How Ankylosing Spondylitis Can Lead to Spinal Stenosis

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Ankylosing spondylitis (AS) is an inflammatory disease that can cause bones in the spine to fuse. Fusing causes the spine to be less flexible and can eventually lead to spinal stenosis in which the spaces in the spine narrow and compress the spinal cord and spinal nerve roots.

AS is characterized by chronic inflammation in vertebral joints of the spine and the entheses, the places where tendons and ligaments attach to bone. Joints are the points where two or more bones meet to allow movement.

Chronic inflammation will cause the wearing away of the bones and joints. When bone tissue is worn down, the body tries to create new bone, and fusing will then occur.

Spinal stenosis causes a pinching of the spinal cord and spinal nerves. This pinching results in symptoms of pain, cramping, weakness, and numbness felt in the lower back and legs, neck, shoulders, or arms.

Person with ankylosing spondylitis being examined by healthcare professional

Natalia Gdovskaia / Getty Images

Spinal changes from AS can lead to bony growths on the edges of bones (bone spurs), thickened ligaments, and bulging discs—all of which narrow the spaces of the spine. AS is linked to other spinal complications, including fractures and kyphosis.

This article discusses AS and its spinal complications, including the symptoms of spinal stenosis, available treatment, and prevention.

The Link Between Ankylosing Spondylitis and Spinal Issues

Most people with AS will never become disabled, or they will have a minimal disability. Some people with the condition will develop restricted spine movement from spine curvature, fractures, or spinal stenosis.

What Is Ankylosing Spondylitis? 

One study from Minnesota estimated that AS occurs in approximately three persons per 100,000 people per year. It usually is diagnosed in teenagers and young adults. But anyone, regardless of age, can be diagnosed with AS. It is three more than times more common in males than females.

Symptoms of AS will vary person-to-person, but most people with AS will experience:

  • Back pain and stiffness
  • Pain and swelling in other joints and inflammation at the entheses
  • Severe fatigue

Symptoms of AS will develop gradually, over several months or even years. They may come and go through periods of flare-ups (worsening symptoms) and remission (few or no symptoms).

With treatment, the condition can improve for most people. For others, however, it will gradually worsen even with treatment.

Spinal Fractures

A spinal fracture is a crack or a break in the vertebrae. Spinal fractures can occur in the low back (lumbar), mid-back (thoracic), or neck (cervical spine).

Lumbar and thoracic fractures are more common, whereas cervical fractures are rarer and can be extremely dangerous and life-threatening. Spinal fractures vary in severity from mild to severe.

When AS leads to fused joints in the spine, the spine will lose its mobility and become stiff and unstable. The fused joints are weak and brittle, which increases the risk of fractures.

A spinal fracture in AS can occur from a traumatic injury, such as a fall, or with minor activity, such as reaching or bending. In people who have both AS and osteoporosis, the risk for fractures is even higher. Osteoporosis is a condition in which bones become weak and brittle. It is a frequent and early complication of AS.

A minor spinal fracture can go unnoticed. However, a severe fracture can cause severe pain and spinal cord damage. A fracture of the lumbar or thoracic spine can cause pain that gets worse with movement. This is different from AS pain, which improves with activity.

Kyphosis 

AS can cause the spine to become less flexible. A less flexible spine can cause a forward curvature called kyphosis. This is also a sign of severe AS.

Kyphosis can negatively affect a person's balance. It causes displacement of the person's center of gravity forward and backward in the sagittal plane—the hypothetical plane used to transect the body into right and left parts. Kyphosis also causes the lower extremities (from the hips to the toes) to compensate for your center of gravity.

People with kyphosis might experience the following symptoms:

  • Pain and stiffness in the back and shoulder blades
  • Numbness, weakness, and tingling in the legs
  • Shortness of breath due to the spine pressing towards the airways
  • Balance problems
  • Bladder and bowel incontinence (inability to control urination or defecation)

Early diagnosis offers the best outlook for someone with kyphosis. Treatment can reduce further problems and the need for surgery. Untreated kyphosis will worsen and lead to health problems that interfere with life quality.

Spinal Stenosis 

Spinal stenosis refers to the narrowing of the spaces within the spine. That narrowing causes pressure on the nerves that travel through the spine.

There are two main types of spinal stenosis based on the part of the spine they affect, which are:

  • Lumbar stenosis: The type of stenosis affects the part of the spine in the lower back. Lumbar stenosis is the most common of the two types.
  • Cervical stenosis: This type of stenosis affects the part of the spine in the neck.

Cauda Equina Syndrome

Cauda equina syndrome (CES) is a condition that causes compression of the cauda equina, the collection of nerves at the end of the spinal cord. It is a rare and serious condition. It is also a medical emergency.

Lumbar stenosis is a risk factor for CES. Symptoms of CES might be similar to those of spinal stenosis and should not be ignored.

Symptoms include:

  • Severe low back pain
  • Urinary retention (inability to empty bladder completely) or incontinence
  • Bowel incontinence
  • Muscle weakness or loss of feeling in the legs
  • Loss or reduction of the reflexes
  • Saddle anesthesia (loss of feeling in the body areas that would sit on a saddle)

How to Recognize the Symptoms

It is possible to have spinal stenosis and not notice symptoms. For many people, the first time they learn they have this condition is after a computed tomography (CT) scan or magnetic resonance imaging (MRI). When symptoms occur, they worsen with time. Symptoms vary based on the location of the stenosis and affected nerves.

Symptoms of lumbar stenosis include:

  • Numbness or tingling in a leg
  • Weakness in the foot or leg
  • Back pain
  • Pain or cramping in one or both legs after standing for long periods or after being active (generally resolves after sitting down or bending forward)

Symptoms of cervical stenosis include:

  • Numbness or tingling in a hand, arm, foot, or leg
  • Weakness of a hand, arm, foot, or leg
  • Problems with balance and gait (the way you walk)
  • Bowel or bladder dysfunction if cervical stenosis is severe

You should see your healthcare provider if you experience any of the signs of spinal stenosis, even if you do not have AS.

Diagnosis 

To diagnose spinal stenosis, your healthcare provider will ask you about the symptoms you are experiencing and your medical history. They will also conduct a physical exam.

In a physical exam, the provider will examine your spine for spinal abnormalities, such as atypical curvatures, kyphosis, and areas of swelling, tenderness, and pain. They will also want to observe your posture and how you stand, sit down, and walk. You will be asked to bend forward, backward, and side-to-side.

Your healthcare provider will also order imaging tests to pinpoint the cause of signs and symptoms. This might include X-rays, MRIs, or CT scans.

  • A back X-ray can reveal bone spurs and the narrowing of spaces of the spinal canal.
  • MRI imaging can produce cross-sectional images of the spine and detect damage to discs and ligaments, tumors, and any compressed nerves.
  • A CT is done if you can't have an MRI. The CT can reveal problems with the spinal cord and nerves, bone spurs, herniated discs, and tumors.

Treating Spinal Stenosis and Other Issues

Treatment for spinal stenosis will depend on the area of the spinal cord affected and how severe pain and other symptoms are.

If you are not experiencing any pain or other symptoms, your healthcare provider will monitor your condition with follow-up visits and testing. They also recommend self-care tips to prevent pain or any further damage to the spine.

If you are experiencing symptoms of spinal stenosis, your healthcare provider will recommend medicines, physical therapy, and nonsurgical therapeutic procedures.

Medications

Medicines to help manage spinal stenosis pain and other symptoms include:

  • Pain relievers, such as Advil (ibuprofen), Aleve (naproxen), and Tylenol (acetaminophen) to temporary ease pain and other discomforts of spinal stenosis
  • Tricyclic antidepressants, such as Elavil (amitriptyline), to help manage nightly chronic pain, so it doesn't interfere with your sleep
  • Anti-seizure drugs, such as Neurontin (gabapentin) to reduce pain caused by damaged nerves
  • Opioids, such as Oxycontin (oxycodone) and Hysingla (hydrocodone), for severe pain, given for short periods

Physical Therapy

Physical therapy can help you manage pain and other symptoms of spinal stenosis. A physical therapist can recommend exercises to build up your strength and endurance, improve your balance, and maintain spine flexibility and stability.

Nonsurgical Procedures

Two commonly used nonsurgical procedures for spinal stenosis are epidural steroid injections and decompression procedures.

  • Epidural steroid injections: A steroid injection is given in the space around the impingement (area where bone is pressing on the spinal cord or other tissues) to reduce inflammation and pain. Because steroid injections can weaken bones and connective tissues, they are only given a few times a year.
  • Decompression procedure: A decompression procedure can provide relief from lumbar spinal stenosis with a thickened ligament. It involves using needle-like instruments to remove the thickened part of the ligament to increase spinal canal space and remove the nerve root impingement. It is typically done without general anesthesia and using indirect image guidance.

Surgery

Your healthcare provider might recommend surgery for spinal stenosis if other treatments have not worked or symptoms are severe and disabling. The goal of surgery is to relieve pressure off the spinal cord or nerve roots by creating more space.

Treating Spinal Fractures

A spinal fracture might take weeks or months to heal. Your healthcare provider might recommend you:

  • Wear a back brace.
  • Take over-the-counter medicines to manage pain and inflammation, including Tylenol and nonsteroidal anti-inflammatory drugs (NSAIDs), such as Advil or Aleve.
  • Use prescription treatments to manage pain, including muscle relaxants, anti-seizure medicines, opioids, and prescription NSAIDs.
  • Rest for a short period and then gradually ease back to your routine.
  • Get physical therapy when you are feeling better to help strengthen your back and reduce your risk for future spine fractures.
  • Take medicines that prevent bone loss and new fractures, such as bisphosphonates like Fosamax (alendronate).

Treating Kyphosis

Treatment for kyphosis depends on the cause and the severity of symptoms.

Your healthcare provider might recommend:

  • Pain relievers
  • Bone-strengthening medicines
  • Calcium and vitamin D supplements to slow down kyphosis progression
  • Physical therapy to improve spine flexibility and reduce back pain
  • A spinal brace
  • Spinal fusion surgery (links bones in the spinal column together) if kyphosis is severe or pinching the spinal cord or nerve roots

Tips to Reduce Your Risk 

The main goal of treating AS is to prevent joint damage to the spine. You will want to follow your treatment plan exactly as prescribed and reach out if you do not see improvement or if symptoms are getting worse.

Additional ways to protect your spine include:

  • Being active: Exercise, especially stretching and weight-bearing exercises (walking, dancing, hiking, stair-climbing, etc.), can protect you against joint damage. Exercise can also help to reduce pain and stiffness. Work with a physical therapist to determine what exercises are safest for you.
  • Getting plenty of calcium and vitamin D: AS increases your risk for osteoporosis and bone fractures even very early in the disease process. To improve bone health, your healthcare provider will recommend you load up on both calcium and vitamin D. Calcium is essential for building and maintaining bones, while vitamin D helps your body absorb calcium.
  • Nixing the bad habits: Both alcohol and smoking weaken your bones. Alcohol might also interact with the medications you take to treat AS. It might be OK to drink alcohol in moderation, but you will want to check with your healthcare provider to be sure. Smoking can accelerate bone loss and increase inflammation. It might also reduce response to AS medications and increase your risk for heart disease.
  • Practicing good posture: Pay attention to your posture to reduce pain and prevent spine damage. Your healthcare provider or a physical therapist can recommend posture exercises for your neck, upper back, and shoulders to help you keep your spine strong and flexible.
  • Getting enough sleep: A good night's sleep can help reduce inflammation in the body. You will want to practice good sleep hygiene, which includes going to bed at the same time every night and getting up at the same time every morning. Avoid caffeine and strenuous activity too close to bedtime. If pain and other AS symptoms are keeping you up at night, let your healthcare provider know so they can help you find solutions for getting a better night's sleep.
  • Protecting your joints: You have plenty of options for assistive devices that can help you perform daily tasks. Work with an occupational therapist who can recommend devices that might be helpful to you. You will also want to minimize your risk of falling by staying steady on your feet. Proper footwear can offer you the support to protect your foot and ankle joints and help you to avoid falls that could damage parts of your spine.

Summary

Ankylosing spondylitis is an inflammatory disease of the spine. Thanks to advanced treatment options, most people with AS will never become disabled. However, some people with AS might experience the restricted movement of the spine, spine fractures, and nerve root compression.

Fortunately, many of the complications of AS, including spinal stenosis, can be managed and treated. But it is crucial to get treatment to avoid disability. Spinal complications of AS might be preventable with different methods, including staying active, protecting your joints, not smoking, avoiding alcohol, and getting plenty of calcium and vitamin D.

A Word From Verywell 

Ankylosing spondylitis can impact your health in many ways. Therefore, it is essential to have a team of healthcare providers to treat AS and your overall health.

The most important person to include on your healthcare team is a rheumatologist—a doctor specializing in musculoskeletal disease and systemic diseases of the joints, muscles, and bones. Other specialists to include are a physical therapist and occupational therapist.

If you find you are experiencing emotional effects, your rheumatologist or primary healthcare provider can recommend a mental health therapist.

Frequently Asked Questions

  • Is ankylosing spondylitis the same as spinal stenosis?

    They are different conditions, and spinal stenosis can be a complication of AS. AS affects the entire spine, whereas spinal stenosis affects the spaces between the individual bones of the spine, either at the low back or at the neck.

    Spinal stenosis causes narrowing of those spaces, which puts pressure on the nerves and leads to symptoms of numbness, weakness, and pain.

  • Do autoimmune diseases cause spinal stenosis?

    Autoimmune diseases that affect the spine, such as ankylosing spondylitis and rheumatoid arthritis, can lead to spinal stenosis. This is often the result of chronic inflammation of the small bones of the spine, which leads to bone loss, bony growths, thickened ligaments, and bulging disks.

  • Is ankylosing spondylitis more severe than spinal stenosis?

    Both ankylosing spondylitis and spinal stenosis are serious conditions that require treatment. Untreated AS can lead to severe spine complications, including spinal stenosis, kyphosis, and spinal fractures. On the other hand, untreated spinal stenosis can cause permanent nerve damage that might lead to paralysis or death.

  • Does ankylosing spondylitis cause your spine to narrow?

    Spine narrowing in ankylosing spondylitis can occur in the spaces between the vertebrae as a result of chronic inflammation. Treatment with disease-modifying antirheumatic drugs (DMARDs) can reduce the potential for this disease complication.

  • Are cervical stenosis and spinal stenosis the same condition?

    "Cervical stenosis" is the name for spinal stenosis of the neck. It causes neck pain and numbness, tingling, and weakness of an arm, hand, leg, or foot.

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