Higher overall success rate found with artifical cervical disc vs. fusion
The cervical disc replacement patients returned to work almost 13 days earlier than the controls.
AUSTIN, Texas The results of a new Level 1 study indicate the safety and efficacy of an artifical cervical disc for patients with symptomatic single-level disc herniation.
In a randomized prospective trial, John G. Heller, MD, and colleagues compared the outcomes of 463 patients with symptomatic single-level disc herniations who were treated with either anterior cervical discectomy and fusion (ACDF) or cervical disc replacement using the Bryan device (Medtronic Sofamor Danek).
Using FDA criteria, the investigators discovered an overall success rate of 82.7% for the Bryan-treated group at 2 years postoperatively compared to 72.6% for the ACDF cohort. They also found that significantly more patients in the Bryan group had at least a 15-point improvement in neck disability index (NDI) scores and returned to work earlier than the ACDF group.
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Superior performance
[The] Bryan device appears safe and effective for the treatment of symptomatic, single-level cervical disc disease at minimum 2-year follow-up, Heller said during his presentation at the North American Spine Society 22nd Annual Meeting. Other observations we note include: the consistent, reliable performance of the control group; the fact that the Bryan shows statistically superior performance with regard to NDI success and overall success; and finally, that the device maintains an average range of motion of 7.5° at 2 years and [provides] approximately 2 weeks earlier return to work.
The multicenter study included patients with radiculopathy or myelopathy caused by disc herniations between C3 and C7 and were unresponsive to 6 weeks of conservative treatment. The ACDF group consisted of 221 patients and 242 patients were in the Bryan group.
The investigators found no significant differences between the groups regarding patient demographics. Intraoperatively, the Bryan group had longer OR times and statistically more blood loss than the ACDF cohort, Heller said.
Better neck pain scores
The 2-year follow-up revealed a 94.4% fusion rate for the ACDF group. Comparatively, the investigators found no significant differences between the ACDF and Bryan groups in arm pain scores of the Visual Analog Scale. However, they discovered statistically better neck pain scores for the Bryan group at all follow-up intervals.
NDI scores showed statistically superior performance in the experimental group compared to control at each follow-up interval out to 2 years, Heller said. NDI success, defined as a minimum 15-point improvement in the NDI score, showed statistically superior performance for the Bryan compared to the control at each follow-up interval.
The investigators also found improvements in both groups regarding Short Form-36 (SF-36) scores, but found no significant differences between the groups.
Neurologic success defined as maintenance or improvement of ones neurology compared to baseline was high in both groups and statistically equivalent, Heller said. Secondary intervention or reoperations were low in frequency and slightly different in character between the two groups consistent with the differences in the type of operation.
Using the FDAs criteria for overall success, which includes a 15-point improvement in NDI scores, neurological maintenance or improvement and a lack of adverse events or reoperations, the investigators also found statistically better rates in the Bryan group compared to the ACDF group at all follow-up time points.
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Lateral cervical extension (a) and flexion (b) radiographs made 2 years after a C6-7 discectomy and Bryan (Medtronic Sofamor Danek) disc replacement in a 36-year-old cardiac surgeon who randomized to the experimental arm of the study. He was symptom free and neurologically normal at last follow-up. Images: Heller JG |
For more information:Reference:
- John G. Heller, MD, can be reached at The Emory Spine Center, 59 Executive Park South South NE #3000, Atlanta, GA 30329; 404-778-7112; e-mail: john.heller@emoryhealthcare.org. He receives royalties, consulting and speaking fees from Medtronic.
- Heller J, Sasso R, Anderson P et al. Bryan cervical disc replacement: Results of the United States prospective randomized clinical trial versus anterior cervical discectomy and fusion. Paper #5. Presented at the North American Spine Society 22nd Annual Meeting. Oct. 23-27, 2007. Austin, Texas.