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.