Cervical Myelopathy – Spinal Cord Compression
Neck pain due to cervical spine and related disorders is a common and often debilitating problem and an important reason for seeking medical attention. Neck pain more often arises without relation to a specific activity or neck trauma. Such is often the case with myelopathy.
We will consider what is often termed cervical spondylotic myelopathy which is a degenerative spine condition with symptoms of neck pain, numb and/or clumsy hands, gait difficulties, sphincter dysfunction, and impotence. We will be somewhat repetitive with symptoms, however, it is important to recognize some of the early indications and be aware of the different findings as many of the symptoms are typically not associated with neck problems. Progressing or advancing symptoms most often require a surgical consultation.
We detailed degenerative disc disease, cervical spondylosis and cervical degenerative disc disease in a previous articles. Unfortunately, the result of this degenerative process may involve myelopathy – pressure on the spinal cord.
Cervical spondylotic myelopathy is the result of narrowing (stenosis) of the cervical spinal canal by degenerative and/or congenital (formed at birth) changes. Degenerative myelopathy is the most common type of spinal cord dysfunction in patients older than 55 years. The onset is usually subtle, with long periods of fixed disability and episodic worsening. The first sign is commonly gait spasticity or difficulty in walking, followed by upper extremity numbness and loss of fine motor control in the hands.
It begins with disc degeneration, which may cause segmental instability and hypertrophy (outgrowths) of vertebrae and facet joints. As this develops, disc spaces become narrowed gradually. Severe disc degeneration can be defined as disc height less than half normal disc height. After severe disc degeneration develops, neighboring discs may sustain increased stress and the biomechanics of cervical spine is changed. Severe disc degeneration is equivalent to an autofusion (fuses on its own) as a compensation process for segmental instability. The mechanical factors involved are divided into two groups: static and dynamic.
Factors Related To Cervical Myelopathy
1) Static factors include: congenital spinal canal stenosis, disc herniation – central type herniations, osteophyte (bony outgrowths or arthritic spurs) of the spinal bones, degenerative outgrowth of the uncovertebral joints at the back of the spinal bones and facet joints, hypertrophy (thickening) of ligaments along the spine (flavum and posterior longitudinal ligaments).
2) Dynamic factors are abnormal forces placed on the spinal column and spinal cord during flexion (bending head forward) and extension (bending head backward) of the cervical spine. An example would be the trauma caused to the spinal cord by repetitively being compressed against a degenerative outgrowth during normal flexion and extension of the cervical spine. Mechanical compression of nerve tissue is only one of the pathologic mechanisms. Another is spinal cord ischemia, which happens when degenerative elements compress blood vessels that supply the spinal cord and nerve roots.
The spinal canal houses the spinal cord and the immediate portion of the cervical nerve roots. Stenosis is a condition of narrowing. Where the spinal cord normally has sufficient room, stenosis may cause a narrowing of the spinal canal leading to spinal cord compression. Typically, this stenosis is from degenerative changes, a herniated disc, and one may have a predisposition from a congenitally narrowed spinal canal which is genetic.
This narrowing in the lower back (lumbar canal stenosis) produces only radiculopathy (pinched nerve) because the tip of the spinal cord called the conus medullaris is at the level of L1-L2, cervical (neck) canal stenosis can produce a sometimes complex picture of cervical myelopathy and radiculopathy.
Proprioception is also impaired. Proprioception describes the sensations generated within the body that contribute to awareness of the relative orientations of body parts, which are fundamental to the normal control of human movement. Therefore, myelopathy can cause impairment of postural stability.
With pressure on the spinal cord, there is a compromise of the blood vessels and the symptoms vary depending on the site of this ischemic damage to the cord. Patients often complain of clumsy or weak hands or feet that may be hypersensitive. Tingling fingers and leg stiffness are also common complaints. Examination may reveal deep touch, vibration, joint movement awareness and the ability to sense 2 points on the skin surface may be disturbed. Patients may claim they cannot feel a cold floor or hot water in the tub. There may also be spasticity with weakness of the upper or lower extremities. Movements may slow down, finger extension may be incomplete, and wrist extension may be exaggerated.
Cervical Myelopathy Symptoms
|In a 2004 study published in the journal SPINE, the most common symptoms of 79 patients with degenerative cervical myelopathy were:|
|Numb arms or hands 91%||Numb legs or feet 85%||Clumsy hands 82%||Neck pain 78%|
Symptoms can include: Pain in the neck, subscapular area, or shoulder. Numbness or altered sensations in the upper extremities. These are usually nonspecific, although specific sensory complaints can occur from a coexisting pinched nerve or radiculopathy. Sensory changes in the lower extremities. Motor weakness in the upper or lower extremities. Gait difficulties. Many patients have what is called a spastic gait which is a broad-based, hesitant, and jerky movement, compared with the smooth rhythmic normal gait.
Some studies have indicated that a subtle gait disturbance is the most common presentation. Bowel and bladder dysfunction is also common. A study in a series of 269 patients, bowel dysfunction was observed in 15% and bladder dysfunction was observed in 18%. Other studies have found that 20% of their patients with degenerative myelopathy over age 65 had bladder dysfunction, mostly associated with urinary retention.
Patients with cervical disorders of one type or another may present with lower extremity and bladder or bowel symptoms often with only minimal neck pain. Therefore, the neck may have symptoms referable to lower extremities as well as bladder and bowel functions, altered sensation in the lower extremities, weakness of the lower extremities, gait disorders, impotence in men, and anorgasmia in women. In a 2006 study in the journal SPINE, symptoms of impotence in men were improved after surgical treatment of myelopathy.
It is important to get a complete examination and for a qualified health care professional to differentiate a peripheral neuropathy, cauda equina syndrome, and cervical myelopathy. To further illustrate the importance of a thorough examination, although the names may be unfamiliar, the differential diagnosis (other conditions which may present similar symptoms) includes multiple sclerosis, transverse myelitis, progressive motor neuron disease, subacute combined degeneration, syringomyelia, spinal cord tumors, cerebral hemisphere disease, peripheral neuropathy and normal pressure hydrocephalus.
The Japanese Orthopaedic Association developed a scoring system for cervical myelopathy:
I Motor function of the upper limbs
– 4 Normal
– 3 Able to eat using chopsticks with slight difficulty
– 2 Able to eat using chopsticks with difficulty
– 1 Able to eat using a spoon only
– 0 Unable to eat unaided
II Motor function of the lower limbs
– 4 Normal
– 3 Able to walk without support with slight difficulty
– 2 Able to walk up and down stairs only with support
– 1 Requires support to walk even on level ground
– 0 Unable to walk
III Sensory function (same in upper and lower limbs, and trunk)
– 2 Normal
– 1 Slight sensory disturbance or numbness
– 0 Distinct sensory disturbance
IV Bladder function
– 3 Normal
– 2 Slight urination difficulty (pollakisuria, retardation)
– 1 Serious urination difficulty (residual urine, dysuria)
– 0 Urine retention
Additional findings: Muscular tone in the legs will be increased, Deep tendon reflexes in the knee and ankle will be accentuated (hyperreflexia), Forced extension of the ankle may cause the foot to beat up and down rapidly (clonus), Scratching the sole of the foot may cause the big toe to go up (Babinski reflex) instead of down (normal reflex), Flicking the middle finger may cause the thumb and index finger to flex (Hoffman’s reflex), Compromised coordination may be evidenced by difficulty walking placing one foot in front of the other (tandem walking).
Shooting pains into the arms and legs like an electrical shock, especially when bending the head forward (neck flexion) is known as Lermitte’s sign. Neck flexion can produce paresthesia (altered sensations), usually in the back, but sometimes into the extremities. Lhermitte’s sign is most commonly associated with an inflammatory process such as multiple sclerosis, but it is sometimes noted with spinal cord compression.
A 2002 study in the journal Spine, noted a dispositional factor that possibly contributes to the prevalence of cervical myelopathy in males. Assessment of the cervical spine radiographs of healthy young adults revealed that the cervical canal/body ratio (size of the spinal canal to vertebral body) was significantly larger in women than in men. The incidence of canal stenosis was 19.4% for men and 4.4% for women. The discrepancy of the canal/body ratio in adulthood was attributed to the growth spurt of the male vertebral body at puberty.
Many studies have been done to find out relationships and risk factors without significant conclusions. A 2014 study in the Spine Journal found that cord compression in combination with vertical spinal cord motion contributes to deterioration in cervical myelopathy.
You should have an understanding of the causes and symptoms. It is important to understand that neck problems may cause symptoms that extend beyond a local area and recognize these symptoms in yourself and others so that prompt attention can be addressed. While home care products can help with relief; the worse the symptoms, the more likely surgery is necessary.