One of the most innovative technologies in spine surgery within the past 20 years has been the ability to replace a damaged cervical or lumbar disc with an artificial joint instead of a fusion.
Because cervical and lumbar disc replacements were considered “novel technologies” by the FDA, multicenter randomized studies were required for approval of each new device before commercialization. These studies were performed under rigorous governmental oversight.
The first lumbar disc replacement studies in the US began in 2000, and cervical disc replacement studies started in 2002. Interested patients had to meet strict inclusion and exclusion criteria before they could enter the trials. The patients were then randomly assigned to receive either a fusion or an artificial disc, and their progress was followed for 5 – 10 years. Today several lumbar and cervical devices have completed this process and have been approved by the FDA. Most are still commercially available in the US.
These studies provided vital data on the clinical outcomes and performance of these arthroplasty devices, as well as for the outcomes of fusion procedures. Although there was some initial fear that surgical indications would be unsafely expanded by introduction of disc replacement devices, there has been no data suggesting that this has occurred. It is unfortunate that some patients are still told they must have a fusion because their spine surgeons are not trained in disc replacement. Those patients should have a second opinion by a surgeon who does both fusion and non-fusion procedures and who can discuss the advantages and disadvantages of both options so the patient can make an informed decision
Patients receiving a cervical or lumbar disc replacement have a statistically significant reduction in the risk of reoperation, less pain, and a higher likelihood of patient satisfaction 5 years after surgery than do patients post-fusion. One of the most exciting findings from these studies is that X-ray evidence of adjacent level degeneration 5 years after surgery is significantly lower in arthroplasty patients than in fusion patients, with the decrease being proportional to the range of motion achieved at the operated segment. In other words, better motion leads to significantly less adjacent level degenerative changes in both cervical and lumbar ADR study patients, and then to lower reoperation rates than we see after fusions.
Insurance coverage for cervical arthroplasty is now excellent for most patients, with over 95% of insured Americans covered for one- or two-level cervical disc replacement. Disappointingly, only about 60% of commercially insured patients may be covered for lumbar ADR if they meet criteria through their insurance company’s medical policy.
Disc replacement provides an ideal model for bundled payments. Experienced surgeons with ownership and policy influence at a short-stay hospital can manage the professional component, implant costs, and the hospital component. Bundles can be customized for all stakeholders and give patients otherwise interested in medical tourism a financially competitive option to travel abroad for their care. It is obviously better to have your surgeons accessible for the rare postoperative issues that need attention.
Several published health economic studies show that direct costs of disc replacement per segment are less than fusion, and indirect costs (factoring in faster recovery, earlier return to work, and lower reoperation rates) make it significantly more cost-effective than fusion.
With experience in the US now going back nearly 20 years, and global use of disc replacement devices numbering in the hundreds of thousands, this technology can no longer be considered experimental. For the appropriately selected patient, cervical or lumbar disc replacement can provide a life-changing, motion preserving alternative to fusion or to continuing with pain, functional impairment, or narcotic dependency.
Patients need to know that disc replacement is not for everyone, but may be an option for them, especially if they’ve been told they need a fusion.
Dr. Jack Zigler is an Orthopedic Spine Surgeon at Texas Back Institute, Co-Director of the Center for Disc Replacement. He is currently the President of the International Society for the Advancement of Spine Surgery (ISASS), Past President of the American Spinal Injury Association (ASIA), and has served on the Board of the Cervical Spine Research Society (CSRS).