New high-tech implants could replace spinal fusion surgery
James Island resident Todd Kay blamed tension headaches and his stressful job in marketing for the pain in his neck. A Bluetooth clasped to his ear, Kay describes himself as the "get 'er done guy."
The pain was unrelenting. "It was like a crick in your neck, only all the time," said the 41-year-old. "It got to the point it was hard to turn my head."
He went to neurosurgeon Dr. Stephen Rawe, who identified Kay as a candidate to receive an artificial cervical disk in a clinical trial.
Doctors have replaced hip, knee and elbow joints for years with artificial devices; now the technology is available for the neck. The Food and Drug Administration approved the first artificial cervical disk in July.
The Prestige ST, made by Memphis-based Medtronic Sofamor Danek, became available in August, and a handful of Lowcountry surgeons are scheduling the procedure.
Newer model disks are already in the pipeline. The disk Kay received at Roper Hospital is a later edition of the Prestige. Two years out from surgery, Kay said, "I can turn my head a full radius like I did when I was 16."
At Trident Medical Center, neurosurgeons Drs. Joseph Marzluff and Jason Highsmith are participating in a trial for another type of disk, the Secure C disk made by Globus Medical.
On Tuesday, Marzluff drilled, chiseled and scraped out a degenerated disk between the neck vertebrae of a 50-year-old patient. Disks connect vertebrae and work as shock absorbers for the spine.
The beginning of the surgery has remained the same for decades. The diseased disk is removed and pressure on nearby nerves is relieved.
After that, the procedure differed. Rather than performing a traditional spinal fusion — fusing bone to the vertebrae above and below where the diseased disk was — Marzluff and Highsmith replaced the old disk with a ball and trough artificial joint.
Fusion has been the gold standard for years, Rawe said. The only problem is that once that disk is taken out and fusion is performed, there is no motion at that level.
Patients rarely notice a restriction in motion after fusion, Marzluff said. But the neck does. Mobility is absorbed by disks above and below the fused vertebrae, transferring the problem to another disk.
Fusion patients have a 2.9 percent chance per year of developing problems above and below the site, Rawe said. In 10 years, that means a 30 percent risk of additional surgery.
"Fusions lead to other fusions," said Dr. Don Johnson with The Southeastern Spine Institute. Johnson has participated in trials for the Bryan disk, also by Medtronic. His patients are four years out from surgery and are doing very well, he said.
It turned out that what Kay did to relax, deep-sea fishing, may have been the culprit for the herniated disk, pounding miles out into the lively waves on a small boat.
But for many, there is no identifiable trigger. Degenerative disk disease is a natural part of aging and can begin as young as age 30. As people get older, disks shrink and lose water and can herniate out, leading to pain and loss of motion.
The artificial disk is not for every patient. Older patients or those with extensive degeneration are not good candidates, Rawe said. The bones above and below must be intact to receive the disk.
In clinical trials performed at 32 sites across the U.S. for the Prestige ST, patients reported an overall success rate of nearly 80 percent two years after surgery. Patients who received a fusion procedure reported a nearly 70 percent success rate after the same time period.
Disk recipients returned to work 16 days faster than those who underwent fusion, and disk patients also required fewer secondary surgeries.
Some insurance companies are covering the procedure, which costs between $32,000 and $34,000, about the same as a fusion. The Prestige ST costs $4,400, according to a manufacturer spokesman.