A Review of Applicable Materials for 3D Printing a Biomechanically Accurate Cervical Spine Model for Surgical Education & Case Preparation

Objectives: The authors review the literature to compare biomechanical properties of the human cervical spine as determined by cadaveric and finite elemental model (FEM) studies, with commercially available three-dimensional (3D) printing materials to aid in the development of 3D-printed cervical spines that can be used as biomechanically accurate educational tools. Specifically, 3D printing materials for fused deposition modeling (FDM) printers were explored. Methods: A literature review of biomechanical specifications such as Young’s Modulus and Poisson’s ratio of certain anatomical aspects of the cervical spine was performed by searching the databases PubMed, MEDLINE via Ovid, Wolters Kluwer, ClinicalKey, and EMBASE via Elsevier for keywords. The anatomical features that were investigated included cortical and cancellous bone, facet joints, intervertebral discs, and ligaments. Additionally, datasheets from companies Stratasys, Fillamentum, NinjaTek, SD3D, Polymakers, Lubrizol and BASF were compiled to review the specifications and mechanical properties of their 3D printing materials. Results: Suggested FDM 3D printing materials were assigned to anatomical features of the cervical spine according to their respective biomechanical properties, namely: cortical and cancellous bone, facet joint articular cartilage and the synovial membrane, both the ground substance and fibers of the annulus fibrosus, nucleus pulposus, anterior and posterior longitudinal ligaments, ligamenta flava, interspinous ligaments, and capsular ligaments. Conclusions: FDM 3D printing can improve development of cervical spine models for educational use and surgical case preparation. Commercially available materials and techniques exist to simulate all of the major anatomical components of the cervical spine

Novel validation of a 3D nonlinear finite element head-neck model for kinematical applications

Computational biomechanical models have the potential to broaden our understanding and to aid the work of many practicing medical professionals. However, these models are only reliable, thus applicable and valuable, insofar as they are able to replicate a specific portion of reality. Therefore, validation of computational models is indispensable. To ensure that our proposed 3D finite element head-neck model does bear meaningful resemblance to real cervical spines, we relied on all available relevant rotation-moment measurements. Previously proposed validation metrics were used to quantify model error and experimental uncertainties. These metrics may be adopted for a wide range of other applications as well. Our model was found to be adequate for the study of kinematical properties of the human cervical spine