Vertebral body tethering for non-idiopathic scoliosis: initial results from a multicenter retrospective study.

Purpose: Vertebral body tethering (VBT) has been described for patients with idiopathic scoliosis. Results of the technique for non-idiopathic scoliosis have not yet been reported.
Methods: An international multicenter registry was retrospectively queried for non-idiopathic scoliosis patients who underwent VBT with minimum 2-year follow-up. Success at 2 years was defined as Cobb angle < 35 degrees and no fusion surgery.
Results: Of the 251 patients treated with VBT, 20 had non-idiopathic scoliosis and minimum 2-year follow-up. Mean age at surgery was 12.4 years (range 10 to 17 years). Mean major Cobb angle at enrollment was 56 degrees. Of those, 18 patients had a major thoracic curve and two had a major lumbar curve. Of the 20 patients, nine met criteria for success (45%). Eight of the 20 patients had poor outcomes (four fusions, four with curve > 50 degrees). Success was associated with smaller preoperative Cobb angle (50 vs. 62 degrees, p = 0.01) and smaller Cobb angle on initial postop imaging (28 degrees vs. 46 degrees, p = 0.0007). All patients with Cobb angle < 35 degrees on 1st postop imaging had a successful result, with the exception of one patient who overcorrected and required fusion. Syndromic vs. neuromuscular patients had a higher likelihood of success (5 of 7, 71%, 2 of 10, 20%, p = 0.03).
Conclusion: Selected non-idiopathic scoliosis can be successfully treated with VBT, but failure rates are high and were associated with large curves, inadequate intraoperative correction and neuromuscular diagnosis. Achieving a Cobb angle less than 35 degrees on 1st standing radiograph was associated with a successful outcome which was achieved in 45% of patients.
Level of Evidence: Level IV (retrospective review study).
(© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)