger body mass index (i.e., being overweight or obese), and certain anatomical variations that cause a bent over posture are thought to be factors that elevate the risk for this condition.

Diagnosis

Spondylolisthesis is measured in grades (degrees) of slippage. There are four grades, each representing 25% slippage.

For example, if a patient is measured to have a grade 2 spondylolisthesis, this means that the two adjacent vertebra maintain a 50% contact with one another.

Grades are measured by taking a side view X-ray.

Other diagnostic methods, such as CT scans or MRIs, might be used to determine the damage to surrounding tissues.

Treatment

Spondylolisthesis is treated according to the grade. For grades 1 and 2, conservative treatment, including nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, physical therapy, home exercises, stretching, and the use of a brace are often given. In physical therapy, core strengthening and stabilization exercises are emphasized.

Over the course of treatment, your doctor will take periodic X-rays to determine whether the vertebra is changing position.

For spondylolisthesis patients who have high-grade slippage, slippage that is progressively worsening, or persistent back pain, spinal fusion surgery may be recommended. In this procedure, the affected vertebrae are fused together so that they heal into a single, solid bone. The theory is that, if the painful spine segment does not move, it should not hurt.

During the procedure, the doctor will first realign the vertebrae in the lumbar spine. Small pieces of your bone—called bone graft—are then placed into the spaces between the vertebrae to be fused. Over time, the bones grow together—similar to how a broken bone heals. Your doctor may use metal screws and rods to further stabilize the spine and improve the chances of successful fusion.

In some cases, patients with high-grade slippage will also have compression of the spinal nerve roots. If this is the case, your doctor may first perform a procedure to open up the spinal canal and relieve pressure on the nerves before performing the spinal fusion.

A Word From Verywell

With nonsurgical and surgical treatments available, having spondylolisthesis does not mean you have to live in pain. In most cases, it is possible to resume activities, including sports, once the condition has been treated.

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