What Is Degenerative Spondylolisthesis?
Degenerative spondylolisthesis occurs when one vertebra gradually slips forward relative to the vertebra below it due to age-related degeneration of the spine. This condition most commonly occurs in the lumbar spine, particularly at the L4–L5 level.
Unlike other forms of spondylolisthesis, degenerative spondylolisthesis does not involve a fracture of the pars interarticularis. Instead, it develops as the result of degeneration of the intervertebral discs and facet joints, which normally help stabilize the spine.
As these structures wear down over time, the vertebrae may gradually shift, leading to spinal instability and possible compression of nearby nerves.
Degenerative spondylolisthesis most commonly affects adults over the age of 50, and it is slightly more common in women.
Causes of Degenerative Spondylolisthesis
Degenerative spondylolisthesis typically develops as part of the natural aging process of the spine.
Several structural changes contribute to the condition:
- Degeneration of the intervertebral discs
- Arthritis of the facet joints
- Weakening of ligaments that stabilize the spine
- Loss of disc height
- Gradual spinal instability
These changes can allow one vertebra to shift forward relative to the vertebra below it, sometimes narrowing the spinal canal and compressing nearby nerves.
Symptoms
Some individuals with degenerative spondylolisthesis have no symptoms, particularly when the vertebral slippage is mild.
When symptoms occur, they may include:
- Lower back pain
- Leg pain or heaviness while walking
- Numbness or tingling in the legs
- Muscle weakness in the legs
- Difficulty walking or standing for prolonged periods
Many patients experience symptoms of neurogenic claudication, which involves leg pain or fatigue while walking that improves when sitting or bending forward.
Grading of Spondylolisthesis
The severity of vertebral slippage is commonly described using a grading system:
- Grade I: 0–25% slippage
- Grade II: 25–50% slippage
- Grade III: 50–75% slippage
- Grade IV: 75–100% slippage
Most cases of degenerative spondylolisthesis are low grade (Grade I or II).
Diagnosis
Diagnosis begins with a medical history and physical examination.
Your physician may assess:
- Back motion and flexibility
- Strength and reflexes in the legs
- Areas of numbness or nerve irritation
Imaging studies help confirm the diagnosis and determine the severity of vertebral slippage.
Common imaging tests include:
- X-rays, which show vertebral alignment and slippage
- MRI scans, which evaluate nerve compression
- CT scans, which provide detailed images of bone structures
Treatment
Treatment depends on symptom severity and the degree of nerve compression.
Non-Surgical Treatment
Many patients begin with conservative treatment options, including:
- Anti-inflammatory medications
- Physical therapy and core strengthening
- Activity modification
- Epidural steroid injections
These treatments aim to relieve inflammation around the nerves and improve spinal stability.
Surgical Treatment
Surgery may be recommended if symptoms persist despite conservative treatment or if significant nerve compression is present.
The most common surgical procedure is lumbar decompression surgery, which removes bone or soft tissue compressing the nerves.
In cases where spinal instability is present, decompression may be combined with spinal fusion to stabilize the affected segment of the spine.
Surgical treatment has been shown to significantly improve leg pain, walking ability, and overall quality of life in appropriately selected patients.
Summary
Degenerative spondylolisthesis is a condition in which age-related degeneration of the spine causes one vertebra to slip forward relative to another. Although some patients remain asymptomatic, others may develop back pain, leg pain, or nerve compression. Many patients improve with conservative treatment, but surgical decompression with or without fusion may be recommended when symptoms significantly affect mobility and quality of life.
