Patients who undergo artificial disc replacement surgery instead of having spinal fusion surgery – especially when several discs are involved – do better long-term and have lower hospital costs. That’s according to two studies published in The International Journal of Spine Surgery.
“Artificial disc is at least as good and in the majority of cases has superior results than fusion,” says lead author and orthopaedic surgeon Rick B. Delamarter, MD, co-medical director of the Cedars-Sinai Spine Center in Los Angeles, Calif. “The problem with fusion is you get stiffness that causes adjacent issues down the road that require further surgery. But with artificial disc, you get normal range of motion.”
Spinal fusion surgery connects, or fuses, vertebrae with bone. Artificial disc replacement, as the name indicates, replaces the damaged disc with an artificial one, which has metal endplates and a high molecular-weight polyethylene core, that is designed to mimic the real thing.
Dr. Delamarter and his team conducted two studies. One gathered data from about 300 patients at 13 centers who had one of the two types of surgery to repair a damaged disc in their neck. Patients’ flexibility and range of motion were measured before and after the procedures, and they filled out questionnaires to describe their level of disability and pain.
Four years after surgery, those who had the procedure involving an artificial disc were four times less likely to need another surgery than those who had a spinal fusion. And while all study participants reported improvement after surgery, four years after the procedures, nearly 88 percent of disc replacement patients were very or completely satisfied, while only 76 percent of fusion patients said the same. When asked if they would have the same surgery again, 89 percent of disc replacement patients said yes – compared with 81 percent of fusion patients.
A second study of 53 patients with three-level, lower back disc disease compared the cost of the two surgeries, specifically looking at the length of the hospital stay and hospital costs. Researchers analyzed patient billing records and found that disc replacement surgery cost half the price of the fusion procedure. The smaller costs were based on factors including shorter hospital stays, less medication, less therapy and less operating time.
“For arthritis patients with back and neck pain, the message is that, in properly selected patients, artificial disc seems to be a very promising option that not only can save health care dollars but appears to have a much lower re-operation rate at longer term follow-up,” Dr. Delamarter says.
Dr. Delamarter consults for a company that makes artificial discs, but says this is a randomized study reviewed and monitored by the U.S. Food and Drug Administration that doesn’t allow him or other doctors to have input on results.
Frank Cammisa Jr., MD, a spine surgeon and chief of the Spine Surgical Service at Hospital for Special Surgery in New York City, says he’s not concerned about Dr. Delamarter’s consulting connection. He also points out that data was collected at centers around the country – including Dr. Cammisa’s – and the researcher simply analyzed what was submitted.
But to really understand the effects of these surgeries long-term, he says studies need to look at patients after 10 or 15 years, not just four. And patients should be wary of blanket statements about these two types of surgeries.
“Artificial disc replacement is not a good option for everyone,” Dr. Cammisa says. “It’s based on a lot of factors. Not everyone is a candidate for this, and you want to go to a surgeon familiar with both procedures to decide what’s best. One size doesn’t fit all.”
Dr. Delamarter says the best candidates for artificial disc replacements are those with incapacitating neck and back pain from degenerative disc disease who have failed conservative care. Fusions may be best in some cases too – like when patients’ bones aren’t strong enough to handle an artificial disc, or their spine is curved in a way that one can’t be used.