A recent development in back care was hailed as a dramatic breakthrough. In a study of nearly 240 patients with lower back pain, the doctors performing the study concluded that the Prodisc, an artificial spinal disk, had worked much better than conventional surgery in which patients’ vertebrae were fused.
“As a surgeon, it is gratifying to see patients recover function more quickly than after fusion and return to their normal activities more easily,” Dr. Jack E. Zigler, a well-known spine specialist and one of the study’s lead researchers, said in a 2006 news release announcing the latest results of the Prodisc clinical trial.

Dr. Zigler had more than his patients’ interest at heart when he spoke of being “gratified.” Dr. Zigler, a spine surgeon at the Texas Back Institute, was the first doctor in the United States to perform the Prodisc disk surgery in October 2001. Texas Back, considered one of the nation’s leading spinal medicine practices, has been among the most aggressive in advocating new devices like artificial disks. Yet confidential documents show that Dr. Zigler invested at least $25,000 in early 2002 in a fund created to finance Spine Solutions. So did doctors at about half of the 17 research centers involved in the study. They stood to profit financially if the Prodisc succeeded, according to confidential information from a patient’s lawsuit settled last year.
In early 2005, when Synthes submitted the Prodisc study to the F.D.A. as part of the company’s application for approval, it used results for 162 patients who had received the device and 80 who had spinal fusion surgery. The results did not include 50 Prodisc patients who were considered “training cases” — surgeries performed to let doctors learn how to implant the devices. Such training is fairly common in device trials. An additional 21 patients, about 10 percent of those studied, were also excluded from the reported results. An unusually large number of patients were not included, and some of those patients have said they fared poorly.
The F.D.A.’s rules allow clinical investigators to have financial ties with the maker of the device or drug they are studying — on the condition that such relationships are fully disclosed. Lawyers who have worked with the F.D.A. say that when it becomes aware of potential conflict, it tends to subject research to a higher level of scrutiny.
The F.D.A. now says it is checking to see whether there was adequate financial disclosure information about the Prodisc researchers during the clinical trial and at the time that the subsequent application for approval was submitted.
The way the Prodisc was tested and approved clearly demonstrates the conflicts of interest among many clinical researchers — conflicts that are seldom evident to doctors and patients trying to weigh the value of a new device or drug. Instead of serving as objective researchers who can identify potentially harmful or ineffective new devices or drugs, clinical researchers with conflicts may stand to profit by overstating the success of testing. Doctors in this country frequently have financial ties to the companies whose devices or drugs they recommend to patients.
Even though fusion surgery continues to be the treatment of choice, there is substantial debate over how many patients actually benefit from it. Now, artificial disks are drawing reconsideration. Thousands of patients worldwide have received the Prodisc, which sells for about $10,000 in the United States. But Medicare and several commercial insurers generally refuse to pay for the surgeries, which can cost tens of thousands of dollars.
And many of the Prodisc investor-researchers are now focusing their attention on newer spinal devices — often for companies with whom they also have financial ties. Dr. Zigler, for example, is a researcher for a new spine-stabilizing device made by Applied Spine Technologies, where he serves as a paid member of the company’s scientific advisory board.
But while doctors may easily move on to the next new treatment, many patients are still struggling with the aftermath of Prodisc procedures.

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