• Tyler A Tetreault, Tiffany N Phan, WrenTishya A LTALJackie and Gene Autry Children's Orthopedic Center, Children's Hospital Los Angeles, Los Angeles, CA, USA., Michael J Heffernan, Michelle C Welborn, John T Smith, Ron El-Hawary, Kenneth Cheung, Kenneth D Illingworth, David L Skaggs, Lindsay M Andras, and Pediatric Spine Study Group.
• Jackie and Gene Autry Children's Orthopedic Center, Children's Hospital Los Angeles, Los Angeles, CA, USA.
• Spine. 2024 Jun 12.

Study DesignRetrospective, Multicenter.ObjectiveAssess curve progression and occurrence of revision surgery following tether breakage after vertebral body tethering (VBT).Summary Of Background DataTether 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.MethodsAdolescent 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° on serial radiographs. Revision procedures and curve magnitude at subsequent visits were recorded.ResultsOf 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°. Tether breakage occurred at a mean of 30.3±11.8 months and mean curve of 33.9°±13.2°. Twelve patients (12/84, 14.5%) underwent 13 revision procedures after VBT breakage, including 6 tether revisions and 7 conversions to fusion. All tether revisions occurred within 5 months of breakage identification. No patients with curves <35° after breakage underwent revision. Revision rate was greatest in skeletally immature (Risser 0-3) patients with curves ≥35° 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° in the first and second year, respectively. By two years, 15/30 (50%) progressed >5° and 8/30 (26.7%) progressed greater than 10°. Overall, 66.7% (40/60) reached a curve magnitude >35° at their latest follow-up, and 14/60 (23.3%) reached a curve magnitude greater than 45°. Skeletal maturity did not affect curve progression after tether breakage (P>0.26), but time to rupture did (P=0.048).ConclusionWhile skeletal immaturity and curve magnitude were not independently associated with curve progression, skeletally immature patients with curves ≥35° at time of rupture are most likely to undergo additional surgery. Most patients can expect progression at least 5° in the first two years after tether breakage, though longer-term behavior remains unknown.Level Of EvidenceIII.Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.

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