Herniated Cervical Disc

Each cervical disc begins as a "pancake" which is a little thicker at the center than at the sides, front or back. It has a rounded front and rounded sides to match the contours of the vertebral column and it is a bit concave on the back surface to accommodate the spinal canal. This results in a "kidney bean" shape. There is an outer ring of rather tough, gristly cartilage (the annulus) and an inner core of different, softer cartilage (the nucleus). Degeneration of the disc can be seen as a change in the signal on an MRI scan as the physical consistency of the nucleus material becomes even softer. With this softening, the material becomes more fluid and deformable. Due to weight and forces on the spine during movements which squeeze the disc between the vertebral bodies, the nucleus tries to bulge outward. Sometimes the annulus is thinned out or pushed ahead of the deforming nucleus material. Sometimes a piece of the nucleus works its way through a crack in the annulus. This is called a disc herniation. I like to describe it as a jelly doughnut being squeezed and the innards coming out. There is nothing that can cause this material to move back into place between the bones. If the herniation is toward the front, neurological symptoms are not expected. However, if it happens toward the rear or toward the openings for the exiting nerves (to the side-rear), the spinal cord or one of the nerves can be compressed. In some individuals, over time, the herniated disc can flatten out or migrate a little. In most people, it just stays there.

Cause of Cervcial Disc Herniation

Disc herniation at any level of the spine is usually preceded by disc degeneration which is primarily a naturally-occurring process. Beginning in some individuals even as early as teenage years, for reasons that are not entirely known, the disc cartilage can soften and degenerate. This process occurs at different ages and at different spinal segments in different individuals although more commonly in certain discs. If there is a herniation, it has probably been the end result of many years of degeneration, movements, muscular straining and perhaps unusual stresses such as accidents. Studies have shown that a surprising proportion of individuals with practically no symptoms will have disc herniations if tested. So, what does it take to make a degenerated or herniated disc symptomatic? Since we usually do not have testing immediately before an accident, it is difficult to know what immediate physical difference has resulted. Likewise, we usually do not have daily testing on individuals after an accident which makes it difficult to document any slow evolution of herniation. It is highly likely that every human develops degenerated discs. The fact that some people have become symptomatic following even minor actions or activities suggests that the problem was "waiting to happen". Other individuals have been found to have such impressive disc herniations following violent accidents which brought on symptoms that we are compelled to believe that most or all of the herniation occurred as a direct result. The practical approach taken by our society has been to blame the final condition of the patient on the event(s) which seem most associated with the onset of symptoms while occasionally acknowledging pre-existing conditions.

Non-Surgical Treatments of Cervical Disc Herniation

Once neurological symptoms appear from a cervical disc herniation, treatment depends to some degree on the severity and type of symptom. Symptoms such as radiating pain can improve over the first several weeks if time can be allowed for conservative treatment in which case a surgery might be avoided. Pain from a "pinched nerve" can be addressed with physical modalities such as traction, heat, ultrasound, exercises, etc. Actually, most of these these treatments are not likely to affect the nerves directly but, rather, they can alleviate the secondary muscular symptoms and reduce the irritability of the spinal structure. Irritability of the nerve itself may diminish over the first several weeks based on its own ability to adapt (which is what nervous systems are supposed to do!). In some individuals, the herniated disc can flatten out or shrink over the course of many months or years but, in most people, it just stays there. Anti-inflammatory medications like those in the ibuprofen family might also help early-on. Some patients have had successes with additional treatments such as acupuncture, steroid and/or anesthetic injections, and spinal manipulations but the long-range benefits in the context of disc herniation are not clear to me. Persons who have a disc herniation but do not require surgery must remain mindful of the possibility that further herniation and perhaps new consequences of this could happen in the future.








Surgical Treatments of Cervical Disc Herniation

The criteria for an operation are called "indications for surgery" and they are judged by the surgeon using information from the medical history, examination and diagnostic testing. Sometimes the need for surgery is overwhelmingly obvious to a physician but, at other times, it takes careful consideration based on expert experience and discussion with the patient. Surgery can be an urgent requirement if signs of nerve damage are present. The occurrence of muscular weakness or spinal cord symptoms can be permanent malfunctions and, if they worsen, the nerve malfunction can remain permanently worse despite a surgical decompression. Generally, I do not recommend delaying surgery when symptoms suggesting nerve damage are present. On rare occasions, an individual can have no apparent neurological symptoms but the tests look so frightening to the surgeon that he believes surgery is necessary to avoid unpredictable but potentially catastrophic malfunctions. Most often, surgery becomes the appropriate option based on persistence of radiating pain after a trial of conservative treatment.

Briefly, cervical disc herniation can be surgically treated by either an anterior approach (from the front) or a posterior approach (from the rear). There are pro's and con's to each. Working from the rear, some bone (lamina) must be removed and the nerve can be directly visualized. However, the disc herniation is usually in front of the nerve which is fixed in its position and one must reach around above or below the nerve to get it. Working from the front of the neck, the disc is the first part of the spine that is accessed and the herniated portion can usually be removed directly from in front without handling the nerve. Replacement of the portion of the disc that used to be between the vertebral bodies with a piece of bone to create an "interbody fusion" is often considered, depending on the surgeon's preference. There are pro's and con's to fusion following any type of disc surgery.

Outcome/Restrictions of Cervical Disc Herniation

The outcome of cervical disc herniation can be exceedingly good if no permanent neurological malfunctions have occurred. Reappearance of neurological symptoms following surgical removal of the disc herniation in the neck is usually not seen and symptoms which have resolved without surgery might never return, although the probability of this is reduced by continuing degeneration and stresses on the neck. Persisting "mechanical" symptoms of neck pain or stiffness can be bothersome but they do not always happen and they are usually not incapacitating. Degenerations at other disc levels, muscular or ligament irritability and "inflammations" can all contribute to pains not necessarily related to one disc. The most dramatic successes I have seen are those involving anterior cervical disc excision and fusion which, if solidly healed, can eliminate even the mechanical symptoms. For the most part, patients are better having had a properly justified surgery than not having had it.

Restrictions following a cervical disc herniation vary tremendously from one individual to the next. One must acknowledge the difference between the most an individual can physically do following a spine problem and the most he can do without experiencing any symptoms. At times, a fully healed surgical patient can seem "as good as new" and even non-operated patients can also seem essentially unrestricted. However, despite maximum healing, a few patients experience some persisting degree of neck discomfort which is usually tolerable. If reasonable arbitrary limitations cannot be easily applied, a test called a "functional capacity assessment" can help identify objective limitations and capabilities. Patients with a non-operated disc herniation can risk further progression if physical exertion is not limited. Lifting and upper body straining, not to mention direct injuries to the neck, can all cause aggravations.


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