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Saturday, September 23, 2006But the group attached several conditions to its approval, including a requirement that Medtronic perform additional safety studies if the product goes on the market. While the F.D.A. is not required to follow the panel's recommendation, the agency is expected to approve Medtronic's application by next spring. How about doing those safety studies before it goes to market? Tuesday's panel recommendation comes nearly two years after Johnson & Johnson introduced the first artificial disk, a device for the lower, or lumbar, portion of the spine called the Charité. That disk has run into strong resistance from insurers and criticism from some surgeons who say it is an unacceptably hazardous alternative to spinal fusion. Several lawsuits have been filed this year by Charité patients whose operations failed. .....the devices are meant to last for decades in patients but virtually all of the clinical data covers much shorter time spans..... The safety data presented to the panel covered about 540 patients, but the effectiveness data was limited to 250 patients, about half of whom received the implant, which is called the Prestige ST. Another challenge for the cervical disks is that cervical fusion surgery is generally considered far more likely to be successful than lumbar fusion. So doctors and patients may see less need for an alternative. ....The advisory panel on Tuesday also recommended that Medtronic be barred from claiming that using artificial disks to preserve a patient's range of motion could protect adjacent natural disks from degeneration. Although orthopedists believe that to be true, and believe that fusion surgery can speed degeneration, the panel said that published research did not support such a conclusion. And most concerning: The panelists were also concerned that Medtronic had shown that small amounts of stainless steel particles can wear away from the device over time, but that when it tested their potential health impact in rabbits the company had been unable to track what happened to the bits of steel. "I'm a bit dumbfounded why the particles were not found anywhere," said Dr. Sanjiv H. Naidu, a surgeon and material science expert from the Pennsylvania State College of Medicine in Hershey, Pa., who was one of the 10 panel members. Similar particles caused inflammation in tissue recovered from four patients who had the device removed during the trial for various reasons. The panel recommended that the F.D.A. require additional animal studies and more research on how the device's end plates interact with the body." Medtronic is optimistic: Medtronic said after the hearing that it intended to press the agency to reach a different conclusion. Press on. posted by Sydney on 9/23/2006 09:06:00 AM 0 comments 0 Comments: |
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