Myelopathy is an inclusive term referring to any disease of the spinal canal. The cervical region specifies the neck region of the spine. The following are examples of myelopathy: carcinomatous myelopathy (spinal cord degeneration associated with cancer); compressive myelopathy (spinal cord changes from the pressure of hematomas or masses); and radiation myelopathy (spinal cord destruction from radiation sources such as x-ray therapy). When the spinal cord destruction is caused as a complication of disease, the specific myelopathy signifies that origin; for example, diabetic myelopathy.
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Cervical disc disorder with myelopathy can result from either a herniation of a cervical disc or spinal cord compression by spinal stenosis. A cervical disc (intervertebral disc) is a cushion-like structure found between the cervical spinal bones (vertebrae C2 through C7) that run from the base of the skull to shoulder level. Discs are composed of a gel-like inner material (nucleus pulposus) encased in a ring of tough, fibrous outer material (annulus fibrosis); intervertebral discs absorb shock and allow movement of the spine. Disc displacement (herniation) occurs when the nucleus pulposus and/or the annulus protrudes abnormally into the spinal canal. Most often, a disc herniation presses on an exiting spinal nerve, causing dysfunction in a nerve root (radiculopathy). Less commonly, the spinal cord can become compressed by a herniated or bulging disc alone, or in combination with degenerative changes (cervical spondylosis) or with a narrow spinal canal (spinal stenosis).
Cervical disc herniation with myelopathy is less common than cervical disc herniation without myelopathy. Although both disorders cause neck pain and disturbances in arm sensation and strength, myelopathy is a more critical problem involving neurological disturbances in the legs and possible impairment of bowel and/or bladder control.
Individuals with cervical disc disorder and myelopathy show signs and symptoms of myelopathy, with or without radiculopathy. Symptoms of the latter typically include pain radiating into the arm or chest with finger numbness and motor weakness. Blood supply to the brainstem and posterior fossa brain structures can also be affected by vertebral artery compression from spondylosis and may include dizziness, syncope, blurred vision, ringing in the ears (tinnitus), and pain behind the eyes. Like radiculopathy or arm symptoms, these brain stem symptoms may coexist with the symptoms of spinal cord compression that define myelopathy.
Discs normally begin the degeneration process by at least the third decade of life; by the fifth decade of life, most individuals exhibit degenerative changes (Windsor). Nevertheless, many individuals have no symptoms, and over the years these degenerative changes can slowly narrow the spinal canal until myelopathy occurs.
Myelopathy can also begin suddenly in the aftermath of a massive cervical disc rupture. Individuals who develop very rare acute cervical disc herniation with myelopathy as a result of injury often participate in sports that place a vertical load on the cervical spine, such as soccer, football, wrestling, ice hockey, diving, rugby, and trampolining.
Risk: Individuals in their twenties who participate in sports and those between 60 and 70 years of age are at greater risk for degeneration of the cervical spine resulting in cervical disc syndrome with myelopathy (Windsor). Displaced cervical discs occur equally as often in men as in women (Furman), but cervical spondylosis begins earlier in men. Radiologic findings show that 90% of men over age 50 and 90% of women older than age 60 have degenerative changes in the cervical spine (Al-Shatoury).
Incidence and Prevalence: One in five visits to an orthopedic practice is for cervical discogenic pain (Windsor). Eight percent of all herniated discs occur in the cervical region of the spine. Cervical spondylotic myelopathy is the most frequent cause of spinal cord dysfunction in individuals older than 55 years in the US and worldwide (Al-Shatoury).
Degeneration of cervical intervertebral discs accounts for 36% of all spinal intervertebral disc disease, second only to lumbar disc disease, which accounts for 62% of all spinal intervertebral disc disease (Windsor).