Shilla Growth Guidance Surgery for Early Onset Scoliosis: Predictors of Optimal Versus Suboptimal Performers

Background: The Shilla Growth Guidance surgery (SGGS) aims to correct a child's spinal deformity while allowing continued spinal growth. Our study used a multicenter early-onset-scoliosis database to determine significant predictors of best candidates. Methods: The Pediatric Spine Study Group multicenter database was analyzed for all patients who had undergone SGGS and had a minimum follow-up of 2 years. Patients without radiographic measurements preoperatively, postoperatively, and at the latest follow-up, as well as patients with myelo gibbus deformities, were excluded. These radiographs were evaluated for major curve, spinal length, and other parameters. Multivariate regressions were conducted to assess the effects of these parameters on the following 4 outcomes: (1) percent of initial curve correction, (2) scoliosis curve progression after surgery per year, (3) at least 1 unplanned SGGS-related reoperation, and (4) T1-S1 height change per year from 1st postoperative erect to final available follow-up. Results: Included were 105 children; the average follow-up was 4.8±2.4 years. Scoliosis etiologies included neuromuscular (n=36; 34%), syndromic (n=31; 30%), idiopathic (n=30; 29%), and congenital (n=8; 8%). Average preoperative, 1st postoperative erect, and latest follow-up major curves measured 69, 32, and 49 degrees, respectively. Average T1-S1 postoperative height change per year was 7±9 mm and average overall T1-S1 height change was 24±35 mm. Forty-eight (46%) patients had C-shaped and 57 (54%) had S-shaped curves; 59 (56%) patients underwent ≥1 SGGS-related reoperation. Multivariate Cox-proportional hazard test revealed younger age at index surgery [hazard ratio (HR)=0.83, P=0.028] and S-shaped curves (HR=0.43, P=0.014) were associated with ≥1 reoperation. Further analysis revealed age younger than 7 years (HR=0.48, P=0.021) was correlated with an increased risk of SGGS-related reoperation. The preoperative major curve was not significantly associated with any outcome measure. A reoperation-free survival rate of 50% corresponded to 3.5 years. Conclusion: SGGS instrumentation in patients younger than 7 years and patients with an S-shaped curve were associated with SGGS-related unplanned surgical interventions. Despite younger age being associated with likely complications, this procedure still benefits these children and provides significant curve correction while allowing growth. Level of Evidence: Level III.