BACK IN MOTION

The Baltimore Sun

Despite having one of the discs in her neck removed last week, Meryl Eddy hopes to soon return to her hobbies: snow skiing, water skiing and ice skating.

"I'm an active person and I want to get back to those things," said Eddy, 48, of Ellicott City, who underwent spine surgery at the University of Maryland Medical Center.

She may be in luck. Doctors replaced her unhealthy cervical disc with an artificial disc designed to relieve pain and loss of function and preserve mobility.

The artificial disc allows greater range of motion of her neck than spinal fusion surgery, a well-established procedure that involves fusing together two or more vertebrae.

Dr. Francois Aldrich, the UM Medical Center neurosurgeon who performed the operation, said recovery time is shorter than for spinal fusion. His patient went back to work Tuesday, a week after her surgery.

The new device is the first of a number of artificial cervical discs developed to expand the treatment options for degenerative disc disease, a common spine disorder.

The Food and Drug Administration approved its use last month. Competing devices are undergoing testing in clinical trials.

"In spine surgery, we're going through the same progression as joint surgeons," said Dr. Paul L. Asdourian, chief of spine surgery at Union Memorial Hospital and a surgeon who is helping conduct one of the trials. "We are entering the area of motion preservation when it comes to spinal arthritis."

Experts expect the artificial discs to be more widely adopted to treat neck problems than similar devices that were approved in 2004 for the lower back.

Some surgeons have criticized devices used in the lower back as difficult to implant and replace, preferring to stick with spinal fusion, and insurers have been reluctant to pay for them.

"They have not generally gained acceptance," Asdourian said. "The surgery is difficult and the revision can be catastrophic."

In contrast, the neck surgery is simpler and the stresses on the cervical spine more conducive to the artificial neck discs, experts said.

"I predict it will be readily accepted and more commonplace [than the lower back surgery]," Asdourian said.

The first device to be approved, called the Prestige Cervical Disc, was cleared on condition that the manufacturer conduct a seven-year follow-up study to assess its long-term safety and effectiveness. The device is made by Medtronic Sofamor Danek and costs $4,400.

The FDA panel that recommended approval expressed concern that parts of the Prestige disc rubbing together might produce harmful stainless-steel particles.

"We know that if you test a person's blood that has a metal-against-metal device, we get metal ions in the blood," Asdourian said. "No one really knows what the health effects are but there is some concern."

FDA officials made their decision based on a clinical trial of the device in 541 patients that showed it was as safe and effective as the fusion surgery, known as anterior cervical fusion.

The stainless-steel Prestige device features a "ball-and-trough" design that enables it to pivot as the spine moves, preserving flexibility. In addition, doctors also expect it to put less stress on adjacent discs than spinal fusion, making them less likely to degenerate.

Eddy was among the first 30 people in the nation and the first in Maryland to receive the device since it was approved, according to medical center officials.

Neck and back pain is usually the result of wear and tear on the flexible discs that act as shock absorbers between the vertebrae. As the discs degenerate with age or injury, they lose fluid and suppleness. They can bulge and, along with the development of bone spurs, put pressure on the spinal nerves.

Nearly everyone older than 50 has some disc degeneration, but surgery is only used in the worst cases, said Dr. Paul McAfee, chief of spine surgery at St. Joseph Medical Center, who helped develop an artificial cervical disc being tested.

Most patients receive nonsurgical treatments such as medication, physical therapy, ice and heat. They may also receive alternative therapies such as acupuncture, biofeedback or chiropractic manipulation.

But each year in the United States about 200,000 people with severe pain and arm dysfunction opt for spinal fusion surgery to support the spine and relieve pressure on the nerves, according to Medtronic.

In Eddy's case, the problem came on quickly in early June, for no apparent reason. Her thumb went numb and she found it difficult to pick up a glass of water or comb her hair.

In mid-July she started having severe pain in her right arm. "It was horrible pain," she said, "like having a toothache, but not in your mouth, in your arm."

Doctors found one of her cervical discs was bulging and pushing on her nerves. After pain medications and other nonsurgical treatments failed, she had the weakened disc replaced with the artificial Prestige disc.

She said the operation relieved her pain and returned function to her arm and hand.

"I can pick up a glass of water and comb my hair now," she said. "I couldn't do those things before the surgery."

Her surgeon cautioned that the new devices are only appropriate for certain patients, and will not replace fusion surgery completely. Those whose bones have been weakened by age or injury might not be eligible since their vertebrae may be incapable of supporting the device.

Patients with little mobility in the damaged area of the neck, he said, would not benefit from the motion-preserving design. "This is not a motion-creating device, it's a motion-saving device," Aldrich said.

He said Eddy was an ideal candidate for the surgery: a relatively young patient with strong bones whose active lifestyle might be hindered by the loss of mobility associated with spinal fusion. "For the younger patient, it's an excellent alternative," he said.

Among the other manufacturers that have developed artificial cervical discs similar to Medtronic's is Globus Medical, maker of Secure-C Cervical Artificial Disc.

Asdourian, who has been implanting the device for nearly a year in Union Memorial patients who are participating in the trial, said it has worked well so far. FDA approval might come in another 2 1/2 years, he said.

St. Joseph's McAfee helped design another version and has implanted it in more than 200 patients as part of a clinical trial. He expects the device, the Porous Coated Motion Artificial Disc, to receive FDA approval in about two years.

"We've put it in a professional English rugby player and a member of the U.S. bobsled team," McAfee said. "Every patient wants to move their neck and every doctor wants them to move their necks."

chris.emery@baltsun.com

Surgical options for upper spine

Damaged spinal discs can be repaired or replaced, depending on the patients' characteristics.

Artificial cervical disc

Neck movement similar to natural range of motion.

Few limitations on activities.

Device is approved for repair of only one disc.

May be more appropriate for younger patients with good bone density.

Spinal fusion

Appropriate for patients whose range of motion is already limited.

Multiple discs can be repaired by fusing two or more vertebrae

May be more appropriate for patients older than 60, depending on bone strength.

Recovery time is about 25 percent longer than after artificial disc implant.

[CHRIS EMERY]

A graphic in Thursday's Health Today section incorrectly illustrated the structure of the spine in the human body. The diagram reversed the curvature of the spine.The Sun regrets the error.
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