What is disc space narrowing?

Disc Space Narrowing Explained

Disc space narrowing is the reduction in the normal distance between adjacent vertebral bodies due to degeneration of the intervertebral disc, which can lead to nerve compression, pain, and reduced mobility.

What Is Disc Space Narrowing?

Disc space narrowing occurs when the cushioning disc between your spine bones (vertebrae) becomes thinner than normal. Here's what happens:

• Normal disc anatomy: Intervertebral discs serve as shock absorbers between the vertebrae, allowing for spine movement while maintaining proper spacing
• Degeneration process: Over time, discs lose water content and height due to aging, injury, or wear and tear
• Measurement: Radiologists measure disc space narrowing as the decreased distance between adjacent vertebral bodies 1

How It Appears on Imaging

Different imaging tests show disc space narrowing in various ways:

• X-rays (radiographs): The initial recommended imaging that shows decreased distance between adjacent vertebral bones 1
• MRI: The gold standard for evaluating disc pathology, showing detailed assessment of narrowing, nerve compression, and associated soft tissue changes 1
• CT scan: Useful when MRI is contraindicated or to better characterize bony changes associated with disc narrowing 1

Effects of Disc Space Narrowing

When disc space narrows, several important changes occur:

• Foraminal narrowing: The spaces where nerves exit the spine become smaller, potentially pinching nerves 2, 1

  • Even 1mm of disc space narrowing can reduce the foraminal area by 20-30%
  • 3mm of narrowing can reduce foraminal area by 35-45% 2

• Facet joint pressure: Increased pressure on the small joints at the back of the spine 3

  • This pressure increases significantly with disc space narrowing
  • Can cause pain, especially when bending backward

• Sclerosis: Hardening of bone at the vertebral endplates, appearing as increased density on X-rays 4

  • Often most noticeable in the anterior (front) part of the vertebral body
  • May be mistaken for infection but has distinctive features

Relationship to Pain

The connection between disc space narrowing and pain is complex:

• Disc space narrowing appears more strongly associated with back pain than other radiographic features of degeneration 5, 1
• Those with disc space narrowing are about twice as likely to report back pain compared to those without it 5
• The relationship between pain and narrowing strengthens as the narrowing becomes more severe 5
• Important caveat: Abnormal findings are common in people without symptoms, so clinical correlation is essential 1

Common Causes

Disc space narrowing typically results from:

• Age-related degeneration
• Injury or trauma
• Herniated disc
• Degenerative disc disease
• Spinal arthritis

Management Considerations

For patients with symptomatic disc space narrowing:

• Conservative management should be the initial approach for at least 6 weeks, including:

  • NSAIDs/COXIBs for pain and inflammation
  • Physical therapy to strengthen supporting muscles
  • Patient education about activity modification 1

• Surgical options should only be considered after failed conservative management for 6+ weeks with persistent symptoms, or with progressive neurological deficits 1

  • Procedures like laminoforaminotomy may be effective for cervical radiculopathy caused by disc space narrowing 6
  • Maintaining proper disc height during surgery is important to prevent nerve compression 2, 7

Important Clinical Pearls

• Disc space narrowing is a normal part of aging but can become symptomatic when it causes nerve compression or joint stress
• Always correlate imaging findings with clinical symptoms, as many people have disc space narrowing without pain
• The degree of narrowing correlates with the likelihood of symptoms - more severe narrowing tends to cause more problems
• When evaluating back or neck pain, consider that disc space narrowing is just one potential contributor to symptoms