Flexion Osteotomy of the Cervical Spine
Bibliographic record
Abstract
STUDY DESIGN: A new surgical technique of cervical osteotomy to correct an extension deformity of the cervical spine is described, and a case is reported. OBJECTIVES: To emphasize the disparate effect of osteotomy level on sagittal balance and gaze angle in surgical correction of global kyphotic deformity, and to describe a new surgical technique. SUMMARY OF BACKGROUND DATA: Previous reports of cervical osteotomy essentially have described extension osteotomy for correction of severe flexion deformity. To the authors' knowledge, flexion osteotomy to correct extension deformity of the cervical spine has not been described previously. METHODS: A 44-year-old woman with global kyphotic deformity caused by ankylosing spondylitis underwent corrective lumbar osteotomy at another institution. Ten years later, she experienced further development of the kyphosis, predominantly at the thoracic level, with resultant restriction of forward gaze. Thoracic corrective osteotomy was performed, which resulted in an upward deviation of her visual field. A flexion osteotomy was performed at C7-T1, using two separate posterior and anterior approaches, in one-stage, in the lateral decubitus. The use of transparent drapes permitted direct visualization of the chin-brow angle during operation. Anterior plate fixation prevented any translation at the osteotomy site. RESULTS: The osteotomy united; the gaze angle was fully corrected (45 degrees to -30 degrees ). No deterioration was noted at 2-year follow-up. CONCLUSIONS: Osteotomy at a higher level in the spine for correction of global kyphotic deformity may result in a significant overcorrection of the gaze angle upward. The authors believe that the new technique described in this report is a technically demanding but adequate and safe approach for correcting such a rare deformity.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".