What is spinal stenosis?

Spinal Stenosis: Definition, Diagnosis, and Management

Spinal stenosis is the narrowing of the spinal canal that results in bony constriction of the cauda equina and the emerging nerve roots, causing neurogenic claudication and varying degrees of pain and neurological symptoms. 1

Clinical Presentation

Spinal stenosis typically presents with:

• Neurogenic claudication: Symptoms of leg pain and occasionally weakness on walking or standing, relieved by sitting or spinal flexion 1
• Burning or cramping pain that radiates to the buttocks and lower extremities, often bilaterally 2
• Pain that worsens with standing, walking, or lumbar extension
• Pain that improves with forward flexion, sitting, or recumbency 3
• Progressive, waxing and waning symptoms that may deteriorate over years 2

Anatomical Considerations

Spinal stenosis can occur at different levels:

• Cervical stenosis: Most commonly affects the cervical spine, with potential for spinal cord compression leading to myelopathy 1
• Lumbar stenosis: Most common form, affecting the lower back and causing compression of nerve roots 3
• Thoracic stenosis: Less common than cervical or lumbar stenosis 1

Stenosis can result from:

• Degenerative changes (most common)
• Disc herniations
• Osteophyte formation
• Facet joint hypertrophy
• Soft-tissue infolding
• Ossification of the posterior longitudinal ligament (OPLL) 1

Diagnostic Approach

Imaging Studies

1. MRI of the spine:

   • First-line imaging modality for suspected spinal stenosis
   • Best for evaluation of the spinal canal, spinal cord, and nerve roots 1
   • Allows cross-sectional measurement of the spinal canal 2

2. CT scan:

   • Superior for evaluating bony structures
   • Helpful for identifying regions of neuroforaminal and spinal canal narrowing
   • Particularly useful in cases of suspected OPLL 1

3. Plain radiographs:

   • May show osteophytic narrowing of the spinal canal
   • Less sensitive than MRI or CT 1

4. CT myelography:

   • May be useful to answer specific questions before surgical intervention
   • Can diagnose severe canal stenosis 1
   • Sometimes performed in flexion and extension to identify position-dependent cord compression 1

Management

Non-Surgical Management

For mild to moderate symptoms, multimodal conservative treatment should be attempted for 3-6 months 4:

• Patient education about the condition
• Pain medications (NSAIDs)
• Physical therapy with emphasis on flexion exercises and "delordosing" techniques
• Epidural steroid injections
• Lifestyle modifications
• Multidisciplinary rehabilitation

However, it's important to note that there is insufficient high-quality evidence to recommend any specific type of non-surgical treatment over others 3.

Surgical Management

Surgery is indicated in the following circumstances:

• Absolute indications:

  • Clinically relevant motor deficits
  • Cauda equina syndrome 4

• Relative indications:

  • Severe symptoms that persist despite 3-6 months of conservative treatment 4
  • Progressive neurological decline

The most common surgical procedure is decompressive laminectomy 5. Recent prospective randomized studies have demonstrated that surgery provides more rapid and profound improvement of symptoms compared to conservative therapy 4, 5.

Outcomes and Prognosis

• Approximately 85% of patients experience significant improvement with surgical treatment

• About 12% feel no significant improvement

• Around 3% report worsening symptoms 6

• Outcomes (leg pain and disability) appear better for surgery than for non-operative treatment, though evidence quality is variable 3

Important Considerations and Pitfalls

1. Diagnostic challenges:

   • Clinical diagnosis requires correlation of symptoms, physical examination, and imaging findings
   • High rates of anatomic stenosis on imaging in asymptomatic older adults can lead to overdiagnosis 3

2. Natural history:

   • Spinal stenosis does not necessarily progressively worsen 5
   • Symptoms often fluctuate or gradually improve without intervention

3. Surgical decision-making:

   • Rapid deterioration is rare, making surgery almost always elective 3
   • Surgery should be considered only after trials of less invasive interventions have failed
   • Age alone should not be a contraindication for surgery if other health parameters are favorable

4. Comorbidities:

   • Medical, social, psychological, and nutritional factors should be evaluated preoperatively 6
   • Patients with spinal stenosis often have other cardiovascular risk factors that need management

By understanding the pathophysiology, clinical presentation, and treatment options for spinal stenosis, clinicians can provide appropriate care that maximizes function and quality of life for affected patients.