"Implanting this device in the neck may be an effective alternative to spinal fusion," said Dr. Russ P. Nockels, associate professor and vice chair, Department of Neurological Surgery, Loyola University Chicago Stritch School of Medicine, Maywood, Ill.
Nockels, who presented the findings, is principal investigator for the Loyola site, which is a participant in a national clinical trial.
"The prosthesis simulates the function of a natural cervical disc," said Nockels.
Researchers tested the disc in the laboratory for mechanical stability under extreme forces.
"The disc is strong enough to withstand sudden movement and support the head," said Nockels, chief of the Division of Neurological Spinal Disorder and director of the Spinal Cord Injury Repair Laboratory, Loyola University Health System, Maywood, Ill. "Patients are able to move their head up and down, and from side to side."
More than half of people over age 40 have cervical disc disease, characterized by degenerative changes in the upper spine.
Symptoms include pain radiating down the arm and numbness, in addition to neck pain. As a result, many people have difficulty sleeping.
Natural discs are gel-like cushions that act as shock absorbers between each vertebra in the spine. Herniation, resulting from disc degeneration, injury or heavy lifting, can occur when a portion of the disc is pushed out of place and presses on adjacent nerve endings.
Cervical discs are located between the seven vertebrae of the neck. Discs dehydrate and shrink over time, producing areas where bone touches bone. Cervical disk disease is expected to increase substantially as baby boomers age.
"The only approved method today to help cervical disc disease patients is to clear away the troublesome bone spurs and disc material and fuse the cervical vertebrae together," said Nockels. "This permanent fusion of bone eliminates normal movement between the fused vertebrae. It also may put added stress on the vertebrae above and below the fusion."
The PRESTIGE
Loyola is one of 20 centers nationwide evaluating the device under a U.S. Food and Drug Administration protocol.
"Although anecdotal, several disc recipients in the clinical trial have been involved in serious motor vehicle accidents," said Nockels. "One was a front-end crash; another occurred 10 weeks after the disc surgery. Some patients were subject to air bag deployment.
"In spite of this, follow-up X-rays of these patients show continued normal function and no device-related problems," Nockels reported. If the new device is proven effective and approved by the FDA, it will eliminate the need for transplanted human bone, which is required with spinal fusion. It will allow motion of the neck, and may reduce the likelihood of degeneration in adjacent discs.
Co-authors of the study are Dr. Vincent C. Traynelis, University of Iowa Hospitals, Iowa City, Iowa; Dr. Regis W. Haid Jr., Emory University School of Medicine, Atlanta; Dr. Thomas A. Zdeblick, University of Wisconsin, Madison, Wisc.; and Craig M. Squires, Medtronic Sofamor Danek, Memphis, Tenn.
This study was funded by Medtronic Sofamor Danek.
The American Association of Neurological Surgeons/CNS meeting runs through March 20, 2004.
For information about participating in this clinical trial, call 708-216-0005. To schedule an appointment with Nockels, call 708-216-0005. Visit the Loyola University Health System Web site http://www.luhs.org for more information.
Loyola University Health System, a wholly owned subsidiary of Loyola University Chicago, includes Loyola University Medical Center (LUMC), 18 specialty and primary care centers in the western and southwestern suburbs, the Loyola Ambulatory Surgery Center at Oakbrook, the Loyola Imaging Center at Oakbrook Terrace, a joint venture with the Rehabilitation Institute of Chicago, and serves as co-owner-operator of RML Specialty Hospital, a long-term-care facility for ventilator-dependent patients in suburban Hinsdale, Ill. LUMC, a private, academic health care institution, is nationally recognized for its specialty care and research in such areas as cancer, cardiology and cardiovascular surgery, pediatrics, neonatology and neurosciences, burn and trauma care and organ transplantation. The 73-acre campus in Maywood, Ill., includes the 523-bed licensed Loyola Hospital with a Level I trauma center, Russo Surgical Pavilion, Cardiovascular Institute, Cardinal Bernardin Cancer Center, Ronald McDonald Children's Hospital of LUMC, Loyola University Chicago Stritch School of Medicine, the Loyola Outpatient Center, 24-bed RIC & LOYOLA acute rehabilitation unit, the region's largest burn unit and one of the Midwest's largest and most comprehensive organ transplant programs.