Though both the following precedures - artificial disc replacement and, spinal fusion surgery - are popular with patients whose discs in the neck are damaged, American spine surgeons seem to prefer the former over the latter.
Experts at Washington University School of Medicine in St. Louis and other U.S. centres found that patients who received an artificial disc lost less motion in the neck and recovered faster than those who had a disc removed and the bones of the spine fused.
"Those who received the artificial disc either did equally as well or a little bit better than those who had fusion surgery. One of the most important findings was that people who got the artificial disc were able to preserve all of their motion," says Dr. K. Daniel Riew, a cervical spine surgeon at Washington University Orthopedics and Barnes-Jewish Hospital.
A disc in the spine is similar to a jelly donut, with a squishy centre surrounded by a tough outer portion. It functions like a shock absorber between the vertebrae.
When a disc ruptures, or becomes herniated, the squishy disc tissue can spread into the spinal canal and press against nerves, causing numbness, weakness or pain.
During the study, the patients were randomly assigned to receive either the BRYAN Cervical Disc or standard fusion surgery.
The researchers revealed that 242 received the artificial disc, and 221 had spinal fusion.
Using a tool called the neck disability index (NDI), the researchers measured improvement following surgery.
Two years after the surgery, patients in both groups had improved NDI scores, had less neck and arm pain, and were less likely to experience numbness.
Overall, the surgery was rated as successful in 83 percent of the patients who received artificial discs, and 73 percent of those who had fusion surgery.
Riew says that the difference could be attributed to a better motion in the neck for those who had artificial discs implanted.
He says the neck is always slightly restricted following spinal fusion surgery.
Since bones in the neck have been fused together, it is impossible to regain full range of motion. However, the defect is subtle.
"Fusion adds a small amount of stress in the spine above and below the fusion site, so bone can break down a little faster than normal. If the patient is a young person, then they may need another operation in 20 or 30 years. The hope with artificial cervical disc replacement is the preserved motion may protect against additional stress at other levels of the spine," Riew says.
In the short term, according to the researcher, most patients receiving artificial disc replacement surgery recovered faster and got back to normal life sooner than fusion surgery patients.
"They didn't need to wear a neck brace after surgery. If they had a job, they returned to work faster. And many had a resolution of their pain faster than fusion patients. With a spinal fusion, there are some pain and activity restrictions until the bone is fully incorporated, but with an artificial disc, as soon as the disc is in, it's 'good to go'," he says
A report on this study has been published in the journal Spine.