Is myelomeningocele a distinct subgroup within neuromuscular early-onset scoliosis (M-EOS)? A clinical and radiographic comparison after graduation from growing rod treatment.

PURPOSE: The aim was to compare clinical and radiographic outcomes between myelomeningocele (MMC) and other neuromuscular early-onset scoliosis (EOS) patients following graduation from growing rod treatment and to evaluate whether MMC should be considered a distinct subgroup within the classification of EOS. METHODS: This single-center retrospective cohort study included 26 patients with neuromuscular EOS (10 with MMC, 16 with other neuromuscular etiologies) treated with traditional or magnetically controlled growing rods between 2004 and 2023, all of whom achieved graduation and had a minimum of 2-year of post-graduation follow-up. Demographic, clinical, radiographic, and complication data were analyzed. Complication burden was assessed using unplanned return to the operating room (UPROR), modified Clavien-Dindo-Sink grading, and negative binomial regression. RESULTS: Wound-related complications were significantly more frequent in the MMC group (80.0% vs. 6.2%, p = 0.002). The MMC patients had a higher complication burden (mean 3.3 ± 2.3 vs. 0.9 ± 1.4, p = 0.003), more multiple reoperations (≥ 2 UPROR: 70.0% vs. 0.0%, p = 0.007), more severe complications (modified Clavien-Dindo-Sink grade 3b: 70.0% vs. 25.0%, p = 0.016), and a 3.52-fold higher overall complication rate (IRR = 3.52, 95% CI 1.63-10.80). Spinal growth and sagittal alignment were also significantly compromised in the MMC patients. CONCLUSION: MMC patients demonstrate a markedly distinct complication profile and clinical trajectory compared to other neuromuscular EOS patients, supporting consideration of MMC as a separate subgroup within EOS classification systems to improve risk stratification and guide individualized treatment. Even within the current framework, recognizing MMC through a diagnosis-specific modifier may offer a practical means of improving risk stratification without requiring structural reclassification.