One-way self-expanding rods for early onset neuromuscular scoliosis: a two-year follow-up of an international cohort.

Introduction: Fusionless surgical techniques are increasingly used to treat patients with early-onset and juvenile neuromuscular scoliosis (NMS) to correct and stabilize the scoliotic curves while preserving natural growth. This study aimed to evaluate clinical and radiological outcomes two years after minimally invasive surgery using a commercially available CE-certified (Conformité Européenne) one-way self-expanding rod (OWSER) system in a large international cohort of patients with NMS.

Methods: Patients who underwent surgical treatment with the OWSER system for NMS correction, with a two-year follow-up were retrospectively included and analyzed for two-year follow-up. The surgery consisted of a bilateral OWSER system from the upper cervico-thoracic spine to the pelvis using a minimally invasive approach. Radiological parameters, including Cobb angle, pelvic obliquity, thoracic kyphosis, lumbar lordosis and spinal length (T1-S1), were assessed preoperatively and at follow-up. Clinical performance was based on complications and unplanned reoperations.

Results: Seventy-six patients from ten international centers were included. The mean age at surgery was 9.6 ± 2.5 years. Diagnoses included cerebral palsy (n = 23), spinal muscular atrophy (n = 14), and other neuromuscular syndromes (n = 39). Mean Cobb angle improved from 80 ± 25° preoperative to 39.7 ± 20.9° at 2-years follow-up, mean pelvic obliquity improved from 19 ± 12° to 6.4 ± 6.2° and mean preoperative kyphosis decreased from 44 ± 24° to 32.9 ± 14°. Segment T1-S1 increased 5.9 cm peri-operatively and patients showed a mean growth after instrumentation from 34 ± 5.cm to 35 ± 5.2 cm in two years due to the OWSER system. Procedure related complications occurred in 22 patients (29%): twelve surgical site infections, and 20 mechanical and alignment-related complication, resulting in 27 revision surgeries in 20 patients (26%).

Conclusion: The OWSER system provides stable correction of Cobb angle at two-year follow-up while allowing continued spinal growth in juvenile or early-onset NMS. Despite a notable complication rate, this technique offers a reliable treatment for NMS patients. We continue to follow-up these patients as long-term outcomes are necessary to confirm these encouraging results.