When Is A Growth-Friendly Strategy Warranted? A Matched Comparison Of Growing Rods Versus Primary Posterior Spinal Fusion In Juveniles With Early-Onset Scoliosis

Background: In 7 to 11-year-old juveniles with severe early-onset scoliosis (EOS) the optimal surgical option remains uncertain. This study compares growing rods (GRs) followed by definitive posterior spinal fusion (PSF) versus primary PSF in this population. We hypothesized that the thoracic height afforded by GRs would be offset by increased rigidity, more complications, and more operations. Methods: This retrospective comparative study included EOS patients aged 7.0 to 11.9 years at index surgery treated with GR -> PSF or primary PSF during 2013 to 2020. Primary outcomes were thoracic height gain (Delta T1-12H), major curve, complications, and total operations. Primary PSFs were matched with replacement 1-to-n to GR -> PSFs by age at index, etiology, and major curve. Results: Twenty-eight GR -> PSFs met criteria: 19 magnetically controlled GRs and 9 traditional GRs. Three magnetically controlled GRs were definitively explanted without PSF due to complications. The remaining 25 GR -> PSFs were matched to 17 primary PSFs with 100% etiology match, mean Delta major curve 1 degree, and mean Delta age at index 0.5 years (PSFs older). Median Delta T1-12H pre-GR to post-PSF was 4.7 cm with median deformity correction of 37%. Median Delta T1-12H among primary PSFs was 1.9 cm with median deformity correction of 62%. GR -> PSFs had mean 1.8 complications and 3.4 operations. Primary PSFs had mean 0.5 complications and 1.3 operations. Matched analysis showed adjusted mean differences of 2.3 cm greater Delta T1-12H among GR -> PSFs than their matched primary PSFs, with 25% less overall coronal deformity correction, 1.2 additional complications, and 2.2 additional operations per patient. Conclusions: In juveniles aged 7 to 11 with EOS, on average GRs afford 2 cm of thoracic height over primary PSF at the cost of poorer deformity correction and additional complications and operations. Primary PSF affords an average of 2 cm of thoracic height gain; if an additional 2 cm will be impactful then GRs should be considered. However, in most juveniles the height gained may not warrant the iatrogenic stiffness, complications, and additional operations. Surgeons and families should weigh these benefits and harms when choosing a treatment plan.