Spinal stenosis is the narrowing of the spaces inside your spine, which puts pressure on the nerves running through it. It happens most often in the lower back (lumbar spine) and the neck (cervical spine), and it’s overwhelmingly a condition of aging. MRI studies have found signs of stenosis in up to 80% of people over age 70, though many of them have no symptoms at all.
The narrowing itself isn’t always a problem. Up to 21% of people over 60 show stenosis on imaging without experiencing any pain or disability. When it does cause symptoms, the hallmark is leg pain and difficulty walking that gets better when you sit down or lean forward.
What Narrows and Why
Your spinal canal is the bony tunnel formed by stacked vertebrae that protects the spinal cord and the nerve roots branching off from it. Several age-related changes can shrink this space. The most common culprits are thickening of a ligament called the ligamentum flavum (which lines the back of the canal), bone spurs from arthritis in the small facet joints, bulging or collapsed discs, and a combination of all three happening at once. Autopsy studies have found disc degeneration, facet joint arthritis, or bone spurs in 90 to 100% of people over 64.
These changes don’t happen in isolation. Research shows a significant correlation between disc degeneration and ligament thickening: as discs wear down and lose height, the ligament buckles inward, and the facet joints enlarge to compensate for the instability. Age, disc degeneration, and facet joint arthritis are the three strongest predictors of how much the canal narrows. The process is gradual, unfolding over years or decades.
Where the Narrowing Happens
Not all stenosis is the same. The location of the narrowing determines which nerves get compressed and what symptoms you feel.
- Central canal stenosis is narrowing of the main spinal canal. It typically results from ligament thickening combined with disc bulging, and it can compress nerves on both sides, producing symptoms in both legs.
- Lateral recess stenosis affects a smaller passageway off to the side, where individual nerve roots travel before exiting the spine. This is usually caused by facet joint arthritis and bone spur formation, and it tends to produce symptoms on one side only.
- Foraminal stenosis narrows the small openings (foramina) where nerves exit the spinal column. Disc collapse, disc protrusions, or bone spurs pinch the nerve root inside this exit tunnel.
How It Feels
The signature symptom of lumbar spinal stenosis is neurogenic claudication: a heavy, aching, or cramping pain in the buttocks and legs that comes on with walking or standing and eases when you sit down. It’s different from the leg pain caused by poor circulation (vascular claudication) because posture matters more than activity level. Leaning forward over a shopping cart, sitting on a bench, or squatting all tend to bring relief because flexing the spine opens the canal slightly. Standing upright or arching the back closes it. This is why many people with stenosis instinctively walk with a forward-stooped posture.
Beyond the claudication pattern, you may notice numbness, tingling, or weakness in the legs. Many people are completely comfortable at rest and only develop symptoms during activity. When stenosis occurs in the neck instead of the lower back, the symptoms shift: you might feel clumsiness in your hands, difficulty with fine motor tasks like buttoning a shirt, or a sense of unsteadiness when walking.
How It’s Diagnosed
Doctors diagnose spinal stenosis using a combination of your symptom history, a physical exam, and imaging. MRI is the preferred tool because it shows soft tissues like ligaments, discs, and nerves alongside the bones. On imaging, a spinal canal with a front-to-back diameter under 12 millimeters suggests narrowing, and under 10 millimeters is generally considered diagnostic. Cross-sectional area measurements also help classify severity: 75 to 100 square millimeters is moderate, and below 75 square millimeters is severe.
These numbers matter less than how they match your symptoms. A canal that looks dramatically narrow on an MRI can belong to someone who walks comfortably for miles, while a mildly narrow canal can cause significant pain in someone else. Imaging findings alone don’t dictate treatment.
Non-Surgical Treatment
Most people with spinal stenosis start with conservative management, and many never need surgery. The first-line approaches focus on reducing the curve in your lower back (which opens the canal) and building the strength to support your spine.
Physical therapy is the cornerstone. A typical program combines posture correction, core and trunk strengthening, stretches for the lower back and legs, and exercises that address nerve-related symptoms. Stationary cycling is often better tolerated than walking because the seated, slightly forward position keeps the canal open. Supportive braces and walking aids like rollator walkers can also help by encouraging a forward-leaning posture.
Body weight plays a surprisingly large role. Research has identified BMI as the single most powerful predictor of day-to-day function in people with lumbar stenosis. Losing weight reduces the mechanical load on the spine and may also lower systemic inflammation that contributes to pain. A combination of gradual increases in walking (even using a pedometer to track steps) and improved nutrition has been studied as a way to break the cycle of pain, inactivity, and weight gain that stenosis often creates.
For pain relief, options range from over-the-counter anti-inflammatories and topical treatments (lidocaine patches, capsaicin cream) to medications that target nerve pain. Epidural steroid injections can provide temporary relief, particularly for people with symptoms radiating down one leg. However, the long-term picture is mixed. In one study that followed patients for five to seven years after epidural injections, only about 15% reported complete resolution of their original pain. Roughly half still had significant pain and needed repeat injections every two to six months or ongoing medication.
When Surgery Helps
The most common surgery for spinal stenosis is a laminectomy, where a surgeon removes part of the bony arch (lamina) at the back of the vertebra to create more room in the canal. Bone spurs, thickened ligament, or other tissue compressing the nerves may be removed at the same time. This is often called decompression surgery. Minimally invasive versions use smaller incisions and a surgical microscope, which can mean less tissue disruption and a shorter recovery.
Surgery tends to provide meaningful improvement in function, but the benefits are more modest and nuanced than many people expect. A randomized controlled trial that followed patients for six years found that people who had surgery improved their functional ability by about 29% from baseline, compared to 8% in the group treated without surgery. The surgical advantage was real and statistically significant, but it slowly declined over the last four years of the study. Pain relief in the legs and back was better with surgery at one and two years, but by six years, pain levels were no longer significantly different between the surgical and non-surgical groups. Walking ability was similar in both groups at every time point.
This doesn’t mean surgery fails. For people whose quality of life is severely limited by stenosis symptoms, decompression can restore years of better function. But it’s not a permanent fix for pain, and the underlying degenerative process continues. The decision to pursue surgery typically comes down to how much your symptoms interfere with daily life and how well you’ve responded to conservative treatment over several months.
Staying Active With Stenosis
People with stenosis tend to avoid walking because it hurts, and that inactivity creates its own cascade of problems: weight gain, deconditioning, and increased risk of heart disease and diabetes. Breaking this cycle matters as much as treating the spine itself. Activities that keep the spine in a slightly flexed position, like cycling, swimming, or using an elliptical machine, are generally well tolerated. Walking shorter distances more frequently, rather than pushing through long bouts that flare symptoms, can help build endurance gradually.
Core strengthening exercises that focus on the deep abdominal and back muscles give the spine more internal support, reducing the load on the narrowed canal. Flexibility work targeting the hip flexors and hamstrings can also improve posture and reduce strain on the lower back. The goal isn’t to reverse the narrowing, which isn’t possible through exercise, but to create the best possible mechanical environment around it so the narrowing causes fewer problems.