Radiographic Outcomes After Growing Rod Treatment in Early-Onset Scoliosis: With Versus Without Final Fusion Surgery

Background/Objectives: Early-onset scoliosis (EOS) is often treated with growing rods, which use distraction-based correction to control deformity while allowing spinal growth. Although effective in the coronal plane, this technique may adversely affect sagittal alignment, particularly thoracic kyphosis and lumbar lordosis. Whether final fusion surgery is necessary after the growing rod treatment remains controversial. This study compared radiographic outcomes, including coronal and sagittal parameters, between patients with and without final fusion to clarify the value of final fusion. Methods: We retrospectively reviewed 19 EOS patients treated with growing rods between 2015 and 2019. Patients undergoing posterior spinal fusion after lengthening were classified as the final fusion group (n = 9), while those with more than 12 months of follow-up without fusion formed the graduated group (n = 10). Demographics, surgical variables, and radiographic parameters (Cobb angle, correction rate, coronal balance, clavicular angle, thoracic kyphosis, lumbar lordosis, sagittal vertical axis) were compared. Results: Baseline characteristics were similar. At final follow-up, the final fusion group had significantly better outcomes in Cobb angle (24.2° vs. 34.9°, p = 0.002), correction rate (66.6% vs. 40.1%, p = 0.001), and coronal balance (−1.5 mm vs. 19.7 mm, p = 0.004). Sagittal alignment did not differ significantly, but preservation of thoracic kyphosis tended to favor the fusion group. Conclusions: Final fusion surgery after growing rod treatment achieved superior coronal correction and balance compared with observation alone. Although sagittal alignment was not statistically different, a trend toward better thoracic kyphosis preservation was observed. Final fusion should be considered for larger residual curves or coronal imbalance, while observation may suffice in well-corrected cases.