The spinal cord serves as the body’s main communication pathway, relaying motor commands from the brain and transmitting sensory information back. Myelopathy is a neurological deficit that occurs when the spinal cord is severely compressed or squeezed within the spinal canal. This compression disrupts the normal flow of nerve impulses, leading to dysfunction in the body parts controlled by the affected spinal level and below. Untreated compression can cause a progressive loss of function and potentially lead to permanent neurological damage.
Defining the Condition and Location
Myelopathy describes damage to the spinal cord itself, resulting from sustained mechanical pressure. This compression impairs the cord’s ability to transmit signals, often leading to widespread neurological symptoms. It is distinct from radiculopathy, which involves the pinching of individual nerve roots as they exit the spinal column, causing more localized symptoms. Myelopathy is generally considered more serious because it affects the central nervous system pathway.
The condition is classified by its location within the spine. Cervical myelopathy, occurring in the neck, is the most frequently diagnosed form due to the relatively small diameter of the spinal canal. Thoracic myelopathy affects the middle and upper back, a less common location because the ribcage provides greater stability. Compression in the lower back (lumbar spine) rarely causes true myelopathy because the spinal cord typically ends higher up, making lower back issues usually a form of radiculopathy.
Primary Causes of Spinal Cord Compression
The most frequent cause of myelopathy is degenerative change related to aging, often referred to as spondylosis. As people age, spinal discs lose hydration and height, causing vertebrae to shift and leading to the formation of bone spurs (osteophytes). This wear and tear narrows the spinal canal, a condition called spinal stenosis, which gradually compresses the spinal cord.
Other mechanical factors also contribute to the narrowing of the space around the spinal cord. A herniated disc, where the soft inner material pushes out, can bulge into the spinal canal and press directly on the cord. While degenerative issues are the most common culprits, myelopathy can also result from acute trauma, such as a fracture or dislocation. Less common causes include spinal infections, tumors, or inflammatory conditions like rheumatoid arthritis.
Recognizing the Neurological Signs
Symptoms of myelopathy often develop slowly and can be subtle, sometimes leading to a delayed diagnosis. One of the earliest and most common signs is a change in gait, presenting as an unnatural, clumsy, or unsteady walking pattern. Patients may feel they have lost control over their leg function, often tripping or needing to watch their feet while walking.
A loss of fine motor skills, particularly in the hands, is a frequently reported symptom of cervical myelopathy. Simple activities requiring dexterity, such as buttoning a shirt or using silverware, become increasingly difficult. Other neurological signs include:
- Reduced grip strength or a tendency to drop objects unexpectedly.
- Sensory changes, such as numbness, tingling, or a “pins and needles” sensation extending into the limbs.
- Hyperreflexia, which is an abnormal increase in reflexes.
- Bowel or bladder dysfunction in more advanced cases.
Diagnosis and Treatment Approaches
The diagnostic process begins with a thorough physical and neurological examination to assess reflexes, muscle strength, and sensation. A physician looks for upper motor neuron signs, such as spasticity and hyperreflexia, which strongly suggest spinal cord involvement. To confirm the diagnosis and identify the precise cause and location of the compression, medical imaging is necessary.
Magnetic Resonance Imaging (MRI) is the preferred imaging modality because it provides detailed visualization of soft tissues, including the spinal cord and surrounding compression. X-rays and CT scans are also used to evaluate bony structures, looking for degenerative changes like bone spurs or spinal stenosis. These tests help distinguish myelopathy from other conditions that cause similar symptoms, such as radiculopathy or various neurological disorders.
Treatment options are determined by the severity and progression of the condition. For mild or stable cases, conservative management may be attempted, including physical therapy, activity modification, and anti-inflammatory medications. However, non-surgical treatments cannot remove the compression and are primarily aimed at symptom relief.
Surgical intervention is the preferred course of action for moderate to severe myelopathy or when symptoms are progressively worsening. The primary goal of surgery, known as spinal decompression, is to relieve pressure to halt the progression of neurological damage. Procedures vary depending on the location and cause, but they may involve removing bone spurs, a herniated disc, or expanding the spinal canal through techniques like laminectomy or laminoplasty. Although surgery aims to prevent further decline, recovery of pre-existing neurological function is often unpredictable.