Proximal Junctional Kyphosis in Adult Spinal Deformity After Segmental Posterior Spinal Instrumentation and Fusion
Why this work is in the frame
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Bibliographic record
Abstract
In Brief Study Design. A retrospective study. Objective. To analyze time-dependent change of, prevalence of, and risk factors for proximal junctional kyphosis (PJK) in adult spinal deformity after long (≥5 vertebrae) segmental posterior spinal instrumented fusion with a minimum 5-year postoperative follow-up. Summary of Background Data. No study has focused on time-dependent long-term proximal junctional change in adult spinal deformity after segmental posterior spinal instrumented fusion with minimum 5-year follow-up. Methods. Clinical and radiographic data of 161 (140 women/21 men) adult spinal deformity patients with minimum 5-year follow-up (average 7.8 years, range 5–19.8 years) treated with long posterior spinal instrumentation and fusion were analyzed. Radiographic measurements included sagittal Cobb angle at the proximal junction on preoperative, 8-weeks postoperation, 2-year postoperation, and ultimate follow-up (≥5 years). Postoperative SRS outcome scores were also evaluated. Results. The prevalence of PJK at 7.8 years postoperation was 39% (62/161 patients). The PJK group (n = 62) demonstrated a significant increase in proximal junctional angle at 8 weeks (59%), between 2 years postoperation and ultimate postoperation (35%), and in thoracic kyphosis (T5–T12) at ultimate follow-up (P = 0.001). However, the sagittal vertical axis change at ultimate follow-up did not correlate with PJK (P = 0.53). Older age at surgery >55 years (vs. ≤55 years) and combined anterior and posterior spinal fusion (vs. posterior only) demonstrated significantly higher PJK prevalence (P = 0.001, 0.041, respectively). The SRS outcome scores did not demonstrate significant differences with the exception of the self-image domain when PJK exceeded 20°. Conclusion. The prevalence of PJK at 7.8 years postoperation was 39%. PJK progressed significantly within 8 weeks postoperation (59%) and between 2 years postoperation and ultimate follow-up (35%). Older age at surgery (>55 years) and combined anterior and posterior spinal fusion were identified as risk factors for developing PJK. The SRS outcome instrument was not adversely affected by PJK, except when PJK exceeded 20°. Proximal junctional kyphosis at 7.8 years postoperation in adult spinal deformity after long (≥5 vertebrae) segmental posterior spinal instrumented fusion demonstrated a prevalence of 39% significant progression at 8-weeks postoperation with minimal effect on Scoliosis Research Society outcome instruments at ultimate follow-up. Older age at surgery (>55 years) and combined anterior/posterior spinal fusion were identified as risk factors for developing proximal junctional kyphosis.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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 it