Etiology remains king: health-related quality of life outcome at 5 years following growth friendly instrumentation for EOS

Purpose: The etiology of early-onset scoliosis (EOS) has been shown to significantly influence baseline parent-reported health-related quality of life (HRQoL) measures as assessed by the Early Onset Scoliosis Questionnaire (EOSQ). However, it remains unclear how etiology influences mid-term outcomes following growth friendly instrumentation (GFI) for EOS. Methods: A retrospective review of a multi-center prospective spinal database was performed. Children undergoing primary distraction-based, GFI for EOS with complete baseline, 2-year, and 5-year post-surgical EOSQ were included. The identified children were subdivided by etiology as classified by the C-EOS system. EOSQ scores were compared over time according to etiology cohorts and between instrumentation types. Minimal clinically important difference (MCID) was defined as ≥ 20% change in domain score and compared across etiologies. Dominance analysis was used to assess for drivers of treatment satisfaction. Results: A total of 178 children (mean 7.3 ± 2.1 years, 51.1% female) were included. The most common etiology was neuromuscular (NM: 36.5%), with the majority of children treated with MCGR (N = 125). Significant differences between etiology groups were present with congenital and idiopathic cohorts demonstrating similar EOSQ domain scores that were significantly higher than neuromuscular and syndromic cohorts. In assessing clinically important changes in EOSQ scores over the 5-year follow-up period, neuromuscular and syndromic patients demonstrated the greatest capacity for improved outcomes. Instrumentation type had no influence on HRQoL scores at 5-year follow-up. Etiology was a driver of satisfaction with syndromic etiology and transfer domain score at 2 years follow-up associated with dissatisfaction. Conclusion: Curve etiology remains a significant driver of HRQoL domains following growth-friendly instrumentation for EOS. Neuromuscular and syndromic patient have significantly lower domain scores. Despite this, or perhaps because of it, they also demonstrate the greatest capacity for clinically important improvement in HRQoL measures 5 years following intervention.