Journal of Pediatric Orthopaedics - 2026-09-03 - Journal Article
When is Vertebral Body Tethering in a Patient With an Open Triradiate Cartilage a Good Idea?
Zale C, Boyce J, Oh T, Davuluri S, Nice E, Pahys JM, Samdani AF, Hwang SW
Topics
Key Takeaway
VBT in patients with open triradiate cartilage achieved successful curve correction (<35°) in only 56% of cases, with undercorrection in 29% and overcorrection in 15%.
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Summary
This study evaluated success and failure rates of thoracic VBT in 115 skeletally immature patients (60 EOS, 55 AIS) with open triradiate cartilage from 2012–2020. Success (final curve <35°) was achieved in 56%; undercorrection was associated with preoperative thoracic curve >51°, first-erect correction <54%, and upright preoperative curve >79°; overcorrection was associated with preoperative curve <46°. These thresholds define a narrow operative window where VBT is most likely to succeed in this cohort.
Key Limitation
The combined EOS and AIS cohort without subgroup-specific success/failure analysis prevents determination of whether these radiographic thresholds apply equally to both diagnoses.
Original Abstract
BACKGROUND
Vertebral body tethering (VBT) is a fusionless surgical technique used to treat adolescent idiopathic scoliosis (AIS). It is unclear what the optimal window is for surgical intervention using VBT. The purpose of this study is to report the rate of success following VBT in patients with open triradiate cartilage (OTC) and to report the rate of reoperation.
METHODS
A retrospective review was performed for patients with early-onset scoliosis (EOS) or AIS with OTC who underwent VBT from 2012 to 2020 with a minimum 2-year follow-up. Success was defined as curves <35 degrees at the last follow-up. Failure was subdivided into undercorrection (curves ≥35 degrees at follow-up or reoperation for tether replacement or conversion to fusion) or overcorrection (curves ≥35 degrees in the contralateral direction or reoperation for tether release, or conversion to fusion). The major coronal curve was measured at preoperative, first erect, and annual visits thereafter. Binary logistic regression models were created to correlate demographic and radiographic variables with failed curve correction.
RESULTS
A total of 115 patients with OTC (60 EOS, 55 AIS) underwent thoracic VBT. Of these, 87% were female, and 91% of the female patients were premenarchal. The median preoperative Sanders score for all groups was 3. Surgery was successful in 64 patients (56%). Fifty-one patients were classified as treatment failures, 34 (29%) were the result of undercorrection, and 17 (15%) were the result of overcorrection. There was a significant difference in the initial thoracic major curve between success and undercorrection groups (53±10 degrees vs. 60± 8 degrees, P<0.05). There was also a significant difference in the first erect thoracic major curve between success and undercorrection (28±11 degrees and 36±9 degrees, P<0.01). There was a significant difference in the first erect percent correction between success and overcorrection (48±17% and 40±13%, P<0.04).
CONCLUSION
VBT with OTC was successful in 56% of the cases. Undercorrection was associated with a thoracic bend of >51 degrees, percent thoracic correction <54%, and upright preoperative thoracic major curve >79 degrees. Overcorrection was associated with an upright preoperative thoracic major curve <46 degrees.
LEVEL OF EVIDENCE
Level IV.