The importance of curve severity, type and instrumentation strategy in the surgical correction of adolescent idiopathic scoliosis: an in silico clinical trial on 64 cases

Abstract

Adolescent idiopathic scoliosis is a three-dimensional deformity of the spine which is frequently corrected with the implantation of instrumentation with generally good or excellent clinical results; mechanical post-operative complications such as implant loosening and breakage are however relatively frequent. The rate of complications is associated with a lack of consensus about the surgical decision-making process; choices about the instrumentation length, the anchoring implants and the degree of correction are indeed mostly based on personal views and previous experience of the surgeon. In this work, we performed an in silico clinical trial on a large number of subjects in order to clarify which factors have the highest importance in determining the risk of complications by quantitatively analysing the mechanical stresses and loads in the instrumentation after the correction maneuvers. The results of the simulations highlighted the fundamental role of the curve severity, also in its three-dimensional aspect, and of the instrumentation strategy, whereas the length of the fixation had a lower importance.

Surgical Outcome Prediction Using a Four-Dimensional Planning Simulation System With Finite Element Analysis Incorporating Pre-bent Rods in Adolescent Idiopathic Scoliosis: Simulation for Spatiotemporal Anatomical Correction Technique

“…There have been computational studies that similarly predicted 3D correction and implant loads ( Wang et al, 2016 ; Le Navéaux et al, 2016 ; La Barbera et al, 2021 ; Galbusera et al, 2021 ). These studies determined how several instrumentation parameters such as screw density and rod contouring angle affected correction and stress in the instrumentation.…”

“…In addition, most planning tools in AIS surgery only simulate morphology-based changes of the spinal alignment, lacking the biomechanical analysis (Ferrero et al, 2008; Pasha and Flynn, 2018 ; Shao et al, 2018 ). A planning simulator based on spatiotemporal morphological postoperative 4D changes with a patient-specific finite element analysis (FEA) can allow surgeons to predict postoperative outcomes and effectively assist in performing AIS surgery ( Galbusera et al, 2015 ; Wang et al, 2016 ; Le Navéaux et al, 2016 ; Cobetto et al, 2020 ; La Barbera et al, 2021 ; Galbusera et al, 2021 ).…”