Spinal News International spoke to Kenneth A Pettine, orthopaedic surgeon at The Spine Institute, Loveland, Colorado, USA. A firm believer in non-fusion surgical options, he spoke on the new crop of artificial discs and general challenges for arthroplasty. Pettine is a co-inventor of the Maverick artificial disc.
You have taken part in several comparison trials with artificial discs. Do you have any thoughts on which discs are the best?
The M6 (Spinal Kinetics) appears to be doing well because it has compressibility and resistance to rotation. All the other discs, other than the NeoDisc, are a ball and socket type design and do not have resistance to rotation. I do believe this is non-physiologic and potentially could result in facet problems in the future.
Are there any interesting early results with the M6?
My understanding is that it has been implanted about 4,000 times in Europe or outside the United States. I have not seen any written data on that but in talking to surgeons who have experience with that disc, the results seem to be very good.
Could you give us some perspective on artificial discs in general. How did it all begin and where we are now?
Artificial discs began in the 1990s with the Charité and ProDisc out of Germany and France, and those discs have undergone some minor modifications and then eventually underwent FDA IDE studies and are currently FDA approved in the United States. I think the Maverick Disc will obtain FDA approval, it has been used extensively outside the United States.
Cervical discs are more recent but the results of all the Class 1 data with these implants both in the lumbar and cervical spine would indicate statistical superiority over fusion in terms of FDA clinical success. Each specific disc has obtained statistically significant superiority in areas such as improved neurologic function at two year follow-up.
We are not seeing catastrophic failures even with more than 10 year follow-up from the European patients so I think this technology with longer follow-up continues to look extremely promising.
Arthroplasty is a relatively new field, do you think it is gaining acceptance in the spinal community?
Yes I do. I think as longer-term follow-up continues to show clinical statistical superiority compared to fusion, insurance authorisation improves and the gap in surgeon reimbursement between fusion and disc replacement equalise the utilisation of artificial discs will continue to increase.
As an inventor yourself, what are the challenges that current artificial discs have yet to meet?
The biggest challenge for all current artificial discs in the United States is FDA approval. The FDA has become increasingly onerous over the last two years. There are regulatory hurdles that are continuing be difficult in the United States.
I think the future for this technology is extremely bright because of improved insurance authorisations and surgeon reimbursement for fusion is continuing to decrease. The difference in surgeon reimbursement between performing artificial discs and fusion is going to equalise itself over the next few years which I think is going to result in a marked increase in the use of artificial discs over fusion.
