Sagittal Parameters of Global Spinal Balance
Bibliographic record
Abstract
STUDY DESIGN: Prospective study of normal sagittal global spinal balance in the Caucasian adult population. OBJECTIVE: To document values for parameters of global spinal balance in 709 asymptomatic adults without spinal pathology. SUMMARY OF BACKGROUND DATA: Previous studies have investigated sagittal spinal balance in the normal population, but there is still a need for a large prospective database with normative values on the basis of gender and age. METHODS: Spinosacral angle (SSA), spinal tilt (ST), and C7 translation ratio were evaluated in 709 asymptomatic adults (354 males and 355 females). Position of C7 plumbline relative to sacrum and hip axis (HA) was also assessed. Comparisons on the basis of gender were performed using analyses of covariance with age as covariate. Relationships between parameters and age were assessed using Spearman's coefficients. RESULTS: Mean SSA, ST, and C7 translation ratio were respectively 130.4° ± 8.1°, 90.8° ± 3.4°, and 0.1° ± 1.9°. Mean ± 2 standard deviations were respectively 110° to 150° for SSA and 85° to 100° for ST. Mean SSA and ST were higher in females but by less than 2°. C7 plumbline was behind the HA in 86% of subjects. Correlations between global balance and age were small (-0.1 ≤ r ≤ 0.1), with only 1 correlation reaching statistical significance (SSA vs. age; r = -0.1), reflecting a slight tendency for SSA to decrease with age. There was no relationship between ST and age. CONCLUSION: Asymptomatic adults tend to stand with a stable global balance and it is expected that 95% of normal adults have an SSA and ST between 110° to 150° and 85° to 100°, respectively. C7 plumbline in front of the HA is not necessarily associated with a spinal pathology. Results suggest that in adults, anterior displacement of C7 plumbline with respect to sacrum cannot be attributed solely to aging and should raise a suspicion for the risk of developing spinal pathology.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| 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) | 0.002 | 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".