Your neck is made up of vertebrae that extend from the skull to the upper torso. Cervical discs absorb shock between the bones. The bones, ligaments, and muscles of your neck support your head and allow for motion. In the healthy neck, there is a disc filled with fluid between each bony element of the spine (vertebra). The disc helps to cushion the vertebrae from moving together under the weight of the head.
Any abnormalities, inflammation, or injury can cause neck pain or stiffness. In many cases, it’s due to poor posture or overuse. Sometimes, neck pain is caused by injury from a fall, contact sports, or whiplash.
Cervical Degenerative Disc Disease
When a disc degenerates (breaks down), the vertebrae may also begin to break down or touch. Patients with degenerative disc disease experience varied levels of pain, less neck motion, and weakness in the arms and hands. Not all disc degeneration results in pain or lack of mobility.
Cervical Herniated Disc Disease
Each disc has a strong outer ring (annulus fibrosus). The outer ring helps keep the disc’s soft centre (nucleus pulposus) in place. When a disc degenerates (breaks down), the disc’s outer ring may form tiny tears or cracks. If the outer ring of the disc fully tears or splits, the gel-like centre can squeeze out. Disc herniation, also called a disc bulge or a ruptured disc, shrinks the space between the vertebrae.
When the disc centre bulges beyond its natural location, the disc may press on a nerve root and/or the spinal cord. Loss of disc height can also cause pressure on nerve roots and the spinal cord. This pressure can cause pain, numbness, and weakness in your neck, shoulders, or arms. The type and location of pain depend on which disc has herniated and how the nerve root and/or spinal cord is pinched (compressed).
Cervical disc herniation or degeneration results in a flattened disc space so losing its height. This height is important as it separates the disc above from the below. When disc height is lost, the nerve root pathways may become narrow and result in nerve impingement, inflammation, and pain. Severity of such pain does not depend only on the pathology caused by the disc shape; the patient’s age or traumatic disc condition and various other factors are also involved.
The standard initial treatment for symptomatic cervical disc disease typically involves physical therapy, medication. If the symptoms continue and are very bothersome for more than 6-12 weeks, surgical treatment can be considered.
Total artificial disc replacement in the cervical spine is the latest innovation technology and is an alternative surgical treatment for patients with chronic neck pain or arm pain caused by cervical disease herniation or degeneration which can give them a chance to return to a permanent symptom-free life.
The most common and traditional operation for symptomatic cervical disc disease involves an anterior cervical discectomy and fusion surgery.
Anterior Cervical Discectomy and Fusion (ACDF)
ACDF is a surgery to remove a herniated or degeneration disc in the neck. An incision is made in the throat area to reach the front of the spine. The disc is removed and a graft or a synthetic cage device is inserted to the fuse together the bone above and below the disc resulting in a complete loss of motion at the surgical level.
Total disc arthroplasty, has become an FDA approved option for surgically treating symptomatic cervical disease.
This procedure is similar to the anterior cervical discectomy and fusion except that the defect that is created by removing the disc from between the two vertebrae is filled with a disc replacement device. A disc prosthesis device is composed of superior and inferior cobalt chromium molybdenum allay endplates coated with plasma sprayed titanium and hydroxyl apatite coating, and a polyethylene mobile bearing insert.
The prosthesis allows for motion between the two vertebrae to be maintained and avoids the need for a fusion.
Cervical disc replacement has been shown to have at least equivalent results to ACDF in relieving neck pain, arm pain, patient function, and satisfaction, and with no increase in peri operation complication.
Benefits of Cervical Artificial Disc Replacement
- No risks related to bone graft and bone graft healing. No bone graft is needed for cervical artificial disc surgery, so it does not include the related potential complications. The most common complication in using bone grafts for ACDF is the potential of the bone graft to fail to heal, resulting in a non-union, or pseudarthrosis.
- Fewer hardware-related complications.
- Possible reduced risk of adjacent segment disease studies have shown that by fusing a segment of the spine, the levels of the spine above and below the fused area may wear out and become symptomatic. This is called adjacent-segment disease.
Artificial disc have been shown to maintain range of motion postoperatively. This should reduce load transfer and degeneration of adjacent disc.
After the cervical disc replacement procedure, the damaged disc is replaced with a mobile prosthesis in order to preserve movement. The stress at the adjacent segment is not increased.
Patients are typically discharged the next day following surgery.
Immobilization in a cervical collar is unnecessary.
Nerve symptoms such as pain and numbness usually improve dramatically within 1-2 days of the surgery, but in some cases can take weeks.