Magnetic controlled growing rods for early-onset scoliosis: a 4-year follow-up

Abstract

Background ContextThere have been no studies with medium-term follow-up of magnetic controlled growing rods (MCGRs). PurposeThis study aimed to report our single center experience of a magnetic growing rod system with an average of 4 years' follow-up. Study Design/SettingA retrospective case series was carried out. Patient SampleThe sample comprised patients with early-onset scoliosis treated with magnetic controlled growth rods who were operated in 2011. Outcome MeasuresCobb angle, spinal growth rate, complications, and revision were the outcome measures. MethodsClinical case notes and radiographs were reviewed. ResultsThere were 8 patients (5 dual-rod construct, 3 single-rod construct) who had a minimum of 44 months' follow-up and average of 48 months (44–55 months). Mean age at surgery was 8.2 years (range 3–10). Mean preoperative Cobb angle was 60° (34–94), whereas mean postoperative Cobb angle was 42° (32–63). The average number of extensions was 13.8 (range: 12–20). There were 6 patients (75%) who required 8 revision surgeries: rod problems (N=4), proximal screw pull-out (N=3), and development of proximal junction kyphosis (N=1). All three patients who had single-rod construct underwent revision procedure. Currently, four patients (50%) still have the magnetic rods in situ. The mean duration of MCGR in the patient in the removed group was 39 months (range: 34–46). ConclusionsMedium-term results of MCGR are not as promising as previously reported early results. Hence, MCGRs should be used with caution. Single-rod constructs should definitely be avoided. The role of MCGRs in revision cases still remains unknown.