UPDATE 2-US FDA panel backs new use for Covidien sealant

* Advisers recommend Duraseal for spinal surgery 4-0

* Panelists call for further study after approval (Adds comments, reaction, background on product)

GAITHERSBURG, Md., May 14 (Reuters) - A U.S. Food and Drug Administration advisory panel recommended expanding approval of Covidien Ltd's (COV.N) Duraseal sealant for use in spinal surgeries as long as the company gathers more data.

The panel of outside experts voted 4-0 in favor of the product, which is already FDA-approved for use in cranial surgeries. The agency will weigh the panel's recommendation in making its final decision.

Covidien is seeking FDA approval to more widely market Duraseal, a synthetic polymer that is sprayed onto the surgical site to provide a watertight seal, for use in addition to traditional sutures.

Properly closing incisions in brain and spinal surgeries prevents cerebral spinal fluid from leaking, which can cause complications such as infection.

But surgical sutures alone can leave small gaps. Currently, surgeons use additional stitches, soft tissue patches or unapproved glues to try to further prevent leaks.

"There are currently no approved products for this indication," said Xavier Lefebvre, clinical vice president for Covidien's device unit, formerly Confluent Surgical Inc.

Panelists expressed some concern about the product, saying there was no clear difference in fluid leakage 90 days after surgery, even though the data showed Duraseal worked better than alternative methods during surgery itself.