In the last half of the 20th century, patients who needed surgery for two-level cervical disease almost certainly were treated with anterior cervical discectomy and fusion (ACDF).
The procedure no doubt served those patients well, presumably reducing pain and improving or preventing neurological problems. The tradeoff for a resolution to their neck pain was decreased range of motion. To many, this was a reasonable compromise, because there were exceedingly few alternatives. In the 21st century, patients with cervical disease have an important new option, two-level artificial disc replacement, and there is much reason to believe this will become the new standard of care.
A New Success Story
ACDF is one of the great success stories of spine surgery. When fusion and healing occur, and they occur more than 90% of the time, patients are thrilled with the resulting relief of symptoms. If ACDF is a success story that has already been written, the first few chapters of artificial disc replacement’s success story have already been penned. We now know that total cervical disc replacement can relieve pain and neurological symptoms as well as ACDF. What’s more, artificial disc replacement preserves spinal range of motion in ways that spinal fusion simply cannot. Large meta-analyses including over 4,500 patients find that cervical disc replacement results in better functional outcomes, fewer adverse events, and fewer surgical revisions and reoperations than ACDF.1,2
Intermediate-term Superiority
Cervical spinal fusion produces abnormal loads and stresses on the spine. These stresses transmit along multiple levels of the spine, but they wreak the most havoc on the on the vertebrae immediately adjacent to the treated levels. Consequently, the annual rate of adjacent segment degeneration in ACDF is between 3% and 8%.3,4 Vertebral degeneration ultimately requires surgical revision surgery. Indeed, patients who had multilevel ACDF are more likely to require revision surgery, and often need more extensive revisions.5 This suggests replacement may be particularly beneficial in two-level disease.
Several recent reports have shown compelling short- and long-term outcomes in patients treated with two-level total disc replacement. Surgeons treated 225 patients with multilevel degenerative cervical disc disease with the Mobi-C™ TDR device. This group was compared to 105 matched patients who were treated with standard multi-level ACDF.6 After two years, patients in both treatment arms had markedly less pain and disability than they did before the surgery. For these symptoms, it essentially didn’t matter to which group patients were assigned, though there was some indication that the disc replacement group had better pain scores than those treated with ACDF. Importantly, patients who received disc replacement had significantly better range of motion.
Differences between the two groups clearly emerged at the four-year follow-up. Patients treated with two-level total cervical disc replacement had significantly better Neck Disability Index scores and Physical Component Summary (PCS) scores on the 12-Item Short Form Health Survey. Moreover, patients treated with disc replacement were more satisfied and had greater overall success (composite variable of several safety and efficacy endpoints) from the surgery compared to those treated with two-level ACDF.7
Long-term Superiority?
I had the pleasure to participate in a clinical trial comparing the Prestige LP™ (Medtronic) TDR device to ACDF in the treatment of two-level cervical disease. Spine surgery candidates were randomized to treatment with either two-level replacement using the Prestige LP™ device (n=209) or two-level ACDF (n=188). The primary endpoint, “overall success,” was defined as substantial reductions in measures of pain and disability without any serious adverse events or surgical failures. At 60 months after surgery, patients higher in the Prestige LP™ group had significantly better scores on the PCS component of the Short Form-36 than the fusion group. At 84 months, replacement with the Prestige LP™ device significantly outperformed ACDF in terms of overall success, neurological success, and Neck Disability Index scores. Patients who had disc replacement also had significantly fewer serious adverse events related to the implant or the surgical procedure. There were also fewer revision surgeries in the replacement arm. While ten years seems to be the standard for assessing long-term outcomes, results at seven years clearly show two-level replacement to be superior to two-level ACDF safety, efficacy, range of motion, and revision surgery. As such, it is time to consider total cervical disc replacement as an attractive alternative to ACDF for two-level cervical disc disease.
A Diplomate of the American Board of Neurological Surgery and a Fellow of the American College of Surgeons, Dr. Todd H. Lanman leads his spinal neurosurgery practice, Lanman Spinal Neurosurgery in the heart of Beverly Hills, which is affiliated with Cedars-Sinai Medical Center, UCLA Medical Center and Saint John's Medical Center.
Dr. Lanman earned his MD at Chicago's Northwestern University in 1983 with top honors and went on to complete his residency in Neurological Surgery at University of California at Los Angeles, under the aegis of Doctors W. Eugene Stern and Donald Becker in 1989. Since then, Dr. Lanman has led his spinal neurosurgery practice in the heart of Beverly Hills, which is affiliated with Cedars-Sinai Medical Center, UCLA Medical Center and Saint John's Medical Center.
As a leading innovator in medicine, as well as a media educator and contributor, Dr. Lanman has published more than 10 peer-reviewed articles, as well as book chapters on topics relating to neurological surgery, and has presented more than two dozen papers at national and regional medical society meetings. His expertise is often sought out as he is often tapped to be the principal medical investigator on a wide swath of clinical trials for motion preserving surgeries and artificial disc replacement devices, most recently the Prestige LP and M6, with the former recently receiving FDA pre-market approval on July 6, 2016, through his continuous support. He has also remained an assistant clinical professor at UCLA for the past 20 years. For more information on Dr. Lanman and Lanman Spinal Neurosurgery, visit the official website: http://www.spine.md
References
1. Zhang Y, Liang C, Tao Y, et al. Cervical Total Disc Replacement is Superior to Anterior Cervical Decompression and Fusion: A Meta-Analysis of Prospective Randomized Controlled Trials. PLoS ONE. 2015;10(3):e0117826.
2. Hu Y, Lv G, Ren S, et al. Mid- to Long-Term Outcomes of Cervical Disc Arthroplasty versus Anterior Cervical Discectomy and Fusion for Treatment of Symptomatic Cervical Disc Disease: A Systematic Review and Meta-Analysis of Eight Prospective Randomized Controlled Trials. PLoS ONE. 2016;11(2):e0149312.
3. Yue WM, Brodner W, Highland TR. Long-term results after anterior cervical discectomy and fusion with allograft and plating: a 5- to 11-year radiologic and clinical follow-up study. Spine (Phila Pa 1976). Oct 1 2005;30(19):2138-2144.
4. Hilibrand AS, Carlson GD, Palumbo MA, et al. Radiculopathy and myelopathy at segments adjacent to the site of a previous anterior cervical arthrodesis. J Bone Joint Surg Am. Apr 1999;81(4):519-528.
5. Veeravagu A, Cole T, Jiang B, et al. Revision rates and complication incidence in single- and multilevel anterior cervical discectomy and fusion procedures: an administrative database study. Spine J. Jul 1 2014;14(7):1125-1131.
6. Davis RJ, Kim KD, Hisey MS, et al. Cervical total disc replacement with the Mobi-C cervical artificial disc compared with anterior discectomy and fusion for treatment of 2-level symptomatic degenerative disc disease: a prospective, randomized, controlled multicenter clinical trial: clinical article. J Neurosurg Spine. Nov 2013;19(5):532-545.
7. Davis RJ, Nunley PD, Kim KD, et al. Two-level total disc replacement with Mobi-C cervical artificial disc versus anterior discectomy and fusion: a prospective, randomized, controlled multicenter clinical trial with 4-year follow-up results. J Neurosurg Spine. Jan 2015;22(1):15-25.
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