Three-Dimensional Analysis of Disc and Vertebral Height and Their Role in Kyphosis Creation in Adolescent Idiopathic Scoliosis
Bibliographic record
Abstract
STUDY DESIGN: Retrospective. OBJECTIVE: Describe three-dimensional (3D) changes after adolescent idiopathic scoliosis (AIS) reconstruction, with attention to anterior column (AC) shortening and middle column (MC) lengthening. SUMMARY OF BACKGROUND DATA: Relative elongation of the AC, particularly the disc, is a common feature of AIS. 3D correction of deformity requires creation of thoracic kyphosis (TK). METHODS: An AIS registry was queried for patients treated with posterior-only instrumented fusion, with pre/postoperative biplanar radiographs and 3D spine models. MATLAB script calculated heights of the anterior disc/vertebral body (VB) and posterior disc/VB for each segment from T1 to L5 in the plane of each disc/VB. The respective disc/VB heights were summed to calculate AC length and MC length. AC and MC lengths of the instrumented segments were compared before and after surgery using paired t tests with a Bonferroni correction ( P <0.001). Linear regression examined factors related to greater MC lengthening. The relationships between AC/MC lengths and 2D/3D TK were analyzed using Pearson correlations. RESULTS: Five hundred sixty-four patients met inclusion (age 15 yr, female 82%; major curve 58°; 3D TK 3°, Lenke 1 44%, Risser 3/4/5 81%). Mean number of levels fused was 11, LIV T12/L1 50%, postoperative major curve 16°, 3D TK 23°. The AC shortened and the MC lengthened at all levels from T5 to T11, whereas both lengthened at T12. From T5 to T12, AC shortened 3.4 mm ( P <0.001) and MC lengthened 4.7 mm ( P <0.001). MC lengthening >10 mm was achieved in 30 (5%) cases. Longer fusions [OR 1.7 (1.2 to 2.4)] and a greater difference between anterior VB height and posterior VB height [OR 7.1, (3.1 to 16.2)] were associated with more lengthening. Anterior shortening was strongly correlated to more 3D kyphosis creation ( r =0.7, P <0.001). CONCLUSION: 3D kyphosis creation requires shortening of the AC and lengthening of the MC through the discs. After the posterior longitudinal ligament (MC) is taut, a discectomy may be required for further 3D kyphosis creation.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".