Eight-Year Clinical and Radiological Follow-Up of the Bryan Cervical Disc Arthroplasty
Bibliographic record
Abstract
STUDY DESIGN: Single institution, prospective cohort study of 21 patients who underwent single- or bilevel cervical disc arthroplasty for radiculopathy. OBJECTIVE: To evaluate the long-term outcome of cervical disc arthroplasty. SUMMARY OF BACKGROUND DATA: There is an increasing trend in the use of cervical arthroplasty; however, no long-term outcome studies exist to verify their safety, functionality, and durability. METHODS: A total of 21 patients underwent 27 total disc arthroplasties using the Bryan cervical disc (Medtronic Sofamor Danek Inc, Memphis, TN) after anterior cervical discectomy. Clinical and radiological data were obtained from the 8-year postoperative review. RESULTS: Nineteen of twenty-one patients were able to perform daily activities without limitation. Twenty of twenty-one patients reported fair to excellent outcome according to Odom criteria and 21 of 27 (78%) operated segments were mobile. Functional prostheses moved an average of 10.6°, which was similar to the range of movement of the adjacent nonoperated segments of the cervical spine. Heterotopic ossification was evident in 13 of the 27 (48%) operated segments and restricted movement of the prosthesis in nine cases. Five of the six patients who received bilevel arthroplasties developed heterotopic ossification. There was one case of posterior migration of the prosthesis, which did not have any clinical repercussion. No other case showed evidence of migration, subsidence, loosening, or wear. Radiological evidence of adjacent segment degeneration was observed in four patients (19%); however, each of these patients had pre-existing degenerative disc disease at these levels on preoperative imaging. CONCLUSION: At 8-year follow-up, the Bryan cervical disc arthroplasty maintains favorable clinical and radiological results, with preservation of movement and satisfactory clinical outcome in the majority of cases. However, the incidence of heterotopic ossification causing restricted range of movement of the prosthesis appears to increase with time, especially in bilevel procedures.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".