CHICAGO (AP) -- Agonizing over sharp pain in his back, a man lies down on a metallic table illuminated by a rich blue light. Moments later he receives a small dose of a clear liquid that kick-starts his cells to rapidly build new bone, beginning the healing process. Above him, masked men nod and smile at one another.

Coming soon to a theater near you? Perhaps.

Coming soon to a surgeon's office near you? Probably.

Medtronic Inc. has spent the last several years developing such a unique and complex material, which it calls a "bone morphogenetic" protein.

Though the Minneapolis company sees many eventual uses for the protein, the first will be in spinal fusion surgery, a common corrective procedure that cements together two or more vertebrae to help patients combat extreme back pain.

Some say the company's product, dubbed InFuse, could replace the widely used and proven surgical technique that uses shavings and chips of hip bone as the cement.

In a series of tests, Medtronic said InFuse demonstrated better overall fusion, less time in the operating room and - more importantly - fewer complications for patients.

"We think this product holds great promise," said Dr. Robert K. Erickson, a surgeon at University of Chicago Hospitals who performs more than 100 spinal fusion surgeries every year.

Back pain caused by disc degeneration and pressure on nerves near the spine affects some 65 million Americans. Common early treatment options include stretching exercises, pain medications or steroid injections into back muscles. If these treatments fail, spinal fusion surgery becomes an option for a small group of patients.

In spinal fusion, vertebrae are essentially welded together into one piece using an assortment of hardware and bits of bone. The welding eliminates friction between the vertebrae and, in turn, excessive pressure on nerve endings.

About 250,000 spinal fusion surgeries are performed every year, mostly on adults between the ages of 45 to 64, according to the American Academy of Orthopaedic Surgeons, of Rosemont, Ill. Patients must spend several months in a brace during recovery, but most can resume activities such as golfing or running.

Though using bone from the hip is considered the "gold standard" of spinal fusion, it has drawbacks.

For one, hip grafting requires a separate incision to get at the bone. For another, about 30 percent of patients have significant pain and tenderness in the hip during recovery - troubles that can go on for years and in some cases outlast the back pain the procedure intended to correct.

"You don't want to create another surgical insult to the patient to make the problem get better," said Michael DeMane, president of Medtronic's spine business. InFuse eliminates the need for the second surgery.

The protein, which exists in bones in very small quantities, can be biologically mass produced and concentrated into a fine white power.

Surgeons in the operating room mix the powder with saline water and use a hypodermic needle to infuse it into a collagen sponge about the size of a thumbnail. The sponge is then inserted into a slightly larger cage - a threaded metal device with open ends - and placed between the bones.

Cells that encounter the protein are prompted to start a process called osteoinduction, or bone creation. After a healing period of several months, bone slowly grows through the collagen sponge and around parts of the cage, fusing the vertebrae together.

"This is a huge, huge thing as far as we're concerned," said surgeon Dr. Brian R. Subach of Emory University in Atlanta, one of 16 InFuse investigational sites. He performs about 300 spinal fusions a year.

There are a number of serious concerns about InFuse. Surgeons worry that InFuse may dramatically speed the growth of cancerous cells or cause noncancerous cells to become more sinister.

Dr. Eric J. Woodard, director of spinal surgery at Brigham and Women's Hospital in Boston, said further use and testing is needed to be absolutely sure there are no risks.

If InFuse gets final FDA approval and a cancer connection is made, "only one case is going to kill the product," he said.

Another concern is unwanted bone creation. There is a chance that InFuse-generated bone could form over the delicate nerve endings in the spine or, worse, somewhere else in the body. The protein also might have toxic effects in the bloodstream, some surgeons fear.

Medtronic's DeMane said that investigations by dozens of outside researchers have failed to draw any link between InFuse and cancer. In fact, the product has been found to have some anticancer characteristics.

There have been no incidences of improper or accidental osteoinduction, DeMane said, and in animal studies the protein was filtered out of the bloodstream using the body's normal processes.

Copyright 2002 The Associated Press. All rights reserved.