CERVICAL DISC HERNIATION

What is the cervical disc herniation?

Cervical disc herniation is a condition characterized by the slippage of the degenerated intervertebral disc into the vertebral canal, causing nerve root and/or spinal cord compression.

What is the structure of the cervical spine?

The human head and neck are supported by the cervical spine, which consists of seven vertebral bones and joints between them. The spinal cord passes through the vertebral canal inside the cervical spine. At each vertebra level, the spinal cord gives off a pair of nerves that travel in the intervertebral foramen to exit the spine. These nerves provide signals to and from the spinal cord.

Each pair of vertebral bones is connected with one big disc joint and two smaller facet joints. The disc joint has a soft and elastic inner core called nucleus pulposus and a tough outer ring – annulus fibrosus. The nucleus is made up of a unique, gel-like substance and serves as an elastic pillow between the neighbor bones. It provides mobility to the spine and serves as a shock absorption buffer. With aging, the nucleus pulposus loses water, shrinks, and breaks to pieces. Fragmented parts break through the annulus fibrosus and slip into the canal. This condition is called cervical disc herniation. Once in the canal, herniated parts compress the spinal cord and nerves. When a cervical nerve root is compromised, this condition is called cervical radiculopathy. Below is a schematic picture demonstrating disc herniation compressing a nerve root as it takes exit from the spine.

Spinal cord compression is referred to as myelopathy. This type of myelopathy is called cervical spondylotic myelopathy. Myelopathy is a more severe condition than radiculopathy and should be treated promptly.

Disc joint degeneration may progress without herniation, and the nucleus disappears almost completely. This leads to a decrease in intervertebral disc height. In other words, vertebral bones become close to each other. Nerve exit foramina, therefore, gets narrower, resulting in nerve pinching. With a lack of support from the center, the load shifts to the outer portions of the vertebral bones. This results in the formation of extra bone tissue to handle the increased load. Newly formed bone spurs or osteophytes additionally compress the spinal cord and nerves. This condition is called cervical stenosis (literally narrowing). Cervical stenosis is a chronic process and takes several years to fully develop. In some instances, cervical stenosis produces very few symptoms because the spinal cord and nerves have time to adapt. However, cervical spondylotic myelopathy is very common in cervical stenosis. Cervical disc herniation may develop on top of cervical stenosis and aggravate chronic symptoms.

What are the symptoms of the cervical disc herniation?

Cervical radiculopathy, presenting as pain in the neck radiating down the arm, is the most common symptom of cervical disc herniation. Sometimes, the pain may also spread to the back of the neck, head, and between shoulder blades.

Radiculopathy is more frequent in disc herniation, and myelopathy is mostly seen with cervical stenosis. Typical radicular pain starts in the neck and radiates to the arm. Typical nerve pain may be difficult to distinguish from thoracic outlet syndrome. Depending on the involved nerve, arm pain location may vary. Numbness and weakness usually develop when there is significant compression of the spinal cord and nerves, compromising their function. Numbness may not be appreciated by the patients since they have pain. However, patients are usually well aware of weakness (paresis). In advanced cases, muscle wasting (atrophy) may develop. Cervical spondylotic myelopathy presents with a combination of muscle weakness (paresis) and ataxia. Paresis may be subtle, so the patients may not have apparent weakness. Rather, fine motor functions can be compromised, resulting in clumsiness. Ataxia or loss of body balance is a very frequent finding, and the patients' walk resembles a drunken person's walk.

In rare cases, bone spurs may cause compression of the vertebral arteries supplying the brain. These patients, therefore, suffer from insufficient blood flow to the brain, and the usual symptom is dizziness, vertigo, and even unconscious falls. Bone spurs may develop in front of the spine, compressing the esophagus. In these cases, patients experience swallowing difficulty and dysphagia.

How is the diagnosis of cervical disc herniation made?

Obtaining a history of the disease and meticulous examination is sufficient to suspect the diagnosis. Neurological examination with complete motor and sensory assessment is absolutely necessary since patients might be unaware of their deficits. Radiological examination like cervical MRI, X-ray, and CT is very important in establishing the diagnosis. X-rays show cervical vertebral bones, their alignment, narrowing of the disc spaces, bone spur formation, and deformity.

However, soft tissue is not visible on X-ray. MRI, on the other hand, is an excellent tool for demonstrating soft tissues like the spinal cord, nerves, and ligaments.

EMG, nerve conduction, and evoked potential studies can be performed to confirm the presence of radiculopathy and myelopathy if suspected.

What is the treatment of cervical disc herniation?

Treatment of degenerative cervical disc disease depends on the severity of symptoms. Initially, patients presenting with pain are usually managed with conservative means like pain medications, chiropractic maneuvers, physical therapy, etc. Local injections and radiofrequency ablation might be helpful in selected cases.

Failure to address pain in long-term and neurological deficits are indications for surgical treatment. The surgery may be done from the front (anterior) or from the back (posterior), depending on the patient's condition and the surgeon's choice. When surgery is performed from the front, it is called anterior cervical discectomy and fusion (ASF or ASDF). The damaged nucleus pulposus is completely removed, and all compression is eliminated by removing soft and hard tissue compressing the nerve roots and spinal cord. Disc joints then are either fused together. Cervical fusion is the most widely used procedure. A cage filled with bone tissue is inserted between the vertebral bones into the space created by the removal of the nucleus. The surgeon then uses a metallic plate and screws to hold neighbor bones together to provide stability. Newly formed bone tissue bridges the adjacent vertebral bones, and eventually, fusion develops.

An alternative technique is disc prosthesis. It is also called motion preservation, and it is a relatively new technology. Instead of fusing the vertebral bones together and losing mobility at that segment of the cervical spine, an artificial joint is placed, which serves as a substitute for the removed disc joint. This way, the surgeon is able to preserve the motion. Preserving the motion is very important since adjacent joints do not experience additional load as in fusion, and therefore, the likelihood of developing additional disc herniations is lower than with fusion.

Tags: cervical disc herniation, cervical disc degeneration, cervical radiculopathy, cervical disc herniation symptoms, cervical disc herniation diagnosis, cervical disc herniation treatment, anterior cervical discectomy and fusion, cervical disc prosthesis.

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CERVICAL DISC HERNIATION

What is the cervical disc herniation?

What is the structure of the cervical spine?

What are the symptoms of the cervical disc herniation?

How is the diagnosis of cervical disc herniation made?

What is the treatment of cervical disc herniation?

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CERVICAL DISC HERNIATION

What is the cervical disc herniation?

What is the structure of the cervical spine?

What are the symptoms of the cervical disc herniation?

How is the diagnosis of cervical disc herniation made?

What is the treatment of cervical disc herniation?

Aska Question