What is Myelopathy?
The spinal cord is a soft, cylindrical column of tightly bundled nerve cells (neurons and glia), nerve fibers that transmit nerve signals (called axons) and blood vessels. It sends and receives information between the brain and the rest of the body. Millions of nerve cells situated in the spinal cord itself also coordinate complex patterns of movements such as rhythmic breathing and walking.
The spinal cord extends from the brain to the lower back through a canal in the center of the bones of the spine. Like the brain, the spinal cord is protected by three layers of tissue and is surrounded by the cerebrospinal fluid (CSF) that acts as a cushion against shock or injury.
The spinal column, which surrounds and protects the spinal cord, is made up of 33 rings of bone (vertebrae), pads of semi-rigid cartilage (discs), and narrow spaces called foramen that act as passages for spinal nerves to travel to and from the rest of the body. The spinal cord is particularly vulnerable to direct injury within these areas. In the spine, a disc or a nucleus pulposus is localized between vertebral bodies. It supports the spine by acting as a shock-absorbing cushion. Myelopathy is a spinal cord injury that inhibits the normal communication that occurs between the brain and the body, typically resulting from spinal cord compression. Often confused with myopathy, myelopathy affects the nerves in the spinal cord while myopathy affects the muscles.
Types of Myelopathy
Myelopathy can affect any area along the spinal cord, resulting in pain, loss of balance and coordination and numbness around the area being compressed. There are three types of myelopathy, depending on the section of the back being compressed: lumbar (lower back), thoracic (mid-region of the spine) and cervical (neck) myelopathy.
Causes of Myelopathy
Some cases of myelopathy are congenital, with a spine deformity developing in utero. However, the most common causes of myelopathy result from compression of the spinal cord and nerve roots related to inflammation, arthritis, age-related spinal degeneration and bone spurs. The following conditions can also cause myelopathy:
- Neurological disorders
- Central disc herniations
- Radiation therapy
- Inflammatory disease
- Degenerative spinal conditions (like spinal stenosis)
- Autoimmune disorders (like rheumatoid arthritis)
- Spinal injury or infection
- Abnormalities (tumors, hematomas, cysts or hernias)
Risk Factors for Myelopathy
Age is the primary risk factor for myelopathy, as gradual degeneration of the spine makes one more vulnerable and can lead to the condition.
Other potential risk factors include genetics, neck and back injuries, and occupations that are physically demanding. Injury to the spinal cord can also result in myelopathy. Congenital myelopathy is typically related to a small cervical spinal canal.
Screening for & Preventing Myelopathy
Preventing myelopathy begins with good health: maintaining a healthy weight and eating a healthy, balanced diet contribute to overall health. Not smoking is also key to spinal health, as smoking weakens the immune system, increasing vulnerability to infections and degeneration in spinal discs.
Additionally, practicing good posture, particularly while sitting, driving and working, can prevent undue strain on the spine. Maintaining an active lifestyle will also help to develop strong muscles that support the spine.
Signs & Symptoms of Myelopathy
Compression and injury can lead to pain, discomfort, loss of sensation and function, and may be a result of myelopathy. Symptoms include:
- Difficulty walking
- Inhibited fine motor skills (like writing or tying shoelaces)
- Deterioration in balance and coordination
- Leg, arm, neck and lower back pain
- Weakness, numbness and tingling in the nerves (back and extremities)
- Change in reflexes
Diagnosing Myelopathy
Following a physical examination and medical history, a doctor may recommend additional tests which may lead to a myelopathy diagnosis, including:
- Torg ratio: A test that measures the spinal canal diameter and detects compression
- X-ray: This exam can help diagnose any spinal conditions that may be causing compression
- Myelography: A test that uses real-time X-ray results (fluoroscopy) as well as a dye contrast test that reveals irregularities in the spinal cord.
- MRI (magnetic resonance imaging): These tests provide clear images of the spinal cord, discs, ligaments and nerve roots. Any compression present will be detected.
- Electromyogram: This scan can detect any inhibited limb movement by stimulating nerves and testing teh function of arm and leg movements.
Treating Myelopathy
In cases where spinal compression is being caused by bacterial infection, treatment will include antibiotics which will relieve pressure on the nerve fibers. In more extreme cases of myelopathy, patients will be fitted with a brace to keep the cervical bones fixed, thereby reducing pain and worsening of the condition and symptoms.
General treatment involves physical therapy and gentle exercises that help to relieve pressure and to develop muscle strength that supports the spine. Only in extreme cases will surgery be recommended, as in cases that involve tumors or bone fragments. Surgery types include spinal fusion (wherein two or more vertebrae are fused to stabilize the spine), laminoplasty (a hinge is created that increases space for the spinal cord to expand to its proper position) or laminectomy (bone fragments in the spinal canal are removed that may be causing cord compression).
Living with Myelopathy
Early detection is crucial for proper treatment and recovery, as compression in the spinal cord can lead to irreversible nerve damage. Pain is typically managed with over-the-counter anti-inflammatory drugs (such as NSAIDs), and sometimes spinal injections like nerve blocks.
Maintaining good health, including a healthy weight, a balanced diet and regular exercise are integral to back and spine health. Not smoking is also key to spinal health, as smoking weakens the immune system, increasing vulnerability to infections and degeneration in spinal discs.
Additionally, practicing good posture, particularly while sitting, driving and working, can prevent undue strain on the spine. Maintaining an active lifestyle will also help to develop strong muscles that support the spine.