Oral Presentation ANZBMS-MEPSA-ANZORS 2022

Background

Vertebral Body Tethering (VBT) has been proposed to work via growth modulation to correct the deformity of idiopathic scoliosis by applying asymmetric forces across the growth plates of the vertebral bodies. This aim of this study is to determine the amount of growth modulation VBT has on skeletally immature patients.

Methods

A retrospective study of patients who have undergone VBT for idiopathic scoliosis. All patients were treated by one surgeon working at two centres in Brisbane, Australia. Data was prospectively collected. Pre and post-operative patient demographics, level of skeletal immaturity, Cobb angle measurements and regular post op follow up were collected.  

Results

14 patients met the inclusion criteria. The mean age was 12.1 years (CI95% 10.5-13.6). The median Risser score was 0 (CI95% 0-0.6), median Sanders score was 2.5 (CI95% 1.7-3.3). The percentage of female patients was 79% and of these, all were premenarchal. The mean main thoracic Cobb angle was 52.5° (CI95% 45.1-59.9°), this corrected to 17.0° (CI95% 10.6-23.4°) on bending films. The mean rib prominence was 15.8° (CI95% 12.0-19.6°). The main thoracic curve corrected to 26.1° (CI95% 19.4-32.8°) at one week, 28.6° (CI95% 21.5-35.7°) an 2 months, 24.0° (CI95% 16.7-31.2°) at 6 months, 28.0° (CI95% 16.7-39.3°) at 12 months, 33.4° (CI95% 21.2-46.7°) at 18 months, and 34.7° (CI95% 22.0-47.3°) at 2 years follow up. At the final follow up, the mean age was 14.2 years (12.9-15.4), median Risser score was 5 (CI95% 2.8-7.2), and 85% were post-menarche.

Conclusion

Research seen in animal models and early human studies demonstrated VBT could induce significant growth modulation. The results seen in this study demonstrate that VBT functions as an internal brace to prevent curve progression and reduce deformity, to an acceptable severity that allows patients to avoid a spinal fusion when skeletally mature.