Intervertebral discs are cartilaginous shock absorbers between each of the bony vertebrae throughout the spine. These discs allow our spinal column to move. The outside of the disc is composed of a tough, fibrous layer called the annulus fibrosis. The center is made of a gelatinous substance called the nucleus pulposus. Our discs are made of cartilage, and cartilage, in turn, is composed of approximately 80% water by weight. As we age, this water content decreases. This loss of water content is accompanied by a loss of disc height as well as a loss of flexibility and strength. The outer annulus fibrosus may develop a small tear through which the inner material protrudes.
A disc herniation occurs when a part of the gelatinous nucleus pulposus protrudes through the border of the outer fibrous layer of the disc into the spinal canal, thereby creating pressure on the spinal cord and/or nerves. Most often, disc herniations in the neck can cause pressure on a specific nerve leading to pain, numbness, tingling and/or weakness radiating into the arm (cervical radulopathy). The most common nerve roots affected are C5, C6, and C7, which correlate with specific patterns of pain, numbness, and weakness in the arm (i.e. C5 supplies the deltoid, C6 supplies the wrist extensor, and C7 supplies the triceps). Occasionally, a disc herniation will compress the spinal cord itself causing more subtle, but more concerning, symptoms of loss of manual dexterity, unsteadiness with walking, arm weakness, and bladder dysfunction (cervical myelopathy).
A cervical disc herniation is typically diagnosed by taking a thorough patient history and physical examination. This can usually determine the specific nerves which are affected. X-rays of the cervical spine may show some evidence of disc degeneration and arthritis. An MRI scan is the study of choice for visualizing the soft tissue structures of the spine including the cervical discs, spinal cord, and nerves. It is important to understand that most asymptomatic individuals over the age of 30 will have degenerative changes on an MRI. More often than not, these degenerative changes are age appropriate and clinically irrelevant.
How do we treat a cervical disc herniation?
Conservative treatment of disc herniation is usually effective 85% of the time. Rest, time and over-the-counter pain relievers may be all that is needed. The addition of muscle relaxers, anti-inflammatory medications and oral steroids including Prednisone may be used as additional treatment. The return to physical activity should be slow and controlled so that symptoms do not recur. Physical Therapy may also be prescribed. If conservative treatment fails, epidural steroid injections may lessen nerve irritation and may allow better participation in physical therapy. These steroid injections may be administered on an outpatient basis and may be repeated up to 3 times over 6 to 12 months. In the 15% of patients for whom conservative treatments are not effective and/or for patients who have progressive neurologic deficits, then surgery may be required.
What does surgery for a cervical disc herniation involve?
While surgery is usually the last option, it is important to understand that cervical radiculopathy typically responds well to a variety of surgical treatments with a greater than 90% success rate. Once all non-surgical treatment options have been exhausted, it may be time to consider surgery. Your surgeon will make a decision about whether to approach the disc from the front (anteriorly) or back (posteriorly) of the spine. Options may include a posterior cervical foraminotomy, anterior cervical disc excision, and fusion, or anterior cervical artificial disc replacement. The procedure is determined by the location and extent of cervical pathology. The surgery is typically performed under general anesthesia and patients are discharged either the same day of surgery or after a single overnight hospital stay. At Connecticut Neck and Back Specialists, minimally invasive techniques are used to limit the size of the surgical incision and to minimize the manipulation and disruption of surrounding healthy muscle tissue. When surgery is performed on an outpatient basis, we usually attempt to allow our patients to return to work within 2 to 6 weeks. When cervical decompression is performed, the nerve that was compressed by the disc herniation is completely freed from all surrounding compression. The rate and extent of nerve recovery are dependent on many factors including the severity of compression, the duration of the compression, the age of the patient, and associated medical conditions including the existence of underlying diabetes, significant smoking history, or a history of significant alcohol consumption.