Back in motion

Artificial device placed in neck is designed to ease patient's pain and increase mobility

By Chris Emery | Sun reporter

August 16, 2007

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.