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. A retrospective investigation was performed on eight 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 (UPROR) were recorded. 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; p<0.001) and was 44.5° ± 14.1° at final follow-up. Pelvic obliquity significantly improved from a mean of 25.6° ± 6.3° to 6.6° ± 3.0° (p<0.001) and was at last follow-up (8.7° ± 2.0°; p=0.08). Annualized T1-S1 growth was 11.6 ± 3.2 mm/year, with a mean "distraction efficiency" of 86.7% compared to the programmed 3 mm target. One mechanical complication (12.5%) occurred (distal iliac screw failure), resulting in a UPROR rate of 6.25 per 100 patient-years. No perioperative respiratory or infectious complications were observed. 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-DMT era. Level IV: Case series. 1. Meaningful deformity correction (45.9% mean Cobb reduction) achieved with preservation of linear spinal growth (11.6 ± 3.2 mm/year); 2. Low peri-operative risk, with no infections, no transfusions, and no peri-operative 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.
Labianca et al. (Sun,) studied this question.