Ensuring anatomical integrity and shared contact surfaces in vertebra and disc models: a segmentation-based smoothing approach

Due to limited MRI resolution, patient-specific simulation models derived from medical images often lack bio-fidelity. To address this, we present a smoothing pipeline for generating high-fidelity meshes of vertebrae and intervertebral discs from medical images, which serve as a base for biomechanical simulations. Using a diverse array of vertebrae smoothing algorithms, including e.g. Laplace and Taubin, we systematically explored 136 combinations across six protocols. Subsequently, an adaptive smoothing algorithm was developed for intervertebral disc meshes. By adjusting vertex locations to those of the vertebra mesh, we ensured seamless alignment of contact surfaces, including shared nodes. Evaluation of our pipeline against conventional smoothing methods demonstrates superior edge preservation and reduced stair-step effects, enhancing the fidelity of the generated meshes. Finite Element Method simulations further confirmed the accuracy of our selective smoothing pipeline, showing increased notch stress. Validated on a diverse dataset, our smoothing pipeline generates patient-specific models with enhanced biomechanical fidelity, enabling large-scale studies and biomechanical insights into spine pathologies.