Outcomes associated with Medtronic’s Prestige LP artificial cervical disc are at least non-inferior to anterior cervical discectomy and fusion (ACDF) outcomes at 24 months, according to a new study published by the Journal of Neurosurgery: Spine.
Matthew F Gornet, The Orthopedic Center of St Louis, USA, and colleagues, write that ACDF has been the standard of care for more than 50 years. In recent years, anterior cervical decompression and fusion with allograft bone and anterior plate fixation has contributed to better outcomes due to improved lordosis and reduced pseudoarthrosis. As the authors note, this approach resulted in concerns over complications including adjacent-segment degeneration, screw loosening, and plate-related complications.
“In response to these concerns and a nascent body of evidence in support of lumbar total disc replacement,” write Gornet and colleagues, “cervical disc arthroplasty devices were developed and implanted beginning in the 1990s.” One of the seven Food and Drug Administration-approved cervical disc arthroplasty devices—Prestige LP—was the focus of this study.
The authors prospectively collected Prestige LP data from 20 investigational sites and compared them with data from 265 historical control ACDF patients in the initial Prestige cervical disc investigational device exemption study.
Key safety and efficacy outcomes included Neck Disability Index (NDI), neck and arm pain numerical rating scale scores, 36-Item Short Form Health Survey (SF-36) scores, work status, disc height, range of motion, adverse events, additional surgeries, and neurological status. Clinical and radiographic evaluations were completed preoperatively, intraoperatively, and at 1.5, three, six, 12 and 24 months postoperatively.
Gornet and colleagues report that there was no significant difference in blood loss (51ml in the investigational group vs 57.1ml in the control group) or hospital stay (0.98 days in the investigational group vs 0.95 days in the control group). The investigational group had a significantly longer operative time than the control group (1.49 hours vs 1.38 hours)—95% Bayesian credible interval of the difference was 0.01–0.21 hours.
Patient follow-up at 24 months was 97.1% for the investigational group and 84.0% for the control group. Follow-up revealed significant improvements in NDI, neck/arm pain, SF-36, and neurological status were achieved by 1.5 months in both groups and were sustained at 24 months. The mean NDI score improvements exceeded 30 points in both groups at 12 and 24 months. SF-36 mental component superiority was established (Bayesian probability 0.993). Mean SF-36 PCS scores improved by 14.3 points in the investigational group and by 11.9 points in the control group from baseline to 24 months postoperatively. Neurological success at 24 months was 93.5% in the investigational group and 83.5% in the control group (probability of superiority ~ 1.00).
At 24 months, 12.1% of investigational and 15.5% of control patients had an adverse event classified as device or device/surgical procedure-related, while 14 (5.0%) investigational and 21 (7.9%) control patients had a second surgery at the index level. The median return-to-work time for the investigational group was 40 days compared with 60 days for the control group (p=0.02 after adjusting for preoperative work status and propensity score).
Following implantation of the Prestige LP device, the mean angular motion was maintained at 12 months (7.9 degrees) and 24 months (7.5 degrees). At 24 months, 90% of investigational and 87.7% of control patients were satisfied with the results of surgery. Prestige LP superiority on overall success (without disc height success), a composite safety/efficacy end point, was strongly supported with 0.994 Bayesian probability.
Gornet et al conclude, “This device maintains mean postoperative segmental motion while providing the potential for biomechanical stability. Investigational patients reported significantly improved clinical outcomes compared with baseline, at least non-inferior to ACDF, up to 24 months after surgery.”
“For Prestige LP and other more recently developed prostheses, if long-term results also confirm initial outcomes trends, this will offer the potential for additional support of cervical disc arthroplasty as a substitute for ACDF in appropriately selected patients with single-level degenerative disc disease,” the authors suggest. “Meanwhile, debate continues regarding the benefits of cervical disc arthroplasty over ACDF, in particular the prospect of reduced adjacent segment degeneration and reoperation rates, as additional long-term evidence continues to be published.”