Spine surgeons, who rely on devices made by companies such as Medtronic ( MDT) and Johnson & Johnson's ( JNJ) DePuy, have started attacking a high-profile study that questions the value of back surgery.

"All patients hear is that back surgery is not necessary," says Brian Subach, a prominent spine surgeon in Virginia. "This study has really done more harm than good."

With millions of Americans suffering from back-related problems, the spine industry keeps introducing new treatments that promise meaningful pain relief and lucrative financial returns. But research studies have offered mixed conclusions about the true value of back surgery, including some that show patients faring much better with surgery than with more-conservative care.

At first glance, the government's latest spine study -- a massive effort known as Sport -- seems to show little difference between those two treatment groups. That study has, in turn, sparked a unique controversy.

Industry-funded studies, tainted by perceived financial conflicts, have long been viewed as fair game for critics. But this time around, the government's own $15 million study -- while lauded as a "landmark" effort by some -- has come under heavy attack by leading spine experts.

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Even Jeffrey Goldstein, a clinical investigator for the Sport trial, has his misgivings. In particular, he worries about publicity surrounding the study.

"The headlines on the news were, 'Oh, my aching back!'" Goldstein says. "But this was not a back-pain study at all."

Rather, Goldstein notes, the Sport study evaluated patients suffering from leg pain as a result of herniated discs. Ultimately, he says, the study showed that the sickest patients fared best with back surgery.

But Charles Rosen, founding director of the Spine Center at the University of California-Irvine, goes a step further. Rosen says the sickest patients, who tend to benefit most from surgery, got excluded from the Sport study altogether. He says patients had to spend at least six weeks being treated for leg pain -- without undergoing surgery -- to participate in the trial.

Hallett Mathews, a spine surgeon who has been hired by Medtronic, makes the same point.

"If patients came in on a stretcher because their disc was so bad, they never got a chance to be randomized," Mathews says. "They were taken straight to the operating room. ... But even with those patients cherry-picked away from the study, the results for surgery were very good."

Switching Sides

Still, some experts say, those results are far from obvious.

Sport was designed as an "intent-to-treat" study. Participants were randomly assigned to receive either conservative care or surgery but, due to obvious ethical issues, could switch their treatment plans if they wished. Thus, some pain-racked patients in the conservative group wound up undergoing surgery.

Similarly, some patients who were scheduled for surgery but started feeling better never went through with operations. The so-called crossover rate was huge: Nearly half of the patients involved received a different treatment from the one that they had originally been assigned. Yet the study reported results as if the patients had never switched treatment groups at all.

Thus, many patients counted as successful conservative care recipients actually underwent surgery, and vice versa.

Sport critics want to see complete "as-treated" data instead.

Actually, they have caught a glimpse of those results already. James Weinstein, lead investigator for the Sport trial, told TheStreet.com that the as-treated results look "almost identical" to those from an observational study -- performed alongside the randomized Sport trial -- that allowed patients to choose their own treatments.

In that observational cohort, Weinstein reports in the Journal of the American Medical Association, patients who underwent surgery reported "significantly better" outcomes than those who received conservative care.

"That message was sort of lost in the editorial process," Weinstein admits. "They wanted to make sure that they did justice with the intent-to-treat" randomized study.

Losing Track

John Peloza, a Dallas spine surgeon and former consultant for Medtronic, believes that Weinstein's intent-to-treat study deserves little justice at all.

Peloza says the study suffers from another major problem, aside from the high crossover rate. Specifically, he says, the study lost track of nearly one-quarter of its patients in the two-year follow-up process.

"Between the high crossover rate and the lost follow-up, you're looking at 70% of the patients who can't even be analyzed," Peloza insists. "That's the science behind this. ... It's just rubbish."

Weinstein disagrees. For starters, Weinstein says he predicted a high crossover rate -- of about 30% -- due to the nature of the study. For another, he says that the lost follow-up rate looks higher than it actually is.

"We reported missed (office) visits," he says. "We weren't missing these patients. We had data on close to 90% of them."

By now, however, Weinstein has attracted plenty of outspoken critics. Some of his colleagues, including Subach and Peloza, now question his credentials and motives. They claim Weinstein infrequently performs surgery and instead focuses on research -- supported by government and managed-care players -- that favors cheaper alternatives instead.

For his part, Weinstein sounds bewildered by such allegations. He believes he operated on patients at the same rate as other surgeons involved in the Sport study. But he says he took care to inform patients of their choices before he did so.

"I'm a spine surgeon, too," Weinstein says. "I'm not against surgery. I know that's the perception because I question things. ... But I just want patients to know the truth."

Weinstein has served as an unpaid consultant for managed-care giant UnitedHealth ( UNH) in the past. He has since resigned from that post.

Doctor's Orders

Regardless of Sport, most experts believe patients will continue to rely on their back doctors for guidance.

Bruce Nudell, an analyst who covers medical-device makers for Bernstein Research, sees little fallout from the study. Indeed, Nudell says the study offers strong support for surgery and conservative care alike. He believes industry leader Medtronic will continue to post healthy, double-digit spine growth as a result.

He has a market-perform rating on Medtronic's stock.

"What Sport really shows is that, for patients who are less impaired, it is safe to wait" instead of rushing to surgery, Nudell explains. "And for patients who are more impaired, it is safe -- and even good -- to go to surgery.

"It's probably what happens in the real world, actually."

Rosen tends to agree. Still, he fears that payers could use the study as a weapon against reimbursement. In the meantime, he worries that the government may have just spent $15 million to simply prove the obvious.

"This doesn't clarify much," says Rosen, who is perhaps better known for criticizing industry-funded studies. "It's just documenting something that I think most people -- who are responsible spine surgeons and have integrity -- already know. ... To me, it's like a big 'so what?'"

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