Adjacent Level Disease: Can Cervical Arthroplasty Decrease the Risk?
Spine Summit 2016 Meeting Highlight: ACDF has become the most rigorously studied spinal procedure
At 7 years, patients treated with a single-level anterior cervical discectomy and fusion have three times the risk of needing surgery for adjacent segment disease compared to patients treated with total disc replacement, Vincent Traynelis, MD, said at Spine Summit 2016.
Anterior cervical discectomy and fusion (ACDF) has become the most rigorously studied spinal procedure, with the associated risk for adjacent segment disease being widely recognized, explained Dr. Traynelis who is a neurosurgeon at Rush University Medical Center in Chicago, IL.
As shown in the classic article by Hilibrand et al,1 the risk for symptomatic adjacent segment disease with multilevel fusion is 12%, and with single-level fusion is 18%. This concern for adjacent segment degeneration has lead to the development of motion-preserving technologies, including total disc replacement.
A number of devices are available for cervical arthroplasty, all of which have shown similar 2-year outcomes data, Dr. Traynelis said. These devices include Bryan, Mobi-C, PCM, Prestige ST, ProDisc C, and Secure-C.
Three meta-analyses comparing the effects of cervical disc replacement versus ACDF, showed no significant difference in development rate for adjacent segment disease.2-4 However, these meta-analysis predated two 7-year randomized controlled studies comparing cervical disc replacement versus ACDF that warrant consideration, Dr. Traynelis said.5,6
Lower Risk for Adjacent Level Degeneration With Arthroplasty Found in Long-Term Studies
In the first of these longitudinal studies, Burkus et al did not find a difference in adjacent segment disease between patients randomized to the Prestige disc (n=276) versus ACDF (n=265) at 5 years; however, at 7 years, nearly twice as many patients in the ACDF group required a second surgery at adjacent levels compared with patients in the Prestige group (11.9% vs 4.6%; P=0.008), Dr. Traynelis said.5
The difference between these two procedures began to emerge at approximately 60 months, with patients in the Prestige group losing a degree of motion and patients in the ACDF group showing adjacent segment degeneration. “I think that 60 months following surgery is when the natural process of aging begins to take its toll. In the arthroplasty patients, perhaps the facets are stiffer, and in the arthrodesis patients there is an increased risk for adjacent segment disease,” Dr. Traynelis said.
In the second longitudinal study, Janssen et al also found a higher rate of adjacent level surgery at 7 years in patients randomized to ACDF (20.8%) that in patients who underwent ProDisc C total disc replacement (5.8%).6 In addition, Dr. Traynelis cited a 10-year follow-up study by Zhao et al, in which no cases of recurrent radiculopathy or myelopathy due to adjacent segment disease were found among 33 patients who received the Bryan cervical disc.7
Pooled data from these 3 studies with ≥7 years of follow-up show rates of adjacent disc disease of 4.1% in patients who received arthroplasty (n=412) and 12.4% in patients who received arthrodesis (n=371). “These numbers compare very favorably to Hilibrand’s numbers,” Dr. Traynelis said.
“In conclusion, the 7-year risk of developing adjacent segment disease that requires surgery is three times greater in the arthrodesis patient as compared to arthroplasty for single-level disease,” Dr. Traynelis said.