Results of a Retrospective FDA Investigational Device Exemption Study for Anterior Vertebral Body Tethering in Adolescent Idiopathic Scoliosis with 3-Year to 10-Year Follow-Up.

Background: Vertebral body tethering (VBT) offers an alternative treatment for patients with idiopathic scoliosis. We present our finalized Food and Drug Administration Investigational Device Exemption (IDE) study results on VBT.

Methods: We retrospectively reviewed patients with Lenke Type IA/B curves who underwent VBT between 2011 and 2015. Clinical, radiographic, perioperative, and complications data were prospectively collected.

Results: Fifty-seven patients (mean age 12.4 ± 1.3 years) were enrolled and followed for 6.6 ± 1.6 years (range: 3.0-10.2 years). Thoracic Cobb angle measured 40.4 ± 6.8° preoperatively with correction to 14.5 ± 9.0° at 2 years and slight regression to 22.1 ± 12.4° at last follow-up. Median Sanders and Risser were 3 and 0, respectively. At last follow-up, 71% of patients (39/56) had curves ≤30° and 98% (55/56) had achieved skeletal maturity. There were no major neurologic or pulmonary complications. However, 10 patients required 13 revisions; 2 required conversion to fusion. Percent predicted forced expiratory volume and forced vital capacity dropped from 85% and 87%, respectively, to 80% and 82% at the final follow-up.

Conclusion: These finalized IDE results highlight VBT as a safe, effective treatment for skeletally immature patients with idiopathic scoliosis. However, complication and revision rates remain concerning, and patients should be counseled appropriately.

Level of evidence: Level III. See Instructions for Authors for a complete description of levels of evidence.