Physical Medicine and Rehabilitation

Cervical Spondylotic Myelopathy (Spinal Cord Compression)

Anatomy

The spinal column is made up of small bones (vertebrae) stacked on top of one another, creating the natural curves of the back. Between the vertebrae are flat, round, rubbery pads (intervertebral disks) that act as shock absorbers and allow the back to flex or bend. Muscles and ligaments connecting the vertebrae allow motion while providing support and stability for the spine and upper body. Each vertebra has an opening (foramen) in the center and these line up to form the spinal canal. Protected by the vertebrae, the spinal cord and other nerve roots travel through the spinal canal. Nerves branch out from the spinal column through vertebral openings, carrying messages between the brain and muscles. Facet joints align at the back of the spinal column, linking the vertebrae together and allowing for rotation and movement. Like all joints, cartilage covers the surface where facet joints meet.

The spine contains three segments: lumbar, thoracic and cervical. The lumbar spine consists of five vertebrae located in the lower back; lumbar vertebrae are larger because they carry more of the body's weight. The thoracic spine consists of 12 vertebrae and begins at the upper chest, extending to the middle back and connecting to the rib cage. The cervical spine includes the neck and consists of seven small vertebrae, beginning at the base of the skull and ending at the upper chest. Disks in the lumbar spine are composed of a thick outer ring of cartilage (annulus) and an inner gel-like substance (nucleus). In the cervical spine, disks are similar but smaller in size. The cervical spine supports the weight of the head and connects it to the shoulders and body. It is less protected than the rest of the spine, making it more vulnerable to injury and disorders that produce pain and restricted motion.

Description

Cervical spondylotic myelopathy (CSM) is one of the most common age-related neck conditions in the United States. Over time, normal wear-and-tear and effects of aging can lead to a narrowing of the spinal canal (spinal stenosis), compressing, or squeezing, the spinal cord. Symptoms usually begin after age 50, but can occur earlier if the patient suffered an injury to the spine at a younger age. Once symptoms of CSM begin, they tend to continue. Typically, patients with CSM experience slow, steady progression of their disease, over several years. In approximately 5% to 20% of patients, CSM worsens more rapidly.

Causes

Neck pain may result from abnormalities in the soft tissues (muscles, ligaments, and nerves) as well as in bones and joints of the spine. The most common causes of neck pain are soft-tissue abnormalities due to injury or prolonged wear-and-tear. In rare instances, infection or tumors may cause neck pain. In some people, neck problems may be the source of pain in the upper back, shoulders, or arms.

• Inflammatory diseases—Rheumatoid arthritis can destroy joints in the neck and cause severe stiffness and pain. Rheumatoid arthritis typically occurs in the upper neck area.
• Cervical disk degeneration—During the aging process, the nucleus of the cervical disk begins to dry out and degenerate (typically occurring at age 40 years and older), narrowing the space between vertebrae. As disk space narrows, added stress is applied to spinal joints, causing further wear and degenerative disease. The cervical disk may also protrude, weakening the disk rim and putting pressure on the spinal cord or nerve roots. This is known as a herniated disk.
• Injury—Because of its flexibility, and because it supports the head, the neck is extremely vulnerable to injury. Diving accidents, contact sports, and falls are some common causes of neck injury, as are motor vehicle accidents. Rear-end automobile collisions can result in hyperextension (backward motion of the neck beyond normal limits), or hyperflexion (forward motion of the neck beyond normal limits). Regular use of safety belts can help prevent or minimize neck injury in automobile accidents. The most common neck injuries involve the soft tissues: the muscles and ligaments. Severe neck injuries with a fracture or dislocation of the neck may damage the spinal cord and cause paralysis.
• Other causes—Less common causes of neck pain include tumors, infections, or congenital abnormalities of the vertebrae.

Symptoms

CSM can cause a variety of symptoms, including: a tingling, prickling or "pins and needles" sensation (paresthesia); numbness; weakness, difficulty lifting objects, or frequent dropping of objects; difficulty walking (loss of balance), wide-based gait; coordination problems, clumsiness, difficulty with simple tasks such as handwriting, buttoning clothes or feeding oneself; neck pain and stiffness.

Diagnosis

To fully assess your condition and confirm your diagnosis, additional imaging studies may be required, such as: X-rays; magnetic resonance images (MRI); or myelogram, a special type of computed tomography (CT). After discussing your medical history and symptoms with you, your physician will examine your neck and look for:

• Abnormal reflexes—Usually overactive (hyper-reflexia)
• Weakness—Typically found in the arms, more than in the legs
• Numbness—Most commonly in the arms and hands
• Atrophy—Deterioration and shrinkage of muscles

Nonsurgical Treatment

Some patients obtain relief from symptoms with nonsurgical treatment options.

• Soft collars—These limit neck motion and allow neck muscles to rest. Soft collars should be worn for short periods of time only, as long-term wear can weaken neck muscles.
• Exercise—Simple exercises may lessen discomfort by improving neck strength and flexibility.
• Nonsteroidal anti-inflammatory medications (NSAIDs)—Medications such as aspirin and ibuprofen may be recommended to address swelling and pain.
• Epidural steroid injections—Although not commonly prescribed for CSM, cortisone (a powerful anti-inflammatory) injections into the space next to the covering of the spinal cord (epidural space) may be recommended.
• Chiropractic manipulation—This option should NEVER be considered for patients with cervical spondylotic myelopathy (spinal cord compression).

Surgery

Whether or not surgery is appropriate for you is a complex decision you must make with your physician, taking into consider a variety of factors, including your overall health. The surgical goal for CSM is to open the space for the spinal cord, or "decompress" the spinal canal, by removing parts of bone or soft tissue, or both. There are a variety of successful surgical techniques for treating CSM, and decompression is performed either from the front (anterior) of the neck, or the back (posterior). Each approach has advantages and disadvantages, and neither is ideal for every patient.

Rehabilitation

It is typical to spend 1 or 2 days in the hospital following surgery, and to begin walking and eating on the first day. However, recovery and rehabilitation vary for each person and your specific experience will depend on how many disk levels were involved and how you respond to the procedure. It is normal to have difficulty swallowing solid foods for a few weeks, or to experience some hoarseness following anterior cervical surgery. You may need to wear a soft or rigid collar at first. How long will depend on the type of surgery you had. Your surgeon will likely encourage you to begin walking as soon as possible.

• New symptoms—Depending on the extent of your surgery and number of spine levels fused, you may notice some neck stiffness or loss of motion. Following surgery, you may experience different nerve symptoms or feelings as nerves begin to awaken—this is normal and may continue to improve for 1 to 2 years after surgery. If nerve symptoms and pain progressively worsen, or you have any wound problems, you should contact your surgeon.
• Physical therapy—Usually by 4 to 6 weeks, you can gradually begin range-of-motion and strengthening exercises. Your physician may prescribe physical therapy during the recovery period to help you regain full function. A spine conditioning program may also be recommended.
• Returning to work—Most patients are able to return to a desk job within a few days to a few weeks after surgery. Depending on the procedure, all daily activities may typically be resumed by 3 to 4 months.

Complications

As with any surgery, there are some risks, and these vary from person to person. These are typically minor, treatable and unlikely to affect your final outcome. For most people, surgery can provide relief of symptoms and return to function with relatively low risk of complications. Discuss the potential risks and benefits specific to each technique with your surgeon prior to surgery.

In general, elderly patients have higher rates of complications from surgery, as do patients who are overweight, diabetics, smokers, or suffering from multiple medical problems. General, potential risks for cervical spine surgery include: infection, bleeding, injury to nerves or spinal cord, reactions to anesthesia, tearing of the sac covering the nerves (dural tear), need for additional surgery in the future, and failure to relieve symptoms.

Outcomes

The primary goal of surgery for CSM, regardless of approach, is to stabilize the spine and prevent worsening of neurologic problems, but not necessarily to restore normal function. A secondary goal is potentially improving associated neck pain, motor (weakness), sensory (numbness/tingling), and gait (walking) disturbances. Although final outcomes vary by patient, compared to pre-surgical symptoms: one-third typically improve, one-third typically remain unchanged, and one-third continue to worsen over time. Patients with CSM are recommended for surgery to make sure that their symptoms do not worsen—in most cases, the symptoms they have going into the operating room are the same symptoms they will experience afterwards. Your surgeon will discuss this with you and provide information on what the likelihood of improvement is in your individual situation.