Lumbar spinal stenosis is narrowing of the spinal canal or nerve passageways in the lower back. This narrowing can place pressure on the nerves that travel from the lumbar spine into the legs.
Lumbar spinal stenosis is common as people age and is usually caused by a combination of disc degeneration, arthritis, bone spurs, thickened ligaments, and enlargement of the facet joints.
Some people have narrowing on an MRI but little or no discomfort. Others develop pain, numbness, weakness, or difficulty walking when the nerves become compressed.
What Is Lumbar Spinal Stenosis?
The spinal canal is the space inside the spine that contains the nerves.
In the lumbar region, the spinal cord has usually ended, and the canal contains a bundle of nerve roots known as the cauda equina.
As degenerative changes develop, this space can gradually become smaller.
Narrowing may occur in several locations:
- The central spinal canal
- The lateral recesses where nerve roots travel
- The neural foramina where nerves exit the spine
The symptoms depend on which nerves are compressed and how severe the narrowing becomes.
What Causes Lumbar Spinal Stenosis?
Lumbar spinal stenosis usually develops gradually.
Common causes include:
- Degenerative disc disease
- Disc bulging
- Facet joint arthritis
- Bone spurs
- Thickening of the ligamentum flavum
- Degenerative spondylolisthesis
- Loss of disc height
- Spinal deformity
- Congenitally narrow spinal canal
Many patients have several of these changes at the same time.
Symptoms of Lumbar Spinal Stenosis
Symptoms may include:
- Low-back pain
- Buttock pain
- Leg pain
- Numbness or tingling in the legs
- Leg weakness
- Heaviness or fatigue in the legs
- Difficulty walking long distances
- Difficulty standing for prolonged periods
Symptoms often affect both legs but may be worse on one side.
Neurogenic Claudication
A characteristic symptom of lumbar spinal stenosis is neurogenic claudication.
Patients may develop:
- Leg pain
- Heaviness
- Numbness
- Weakness
- Fatigue
while standing or walking.
Symptoms often improve when sitting, bending forward, or leaning over a shopping cart.
This happens because bending forward temporarily increases the amount of space available for the nerves.
Some patients notice they can walk much farther while leaning over a grocery cart or riding a bicycle than while walking upright.
Why Does Sitting Often Relieve the Symptoms?
Standing and extending the lower back can make the spinal canal and neural foramina slightly smaller.
Sitting or bending forward tends to open these spaces.
This is why lumbar stenosis frequently causes:
- Worse symptoms with standing
- Worse symptoms with walking
- Improvement with sitting
- Improvement when leaning forward
This pattern can help distinguish spinal stenosis from some other causes of leg pain.
Lumbar Spinal Stenosis Versus a Herniated Disc
Both conditions can compress spinal nerves, but they often develop differently.
A herniated disc commonly causes relatively sudden pain involving one nerve root.
Lumbar spinal stenosis typically develops gradually and may involve several nerve roots.
Patients with stenosis are more likely to experience:
- Walking intolerance
- Bilateral leg symptoms
- Neurogenic claudication
- Symptoms that improve with sitting
However, a patient can have both a herniated disc and spinal stenosis at the same time.
Lumbar Stenosis and Spondylolisthesis
Degenerative spondylolisthesis occurs when one vertebra slips forward relative to another because of degeneration of the disc and facet joints.
This commonly occurs at L4-L5.
The slip can further narrow the spinal canal and contribute to nerve compression.
When spinal stenosis occurs together with spondylolisthesis, treatment depends on whether the segment is stable and whether decompression alone would be likely to create additional instability.
How Is Lumbar Spinal Stenosis Diagnosed?
Diagnosis begins with a history and physical examination.
The physician may evaluate:
- Strength
- Sensation
- Reflexes
- Walking
- Balance
- Hip motion
- Pulses in the legs
Imaging is then used to determine where the nerves are compressed.
MRI
MRI is usually the most useful imaging study.
It can show:
- Central canal stenosis
- Lateral recess stenosis
- Foraminal stenosis
- Disc bulging
- Facet joint enlargement
- Ligament thickening
- Nerve compression
MRI findings should always be interpreted together with the patient’s symptoms.
Many people have narrowing on MRI without significant symptoms.
X-Rays
Standing X-rays can provide information about:
- Spinal alignment
- Spondylolisthesis
- Scoliosis
- Disc degeneration
- Loss of disc height
Flexion-extension X-rays may sometimes be used to look for abnormal movement or instability.
CT Scan
CT provides detailed images of bone.
It can be useful for evaluating:
- Bone spurs
- Facet arthritis
- Previous spinal fusion
- Surgical anatomy
CT myelography may occasionally be used when MRI cannot be performed or when additional detail is needed.
Nonsurgical Treatment
Many patients can initially be treated without surgery.
Treatment may include:
- Activity modification
- Physical therapy
- Anti-inflammatory medications
- Pain medications
- Exercise
- Weight management
- Epidural steroid injections
The goal is to reduce symptoms and maintain mobility.
Physical Therapy
Physical therapy may focus on:
- Core strength
- Hip strength
- Flexibility
- Posture
- Walking mechanics
- Flexion-based exercises
- Cardiovascular conditioning
Exercise does not physically enlarge a severely narrowed spinal canal, but it can improve function and help many patients manage symptoms.
Epidural Steroid Injections
An epidural steroid injection places anti-inflammatory medication around irritated spinal nerves.
It may provide temporary relief of:
- Leg pain
- Numbness
- Neurogenic claudication
The amount and duration of relief vary.
Injections do not remove the underlying narrowing but can sometimes reduce inflammation around compressed nerves.
When Is Surgery Considered?
Surgery may be considered when:
- Walking becomes significantly limited
- Leg symptoms interfere with daily activities
- Symptoms persist despite appropriate nonsurgical treatment
- Progressive weakness develops
- Quality of life is substantially affected
The decision is generally based more on symptoms and function than on the appearance of the MRI alone.
Lumbar Decompression
The most common surgical treatment is lumbar decompression.
The goal is to remove bone, ligament, or other tissue that is compressing the nerves.
Procedures may include:
- Laminectomy
- Laminotomy
- Medial facetectomy
- Foraminotomy
These procedures create additional space for the nerves.
Minimally Invasive Lumbar Decompression
Some patients may be candidates for a minimally invasive decompression.
Through a smaller incision, specialized instruments are used to remove the structures causing nerve compression.
Potential advantages may include:
- Less muscle disruption
- Smaller incision
- Reduced blood loss
- Shorter hospital stay
- Faster early recovery
The most important goal, however, is adequate decompression of the nerves.
The surgical approach should be selected based on the anatomy of the stenosis rather than incision size alone.
Is Fusion Always Necessary?
No.
Many patients with lumbar spinal stenosis can be treated successfully with decompression alone.
Fusion may be considered when stenosis is associated with:
- Significant spinal instability
- Spondylolisthesis
- Spinal deformity
- Recurrent stenosis after previous surgery
- Extensive facet joint removal
- Severe mechanical back pain from an unstable segment
The decision depends on the individual anatomy and surgical goals.
Decompression With Fusion
When fusion is necessary, decompression is performed to relieve pressure on the nerves while instrumentation stabilizes the spine.
Fusion may involve:
- Pedicle screws and rods
- Bone graft
- Interbody fusion
- Other fusion techniques
The objective is to relieve nerve compression while maintaining or restoring spinal stability.
Lumbar Stenosis in Older Adults
Lumbar spinal stenosis commonly affects older adults.
Age alone does not determine whether surgery is appropriate.
The decision should consider:
- Overall health
- Severity of symptoms
- Walking ability
- Neurologic function
- Bone quality
- Other medical conditions
- Patient goals
Many older patients can undergo decompression successfully when symptoms are significantly affecting mobility and independence.
Can Lumbar Spinal Stenosis Cause Permanent Nerve Damage?
Most lumbar stenosis progresses gradually.
Severe or prolonged nerve compression can sometimes result in persistent:
- Weakness
- Numbness
- Balance problems
- Walking difficulty
Progressive weakness is generally more concerning than pain alone.
Early evaluation is particularly important when neurologic function is deteriorating.
Cauda Equina Syndrome
Rarely, severe compression of the nerves in the lower spinal canal can cause cauda equina syndrome.
Symptoms may include:
- Severe or rapidly worsening leg weakness
- Saddle numbness
- Urinary retention
- Loss of bladder control
- Bowel dysfunction
Cauda equina syndrome requires urgent medical evaluation and may require emergency surgery.
Recovery After Lumbar Decompression
Recovery depends on:
- Number of levels treated
- Whether fusion is performed
- Age and overall health
- Severity and duration of nerve compression
Patients undergoing decompression alone are often encouraged to begin walking soon after surgery.
Leg pain and walking tolerance may improve relatively quickly, although numbness and weakness can take longer to recover.
Patients undergoing fusion generally have a longer recovery period.
What Results Can Be Expected?
Surgery for lumbar spinal stenosis tends to be most effective for symptoms caused by nerve compression, particularly:
- Leg pain
- Neurogenic claudication
- Walking intolerance
- Nerve-related weakness
Low-back pain may also improve, but the response is less predictable when the pain is primarily caused by generalized degeneration rather than nerve compression.
When Should Lumbar Spinal Stenosis Be Evaluated Urgently?
Seek prompt medical attention for:
- New or progressive leg weakness
- Rapid loss of walking ability
- Saddle numbness
- Urinary retention
- Loss of bowel or bladder control
These symptoms can indicate severe nerve compression.
Outlook
Lumbar spinal stenosis is a common degenerative condition that can significantly limit walking and daily activity.
Many patients can initially manage their symptoms with physical therapy, medications, activity modification, or injections.
When symptoms remain severe despite nonsurgical treatment, lumbar decompression can create additional space for the nerves and improve walking and leg symptoms.
Fusion is not required for every patient and is generally reserved for situations in which instability or deformity is also present.
Treatment should be based on the combination of:
- Symptoms
- Neurologic examination
- Imaging findings
- Spinal stability
- Functional limitations
- Patient goals
The goal is not simply to treat an abnormal MRI, but to relieve nerve compression and help the patient return to the activities that matter to them.
Related Topics
- Lumbar Foraminal Stenosis
- Lumbar Radiculopathy
- Neurogenic Claudication
- Degenerative Spondylolisthesis
- Lumbar Disc Herniation
- Lumbar Laminectomy
- Lumbar Foraminotomy
- Minimally Invasive Lumbar Decompression
- Lumbar Spinal Fusion
- Cauda Equina Syndrome