The Fate of The Broken Tether
Bibliographic record
Abstract
STUDY DESIGN: Retrospective, multicenter. OBJECTIVE: The aim of this study was to assess curve progression and occurrence of revision surgery following tether breakage after vertebral body tethering (VBT). SUMMARY OF BACKGROUND DATA: Tether breakage after VBT is common with rates up to 50% reported. In these cases, it remains unknown whether the curve will progress or remain stable. MATERIALS AND METHODS: Adolescent and juvenile idiopathic scoliosis patients in a multicenter registry with ≥2-year-follow-up after VBT were reviewed. Broken tethers were listed as postoperative complications and identified by increased screw divergence of >5 degrees on serial radiographs. Revision procedures and curve magnitude at subsequent visits were recorded. RESULTS: Of 186 patients who qualified for inclusion, 84 (45.2%) patients with tether breakage were identified with a mean age at VBT of 12.4±1.4 years and mean curve magnitude at index procedure of 51.8±8.1 degrees. Tether breakage occurred at a mean of 30.3±11.8 months and mean curve of 33.9±13.2 degrees. Twelve patients (12/84, 14.5%) underwent 13 revision procedures after tether breakage, including six tether revisions and seven conversions to fusion. All tether revisions occurred within 5 months of breakage identification. No patients with curves <35 degrees after breakage underwent revision. Revision rate was greatest in skeletally immature (Risser 0-3) patients with curves ≥35 degrees at time of breakage (Risser 0-3: 9/17, 53% vs. Risser 4-5: 3/23, 13%, P =0.01). Curves increased by 3.1 and 3.7 degrees in the first and second year, respectively. By 2 years, 15/30 (50%) progressed >5 degrees and 8/30 (26.7%) progressed >10 degrees. Overall, 66.7% (40/60) reached a curve magnitude >35 degrees at their latest follow-up, and 14/60 (23.3%) reached a curve magnitude >45 degrees. Skeletal maturity did not affect curve progression after tether breakage ( P >0.26), but time to rupture did ( P =0.048). CONCLUSIONS: While skeletal immaturity and curve magnitude were not independently associated with curve progression, skeletally immature patients with curves ≥35 degrees at time of rupture are most likely to undergo additional surgery. Most patients can expect progression at least 5 degrees in the first 2 years after tether breakage, though longer term behavior remains unknown. LEVEL OF EVIDENCE: Level III.
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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 | 0.005 |
| 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 | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| 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".