Spinal Stenosis
Spinal stenosis is a narrowing of the spaces within the spine that can put pressure on the spinal cord and the nerves traveling through the spine. This narrowing most commonly affects the lower back (lumbar spine) and neck (cervical spine) and typically develops gradually over time due to age-related degenerative changes. As the spaces narrow, they can compress neural structures, leading to pain, numbness, weakness, and difficulty walking. Spinal stenosis is particularly common in adults over 50 and is one of the leading causes of spine surgery in older adults.
What is it?
The spinal canal is a hollow channel running through the center of the vertebral column that houses and protects the spinal cord in the cervical and thoracic regions, and the bundle of nerve roots called the cauda equina in the lumbar region. Spinal stenosis occurs when this protective space becomes narrowed, reducing the room available for neural structures. The narrowing can occur in different locations: central canal stenosis involves the main spinal canal; lateral recess stenosis affects the sides of the canal where nerve roots exit; and foraminal stenosis involves narrowing of the neural foramina—the openings between vertebrae through which individual spinal nerves pass to reach the body.
Spinal stenosis is primarily classified as acquired or congenital. Acquired stenosis, which accounts for the vast majority of cases, develops over time due to age-related degenerative changes including osteoarthritis with bone spur formation (osteophytes), thickening of spinal ligaments (particularly the ligamentum flavum which can double or triple in thickness), bulging or herniated intervertebral discs, facet joint hypertrophy and arthritis, and spondylolisthesis (forward slippage of one vertebra over another). Congenital stenosis, much less common, occurs in people born with a naturally narrow spinal canal, making them more vulnerable to symptoms with even minor degenerative changes. Risk factors include age over 50, previous spinal injury or surgery, long-term occupations involving repetitive spinal stress, and certain conditions like achondroplasia or Paget’s disease. The lumbar spine, particularly the L4-L5 and L3-L4 levels, is most commonly affected, while cervical stenosis typically involves C4-C5, C5-C6, and C6-C7 levels.
Important to Know
Lumbar spinal stenosis characteristically causes neurogenic claudication—pain, cramping, numbness, tingling, or weakness in the legs that worsens with walking or prolonged standing and improves with sitting or bending forward. Patients often report they can walk farther when leaning on a shopping cart or walking uphill (both positions flex the spine, opening the canal) compared to walking upright. Back pain may be present but is not always the predominant symptom. Cervical stenosis can cause neck pain and arm symptoms, but more concerning is cervical myelopathy—compression of the spinal cord causing difficulty with fine motor tasks and hand coordination, gait instability and balance problems, weakness in arms or legs, and in severe cases, bowel or bladder dysfunction. It’s important to note that not everyone with stenosis visible on imaging has symptoms, while some with relatively mild narrowing experience significant problems. Diagnosis is confirmed with MRI, which provides detailed images of soft tissues including the spinal cord, nerve roots, discs, and ligaments. CT scan with myelography (contrast injected into spinal fluid) is an alternative when MRI cannot be performed. Plain X-rays show bony changes and alignment but cannot visualize soft tissue compression. Treatment begins conservatively with physical therapy emphasizing flexion-based exercises, core strengthening, and posture training; medications including NSAIDs for inflammation and pain, and medications for nerve pain (gabapentin, pregabalin); and epidural steroid injections to reduce inflammation around compressed nerves. Surgery (decompressive laminectomy, with or without spinal fusion for instability) is considered when conservative treatments fail to provide adequate relief, symptoms significantly impact quality of life, or progressive neurological deficits develop, particularly cervical myelopathy which requires more urgent intervention. Surgical outcomes are generally favorable for appropriately selected patients, with most experiencing significant symptom improvement. The natural history of untreated lumbar stenosis is variable—some patients remain stable or improve, while others gradually worsen. Cervical myelopathy, however, often progresses without treatment and can lead to irreversible spinal cord damage, making timely surgical intervention more critical.