Spinal Stenosis Center

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Modern plumbing is a technological miracle, but it’s not without its problems. What happens over time when the walls of your pipe get coated with minerals and…other gunk? It impedes the flow of water and creates problem for the whole system. 

There are parts of your body where the same thing happens. In the arteries, the gunk that adheres to the artery walls is called plaque. If a piece of plaque breaks off, a blood clot may form around it and block blood flow to the heart or brain and boom. Heart attack or stroke. Bad news.

Something similar can happen within your spine. The spinal canal should have enough room for the spinal cord to travel the length of the spine. However, if that space narrows—usually due to a herniated disc or sometimes a bony overgrowth—nerve roots or the spinal cord itself can become compressed. The narrowing of the spinal canal is called stenosis, and it’s responsible for a huge number of back pain cases and conditions, including the dreaded sciatica. 

Spinal stenosis is a narrowed passageway for nerves and spinal cordSpinal stenosis means a tight squeeze for your nerve roots or spinal cord.

Want to learn more about spinal stenosis, how it happens, its symptoms, and its treatments? You’ve come to the right place. Read on. 

What Is Spinal Stenosis?

A clue to answering this question is found in the meaning of each word. Spinal refers to the spine. Stenosis is a medical term used to describe a condition where a normal-size opening has become narrow. Spinal stenosis may affect the cervical (neck), thoracic (chest), or lumbar (lower back) spines.

The most commonly area affected is the lumbar spine followed by the cervical spine.

MRI L4-L5 spinal stenosisThe above axial (overhead) MRI shows L4-L5 spinal stenosis with facet degeneration and thickening of the ligamentum flavum; a ligament that helps to support the spine. Photo Source: SpineUniverse.com.
Illustration of spinal stenosisStenosis is a medical term used to describe a condition where a normal-size opening has become narrow. Photo Source: 123RF.com.

Visualizing Spinal Stenosis

Just like your home’s plumbing system, your spinal column has a number of passageways that need to be unimpeded for efficient flow. In the spine, the passageways are the spinal canal and the neuroforamen. The spinal canal is a hollow vertical hole that contains the spinal cord (from the cervical spine down to the upper lumbar L1 level). Below L1, the spinal canal contains nerve roots for the motor and sensory function of lower extremities and bowel/bladder sphincters. The neuroforamen are the passageways that are naturally created between the vertebrae through which spinal nerve roots exit the spinal canal.

vertebral body, labeled structures, color drawing

The neuroforamen are the passageways that are naturally created between the vertebrae through which spinal nerve roots exit the spinal canal. Photo Source: SpineUniverse.com.


Illustration above: The spine's bony structures encase and protect the spinal cord. Small nerve roots shoot off from the spinal cord and exit the spinal canal through passageways called neuroforamen.

Lumbar (low back) spinal stenosis is illustrated below. Notice the narrowed areas in the spinal canal (reddish-colored areas). As the canal space narrows, the spinal cord and nearby nerve roots are squeezed causing different types of symptoms. The medical term is nerve compression.

lumbar spinal stenosis

Lumbar central spinal stenosis. Photo Courtesy of: SpineUniverse.com.

Anatomy and Spinal Stenosis

The spine is a column of connected bones called vertebrae. There are 24 vertebrae in the spine, plus the sacrum and tailbone (coccyx). 

At the back (posterior) of each vertebra, you have the lamina, a bony plate that protects your spinal canal and spinal cord. Your vertebrae also have several bony tabs that are called spinous processes; those processes are attachment points for muscles and ligaments.

Ligaments connect and stabilize the vertebrae. A special ligament, called the ligamentum flavum, is a usual suspect in spinal stenosis. When you're sitting down and leaning forward, the ligamentum flavum is stretched out, giving your spinal canal more room for the spinal nerves. When you stand up and lean back, though, the ligamentum flavum becomes shorter and thicker, meaning less room for the spinal nerves. This dynamic capability helps explain why people with spinal stenosis find that sitting down feels better than standing or walking.

In between each vertebra are tough fibrous shock-absorbing pads called the intervertebral discs. Each disc is made up of a tire-like outer band (annulus fibrosus) and a gel-like inner substance (nucleus pulposus).

The spinal cord, the thick bundle of nerves that extends downward from the brain, passes through a ring in each vertebra. Those rings line up into a channel called the spinal canal.

Between each vertebra, two nerves branch out of the spinal cord, one to the right and one to the left, through spaces called the foramen. 

Normally, the spinal channel is wide enough for the spinal cord, and the foramen are wide enough for the nerve roots. But either or both can become narrowed, and cause spinal stenosis.

slice of a lumber vertebra; herniated disc, compressed nervesIn the overhead slice of a lumbar vertebra, the key anatomical structures are labeled, including causes of low back spinal stenosis: herniated disc and compressed nerves. Photo Source: Shutterstock.com.

Spinal Stenosis Signs and Symptoms

Typically, symptoms of stenosis progress over time. This is because nerves increasingly become more compressed, so minor signs of stenosis might eventually become more significant, and possibly chronic. For cervical or thoracic spinal stenosis in which the spinal cord is impinged (myelopathy), the symptom typically consist of balance and gait difficulty, clumsy or dexterity issues using the hands.  Symptoms of lumbar stenosis can include:

  • Pain or difficulty walking (neurogenic claudication)
  • Weakness in the legs
  • Occasional or ongoing numbness and/or burning, particularly in the buttocks or legs
  • Lower back pain, especially while walking
  • Foot drop, when there’s difficulty lifting the front part of the foot

Sometimes, resting may help alleviate symptoms but they tend to return during movement. 

Spinal Stenosis Causes and Risk Factors

Aging is the most common cause of spinal stenosis, due to normal narrowing in the spinal canal. According to the American Academy of Orthopaedic Surgeons (AAOS) degenerative changes of the spine are seen in up to 95% of people by age 50, with spinal stenosis occurring most often in adults over age 60. The condition affects men and women equally.

Although you can’t stop yourself from aging (we’ve tried), there are some factors that can raise your risk of developing stenosis, including:

  • Congenital and inherited issues, such as achondroplasia, which interferes with bone formation in the spine, and scoliosis, which can result from a genetic condition.
  • Arthritis conditions that affect the spine such as ankylosing spondylitisrheumatoid arthritis,  and spondylosis(osteoarthritis in the spine), which can cause chronic inflammation and negatively affect cartilage between vertebrae, potentially prompting bone spur growth in the spine.
  • Bone diseases like osteoporosis and Paget’s disease, causing bones to weaken.
  • Injuries or tumors, such as fractures, slipped discs, and abnormal tissue growth, which can all put pressure on nerves in the spine and affect bone health.

The AAOS notes that among these factors, arthritis is the most prevalent for stenosis. With that condition, the body forms bone spurs to stabilize the joint and ligaments begin increasing in size. Both of those effects reduce the space for nerves, increasing risk of stenosis.

Spinal Stenosis Diagnosis and Tests

Stenosis is diagnosed though an examination that includes discussion of medical history, including any conditions like arthritis, as well as imaging tests such as:

  • General mobility: For example, you may be asked to bend forward or to the side to determine limitations or onset of pain.
  • X-rays: X-rays best depict hard tissue such as bone. They can show age-related changes like bone spurs or loss of disk volume, and you may be asked to have an X-ray taken while you lean forward. This may show instability in the joints.
  • Magnetic resonance imaging: An MRI will be able to provide images of soft tissues—including nerves, discs, ligaments, and more—that run through the spinal cord.
  • Computed tomography: CT scans can indicate damage or weakness in bones through a cross-section image of the spine.
  • Myelogram: This procedure uses contrast dye to highlight nerve pathways, which can help detect nerve compression.

Spinal Stenosis Treatment Options

As with many other back pain conditions, your treatment options will depend on the severity of your symptoms and how much they affect your quality of life. In general, however, if stenosis is diagnosed when there’s still fairly good mobility, the treatment will focus on alleviating symptoms. 

First Line Treatment

Physical therapy is often recommended as a first step in stenosis treatment since this can help strengthen muscles—relieving pressure on the spine. Your doctor may also suggests stretching exercises and core strengthening to provide better flexibility and support for the spine.

Medications

Because pain is caused by pressure on the spinal nerve, medication usage usually focuses on reducing inflammation. This can be done through cortisone injections into the spinal column, and/or nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief.

Surgery

If front-line treatments are ineffective or there is severe pain and loss of mobility, surgery may be an option. The patients with cervical or thoracic myelopathy due to spinal canal stenosis typically have neurologic deficits with numbness, weakness, and gait imbalance, and therefore, surgery should be considered earlier than later to prevent permanent nerve damage. 

Surgical techniques to treat cervical or thoracic stenosis include cervical laminoplasty, cervical laminectomy and fusion, anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion, thoracic laminectomy, thoracic decompression and fusion, etc.   

Procedures used to treat lumbar stenosis include:

  • Laminectomy. This removes the lamina of the affected vertebra. Sometimes called decompression surgery, this is meant to ease pressure on the nerves by creating more space for them. In some cases with associated instability or deformity of the spine such as spondylolisthesis or scoliosis, a laminectomy will include a spinal fusion, when a vertebra is attached to adjoining bone to maintain support in the spine.
  • Laminotomy and Foramintomy. In this procedure, only a portion of the lamina and facet joint is removed, with just a small hole allowing a nerve more room.

Home Remedies for Spinal Stenosis

In addition to front-line treatment, there are some home care strategies and complementary therapies that may reduce symptoms:

  • Acupuncture and massage
  • Gentle yoga or Tai Chi
  • Heat therapy with a heating pad or warm towel to relax muscles
  • Cold therapy with cold pack to relieve swelling and pain

Complications of Spinal Stenosis

According to Mayo Clinic, many of the surgeries for spinal stenosis help reduce symptoms, but that’s not always the case. Some people may find their symptoms stay the same or even worsen after surgery. Also, risks can include infection, a tear in the membrane covering the spinal cord, a blood clot in the leg vein, and potential neurological deterioration.

Any time you have surgery there is a small risk of complications, but doing nothing may be no better. Difficulties from untreated spinal stenosis can include:

  • Numbness and weakness
  • Balance problems
  • Incontinence
  • Paralysis

When Is Spinal Stenosis Serious?

If you have loss of mobility, debilitating pain, or disruption of everyday life, then stenosis may be serious

One other sign that’s considered significant but rare is numbness in your genital region with loss of control in the bowel or bladder. This is called acute cauda equina syndrome, and is considered a medical emergency.

What Is the Long Term Outlook for Spinal Stenosis?

With adequate treatment to reduce symptoms and slow progression, you can often manage spinal stenosis. However, you may need to adjust your type of physical activity, and keep on top of inflammation and pain management to ensure that you maintain a high degree of mobility.

Sources

AAOS. “Lumbar Spinal Stenosis.” https://orthoinfo.aaos.org/en/diseases--conditions/lumbar-spinal-stenosis/

Mayo Clinic. “Spinal Stenosis.” https://www.mayoclinic.org/diseases-conditions/spinal-stenosis/diagnosis-treatment/drc-20352966

Johns Hopkins Medicine. “Foraminotomy.” https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/foraminotomy

New England Journal of Medicine. (2008.) “Surgical versus Nonsurgical Therapy for Lumbar Spinal Stenosis.” https://www.nejm.org/doi/full/10.1056/nejmoa0707136  

Updated on: 09/20/21

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Howard S. An, MD
Professor, Orthopaedic Surgery
Rush University Medical Center
Chicago, IL
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Spinal stenosis compresses the spine's nerves and/or spinal cord. Lumbar spinal stenosis affects the low back and cervical spinal stenosis causes symptoms in the neck. Back or neck pain is the foremost symptom.
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