Artificial disc replacement after cervical fusion?

Written by Todd H. Lanman, MD | August 17, 2017 | Print  |

In my practice as a spinal neurosurgeon, I emphasize motion preservation surgery.

As such, I have had several patients with previous cervical spine fusions who asked me if there was any hope of switching to an artificial disc. While many spine surgeons may think it is impossible, I have been able to answer, “Yes” to select patients. In my practice I have found that artificial discs can be used to revise cervical fusions safely and effectively in specific situations.

 

Artificial disc replacement corrects a failed fusion
A young man with a previous anterior cervical fusion came to see me complaining of severe, chronic neck and arm pain. He was interested in motion preservation surgery and was keenly interested in the possibility of having an artificial disc replacement—he certainly did not want another fusion.

 

CT scan revealed nonunion of his fusion. Additionally, the plate and screws were coming loose. Obviously, the bone had never healed properly. This afforded me the intriguing possibility of revising his failed fusion with an artificial disc replacement procedure. In fact, the reason I chose CT over MRI for his workup was to examine his facet joints. The CT scan also revealed that his facet joints appeared entirely normal. I knew from previous experience that because of his normal facet joints, he could be a candidate for disc replacement.

 

I advised the young man that this sort of procedure would be considered an "off label" use of a medical device. The patient understood and, in fact, retained an attorney to work with the insurance company to approve reimbursement for the device and the procedure.

 

During the disc replacement surgery, I removed the plate, drilled off the failed fusion, and reopened the foramen. I then placed the artificial disc in virtually the same way I would have in a surgically naive patient. Quite amazingly, he returned to full work duties within three weeks of the surgery and has been pain-free ever since.

 

Facing four levels of cervical fusion, artificial disc replacement offers hope
I recall another patient, an avid golfer from Texas, who presented to me with three-level cervical disc fusion. The cervical level just below the existing fusions was beginning to degenerate, causing her symptoms that by know she knew very well. Given her extensive, personal experience with anterior disc fusion surgery, she realized that she might be headed to a fourth fusion. She had heard I specialized in motion preservation spinal surgery, so the avid golfer came to me hoping there was some way to avoid another fusion. During our frank discussion she asked if there was a way to reverse the existing fusion. She seemed surprised when I told her I may be able to do that very thing.

 

I ordered a CT scan to examine her facet joints. Oftentimes people who have had an anterior fusion have normal facet joints that have not fused, as was the case for our golfer. I agreed to treat the fourth level of degenerative disc disease with an artificial disc replacement, instead of fusion. I also explained to her that if things looked good during the procedure, I would essentially reverse one level of her fusion and put an artificial disc in its place. Since this was an “off label” use of the device, the informed consent process was a bit more involved than usual. By the end of the consultation, she agreed to proceed, knowing that I may or may not have revised the fusion depending on the circumstances.

 

I began the procedure by treating the previously untreated “fourth” level with artificial disc replacement. After verifying that her facet joints were indeed normal at the previously fused level, I drilled out the fusion and used distractors to spring open and close the disk space. X-ray imaging during the procedure showed the area moved normally, so I proceeded to treat that level with artificial disc replacement as well. In essence, she went from a three level fusion with a fourth level of degenerative disc disease to a two-level fusion with two adjacent artificial discs. Incidentally, she did very well with the surgery and when she returned to full activities, our avid golfer actually increased her mobility and regained much of her prowess on the golf course.

 

Artificial disc replacement is an option for fusion revision
These are just two of several patients I have successfully revised using artificial disc replacement. In one case, it was a failed fusion or and in the other, the fusion had healed but the patient wanted greater range of spinal motion. Ideally, spine surgeons would offer artificial disc replacement to patients who want to preserve their spinal mobility instead of and ahead of fusion, where appropriate. Short of that, surgeons should consider artificial disc replacement for cervical fusion revision in patients who are already candidates for revision surgery and who have normal facet joints.

 

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