Robert F. McLain, M.D., a spine surgeon in the Spine and Orthopedic Institute at St. Vincent Charity Medical Center, recently published the following article to provide information regarding cervical disc injury, cervical fusion, disc replacement surgery and more.

Neck pain, arm pain, numbness, tingling and weakness are symptoms that can trigger alarm in any previously healthy patient. Whether the symptoms come on after a recognized and sudden injury (a car accident, sports injury or a fall), after excessive activity (yard work or heavy lifting on the job) or just slowly develop out of the blue, patients usually know they have a "neck problem." While many patients will cope with neck pain and chalk it up to over-use or wear and tear, they often have a fear the arm pain is coming from something more serious than a simple strain.

What is a cervical disc injury?

The neck, like all segments of the spinal column, is made up of separate bony structures - the vertebrae - that provide strength and bear the loads of the body. The vertebrae are connected by soft tissues - muscles and ligaments - which support and align the spine, and the tough intervertebral discs - the spacers in between each vertebra that act as shock absorbers and stabilizers for every segment of the spine. Any of these structures can be damaged and cause pain.

Most commonly, injuries to the neck involve the ligaments and muscles, and are classified as sprains or strains. These injuries usually get better on their own, without specific treatment.  Most patients that go to the ER with a neck injury will come away with a diagnosis of "Cervical Sprain," which is usually correct, and will get better with supportive care, anti-inflammatory medications (NSAIDs) and physical therapy.

Vertebra can be fractured or broken following a major injury such as a fall or collision, which will cause severe neck pain and spasm, and can cause numbness, weakness, or paralysis if bone fragments press on the nerves or the spinal cord. Fractures are uncommon, but they are serious, always require medical management, and often require surgery. 

Cervical disc injuries are less frequent, and sometimes harder to diagnose, because they usually occur with an obvious strain or sprain. They may produce persistent neck pain symptoms, but not always. The most important feature of a serious disc injury, compared to a simple sprain, are the symptoms of arm pain or weakness, numbness or tingling, usually running down the arm into the hand and fingers. This set of symptoms is called a radiculopathy, meaning that it is caused by irritation or pressure on a spinal nerve coming out of the cervical spine.  Radiculopathy is often more intense and of a different quality than the deep ache of a muscular injury, and most patients recognize this pain as a different kind of problem.

Disc injuries can come on after years of heavy use or may result from a single, quite distinct accident. Surgeons discuss different types of injury in terms of mechanism, but each can produce a disc herniation that requires treatment. An axial injury - where the force comes down the neck through the top of the head - can occur with a football tackle or by standing up under a low beam. A flexion-extension injury - what we used to call whiplash - is often experienced in a motor vehicle collision. A torsional or twisting injury can occur with a nasty tumble on the ice.

In each case, some of the tough connecting fibers that make up the outer disc get stretched or ruptured.  These fibers keep the soft inner disc material - the nucleus - in place and under pressure, and if they are damaged badly enough, the nucleus may push out into the spinal canal and put pressure on the nerve or spinal cord. Often, stretched annular fibers continue to weaken with time and activity, and the nucleus will progressively push out into the spinal canal until it starts to "pinch" the nerve.

A herniation that just irritates the nerve root may improve with anti-inflammatory medications, injection therapy, or with simple supportive care and time. If the disc fragment physically compresses the nerve root, then surgical treatment may become necessary. If pressure on the nerve is enough to cause weakness, then urgent surgery may become necessary to prevent permanent nerve damage or even paralysis.

What can be done about a cervical disc herniation?

The treatment of a herniated or protruding cervical disc is pretty simple, in principle. By removing the herniated disc material, decompressing the cord and the nerve root, we often get relief of arm pain and weakness right away. Some people report their pain is gone when they wake up in the recovery room. The decompression procedure is called a discectomy.

Removing the disc leaves a gap between the vertebral levels, however.  If nothing more was done than the discectomy, the vertebrae would collapse down on the other, and neck pain would likely be severe. Stabilizing the disc level is necessary to restore normal cervical alignment, and allow motion without pain. For decades, the traditional way to do this has been a cervical fusion. The surgeon places a bone or synthetic spacer between the vertebrae, and locks it in place with a plate that holds that segment still. The bone grows from one level to the next to fuse the level and prevent any further motion there. It's a good operation, with a high success rate, and many people that have an anterior cervical discectomy and fusion (ACDF) do very well and never need any further treatment. The primary concerns for ACDF are two-fold, however: First, to be successful, the patient must get a solid fusion, and that does not happen in every case.  If the fusion doesn't "take," another surgery must be done to get a successful, solid fusion. Second, if the fusion is successful, the operated level will never bend or move again, shifting stresses to the adjacent levels that haven't been treated. This extra stress may accelerate degeneration at the level above or below, eventually requiring surgery for adjacent level disc degeneration. That risk is higher among patients who needed a two-level fusion to start with.

So, do I have to have a fusion?

There are now real and reliable alternatives to fusion surgery that your surgeon should discuss with you.  Disc Replacement Surgery, or disc arthroplasty, has been available for more than 30 years now, and has been available through clinical trials for more than 15 years in the United States. The disc replacement device allows your surgeon to fill the gap left after discectomy with an implant that permits a small, but important, amount of motion, similar to what the healthy disc allowed. A number of high-quality research studies have shown that disc replacement provides pain relief and patient satisfaction as reliably as the traditional ACDF procedure, but with a lower risk of complications, and with fewer revision operations. Long-term studies have shown that adjacent level degeneration is less likely after disc arthroplasty, particularly after two-level surgeries.

Advantages include a more rapid return to activity - prolonged immobilization in a brace or collar is not part of the plan, and getting back to light activity and normal motion is encouraged from the start. Also, NSAID medications, which can interfere with a fusion, can be used right from the start after disc replacement, and provide important, non-narcotic pain relief.

Disc arthroplasty isn't right for everyone. If disc degeneration is advanced and motion is already lost, then there is no benefit to a disc replacement. If the disc space is too narrowed, it may not be possible to fit in the replacement. And sometimes, previous neck surgery or a history of a fracture or infection makes disc replacement unsafe.  In these cases, the traditional fusion makes great sense.

What should I ask my doctor? 

If you have the symptoms of persistent neck pain and arm pain we discussed here, you may be a candidate for disc replacement surgery. It is important for your doctor to discuss the options with you, including disc replacement. They should discuss the major risks of spinal surgery and tell you how they will protect you during your operation. And, they should explain how the disc replacement may benefit you compared to fusion surgery, and what their experience and training in disc replacement surgery is. 

So, you may need to have an operation, but you may not have to have a fusion.

Robert F. McLain, M.D., a spine surgeon in the Spine and Orthopedic Institute at St. Vincent Charity Medical Center, has more than 20 years of experience in disc replacement surgery, and has served as an instructor and educator in disc replacement surgical training, as Principal Investigator for an FDA cervical disc replacement clinical trial, and provides both lumbar and cervical disc replacement to carefully selected patients who need those procedures.