Neck and low back pain accounts for between $50 billion and $75 billion in direct and indirect costs each year in the United States, and more than 1 million surgeries are performed to address these issues annually. Back pain is particularly problematic, as it’s the fifth leading cause of hospital admission and third most common reason for surgery. Among the working population, 90% will have an incident of low back or neck pain during their career. Although the vast majority of these cases will heal within 3 to 6 weeks with conservative physical therapy and medications, a small percentage of patients will often turn to surgery as a last resort.
The gold standard over the past 30 years for degenerative discs or damage to spinal discs has been to fuse that level of the spine with bone using plates and screws. Fusion surgeries, however, can cause stiffness and may take 6 to 12 months to solidify. These surgeries may also increase stress on adjacent spinal levels, leading to degeneration. These discs adjacent to a fusion may become diseased at higher rates than discs not adjacent to a fusion.
Preserving Motion with Artificial Disc Replacement
About a decade ago, several level 1 FDA trials began exploring motion-preservation treatments, primarily artificial disc replacement. This procedure cleans out a bad disc and replaces it with an artificial device that allows normal range of motion. The half dozen completed trials comparing treatments have shown that the outcomes of artificial disc replacement appear to be superior, or at least equivalent, to fusion surgery.
“The outcomes of artificial disc replacement appear to be superior, or at least equivalent, to fusion surgery.”
In the December 2010 SAS Journal, my colleagues and I published results using data from two of these studies. Both compared fusion to disc replacement surgery for patients with degenerative disc disease. The first compared costs, use of resources, and length of hospital stay for 53 patients receiving either 3-level artificial disc replacement or 3-level fusion for low back spinal damage. Our analysis showed that artificial disc replacement was about 50% less expensive than fusion surgery.
The second study compared patient satisfaction and outcomes in 209 patients suffering from cervical disc disease who were randomized to an artificial disc or fusion surgery and followed for at least 4 years. An additional 136 patients received an artificial disc and were followed for at least 2 years. Regardless of surgery type, all patients experienced improvements in neurological and physical health, neck disability, and neck and arm pain intensity. In fact, 89% of disc replacement patients and 81% of fusion patients said they would undergo the same surgery again. Results tended to be at least somewhat better for those who underwent disc replacement. Range of motion was normal for those in the disc replacement group, whereas the fusion surgery patients experienced stiffness. At 4 years, patients in the artificial disc group were four times less likely to undergo a revision surgery than those in the fusion group.
Candidates for Artificial Disc Replacement
Artificial disc replacement may not be the optimal surgical option for all patients. Fusion surgery is clearly indicated for instability with spondylolisthesis, fractures, and scoliotic deformity. That said, patients with degenerative discs or failed discectomy syndrome appear to be ideal candidates for artificial disc replacement technology. The evidence is clearly mounting that this procedure is a good alternative to fusion surgery, especially in well-selected patient groups. Artificial disc replacement should be considered a potential surgical intervention should patients fail with conservative treatment.
Delamarter RB, Murrey D, Janssen ME, et al. Results at 24 months from the prospective, randomized, multicenter Investigational Device Exemption trial of ProDisc-C versus anterior cervical discectomy and fusion with 4-year follow-up and continued access patients. SAS Journal. 2010;4:122-128. Available at:www.journals.elsevierhealth.com/periodicals/esas/article/S1935-9810(10)00076-9/abstract.
Buttacavoli FA, Delamarter RB, Kanim LE. Cost comparison of patients with 3-level artificial total lumbar disc replacements versus 360° fusion at 3 contiguous lumbar vertebral levels: an analysis of compassionate use at 1 site of the US investigational device exemption clinical trial. SAS Journal. 2010;4:107-114. Available at: www.journals.elsevierhealth.com/periodicals/esas/article/S1935-9810(10)00049-6/abstract.
Rajaee SS, Bae HW, Kanim LE, Delamarter RB. Spinal Fusion in the United States: Analysis of Trends from 1998 to 2008. Spine . 2011 Feb 9. [Epub ahead of print].
Delamarter RB, Bae HW, Pradhan BB. Clinical results of ProDisc-II lumbar total disc replacement: report from the United States clinical trial. Orthop Clin North Am. 2005;36:301-313.