Spinal stenosis refers to the narrowing of the spinal canal, which is the space in the center of the vertebrae containing the spinal cord and nerve roots. At its most severe or final stage — known as grade 3 — it can squeeze and change the spinal cord, causing pain, weakness, and disability.

Spinal stenosis symptoms can worsen over a long period. Over time, it can cause severe pain, mobility issues, and weakness in the arms or legs.

Read on to learn more about severe spinal stenosis. This article discusses what to expect in the final stages, what causes the condition, symptoms, diagnosis, and more.

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There are numerous stages of spinal stenosis.

The lumbar and cervical neural foramina are small openings in the lower and upper spines where the nerves exit and branch out to the rest of the body. Sometimes, these openings can shrink as the gap between vertebrae narrows. This can squeeze the nerves and cause pain, numbness, or weakness in the back, legs, neck, and arms.

Doctors refer to different grades to describe the reduced size of the opening and how much pressure the nerve is under. These grades refer to the findings from imaging scans rather than the severity of a person’s symptoms.

  • Grade 1 or mild spinal stenosis: The opening is smaller in one direction, but the nerve still looks as it should.
  • Grade 2 or moderate spinal stenosis: The opening is smaller in two or more directions, but the nerve has a typical appearance.
  • Grade 3 or severe spinal stenosis: This occurs after pressure flattens the nerve or alters its shape because of the pressure. Sometimes, the nerve can be flat in one direction but still have some space around it.

Spinal stenosis can also cause pressure at the center of the spinal cord or between the bones of the spine. Doctors would still grade severe stenosis that affects these parts of the nervous system regarding how much pressure it causes.

Spinal stenosis typically develops over time. This means that a person will usually experience mild spinal stenosis to begin with, and symptoms may worsen to moderate or severe spinal stenosis.

Aging most commonly causes spinal stenosis. Different types of arthritis, such as osteoarthritis, can also cause severe spinal stenosis over time.

Other causes include:

When spinal stenosis reaches the final stage, a person may experience the following symptoms:

  • weakness in one or both legs
  • severe pain when walking for short distances
  • pain, numbness, and tingling that spreads down both arms or both legs, depending on the site of the stenosis
  • reduced or severe loss of mobility
  • complete leg paralysis that requires emergency treatment
  • cauda equina syndrome, a medical emergency that can lead to loss of bowel and bladder control and permanent paralysis

To assist with grading spinal stenosis, a doctor may begin by asking questions about:

  • the exact location of the pain
  • where it spreads to
  • when the pain began
  • how the pain feels

They will also perform a physical exam to check movement, pain when leaning forward or bending backward, and nerve function. This might also include checking walking ability, the ability to feel sensations, and muscle strength.

Doctors may then order an MRI. This scan creates an image of the gap distance between the bones of the spine and the spinal cord. It also shows whether the spinal cord is still sending the nerve signals it should be.

Doctors may use other imaging scans, including:

  • X-ray
  • CT scan
  • a myelogram, which involves injecting a dye into the cerebrospinal fluid that can outline the nerves and spinal cord, showing areas of pressure

There are different treatment options for spinal stenosis, depending on the stage. People with severe or worsening stenosis may need surgery. This will not cure the condition but may help restore some comfort, mobility, and quality of life.

Procedures might include:

  • Laminectomy or decompression: During a laminectomy, the surgeon removes the bones, ligaments, and bone spurs that are pressing on the spinal cord or nerve roots.
  • Spinal fusion: A surgeon fuses two vertebrae to make the spine more stable and may use several laminectomy techniques to remove pressure from the spinal cord.

With treatment, it is possible to relieve pressure on the spinal column. This may slow the progression of spinal stenosis, delaying the progression to the final stage. In some cases, it may prevent it.

It is important to contact a doctor for advice as soon as a person has concerns about spinal stenosis. People should also contact their doctor if they do not have relief from symptoms or if their symptoms worsen despite treatment.

Surgery can help improve the outlook for a person in the final stages of spinal stenosis.

A person may need rehabilitation after surgery to support recovery. A physical therapist can teach exercises to build flexibility and strength.

Leg pain also tends to improve after surgery. However, someone may still need to adjust their daily routine. It is important to avoid activities that may result in overexertion.

People can also use assistive devices, including braces and canes, for extra stability. Life choices, such as avoiding smoking and maintaining a moderate weight, may also help improve a person’s outlook.

Here are answers to common questions about spinal stenosis.

Will I end up in a wheelchair with spinal stenosis?

Severe spinal stenosis can lead to partial or complete leg paralysis. This may lead to some individuals using mobility devices such as a wheelchair. However, most people with stenosis regain the use of their legs following surgery, and the outlook is positive depending on their overall health.

When is spinal stenosis considered severe?

Doctors consider spinal stenosis severe when leg weakness or paralysis occurs, if a person is only able to walk for extremely short distances, or they lose control of their bladder, bowel, and sexual functions.

How can you tell if your spinal stenosis is getting worse?

As spinal stenosis worsens, mobility may start to reduce. The pain can spread to the feet as the condition advances, and leg weakness indicates that the nerves are under increasing pressure.

Grade 3 or severe spinal stenosis occurs when the spinal cord becomes completely compressed, changes shape, and loses or alters its ability to send signals to the rest of the body through the nerves. This is often due to aging or arthritis. Severe spinal stenosis can cause paralysis, limb weakness, and loss of bladder, bowel, and sexual function.

Decompression or fusion surgeries usually have a positive outlook and often improve leg function. Physical therapy and ongoing lifestyle adjustments can also help.