The spinal cord passes through a ring of bone termed the spinal, which is comprised of the vertebral body, the pedicles at the side and the lamina at the back. Cervical myelopathy occurs when there is pressure on the spinal cord, and this results in dysfunction of the nerves below the area of pressure.
The most common cause is degenerative changes within the cervical spine, which leads to narrowing (cervical spine stenosis) and ultimately pressure on the cord. Other causes including a central cervical disc prolapse, tumours or infection. Patients may have a predisposition if they are born with a narrow canal or have a deformity secondary to previous neck injury.
The combination of direct pressure on the spinal cord and ischemia (reduction of the blood supply) of the spinal cord leads to the spinal cord damage. Eventually the damage to the cord affects the patient’s neurological function. They may experience difficulty with balance and walk with an unsteady (ataxic) gait. A common finding is numbness particularly in the hands but also in the feet, as well as progressive difficulty in performing intricate functions such as doing up buttons or writing.
The progression of these symptoms is very variable between different patients and depends upon the degree of damage as well as the severity of the spinal cord compression.
Differential diagnosis depends on the age of the patient, but includes neurological problems such as multiple sclerosis.
An examination of the nerves is performed in the outpatient clinic to assess the severity of the cord damage. Patients will then usually require an MRI scan of the neck to confirm the diagnosis of myelopathy and to localise the site and extent of the problem. X-rays of the cervical spine are useful to assess if there is any instability of the spine, or kyphosis (excessive forward bending of he spine). This is particularly important when planning surgery.
The treatment for the cervical myelopathy is surgical decompression (surgically relieving the pressure on the spinal cord).
The decision to proceed to surgery depends on the extent of the damage to the spinal cord, the extent of the symptoms, as well as speed of their deterioration.
Myelopathy symptoms vary greatly, in both the extent and speed of progression of the symptoms. The majority of patients will experience some progression of symptoms, but this may be very slow in certain individuals.
The aim of decompressive surgery is to relieve the pressure on the spinal cord and prevent further neurological damage to the spinal cord, unfortunately the nerves that are already damaged may not recover.
The timing of surgery is critical to prevent further neurological damage, and yet in some patients where there are no signs of neurological deterioration, then continued non operative treatment may be undertaken while regularly reviewing the patient in out patient clinic.
Cervical Myelopathy Surgery involves either decompression of the spinal cord from the front of the spine, with either, an anterior cervical discectomy and fusion, or if larger area of the cord is involved then a cervical vertebrectomy (removal of one or more of the vertebral bodies) may be required. Alternatively the spine can be decompressed from the back of the spine by a laminectomy (the lamina is removed) +/- instrumentation.