Magnetically controlled growing rods increase 3D true spine length in idiopathic early onset scoliosis patients: results from a multicenter study.

Purpose: To determine, at 2 year follow-up, 3D spine growth for idiopathic early onset scoliosis (iEOS) patients treated with magnetically controlled growing rods (MCGR).
Methods: From an international EOS registry, patients with iEOS treated with MCGR were identified. Scoliosis, kyphosis, traditional coronal height, and 3D true spine length (3D-TSL) were measured pre-index surgery, post-index, and at 2 year follow-up.
Results: 135 participants, mean age 8.1 years (2.7-15.6) were included. Scoliosis improved from 71° pre-index to 41° post-index (p < 0.001) and remained constant at 2 years (43°, p = 0.58). Kyphosis improved from 49° to 36° (p < 0.001); then increased by 2 years to 42° (p = 0.002). Traditional T1-S1 height, which reflects both spine growth and changes in deformity, increased from pre-index to post-index (274 mm vs. 310 mm; p < 0.001), and again at 2 years (332 mm, p < 0.001). As 3D-TSL reflects growth of the spine, independent of changes in deformity, as expected it did not change perioperatively (335 mm vs. 339 mm, p = 0.83), but significantly changed by 2 years (367 mm; p < 0.001). Participants < 5 years at surgery increased 22 mm (8.2%), 5-10 years increased 26 mm (7.8%), and > 10 increased 41 mm (11.0%). For instrumented levels, mean vertebral growth was 1.3 mm/level for < 5 years, 1.4 mm/level for 5-10 years, and 2.2 mm/level for > 10 years.
Conclusions: As kyphosis increased over time, these out of the coronal plane changes justify the use of 3D-TSL for this cohort of patients. For idiopathic EOS patients treated with MCGR, 3D spine length increased by 28 mm during the 2 year post-operative period.
Competing Interests: Declarations Conflict of interest Jennifer Hurry reports a research fellowship from Depuy Synthes. John-David Brown received the Dalhousie Medical Research Foundation Lalia B. Chase Studentship. Oheneba Boachie-Adjei reports personal fees from K2M, grants from K2M, board or editorial member with Scoliosis Research Society and Springer, other from WEIGAO and K2M, outside of submitted work. Michael Vitale reports grants from Childrens Spine Foundation, OREF, SRS, POSNA, and OSRF, personal fees from Biomet, Globus Medical, Nuvasive and Stryker, board or committee member for Childrens Spine Foundation, IPOS, Pediatric Orthopaedic Society of North America, Project for Safety in Spine Surgery, and other for FOX, Childrens Spine Foundation, and Biomet outside the submitted work. Joshua Pahys reports personal fees from DePuy, Nuvasive and Zimmer outside the submitted work. Scott Luhmann reports personal fees from Orthopaediatrics and Stryker, board or committee member for Pediatric Orthopaedic Society of North America and Scoliosis Research Society, editorial or governing board for Spine Deformity Journal, other from Globus Medical, Medtronic Sofamor Danek, Stryker, and Wolters Kluwer Health outside the submitted work. Pediatric Spine Study Group reports grants from DePuy Synthes Spine, grants from Medtronic, grants from NuVasive, grants from Globus Medical Inc., grants from OrthoPediatrics, grants from Zimmer Biomet, grants from Pediatric Spine Foundation, grants from Stryker, outside the submitted work. Ron El-Hawary reports personal fees from Depuy Synthes Spine, personal fees from Medtronic Spine, grants from Depuy Synthes Spine, grants from Medtronic Spine, personal fees from Orthopediatrics, other from Pediatric Spine Foundation, other from Scoliosis Research Society, outside the submitted work. The remaining authors have nothing to declare. Ethical approval This work is a sub-study of the Pediatric Spine Study Group Registry which was approved by the Research Ethics Board at the IWK Health Centre (#1002256) in accordance with the ethical standards outlined in the Tri-Council Policy Statement and the 1964 Declaration of Helsinki and its later amendments. Consent to participate All research participants or their legal guardians provided written consent to be a part of the registry and have the data collected be used in ongoing research on scoliosis. Consent for publication Not applicable.
(© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)