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Narrowing of the spinal canal and foramen:
- Spondylosis or degenerative arthritis is the most common cause of spinal stenosis, resulting from compression of the spinal cord by disc degeneration, facet arthropathy, osteophyte formation, and ligamentum flavum hypertrophy.
- The L4–L5 level is most commonly involved.
The prevalence of spinal stenosis increases with age due to “wear and tear” on the normal spine.
Symptomatic spinal stenosis affects up to 8% of the general population.
- The prevalence of spinal stenosis is high if assessed solely by imaging in elderly patients. Not all patients with radiographic spinal stenosis are symptomatic. The degree of radiographic stenosis does not always correlate with patient symptoms. Lumbar MRI shows significant abnormalities in 57% of patients >60 years.
- Predominant age: Symptoms develop in 5th to 6th decades (congenital stenosis is symptomatic earlier).
Etiology and Pathophysiology
- Spinal stenosis can result from congenital or acquired causes. Degenerative spondylosis is most common.
- Disc dehydration leads to loss of height with bulging of the disc annulus and ligamentum flavum into the spinal canal, increasing facet joint loading.
- Facet loading leads to reactive sclerosis and osteophytic bone growth, further compressing spinal canal, and foraminal elements.
- Other causes of acquired spinal stenosis include:
- Neural cysts and lipomas
- Postoperative changes
- Rheumatoid arthritis
- Diffuse idiopathic skeletal hyperostosis
- Ankylosing spondylitis
- Metabolic/endocrine causes: osteoporosis, renal osteodystrophy, and Paget disease
No definitive genetic links
Increasing age and degenerative spinal disease
There is no proven prevention for spinal stenosis. Symptoms can be alleviated with flexion at the waist:
- Leaning forward while walking
- Pushing a shopping cart
- Lying in flexed position
- Avoiding provocative maneuvers (back extension, ambulating long distances without resting)