Sciatica and nerves
Lumbar spinal stenosis narrows the space that holds nerves in the lower back
Lumbar spinal stenosis means the space inside the lower spine has become too tight for the nerves running through it [1]. It often causes leg pain when you stand or walk, and the pain usually eases when you lean forward or sit [1][2].
Key points
- Wear and tear from aging is the most common cause of the narrowing [1][2].
- Pain, numbness or cramping in the legs often gets worse with standing or walking and better with leaning forward [1][2].
- Numbness in the private area, loss of bladder or bowel control, or losing leg strength so that you cannot walk is an emergency [1].
- Stretching, strengthening and anti-inflammatory medicines are common first steps, and surgery is an option when other care has not worked [1][3].
Lumbar spinal stenosis squeezes nerves in the lower back
The spinal canal is the hollow space in the center of the spine's bones. It holds the spinal cord and spinal nerves. When that space gets smaller, the nerves can be squeezed, and this is called spinal stenosis [1][2].
It most often develops in the lower back and the neck [2]. It happens most often in adults over 60 and affects men and women equally [1]. Some people have no symptoms at all, and for most people symptoms build slowly over time [2].
Some imaging findings of narrowing can be present without any symptoms [3]. Symptoms and outlook can also differ a lot between people who have similar MRI findings [3].
Leg pain that eases when you bend forward is the classic sign
Pain tends to get worse when you stand up straight or walk, and better when you lean forward or sit [1][2].
- A burning pain or ache that starts in the buttocks and moves down the leg, sometimes reaching the foot [1][2].
- Numbness, tingling or cramping in the legs and feet, often stronger during standing or walking [1][2].
- Weakness in one or both legs, or foot drop, where the foot seems to slap the ground as you walk [1].
- Walking more than 1 or 2 blocks can bring on severe leg pain or weakness [1].
Leaning forward can increase the space available for the nerves. That is why some people find they can ride a stationary bike or walk while leaning on a shopping cart [1]. Stenosis in the neck can instead cause numbness or tingling that runs down the arms into the hands [2].
When to get care
Cauda equina compression is a medical emergency that needs prompt treatment
Severe compression of the nerves is rare, but it is considered a medical emergency that needs prompt treatment [1].
- Numbness in your private area needs emergency care [1].
- Losing control of your bowel or bladder needs emergency care [1].
- Losing strength in your legs so that you cannot walk needs emergency care [1].
If these symptoms occur, you may need emergency surgery [1]. Delaying surgery when nerve compression of this kind or other sudden worsening of nerve function is present can reduce the chances that symptoms improve [3].
If you think you may have a medical emergency in the United States, call 911 or go to the nearest emergency room.
Aging and arthritis are the most common causes of narrowing
Arthritis from wear and tear is the most common cause [1]. As disks between the spine bones age, they lose water, shrink and can collapse. This puts more pressure on the small joints at the back of the spine and makes the openings where nerves exit smaller [1].
The body responds to the worn joints by growing bone spurs. The ligaments near the joints also thicken. Together these crowd the nerves [1][2].
| Cause | How it narrows the space |
|---|---|
| Aging changes | Ligaments thicken, bones and joints enlarge, and bone spurs form [2] |
| Bulging disk | A dried, cracked disk bulges and presses on a nerve [2] |
| Spondylolisthesis | One vertebra slips forward on another and misaligns the spine [2] |
| Osteoarthritis or rheumatoid arthritis | Joint damage and bone overgrowth narrow the canals [2] |
| Injury or fracture | Misalignment or bone fragments affect the canal [2] |
| Born with a small canal | Less space means wear and tear causes symptoms sooner [1][2] |
People born with a narrow canal usually first notice symptoms between ages 30 and 50 [1]. Most cases, though, are acquired rather than present from birth [3].
Your doctor diagnoses stenosis with an exam and imaging
Your doctor will talk through your symptoms and history, then examine your back. This includes looking at it, pressing on different areas, and having you bend forward, backward and side to side [1].
| Test | What it shows |
|---|---|
| X-ray | Bones only, such as lost disk height or bone spurs [1] |
| Bending X-rays | Possible instability or too much movement in the spine [1] |
| MRI | Soft tissues such as muscles, disks, nerves and the spinal cord [1] |
| CT scan | Bony structures in cross-section, better than X-rays [1] |
| CT myelogram | Dye makes the nerves show up more clearly, to see if they are compressed [1] |
MRI is the preferred way to assess stenosis, but severity grading can vary between readers and institutions [4]. One MRI grading system runs from Grade A, no or minor stenosis, to Grade D, extreme stenosis [3].
Nonsurgical care aims to ease symptoms but does not widen the canal
Nonsurgical treatment focuses on restoring function and relieving pain. It does not improve the narrowing itself, yet many people report that it helps their symptoms [1].
- Stretching exercises, massage, and strengthening of the lower back and abdominal core often help manage symptoms [1].
- Anti-inflammatory medicines can give initial pain relief because swelling around the nerve may add to the pain [1].
- Traction offers very limited results, and there is no scientific evidence that it works [1].
- Epidural steroid injections are often used, but evidence for long-term benefit is limited [3].
Over 3 to 10 years of conservative care, symptoms improved in 33% of people, stayed stable in 50%, and worsened in 10 to 20% [3]. People with milder MRI grades often stay stable or improve without surgery [3].
Surgery for lumbar stenosis includes open laminectomy and minimally invasive options
Open laminectomy is the long-standing standard for severe stenosis [3]. It carries real risks, especially for older patients. These include dural tears, wound infection, heart and lung complications, and hospital readmission within 30 days [3]. It can also mean muscle dissection, more blood loss and a risk of instability [5].
Less invasive approaches have been developed. These include interspinous spacers, endoscopic decompression, and a procedure that removes thickened ligament through the skin [3]. One technique alternates the side of approach at each affected level in multilevel stenosis. It looks safe in case series, but no randomized trials have tested it [5].
Timing
Surgery is often elective and based on patient preference. A rapid decline in nerve function is uncommon [3].
Sources
- Lumbar Spinal Stenosis orthoinfo.org
- Spinal Stenosis Symptoms, Causes, & Risk Factors niams.nih.gov
- Minimally Invasive Surgery for the Treatment of Lumbar Spinal Stenosis: A Comprehensive Review Current pain and headache reports
- Automated Severity Grading of Lumbar Spinal Stenosis on Sagittal MRI Using a Two-Stage Deep Learning Framework with External Clinical Validation Journal of imaging informatics in medicine
- The Slalom Technique as a Motion-Preserving Approach for Multilevel Lumbar Spinal Stenosis: A Systematic Review and Meta-analysis Asian journal of neurosurgery
Not medical advice. This page is general education written from the sources above. It cannot diagnose a condition or replace a licensed clinician who knows your history. If you may be having an emergency, call your local emergency number or go to the nearest emergency department.