The effect of magnetically controlled growing rods on three-dimensional changes in deformity correction

Area of Science:

• Orthopedics
• Spinal Surgery
• Pediatric Orthopedics

Background:

• Early onset scoliosis (EOS) presents complex challenges in spinal deformity management.
• Magnetically controlled growing rods (MCGRs) offer a less invasive approach to spinal lengthening compared to traditional growing rods.
• Understanding the three-dimensional (3D) changes induced by MCGR distractions is crucial for optimizing treatment outcomes.

Purpose of the Study:

• To evaluate the 3D changes in spinal deformity correction following magnetically controlled growing rod (MCGR) distractions in patients with early onset scoliosis.
• To assess the impact of MCGR distractions on coronal, sagittal, and axial spinal planes.
• To determine if frequent MCGR distractions can improve axial plane deformities comparable to coronal and sagittal plane corrections.

Main Methods:

• Prospective radiographic study involving 10 EOS patients treated with dual MCGRs and a minimum 2-year follow-up.
• 3D reconstructions from bi-monthly images analyzed changes in coronal, sagittal, and axial planes.
• Growth parameters (height, arm span) correlated with spinal deformity parameters (Cobb angles, sagittal profile, rotational profile, pelvic parameters).

Main Results:

• Significant spinal deformity correction was primarily observed during the initial MCGR implantation, with minimal changes during subsequent distractions.
• Consistent gains in height and arm span were noted, but spinal profile changes were limited post-implantation.
• Patients with preoperative proximal junctional angles experienced initial sagittal plane flattening followed by early rebound; no significant pelvic parameter changes occurred.

Conclusions:

• The primary 3D spinal deformity correction with MCGRs occurs at the time of initial rod implantation, not during distraction phases.
• MCGRs demonstrate efficacy in preventing the progression of axial plane deformities in EOS.
• Further research may be needed to optimize distraction protocols for maximizing 3D deformity correction.