OHSU Trains Doctors On New Artificial Disc For Back Pain

05/18/05    Portland, Ore.

FDA-approved device brings relief by replacing damaged, worn spinal disc.

To a bicycling, hiking, fishing and general outdoor enthusiast like Joe Dwan of Beavercreek, Ore., slowing down is not part of life's equation.

Yet, by summer 2004, that's exactly what lower back pain had forced the 52-year-old respiratory therapist to do. "I'd been having back problems. They'd been pretty bad for about a year," said Dwan, who often felt stabbing pain shooting down one leg. "It interfered with my sleep, and it was just difficult to lift things and do things. My activity level dropped quite a bit."

But Dwan is hopeful a new treatment for severe lower back pain he received at Oregon Health & Science University in February allows him to return to the brisk activity level he once enjoyed.

The CHARITE Artificial Disc, manufactured by DePuy Spine Inc., is the first device approved by the Food and Drug Administration for replacing a damaged or worn out spinal disc. In addition to treating patients, OHSU is teaching doctors how to perform the disc-replacement operation after having been selected as a regional training site.

"It?s a radical change in concept from spinal fusion," Robert Hart, M.D., associate professor of orthopaedics and rehabilitation, said of the artificial disc. "While the results are still very preliminary, so far they have been promising."

Hart is one of three surgeons - in addition to Jung Yoo, M.D., professor and chairman of orthopaedics and rehabilitation, and Johnny Delashaw, M.D., professor of neurological surgery, and otolaryngology/head and neck surgery - who will conduct the training. OHSU, one of 50 national training sites, is the only training site in Oregon.

The disc is a three-piece device made of a medical-grade plastic sandwiched between two chromium alloy endplates. The surgery to implant the disc involves locating the spine through an incision near the belly button, removing the diseased disc and replacing it with the artificial disc. Patients are in the hospital about four days.

Candidates for the disc are individuals with degenerative lumbar disc disease who have failed at least six months of treatment with pain medication, a back brace or physical therapy. Degenerative disc disease in the lumbar spine or lower back can occur when the discs wear out or are injured, leading to abnormal function as well as pain that limits daily activities.

The CHARITE disc is considered an alternative to spine fusion, a standard treatment for back pain that uses metal rods and screws to stabilize the lower spine, stopping motion across the disc.

"One long-term problem is the discs above and below that level can wear out with time," Hart said. The CHARITE disc has been shown to be at least as effective as fusion in carefully selected patients. "The long-term benefit in terms of avoiding problems with adjacent discs will require review as our experience with the device grows."

The artificial disc isn't for everyone with back pain, Hart emphasized. For example, those with unstable spines, such as from a fracture, infection, disc deterioration or instability at more than one spine level, or poor bone quality due to osteoporosis or osteopenia should not get the device.

"It's certainly not a cure-all, but it offers a new option for some patients," he said. "It's an alternative that we hope will reduce the long-term problems associated with fusion."

Yoo said the disc is an option only for those patients who have carefully evaluated potential long-term complications - as a mechanical device, it has the potential to fail ? in addition to benefits. "It's not the only choice or the best choice for everyone. We don?t know what the best choice is. But it does give both the surgeon and the patient another option," he said.

About 190,000 Americans undergo spinal fusion surgery each year. About 85 percent of the U.S. population shows evidence of disc degeneration by age 50. Overall, disc degeneration affects about 12 million people nationwide. Hart said recent studies suggest the artificial disc will be appropriate for about 5 percent of spine fusion patients.

"That's still a large number of people, and it may well turn out to be more than 5 percent," Hart said.

Dwan, who researched the new artificial disc extensively long before it was FDA approved, is grateful to be among those who qualified for the device. While he's trying to take it easy as he recovers from the surgery, including dealing with some soreness, he no longer feels the stabbing pain in his leg.

"I have great hopes for it," Dwan said. "It takes a long time to get on your feet after these things, but it'll get better. My goal was to be as active as I can. That was always my push for this surgery."