Cervical Artificial Disc Replacement vs. Spinal Fusion
SpineUniverse: In terms of outcomes, what is the data showing us?
Early studies showed that when disc replacement is used to treat people with neck and arm pain, the results are the same as doing a fusion. What we’re learning, however, is that the additional surgery rate is about 2-3 times higher with a fusion as compared disc replacement. That’s a significant argument for disc replacement surgery instead of fusion.
Another disadvantage to fusion is that you worry about patients not healing or perhaps developing pseudoarthrosis, as a result. The notion that fusion contributes to the development of adjacent segment disease is controversial, but the five and seven year data is showing that adjacent segment disease is, in many cases, much lower with the cervical disc. Granted, you can still find studies that indicate the contrary, but in general, most people feel that by maintaining the normal motion of the neck, we create fewer problems at the level above or below. Hildebrand was the first to show that with fusion, there’s about a 3% chance of causing adjacent segment disease for every 10 years, for every year. Once patients hit the 10-year mark post-fusion, the chance of adjacent segment disease leaps to about 25.9%.
Below: a post-operative x-ray of a cervical spine fusion.
Probably the biggest difference is that after you have artificial disc surgery, there is no need for bracing. An artificial disc removes the concern about whether or not the fusion is going to heal out of the equation. In fact, some surgeons are confident that there’s no need for even a soft collar following disc replacement.
To give you another perspective, there are surgeons who question why fusions are being done in the first place. We can go back and forth with that argument, but here’s the bottom line: After an artificial disc surgery, the patient can get back to normal activities. Of course, they’re not participating in vigorous sports activities, because we’re still waiting for the bone to grow into the metal surfaces of the artificial disc. But once that happens, usually around 12 weeks, patients can do anything they want.
Now compare that to a fusion where there’s uncertainty surrounding whether it’s healed, not to mention the activity restrictions on the patient. I tell patients who are deciding between treatment options that about a week after disc replacement, they can drive a car and get back to work. I have my patients in a soft collar for two weeks, but then after 2-6 weeks I get them back to normal.
Jogging or vigorous physical activities have to be postponed until 3 months. The beauty of disc replacement is that patients can get back to their activities much faster. They have very few restrictions, especially at the beginning. I would be much more cautious with a fusion patient.
SpineUniverse: Which types of neck disorders do you consider most appropriate for treatment with artificial disc replacement?
The reason so many cervical artificial discs are approved is that this type of surgery is recommended for patients who have neck and arm pain. Patients who have neck and arm pain because of a pinched nerve, whether from a soft disc or a bone spur that doesn’t respond to conservative treatment, suffer greatly. Generally speaking, cervical artificial disc replacement surgery is a viable option for patients with degenerative disc disease and/or acute herniated disc. This surgery can relieve pressure on the nerves and/or spinal cord, as well as restore spinal alignment and stability. To me, fusion versus disc replacement is analogous to a marathon run. The data we have now shows that the artificial disc patients can run faster and further than fusion patients. In addition, disc replacement surgery lowers the risk for developing adjacent segment disease later on down the road.
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