CERVICAL SPONDYLITIC MYELOPATHY - SPINAL CORD COMPRESSION
The cervical spine is located in the neck. Your cervical spine supports your head and connects it to your trunk. The cervical spine supports less weight than any other portion of the spine. It also has the greatest amount of mobility and flexibility. Your neck can bend forward and backward, tilt from side to side, and rotate to the right and left.
Seven vertebrae make up the cervical area of your spine. The back part of the vertebra arches to form the lamina. The lamina creates a roof-like cover over the back of the opening in each vertebra. The opening in the center of each vertebra forms the spinal canal.
Intervertebral discs are located between the vertebrae in the cervical spine. The discs are made up of strong connective tissue. Their tough outer layer is called the annulus fibrosus. Their gel-like center is called the nucleus pulposus. The discs and two small joints connect one vertebra to the next. The discs and joints allow movement and provide stability. The discs also act as a shock-absorbing cushion to protect the cervical vertebrae.
The top section of the cervical spinal canal is very spacious. It allows more room for the spinal cord than any other part of the vertebral column. The extra space helps to prevent pressure on the spinal cord when you move your neck.
Your spinal cord, spinal nerves, and arteries that supply blood travel through the protective cervical spinal canal. The spinal cord segments in the neck are indicated by C1-C8. Nerves exit the spine at different levels. Compression of the spinal cord from cervical spondylitic myelopathy most frequently occurs at C4-C7. The nerves from the spinal cord at this level supply the shoulders, arms, and hands.
Cervical spondylitic myelopathy is caused by degenerative changes that take place in the cervical spine and put pressure on the spinal cord. Arthritis, termed cervical spondylosis, causes the shape of the vertebrae to change. The facet joints enlarge and the spinal canal narrows. Bone spurs may grow into the spinal canal. Degenerative changes, “wear and tear,” and trauma can affect disc spacing. The ligaments surrounding the spinal canal can thicken and reduce the space for the spinal cord.
Compression of the spinal cord most frequently occurs at the C4-C7 levels. The nerve roots extending from the spinal cord may be compressed as well. Compression can cause damage to the spinal cord, impaired blood flow, and neurological dysfunction.
Cervical spondylitic myelopathy commonly causes weakness, clumsiness, and numbness in the arms, hands, and fingers. You may drop items or have a difficult time manipulating buttons, fasteners, and small objects. Your balance and walking ability may change. You may experience weakness, heaviness, or numbness in your legs. Your neck may feel stiff. Bending your neck forward (flexing) may cause electrical-like sensations that move down your spine. Pain may spread from your neck to your arms and fingers. You may have burning, tingling, stabbing, or dull aching pain or a sensation of “pins and needles.” However, about half of people with cervical spondylitic myelopathy do not experience pain.
As cervical spondylitic myelopathy progresses, the legs become weaker and stiffer. It may be difficult to straighten your legs. You may have difficulty controlling your bowel and bladder. People with advanced cervical myelopathy may need an ambulation device, such as a cane or walker, to aid walking.
Your doctor can diagnosis cervical spondylitic myelopathy after reviewing your medical history, conducting an examination, and considering the results of medical imaging tests. You should tell your doctor about your symptoms, risk factors, and functional problems, such as difficulty getting dressed, feeding yourself, or walking. Your doctor may check your muscle reflexes, tone, strength, coordination, and range of motion. Your balance and gait pattern will be assessed. Your sense of touch and temperature will be tested.
Your doctor may order X-rays to see the condition of the vertebrae in your cervical spine.
Sometimes doctors inject dye into the spinal column to enhance the X-ray images in a procedure called a myelogram. A myelogram can indicate if there is pressure on your spinal cord or nerves from herniated discs, bone spurs, or tumors.
Your doctor may order computed tomography (CT) scans or magnetic resonance imaging (MRI) scans to get a better view of your spinal structures. CT scans provide a view in layers, like the slices that make up a loaf of bread. The CT scan shows the shape and size of your spinal canal and the structures in and around it. The MRI scan is very sensitive. It provides the most detailed images of the discs, ligaments, spinal cord, nerve roots, or tumors. X-rays, myelograms, CT scans, and MRI scans are painless procedures.
In some cases, doctors use nerve conduction studies to measure how well the cervical spinal nerves work and to help specify the site of compression. Doctors commonly use a test called a nerve conduction velocity (NCV) test. During the study, a nerve is stimulated in one place and the amount of time it takes for the message or impulse to travel to a second place is measured.
Somatosensory evoked potentials (SSEPs) or motor evoked potentials (MEPs) are used to test how the spinal cord transmits nerve signals about sensory or movement information. Your doctor will place sticky patch-like electrodes on your skin that covers a spinal nerve. The NCV test may feel uncomfortable while it is performed.
An electromyography (EMG) test is often done at the same time as the NCV test. An EMG measures the impulses in the muscles to identify damage or decay. Muscles need impulses to perform movements. Your doctor will place fine needles through your skin and into the muscles that the spinal nerve controls. Your doctor will be able to determine the presence of muscle damage, as well as the quality of the nerve impulses conducted when you contract your muscles. The EMG may be uncomfortable, and your muscles may remain a bit sore following the test.
The symptoms of some cases of cervical spondylitic myelopathy may be relieved with non-surgical treatments. Neck immobilization, such as with a collar or bracing, medications to reduce pain and inflammation, and physical therapy may be helpful. If symptoms do not improve or become worse, surgery may be necessary.
Surgery is used to relieve spinal cord compression. The majority of conditions that cause spinal cord compression are located in front of the spinal cord. For this reason, anterior cervical decompression and fusion (ACDF) surgery is commonly used to treat cervical spondylitic myelopathy. The goals of ACDF surgery are to remove pressure from the spinal cord, relieve pain, restore function, and stabilize the spine.
ACDF surgery is performed through an incision at the front of the neck. Your surgeon will make an incision approximately two inches long carefully avoiding your throat and airway. Your muscles and arteries will be moved aside with care to allow access to the vertebrae. Your surgeon will remove abnormal disc and bone structures.
Next, the surgeon replaces the disc or discs with a bone graft or interbody fusion cage to support the cervical spine. Surgical hardware including plates and screws may be used. The surgical hardware secures the vertebrae together and allows the bone grafts to heal.
At the completion of your ACDF surgery, your surgeon will close your incision with stitches. You will receive pain medication immediately following your surgery. You will wear a neck brace or collar while your fusion heals.
You should expect to stay overnight in the hospital. You may need some help from another person during the first few days or weeks at home.
Following surgery, your doctor will initially restrict your activity and body positioning. You should avoid lifting, housework, and yard-work until your doctor gives you the okay to do so. You will wear a neck brace for support. Once your neck has healed, physical therapists will teach you flexibility and strengthening exercises. You will also learn body mechanics and proper postures.
The recovery process is different for everyone. It depends on the particulars of your surgery and the extent of your condition. Your surgeon will let you know what to expect.
It is important to adhere to your restrictions and exercise program when you return home. You should use proper body mechanics during all activities. Do not smoke. Smoking increases the risk of surgical complications and may hinder the bone from fusing. If you have difficulty quitting smoking on your own, ask your doctor about medications and resources that may help you.
There are several factors which may contribute to cervical spondylitic myelopathy including:
• Increasing age is associated with an increased risk for cervical spondylitic myelopathy. It most frequently occurs in people over the age of 50, but may occur at any age.
• Osteophytes or bone spurs increase the risk of cervical spondylitic myelopathy.
• Arthritis in the neck can cause the facet joints to enlarge, which increases the risk of cervical spondylitic myelopathy.
• Thickened ligaments in the spinal canal, particularly the ligamentum flavum, can narrow the spinal canal and may lead to cervical spondylitic myelopathy.
• Dislocated or subluxed vertebrae, bones that have moved out of position, increase the risk of cervical spondylitic myelopathy.
• People that are born with a small spinal canal have an increased risk of cervical spondylitic myelopathy.
• “Wear and tear” or trauma increases the risk of cervical spondylitic myelopathy.
It is important to receive prompt treatment for cervical spondylitic myelopathy. Early treatment may reverse spinal cord dysfunction and is associated with the best outcomes. Untreated or advanced cervical spondylitic myelopathy has a poorer prognosis.
Ongoing trials are trying to determine the best techniques to improve clinical outcomes following anterior cervical discectomy and fusion, including the use of titanium cages, autograft bone fusion and microdiscectomy.