UPDATE 2-US panel rejects wider use of Zimmer spine device

* FDA advisory committee votes 5-1 against approval

* Advisers say data unclear, question long-term impact

* Zimmer says will make statement later (Adds details from meeting, quotes, byline)

By Susan Heavey

GAITHERSBURG, Md., Nov 4 (Reuters) - A U.S. panel of medical experts on Wednesday recommended against wider use of a Zimmer Holdings Inc (ZMH.N) spine stabilization device, questioning the company's data but adding that the device holds promise.

The Food and Drug Administration's advisory panel, in a 5-1 vote, said the company's Dynesys Spinal System data were unclear and that some changes should have been made to its clinical trial. They also questioned how the device would hold up over time and expressed concern about possible breakage.

"I'm unconvinced," panel member Brent Blumenstein, a Washington-based clinical trial consultant, said of the product's efficacy.

Zimmer's device, a series of screws and flexible spacers that aim to help align and support the spine, is already approved for use in patients with back problems who undergo surgical fusion. The company is seeking the agency's permission to market Dynesys for stand-alone use.

The company, which also sells another similar spinal device called Silhouette, has said the Dynesys device can allow a greater range of motion for patients than other products and told the panel it was safe and effective.

FDA officials will weigh the panel's recommendation before later making a final approval decision.

Dynesys is a type of dynamic stabilization system, a type of device that aims to offer an alternative to traditional spinal fusion or disc replacement surgeries known to limit patient's ability to bend and move. The market could reach more than $1.2 billion in 2012, according to a 2007 analysis by Medtech Insight/Windhover Information.

Many other devicemakers are either marketing or studying such products, including Johnson & Johnson's (JNJ.N) Depuy unit, Synthes Inc (SYST.VX), Medtronic (MDT.N) and others.

But even Dr. Edward Hanley, the lone panel member to back the device, said the rate of breakage with Dynesys' screws was a concern. "I'm worried about these screws having to last a lifetime," he said.

Still, panel chairman Dr. John Kelly of the University of Pennsylvania said he "thought the device held some promise."

At the meeting, FDA reviewers pointed to a number of problems with Zimmer's study, including missing data and a lack of follow-up with some patients, among other issues.

In an unprecedented move, FDA reviewers earlier this week also pointed to potential bias in the company's study, noting that a majority of patients were treated by researchers with a financial interest in the company. But they added that the bias could have been due to chance.