As we age, the spine changes, often leading to degeneration of the vertebrae (bones), discs, muscles, and ligaments that together make up the spine.
These changes can lead to spinal stenosis.
The term stenosis is often the result of degenerative conditions such as osteoarthritis and / or degenerative spondylolisthesis . When the spinal nerves in the lower back become blocked, lumbar spinal stenosis occurs and, more often, causes pain in the legs and other symptoms.
Lumbar stenosis is a condition of the lower back in which the spinal canal (central stenosis) or one or more of the vertebral foramina (foraminal stenosis) is narrowed.
Surgery is recommended when other non-surgical treatments have failed and for patients with increased leg weakness or loss of bowel or bladder function.
Surgery includes a lumbar decompression with or without lumbar fusion. Surgery is more reliable for the relief of leg symptoms and less reliable for the relief of back pain.
What Causes Lumbar Stenosis?
The most common cause of lumbar spinal stenosis is degenerative arthritis and degenerative disc disease.
As with other joints in the body, arthritis commonly occurs in the spine as part of the normal aging process and as a result of osteoarthritis.
This can lead to the loss of cartilage between the bones in the joints, among other conditions.
Additional degeneration of the lumbar discs can lead to the slippage of one vertebra over another, a process called spondylolisthesis.
Each of these processes can reduce the space available for nerves in the spinal canal and result in direct pressure on nerve tissues for symptoms of lumbar spinal stenosis.
Lumbar spinal stenosis can also be caused by other conditions that decrease the space of the spinal canal or vertebral foramen.
These may include:
- Tumor of local structures or metastatic tumors (tumors that originated in another part of the body and have spread to this location).
- Various metabolic bone disorders that cause bone growth, such as Paget’s disease of bone.
These causes, however, are much less common than degenerative arthritis.
Lumbar spinal stenosis can cause:
- Lumbar pain
- Soft spot.
- Loss of sensation in the legs and feet.
In most situations, symptoms improve when the patient is sitting or leaning forward. Generally, the painful sensations lower the legs with continuous walking and diminish with rest. These sensations in the legs sometimes mimic sciatica.
This particular activity-related symptom is sometimes called neurogenic claudication. This is because it mimics the true claudication of poor circulation of the narrowed blood vessels of peripheral vascular disease.
Standing and bending back can make symptoms worse. This is because leaning forward increases the space in the spinal canal and vertebral foramina, while leaning back decreases this space.
Therefore, it is more comfortable for patients to sit or lean forward. Patients are often unable to walk long distances and frequently report that their symptoms improve when they lean forward while walking with the support of a walker or shopping cart.
Symptoms commonly get worse over time. This is because degenerative arthritis is a progressive disease that gradually becomes more severe over time.
If left untreated, compression on the nerves from lumbar spinal stenosis can lead to increased weakness and loss of function in the legs.
It can also lead to loss of bowel and bladder control and loss of sexual function. A doctor can help determine if the symptoms are from a lumbar spinal stenosis or a different condition.
Many other disorders can cause similar symptoms that mimic lumbar stenosis including:
- Diabetic neuropathy.
- Peripheral vascular disease.
- Vascular claudication.
Lumbar stenosis diagnosis
The medical evaluation begins with a complete medical history and physical examination to obtain clues to the diagnosis of lumbar spinal stenosis.
During the medical history, the patient will be asked questions about the symptoms, including how long they were present, what makes them better or worse, what previous treatment the patient has had, and what other medical conditions they have.
These questions can also help the doctor distinguish lumbar spinal stenosis from other conditions that can produce similar symptoms.
The definitive diagnosis of lumbar spinal stenosis is made by magnetic resonance imaging (imaginary magnetic resonance imaging) or a computed tomography (CT) or computed tomography (CT) scan.
These are more advanced tests used to visualize the nerves in the lower back and detect if they are being compressed from the lumbar spinal stenosis.
Sometimes special nerve tests may be ordered, including electromyograms (EMGs) or nerve conduction studies.
These tests can identify nerve damage or irritation caused by long-term compression of lumbar spinal stenosis.
These tests can also help determine exactly which nerves are involved.
In most situations, treatment for lumbar spinal stenosis begins with conservative (non-surgical) treatments.
This can include medications to reduce inflammation, even short courses of oral cortisone medications and pain relievers.
There are also several medications specifically targeting nerve pain that are helpful in lumbar spinal stenosis, including gabapentin (Neurontin) and pregabalin (Lyrica).
Physical therapy can help many.
Cortisone (steroid) injections into the lumbar spine, known as epidural injections, can also reduce symptoms by decreasing inflammation and swelling around nerve tissue.
Unfortunately, the degenerative changes responsible for lumbar spinal stenosis can occur as part of the normal aging process.
There is little that can be done to prevent lumbar spinal stenosis. For some patients, exercises and / or physical therapy can prevent aggravation of symptoms.
Surgery may be indicated for those who do not improve with previous treatments or if there is severe or progressive weakness or loss of bowel or bladder function (cauda equina syndrome).
Depending on the findings of the examination and imaging studies, there are surgical procedures available to treat lumbar stenosis, ranging from laminectomy to fusion procedures.
The main goal of the surgery is to remove the structures that are compressing the nerves in the spinal canal or vertebral foramen.
This is known as lumbar decompression surgery (laminectomy, laminotomy, foraminotomy).
In some patients, this can be done alone, but in other patients, it must be combined with lumbar fusion.
If it is necessary to remove too many compression structures to free the nerve, the vertebrae can become unstable (spinal instability).
This leaves the vertebrae with abnormal movement. If this occurs, a spinal fusion can be performed to unite the vertebrae and eliminate movement at that level.
Sometimes this requires metal hardware to be installed in the vertebrae to properly support and repair the affected bone.
Lumbar spinal stenosis surgery can be very successful in most patients in relieving leg symptoms of ambulatory pain, sciatica, and numbness.
However, depending on the severity of the nerve compression and the duration of the nerve compression, there may be permanent damage that is not relieved by surgery.
Successful back pain relief is less reliable with surgery than relief of leg symptoms.
More recently, surgical procedures have become available that are somewhat less invasive than traditional lumbar decompression.
Intraspinatus devices that have been used in certain patients for this purpose include X-Stop and Coflex devices.