Cervical Spondylitic Myelopathy – Spinal Cord Compression

The cervical spine, located in the neck, plays a crucial role in supporting the head and connecting it to the trunk. Among all segments of the spine, the cervical region supports the least weight while offering the greatest range of motion and flexibility. This allows the neck to bend forward and backward, tilt side to side, and rotate.

The cervical spine is made up of seven vertebrae. The posterior portion of each vertebra arches to form the lamina, which creates a protective cover over the spinal canal. This central opening within each vertebra forms the spinal canal, which houses the spinal cord.

Intervertebral discs are situated between the cervical vertebrae and are composed of strong connective tissue. The tough outer layer, known as the annulus fibrosus, encases a gel-like center called the nucleus pulposus. These discs, along with two small joints, link each vertebra, allowing for movement and providing stability. They also serve as shock absorbers to protect the cervical vertebrae.

The upper section of the cervical spinal canal is notably spacious, providing more room for the spinal cord than any other part of the vertebral column. This extra space helps prevent pressure on the spinal cord during neck movements.

The spinal cord, spinal nerves, and arteries that supply blood traverse the protective cervical spinal canal. The spinal cord segments in the neck are designated as C1-C8, with nerve roots exiting at various levels. Compression from cervical spondylitic myelopathy most commonly occurs between the C4 and C7 vertebrae, affecting nerves that supply the shoulders, arms, and hands.

Cervical spondylitic myelopathy is primarily caused by degenerative changes in the cervical spine that exert pressure on the spinal cord. Arthritis, known as cervical spondylosis, alters the shape of the vertebrae, leading to the enlargement of facet joints and a narrowing of the spinal canal. Bone spurs may develop within the canal, while “wear and tear” and trauma can impact disc spacing. Additionally, ligaments surrounding the spinal canal may thicken, further reducing the space available for the spinal cord.

Compression of the spinal cord is most frequently observed at the C4-C7 levels, and the nerve roots extending from the spinal cord may also be affected. Such compression can damage the spinal cord, impair blood flow, and result in neurological dysfunction.

Cervical spondylitic myelopathy commonly results in weakness, clumsiness, and numbness in the arms, hands, and fingers. Patients may find it challenging to grasp small objects, manipulate buttons, or fasten clothing. Changes in balance and walking ability may occur, along with weakness, heaviness, or numbness in the legs. A stiff neck is also common, and bending the neck forward can provoke electrical-like sensations traveling down the spine. Pain may radiate from the neck to the arms and fingers, manifesting as burning, tingling, stabbing, or dull aching sensations, or a feeling of "pins and needles." Notably, about half of individuals with this condition do not experience pain.

As the condition progresses, weakness and stiffness in the legs may intensify, making it difficult to straighten them. Additionally, loss of control over bowel and bladder function can occur. Individuals with advanced cervical myelopathy may require mobility aids, such as a cane or walker, to assist with walking.

Cervical spondylitic myelopathy is diagnosed through a thorough review of medical history, physical examination, and imaging tests. Patients should provide detailed information about their symptoms, risk factors, and functional difficulties, such as challenges with dressing, feeding, or walking. The physician may assess muscle reflexes, tone, strength, coordination, and range of motion, as well as balance and gait.

X-rays may be ordered to evaluate the condition of the cervical vertebrae. In some cases, a myelogram is performed, where dye is injected into the spinal column to enhance X-ray images, revealing potential pressure on the spinal cord or nerves due to herniated discs, bone spurs, or tumors.

Additional imaging, such as computed tomography (CT) scans or magnetic resonance imaging (MRI) scans, may provide more detailed views of spinal structures. CT scans present layered images, offering insights into the shape and size of the spinal canal, while MRI scans are particularly sensitive and can detail the discs, ligaments, spinal cord, nerve roots, and tumors. These imaging tests are painless.

In certain cases, nerve conduction studies may be utilized to evaluate cervical spinal nerve function and pinpoint the site of compression. A common test, the nerve conduction velocity (NCV) test, measures how quickly a nerve impulse travels between two points. Somatosensory evoked potentials (SSEPs) or motor evoked potentials (MEPs) may also be conducted to assess the spinal cord's transmission of nerve signals related to sensory or motor functions. For these tests, electrodes are placed on the skin over spinal nerves.

An electromyography (EMG) test is frequently performed alongside the NCV test to measure muscle electrical activity and identify potential nerve or muscle damage. Fine needles are inserted into the muscles controlled by the spinal nerve, allowing the doctor to assess nerve impulse quality during muscle contractions. The EMG may cause discomfort, and mild soreness in the muscles can persist afterward.

Non-surgical treatments can alleviate symptoms in some cases of cervical spondylitic myelopathy. Options include neck immobilization with collars or braces, medications to reduce pain and inflammation, and physical therapy. If symptoms do not improve or worsen, surgical intervention may be necessary.

Surgery aims to relieve spinal cord compression. Most conditions causing this compression are located anteriorly to the spinal cord, making anterior cervical decompression and fusion (ACDF) surgery a common treatment option. The objectives of ACDF surgery include relieving spinal cord pressure, alleviating pain, restoring function, and stabilizing the spine.

During ACDF surgery, a two-inch incision is made at the front of the neck, carefully avoiding the throat and airway. The surgeon will reposition muscles and arteries to access the vertebrae and remove any abnormal discs or bone structures.

The surgeon will then replace the removed discs with a bone graft or interbody fusion cage to support the cervical spine. Surgical hardware, such as plates and screws, may be used to secure the vertebrae together, allowing for proper healing of the grafts.

Once the ACDF surgery is completed, the incision will be closed with stitches, and immediate pain relief will be provided through medication. A neck brace or collar will be worn during the healing process.

Patients should expect to stay overnight in the hospital and may require assistance during the initial recovery period at home. Following surgery, doctors will initially limit activity and body positioning, advising against lifting or housework until cleared. Physical therapists will guide patients through flexibility and strengthening exercises once healing has progressed.

Recovery timelines can vary significantly depending on individual circumstances, surgical details, and the extent of the condition, with specific expectations outlined by the surgeon.

Adhering to post-operative restrictions and exercise programs is crucial for recovery. Practicing proper body mechanics during all activities is essential. Smoking should be avoided, as it can increase surgical complications and hinder bone healing. Those struggling to quit smoking should consult their doctor about potential medications and resources.

Am I at Risk?

Several factors may contribute to the development of cervical spondylitic myelopathy, including:

- Increasing Age: The risk is higher for individuals over 50, although it can occur at any age.

- Bone Spurs: Osteophytes increase the likelihood of developing this condition.

- Arthritis: Arthritis in the neck may lead to enlargement of facet joints, elevating the risk.

- Thickened Ligaments: Thickening of ligaments, particularly the ligamentum flavum, can narrow the spinal canal.

- Dislocated or Subluxed Vertebrae: Misalignment of vertebrae raises the risk.

- Congenital Narrow Spinal Canal:Individuals born with a smaller spinal canal have an increased risk.

- Degenerative Changes: “Wear and tear” or trauma contribute to heightened risk.

Timely treatment for cervical spondylitic myelopathy is critical. Early intervention may reverse spinal cord dysfunction and is associated with optimal outcomes. Delayed or untreated conditions can lead to a worse prognosis.