Retrospective Review of the Early Outcomes in Hybrid Spine Fixation for Adolescent/Juvenile Idiopathic Scoliosis: Posterior Spinal Fusion Combined with Anterior Vertebral Body Tethering

Introduction: Anterior vertebral body tethering (aVBT) and posterior spinal fusion (PSF) are options for patients with idiopathic scoliosis with the former having a higher reoperation rate balanced with maintained motion. Combining both procedures in patients with double curves where a PSF is performed for the thoracic curve and aVBT for the lumbar curve provides maximal correction of the thoracic curve with a maintenance of motion for the lumbar spine.

Methods: A retrospective chart review of 20 patients at a single pediatric institution with a diagnosis of idiopathic scoliosis who have undergone thoracic PSF combined with lumbar aVBT were included. Demographic, clinical and radiographic variables were collected, and univariate statistics were compared via t-test analysis.

Results: Twenty patients were identified with an average age of 12.7±1.6 years (female=65%) with an average follow-up of 8 months (range 1-24). These patients were skeletally immature (Sanders 3.8±1.8) with the following Lenke curve types: 6C (eleven), 3C (five), 1C (three) and one 4C. All patients underwent staged PSF and aVBT procedures, and of the 18 patients who had both procedures in the index admission, procedures were performed with an average 3.3±2.0 days apart. PSF procedures took an average of 276±63 minutes, and aVBT procedures had a duration of 275±54 minutes. Following hybrid correction, thoracic cobb angles improved from 67.6° to 18.7° (p < 0.001), and lumbar cobb angles improved from 65.2° to 41.2° (p < 0.001). Sagittal T2-12 Cobb angles remained unchanged, from 28° to 28.8° postop (p = 0.403). Sagittal T5-12 Cobb angles remained unchanged, from 23.2° to 21.2° postop (p = 0.225).In patients with one-year follow-up, cobb angles did not progress in either thoracic (p < 0.001) or lumbar (p < 0.001) regions.

Conclusion : A combined approach of PSF with aVBT is a safe and effective approach for idiopathic scoliosis. This approach applies the gold standard approach to perform a selective thoracic fusion and combines this with the purported benefits of motion preservation of aVBT for the lumbar spine. This study will continue to further refine indications for aVBT.