Effects of Growing Rod Technique with Different Surgical Modes and Growth Phases on the Treatment Outcome of Early Onset Scoliosis: A 3-D Finite Element Analysis

Abstract

Early onset scoliosis (EOS) is emerging as a serious threat to children’s health and is the third largest threat to their health after myopia and obesity. At present, the growing rod technique (GRT), which allows patients to regain a well-balanced sagittal profile, is commonly considered as an invasive surgical procedure for the treatment of EOS. However, the risk of postoperative complications and instrumentation breakage remains high, which is mainly related to the choice of fixed mode. Several authors have studied primary stability and instrumentation loads, neglecting the mechanical transmission of the spinal long-segment model in different growth phases, which is fundamental to building a complete biomechanical environment. The present study aimed to investigate the kinematic and biomechanical properties that occur after GRT, across the long spinal structure and the posterior instrumentation, which are affected by unilateral or bilateral fixation. Accordingly, spinal segments (C6-S1) were loaded under flexion (Flex), extension (Ext), left lateral bending (LB), right lateral bending (RB), left torsion (LT), and right torsion (RT) using 11 established spinal models, which were from three growth phases. The stress distribution, spinal and intervertebral range of motion (ROM), counter torque of the vertebra, and bracing force on the rods were measured. The results showed that bilateral posterior fixation (BPF) is more stable than unilateral posterior fixation (UPF), at the expense of more compensations for the superior adjacent segment (SAS), especially when the superior fixed segment is closer to the head. Additionally, the bracing force of the instrumentation on the spine increases as the Cobb angle decreases. Accordingly, this biomechanical analysis provides theoretical suggestions for the selection of BPF or UPF and fixed segments in different growing phases.

Kinematic and biomechanical responses of the spine to distraction surgery in children with early onset scoliosis: A 3-D finite element analysis

“…It exhibited that the intragroup trend was consistent with the trend mentioned above, while the difference between groups is not obvious. Among the results, the curve of distraction force had a gradually rising slope and the T3/T4-L3/L4 fixed model had the largest distraction force (Pei et al, 2022). The spinal structure itself has a stage of easy deformation due to the elasticity of soft tissue, which includes stages of compression and tension.…”

Is refractive error a factor affecting scoliosis?

“…Scoliosis has been listed as one of the top three diseases endangering the health of Chinese adolescents [ 6 ]. Screening for scoliosis in school-aged children is crucial for early detection, prevention of further deformities, and healthy child growth.…”

“…The progression of untreated idiopathic scoliosis may lead to severe deformities and may be accompanied by restrictive lung disease [ 4 ] and psychosocial issues [ 5 ]. In China, scoliosis has also been listed as one of the top three diseases endangering the health of adolescents [ 6 ].…”

Validation of a patient-specific finite element analysis framework for identification of growing rod-failure regions in early onset scoliosis patients

“…across FEA model predictions compared with the mean intra-observer variability for three patients [ 15 ]. The second area focuses on the same clinical outcomes but with different correction maneuvers and different instrumentation strategies [ 17 – 21 ]. For example, a recent study by Wang et al explored the effect of various configurations of rod contouring on three-dimensional spinal correction.…”