Creation of a three-dimensional printed spine model for training in pain procedures

Objective Technological developments have made it possible to create simulation models to educate clinicians on surgical techniques and patient preparation. In this study, we created an inexpensive lumbar spine phantom using patient data and analyzed its usefulness in clinical education. Methods This randomized comparative study used computed tomography and magnetic resonance imaging data from a single patient to print a three-dimensional (3D) bone framework and create a mold. The printed bones and structures made from the mold were placed in a simulation model that was used to train residents. The residents were divided into two groups: Group L, which received only an audiovisual lecture, and Group P, which received an additional 1 hour of training using the 3D phantom. The performance of both groups was evaluated using pretest and post-test analyses. Results Both the checklist and global rating scores increased after training in both groups. However, some variables improved significantly only in Group P. The overall satisfaction score was also higher in Group P than in Group L. Conclusions We have described a method by which medical doctors can create a spine simulation phantom and have demonstrated its efficiency for procedural education.

Biomechanics of Lumbar Spine Injury in Road Barrier Collision–Finite Element Study

Literature and field data from CIREN database have shown that lumbar spine injuries occur during car crashes. There are multiple hypotheses regarding how they occur; however, there is no biomechanical explanation for these injuries during collisions with road safety barriers (RSBs). Therefore, the objective of this study was to investigate the mechanics of vertebral fractures during car collisions with concrete RSBs. The finite element method was used for the numerical simulations. The global model of the car collision with the concrete RSB was created. The lumbar spine kinematics were extracted from the global simulation and then applied as boundary conditions to the detailed lumbar spine model. The results showed that during the collision, the occupant was elevated, and then dropped during the vehicle landing. This resulted in axial compression forces 2.6 kN with flexion bending moments 34.7 and 37.8 Nm in the L2 and L3 vertebrae. It was shown that the bending moment is the result of the longitudinal force on the eccentricity. The lumbar spine index for the L1–L5 section was 2.80, thus indicating a lumbar spine fracture. The minimum principal strain criterion of 7.4% and damage variable indicated L2 and L3 vertebrae and the inferior part of L1, as those potentially prone to fracture. This study found that lumbar spine fractures could occur as a consequence of vehicle landing during a collision with a concrete RSB mostly affecting the L1–L3 lumbar spine section. The fracture was caused by a combination of axial forces and flexion bending moments.

Biomechanical Analysis of the Spine in Diffuse Idiopathic Skeletal Hyperostosis: Finite Element Analysis

Patients with diffuse idiopathic skeletal hyperostosis (DISH) develop fractures of the vertebral bodies, even in minor trauma, because of the loss of flexibility, which causes difficulties in fusing vertebrae; therefore, the diagnosis of spine injuries may be delayed. We used the three-dimensional finite element method to add data on ossification to the healthy vertebral model in order to investigate how stress in intervertebral discs changes with bone shape and whether these changes present any risk factors. A healthy spine model and a DISH flat model (T8–sacrum) were generated from medical images. As an ossified hypertrophic model, T11–T12 was cross-linked with hypertrophic ossification, and hypertrophy was found to be 5 and 10 mm. An ossifying hypertrophic groove model (5 and 10 mm) was created at T11–T12 and T11–L1. A groove was created at the center of T12, and the radius of curvature of the groove was set to 1 and 2.5 mm. An extension force and flexion force were applied to the upper part of T8, assuming that external forces in the direction of flexion and extension were applied to the spine. Stresses were greater in the DISH flat model than in the healthy model. In the hypertrophic ossification model, the stress on the vertebral body was similar to greater ossification in extension and flexion. In the ossified hypertrophic groove model, the stress at the center of the groove increased. In DISH, vertebrae are more susceptible to stress. Furthermore, depending on the morphology of ossification, stresses on the vertebrae and intervertebral discs differed even with similar loads. An examination of ossification geometry may help surgeons decide the thoracolumbar spine’s stress elevated position in patients with DISH, thereby contributing to the understanding of the pathogenesis of pain.

Artificial intelligence data-driven 3D model for AIS

Scoliosis is a 3D deformation of the spinal column, characterized by a lateral deviation of the spine, accompanied by axial rotation of the vertebrae. Adolescent Idiopathic Scoliosis (AIS), is the most common type, affecting children between ages 8 to 18 when bone growth is at its maximum rate. The selection of the most appropriate treatment options is based on the surgeon’s experience. So, developing a clinically validated patient-specific model of the spine would aid surgeons in understanding AIS in early stages and propose an efficient method of treatment for the individual patient. This project steps include: Developing a clinically validated patient-specific Reduced Order Finite Element Model (ROFEM) of the spine, predicting AIS progression using data mining and proposing a method of treatment. First we implement FE synergistically with bio-mechanical information, image processing and data science techniques to improve predictive ability. Initial geometry of the spine will be extracted from the x-ray images from different planes and imported to FEM software to generate the spine model and perform analysis. A RO model is developed based on the detailed spinal FEM. Next, a neural network is used to predict the spinal curvature. The ability to predict the severity of AIS will have an immense impact on the treatment of AIS-affected children. Access to a predictive and patient-specific model will enable the physicians to have a better understanding of spinal curvature progression. Consequently, the physicians will be able to educate families, choose the most appropriate treatment option and asses for surgical intervention.

Effect of Model Parameters on the Biomechanical Behavior of the Finite Element Cervical Spine Model

Finite element (FE) models have frequently been used to analyze spine biomechanics. Material parameters assigned to FE spine models are generally uncertain, and their effect on the characterization of the spinal components is not clear. In this study, we aimed to analyze the effect of model parameters on the range of motion, stress, and strain responses of a FE cervical spine model. To do so, we created a computed tomography-based FE model that consisted of C2-C3 vertebrae, intervertebral disc, facet joints, and ligaments. A total of 32 FE analyses were carried out for two different elastic modulus equations and four different bone layer numbers under four different loading conditions. We evaluated the effects of elastic modulus equations and layer number on the biomechanical behavior of the FE spine model by taking the range of angular motion, stress, and strain responses into account. We found that the angular motions of the one- and two-layer models had a greater variation than those in the models with four and eight layers. The angular motions obtained for the four- and eight-layer models were almost the same, indicating that the use of a four-layer model would be sufficient to achieve a stress value converging to a certain level as the number of layers increases. We also observed that the equation proposed by Gupta and Dan (2004) agreed well with the experimental angular motion data. The outcomes of this study are expected to contribute to the determination of the model parameters used in FE spine models.

Parameter Dependencies of a Biomechanical Cervical Spine FSU - The Process of Finding Optimal Model Parameters by Sensitivity Analysis

The knowledge about the impact of structure-specific parameters on the biomechanical behavior of a computer model has an essential meaning for the realistic modeling and system improving. Especially the biomechanical parameters of the intervertebral discs, the ligamentous structures and the facet joints are seen in the literature as significant components of a spine model, which define the quality of the model. Therefore, it is important to understand how the variations of input parameters for these components affect the entire model and its individual structures. Sensitivity analysis can be used to gain the required knowledge about the correlation of the input and output variables in a complex spinal model. The present study analyses the influence of the biomechanical parameters of the intervertebral disc using different sensitivity analysis methods to optimize the spine model parameters. The analysis is performed with a multi-body simulation model of the cervical functional spinal unit C6-C7.