My brother was involved in developing and testing disc replacements for the neck when he had a car accident and died. That was two years ago. I was just browsing the web and wondering whatever happened with those anyway?
We are sorry for your loss and applaud your brother's contribution to this fast-changing area of medicine. Much has happened in the last few years related to disc replacements for the neck called cervical disc arthroplasty. The first FDA-approved studies on the subject have been published for three different devices: the Prestige System, the ProDisc-C system, and the Bryan disc. Since the first cervical disc replacement didn't come out until 2007, the results so far are fairly limited. Later implant systems weren't available until 2009, so research data is fairly limited as well.
What do we know so far? Short- and mid-term results are very favorable. Patients are able to get pain relief and return of motion and function. Results are measured using a specific Neck Disability Index (NDI) and assessment of neurologic function after surgery. A report of any adverse events, implant failures, or need for a second surgery is also reviewed.
One of the key areas of interest in these studies is the rate of adjacent-level degeneration. There is a belief and hope that disc replacement will reduce the risk of deterioration at the spinal level above and below the new disc. Disc replacements allow for continued neck motion so that force and load transmitted through the neck are not transferred to the adjacent segment.
It is believed that this scenario is more likely after a fusion procedure (compared with a disk replacement). But proving that normal neck joint motion prevents or reduces adjacent segment degeneration remains a goal for the industry.
In the future, we can expect to see continued changes and improvements in the technology behind cervical disc replacement. Answers are still needed to the question of whether cervical disc arthroplasty have similar problems to other joint replacements (e.g., wear and debris creating an inflammatory response).
Indications and precautions for the use of cervical disc replacements are also under investigation. Currently, anyone who is a candidate for a discectomy and fusion is also likely to do well with disc replacement. Patients with bone deformities, severe spinal joint arthritic changes, or osteoporosis (brittle bones) may be excluded from having a disc replacement. A history of prior neck surgery, bone or disc infection, and cancer metastases may also prevent a patient from having a disc replacement at this time.