Safety and Efficacy of Magnetically Controlled Growing Rods for Early Onset Scoliosis in the Era of Disease-Modifying Therapies: Mid-term Results in a Homogeneous Cohort of Spinal Muscular Atrophy Type 1 Patients.

Background: The advent of disease-modifying therapies (DMTs) has fundamentally altered the clinical course of spinal muscular atrophy type 1 (SMA-I), resulting in prolonged survival and a higher incidence of early onset scoliosis (EOS). Although growth-friendly surgery is a keystone of management, specific evidence regarding magnetically controlled growing rods (MCGR) in the SMA-I population remains sparse. We evaluate the safety and efficacy of MCGR in a specific, homogeneous cohort of SMA-I patients. Methods: A retrospective investigation was performed on 8 consecutive children with genetically confirmed SMA-I who underwent MCGR implantation for progressive EOS at our institution. To overcome profound osteopenia, we utilized a proximal rib-based "ring hook" foundation and distal pelvic/sacroiliac fixation. Outcomes included coronal Cobb angle correction, pelvic alignment, and annualized T1-S1 spinal growth. Distractions were performed at 10-12-week intervals and validated via ultrasonography. Complications and unplanned returns to the operating room (UPRORs) were recorded. Results: Eight patients (mean age 6.9 ± 0.92 years) were followed for a mean of 29.25 ± 4.0 months. The mean Cobb angle improved from 71.9° ± 20.8° to 38.9° ± 15.7° postoperatively (45.9% initial correction; Conclusions: In this medically fragile SMA-I cohort, MCGR provided effective deformity control and supported longitudinal spinal growth. A multidisciplinary perioperative pathway and rib-based proximal anchoring are essential for optimizing results. While mid-term outcomes are encouraging, further research is needed to evaluate the long-term impact on pulmonary function and construct durability in the post-disease-modifying therapy era. Key Concepts: (1)Meaningful deformity correction (45.9% mean Cobb reduction) achieved with preservation of linear spinal growth (11.6 ± 3.2 mm/y).(2)Low perioperative risk, with no infections, no transfusions, and no perioperative respiratory deterioration.(3)A 12.5% mechanical complication rate (one unplanned revision for distal iliac screw failure) over a mean follow-up of 29.25 months. Level of Evidence: IV: Case series.