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July 24, 2007

BehindTheMedspeak: Artificial Spinal Disks


Barnaby J. Feder's July 18, 2007 New York Times article about new artificial cervical spine (neck) disks from Medtronic (above and below) caught my eye, mostly because the currently approved artificial lumbar spine (low back) disks have proved to be "a disappointment."

The prosthetic disks are lauded as being superior to spinal fusion, a difficult and demanding (for both patients and surgeons) procedure.

I'm an anesthesiologist with some expertise and experience in anesthesia for spine surgery and the thing that jumps out at me as an informed observer of the closest kind is that the downside of a disaster at the level of the cervical spine dwarfs that of trouble down below in the lumbar region.

Consider worst case scenarios: loss of function from the waist vs. the neck down.

Tell you what: I wouldn't be among the iPhone-line-equivalent-patients when it comes to the first few years of placing these new cervical disks.


Here's the Times story.

    2nd Medtronic Neck Disk Wins Panel Approval

    Medtronic, which late Monday became the first medical device maker cleared to sell an artificial neck disk in the United States, may also become the first company to sell a device that would compete with it.

    An independent panel of orthopedics experts recommended late yesterday by a 7-1 vote that the Food and Drug Administration approve the second device, the Bryan cervical disk [above], a newer design. The company says the Bryan more closely resembles a natural spinal disk than the Prestige ST disk that the F.D.A. cleared for sale a day earlier.

    Both the Prestige and Bryan devices are already in use in Europe.

    Analysts said that the expert panel’s recommendation was unlikely to translate into full F.D.A. approval of the Bryan before winter, but yesterday’s vote confirmed Medtronic’s commanding head start in the race to move artificial disk technology from the lower spine, where the products have been a disappointment, into the upper spine, where many doctors think the disks have a better chance of becoming a popular alternative to spinal fusion.

    Estimates of the number of cervical, or upper spine, fusions performed annually in the United States are as high as 250,000.

    Although Wall Street expects a cautious response from insurers and surgeons to lead to slow growth initially, some analysts say the market for the cervical devices could eventually top $1 billion.

    The news yesterday was not all good for Medtronic, though. In a separate development, the F.D.A. posted on its Web site a warning letter that the agency sent the company last week detailing a range of device safety reporting and monitoring violations at the Minneapolis factory where the company makes implantable pumps to control pain.

    Among other things, the agency cited Medtronic for failing to follow up on at least 37 reports from doctors, patients or patient’s families of potential injuries like lower limb paralysis that may have been linked to problems with the pumps. The company received a separate F.D.A. warning letter about manufacturing violations at the same plant last year. Medtronic, which is based in Minneapolis, said it was working with the agency on both warnings.

    While spinal products have been an important growth area for the company, its primary focus remains cardiovascular devices like its implanted defibrillators and the drug-coated Endeavor stent, which it expects to bring to the American market within the next year.

    Artificial cervical disks like Prestige and Bryan can relieve conditions like numbness in the arms or the disabling pain sometimes associated with degeneration of the disks in the upper spine. Such relief can often be obtained by fusing the bones around the diseased disk if rest, drugs and exercise fail to help. But patients receiving the disks may recover more quickly than those who undergo fusion and often retain more flexibility in their necks.

    “We wanted to place our bets in more than one area,” said Peter L. Wehrly, president of Medtronic’s spinal and biologics group, when asked why the company had invested in two different cervical disk designs.

    The Prestige is made of stainless steel, while the Bryan consists of a dense polymer core and titanium end plates meant to more closely resemble a natural disk. The Prestige is approved for replacing only a single disk. The company said the Bryan was likely emerge as the better design for patients needing multiple disks replaced.

    Skeptics said doctors may be reluctant to steer patients away from fusion because of its high success rate and relatively good insurance coverage. Cervical disk implantation is likely to end up costing patients — or insurers — about as much as fusion surgery, which is about $32,000, according to Medtronic.

July 24, 2007 at 12:01 PM | Permalink


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I had at L-4 a wedge of crushed disc migrate and impinge - and my surgery lasted less than 30 min. I wish I could have watched.

This device doesn't look ready for prime time.... Isn't rodding the preferred repair?

Posted by: 6.02*10^23 | Jul 25, 2007 1:45:03 PM

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