Todd Lanman, MD, is founder of Lanman Spinal Neurosurgery in Beverly Hills, Calif.
Dr. Lanman is a big advocate for cervical artificial disc replacement and published a paper in the Journal of Neurosurgery in October, comparing the efficacy of the procedure at two adjacent levels to the use of anterior cervical discectomy and fusion.
The 10-year follow-up paper found that discs next to the point of fusion required surgery twice as often as discs adjacent to artificial discs.
Here, Dr. Lanman shares his insight on the development of cervical artificial disc replacement, why it's more popular on the west coast and how he sees it rising above spinal fusions in the future.
Q: Artificial cervical disc replacement has come a long way since it was approved in 2007. How do you see it developing in the next five to 10 years?
TL: I believe the whole industry will be changing in the next five to 10 years, with surgeons moving away from fusions and toward artificial discs. You're seeing more artificial discs on the market and new FDA trials being done on new discs, so I think there will be an incredibly large variety of artificial discs to choose from. I believe fusion will be considered archaic, particularly cervical, because the data is so clear that ADR is superior to fusion in almost every outcome measure. Over a 10-year follow-up period re-surgical rates are half as much, so you're going to see new artificial discs created with even better designs and functionality, and surgeons are going to more rapidly move toward artificial discs. Many surgeons, particularly on the east coast, still fuse a lot of patients. I think more disc replacements are done on the west coast with people living more active lifestyles in a better climate.
Q: For patients with a cervical herniated disc, what are the scenarios where you would opt for a spinal fusion over an artificial disc replacement?
TL: In the beginning we were pretty limited to younger patients who had a pure herniated disc with mild degeneration with neck and arm pain, who had otherwise intact and healthy facet joints and spine. Since we received approval in 2007, we've continued pushing the limits and expanded the indications. We're operating on patients who are older with severely degenerative discs, more bone spurs and being more aggressive on reconstructing the natural angular curvature of the neck as discs degenerate. We think of corrective surgery as correcting sagittal balance and we would always consider fusions to correct those, but we've also had success with artificial discs.
Instead of defaulting to fusion for a kyphotic neck or cervical sagittal plain alignment issue, if they are moderate to mild you can go to artificial disc replacements to correct many of those issues. Even in the face of moderate to severe facet joint disease, we're using artificial discs with great results by replacing the severely degenerated discs, decreasing stress on the arthritic joints and relieving neck pain while preserving motion. In the last several years we've gotten more aggressive in using disc replacements, even in the arthritic and more degenerative spine, whereas we were more limited in the beginning to a healthier spine with just a pure herniated disc.
Q: What about cervical disc replacement in revision surgery?
TL: Cervical artificial disc replacement will also become a revision strategy. I just published an article that will soon be published in The International Journal of Spine Surgery on patients with fusions that did not take and resulted in non-unions. I had one patient — a competitive wrestler aged 24 — who had a fusion, because that was all that was offered to him. He had a non-union and pain continued as the bone never healed. He came here to Beverly Hills and wanted an artificial disc. I took the plate off, drilled out the fusion and implanted an artificial disc. He regained motion, pain was relieved, and he sent me his gold medal six months later after winning a competition.
Q: What devices are on the forefront of cervical artificial disc replacement? What devices do you use in your practice?
TL: I use the Prestige LP, M6 and Prodisc-C. I also like several others that have demonstrated good data. I select different discs depending on different anatomic issues that a patient has. I don't have just one I use for everybody. If there's certain cervical parameters of the anatomy such as T1 slope angles, I may choose one disc over another. Age, patient activity and goals all dictate which device I'll use. Sometimes I'll mix and match with one disc at one level and a different type at another level, depending on the anatomy and biomechanical function.
Q: Why do you think that certain payers are holding back from covering artificial disc replacement?
TL: In California, almost all payers will approve a disc now at one or two levels, because the data is so solid it's hard for them to call it experimental anymore. I think the thing that really beat up the artificial disc market was the first lumbar artificial disc, Charité, which had some issues and received negative press. I think patients have been reluctant to try artificial discs after that, but the cervical data has always shown overwhelming success — not only showing equivalency, but superiority over fusion. I think there's more reluctance on the east coast with some payers to authorize it. I see some spine surgeons who default to fusion because it's easier to do. You don't have to place a fusion dead center or get the center rotation lined up. It's easier and you still get a great result, but I don't want my patients coming back in 10 years to have another surgery.
Q: Do you see artificial disc replacement evolving in the thoracic and lumbar spaces in the future?
TL: I think the lumbar space will definitely expand. We have two [lumbar discs] that we use now — the Prodisc and activL — but there's no real reason for thoracic because the ribs stabilize the spine and we have very little motion in that area. I do think lumbar will gain ground. The thing that stops companies in investing in lumbar trials is the cost involved. To run an FDA IDE trial, it's about $40 million or $50 million. You have to be a major corporation to afford to do that and even then, you always have the risk of not gaining approval. The FDA is tough, and it can be cost prohibitive. I believe it slows down our speed of development and that's why you see a lot of these newer discs being released in Europe, South Africa and Australia, because they don't have as big hurdles to jump through.