Outcomes of Vertebral Body Tethering in Adolescent Idiopathic Scoliosis: A Prospective, Multicenter Study.

Background: Vertebral body tethering (VBT) for adolescent idiopathic scoliosis (AIS) is an alternative to posterior fusion. There are limited prospective, multicenter data available on VBT following US Food and Drug Administration approval. We hypothesize that curve correction on first postoperative standing (first erect, FE) imaging is associated with higher rates of successful correction at final follow-up. Methods: All qualifying patients with AIS who underwent thoracic and lumbar VBT between 2019 and 2022 were prospectively enrolled from 9 institutions. Radiographic and clinical data were compared preoperatively, at FE, and at final follow-up with minimum of 2 years. Success was defined as major curve magnitude of ≤35° at final follow-up and no fusion surgery. Results: One hundred twenty-seven patients were enrolled (79.5% female), with mean follow-up 2.4 years. Mean age at surgery was 12.9 ± 1.4 years, most had bone age of Sanders 4 or lower (93/112, 83.0%). In average, 7.6 ± 1.7 levels were tethered. Mean preoperative major curve magnitude was 50 ± 8°, with mean initial correction at FE of 29 ± 8° (% correction, 39 ± 18%). At final follow-up, mean curve magnitude was maintained at 26 ± 11° (% correction, 45 ± 23%) despite 29% of tether breakage. Patients who had mean FE curve magnitude of ≤35° were 88% successful compared with only 60% in those with >35° on FE (p = 0.0021). Patients showed stable sagittal alignment across all timepoints. Scoliosis Research Society-22 scores improved significantly by 2 years (p < 0.0001). Conclusion: This was the first prospective, multicenter study to assess outcomes of VBT for patients with AIS. VBT shows promise, but optimal results may depend on careful patient selection and surgical technique. FE major curve magnitude of ≤35° was associated with 88% success rate compared with only 60% success for those with poor correction. Level of Evidence: Level II. See Instructions for Authors for a complete description of levels of evidence.