In vitro comparison of a new stand-alone anterior lumbar interbody cage device with established fixation techniques

Around 70% of the population in the United States experience low back pain at some point of their lives, of these 4% underwent surgical intervention on the lumbar spine to relieve the pain. Spinal arthrodesis, i.e. joint fusion, is beneficial in many cases as the final option for patients suffering from certain types of low back pain (LBP). In order to promote solid fusion across a decompressed spinal segment, interbody spacers/cages are used with and without posterior instrumentation to provide an initial rigid fixation of the segment. In this study three fresh/frozen human cadaveric lumbar spines were used. Each lumbar spine was dissected into two Functional Spinal Units (FSUs, L3-L4 and L5-S1) making a total of 6 motion segments. The objective of this study was to evaluate the biomechanical behavior of a new stand-alone anterior lumbar interbody device, by assessing its performance in terms of FSU motion in comparison with the intact FSU and FSUs additional posterior fixation (i.e., facet bolts and pedicle screws). Descriptive statistics and analysis of variance (ANOVA) was used to determine if the differences between the different treatment groups are significant or not. Statistical analysis was also used to determine the contribution of the supplemental fixation for the anterior interbody fusion device (AFD) system

Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization

In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.). The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging. In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place. We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf

Combined numerical and morphological study of the lumbar spine: parametric finite element model and evaluation of dynamic implants

Low back pain is a major cause of disability and requires the development of new devices to treat pathologies and improve prognosis following surgery. Finite Element (FE) Methods represent an appealing solution to provide mechanical evaluations of new devices speeding up the design process, as well as evaluating several anatomical scenarios. The aim of this thesis was to develop an accurate FE of the lumbar spine and the evaluation of the variability introduced by morphological and material parameters. The generation of the geometrical model were implemented in a toolbox, the LMG (Lumbar Model Generator), with dimensions based on correlation analyses or subject-specific measurements. It allows the automatic preparation of the FE model, performing the mesh generation and evaluation, assigning material properties, boundary conditions and analysing the results. The FE model of a functional unit (L1-L2) was evaluated and the FE results were in agreement with studies available in literature. Sensitivity analyses on the material properties and morphological parameters were performed and the most influential parameters identified. Moreover, the mechanical behaviour of two devices, the BDyn (S14 Implants (Pessac, France)) and the GsDyn (a device for the paediatric scoliosis developed as part of the Spinal Implant Design project) were evaluated

Additively manufactured metallic biomaterials

Metal additive manufacturing (AM) has led to an evolution in the design and fabrication of hard tissue substitutes, enabling personalized implants to address each patient's specific needs. In addition, internal pore architectures integrated within additively manufactured scaffolds, have provided an opportunity to further develop and engineer functional implants for better tissue integration, and long-term durability. In this review, the latest advances in different aspects of the design and manufacturing of additively manufactured metallic biomaterials are highlighted. After introducing metal AM processes, biocompatible metals adapted for integration with AM machines are presented. Then, we elaborate on the tools and approaches undertaken for the design of porous scaffold with engineered internal architecture including, topology optimization techniques, as well as unit cell patterns based on lattice networks, and triply periodic minimal surface. Here, the new possibilities brought by the functionally gradient porous structures to meet the conflicting scaffold design requirements are thoroughly discussed. Subsequently, the design constraints and physical characteristics of the additively manufactured constructs are reviewed in terms of input parameters such as design features and AM processing parameters. We assess the proposed applications of additively manufactured implants for regeneration of different tissue types and the efforts made towards their clinical translation. Finally, we conclude the review with the emerging directions and perspectives for further development of AM in the medical industry.National Institutes of Health || The Natural Sciences and Engineering Research Council of Canada || Network for Holistic Innovation in Additive Manufacturin

Trauma, Tumors, Spine, Functional Neurosurgery

This book is written for graduate students, researchers, and practitioners who are interested in learning how the knowledge from research can be implemented in clinical competences. The first section is dedicated to deep brain stimulation, a surgical procedure which is the paramount example of how clinical practice can take advantage from fundamental research. The second section gathers four chapters on four different topics and illustrates how significant is the challenge to translate scientific advances into clinical practice because the route from evidence to action is not always obvious. It is hoped that this book will stimulate the interest in the process of translating research into practice for a broader range of neurosurgical topics than the one covered by this book, which could result in a forthcoming more comprehensive publication

Análise e projecto de estruturas para substituição do disco intervertebral

Dissertação para obtenção do Grau de Mestre em Engenharia MecânicaA presente dissertação tem como principal objectivo a análise e projecto de estruturas para substituição de um disco intervertebral. Mais especificamente, determinar a distribuição de material que oferece a maior rigidez possível ao dispositivo de substituição considerando um constrangimento de volume. Tal foi conseguido efectuando, numa fase inicial, um estado de arte sobre a área da medicina da coluna vertebral humana e alguns procedimentos cirúrgicos relativos à substituição do disco intervertebral. Uma revisão de trabalhos na área da fusão intervertebral e optimização topológica foi feita, entre eles, de um modo mais aprofundado, um modelo de elementos finitos duma coluna lombar suína. Neste tinha sido efectuada uma análise e optimização de um dipositivo de fusão intervertebral. Com os conhecimentos adquiridos no decorrer destas várias pesquisas e revisões de trabalhos anteriormente realizados, foi então possível analisar e melhorar um modelo de elementos finitos da coluna lombar humana. Esta possuía um dispositivo de fusão intervertebral que foi posteriormente optimizado utilizando um método de optimização topológica através de um código de programação escrito em FORTRAN. Outros assuntos em estudo no decorrer desta dissertação incluem análises linear e não linear, método da homogeneização para identificação de propriedades mecânicas de scaffolds. O estudo destes assuntos aplica o método dos elementos finitos através do software ANSYS

Defining Multi-Scale Relationships Between Biomechanics & Neuronal Dysfunction In Ligament Pain Using Integrated Experimental & Computational Approaches

Capsular ligaments can encode the mechanical state of joints owing to their innervation. For example, the spinal facet capsular ligament that encloses the facet joint is innervated by mechanoreceptors and nociceptors, and is a major source of neck and low back pain from aberrant spinal motions. The cervical facet capsule is commonly injured by its excessive stretch during neck trauma. Although supraphysiologic deformation of the facet capsular ligament can activate its afferents and induce pain, the local biomechanical and neuronal mechanisms underlying sensory transduction for pain from mechanical inputs remain unclear. The studies in this thesis use integrated in vitro, in vivo and in silico methods to investigate the interplay between the mechanical and nociceptive functions of the cervical facet capsular ligament. Tissue-level mechanics, collagen network restructuring and neuronal dysfunction are all assessed across length scales using a neuron collagen construct (NCC) system as well as animal and computational modeling. Afferent activation, nociception and dysfunction are found to depend on the macro-scale tissue strains. Yet, relationships between macroscopic stretch and micro-scale pathophysiology in the facet capsule is confounded by its heterogeneous fibrous architecture. Studies in this thesis show that localized collagen disorganization is associated with excessive network-level reorganization and fiber-level stretch using network analysis and finite element-based modeling. Integrated imaging of the extracellular matrix structure and neuronal dysfunction in the NCC system provides evidence for collagen network organization and local fiber kinematics as mediators of pain-related neuronal signaling. Stretch-induced production of nociceptive neuropeptides in NCCs is prevented by inhibiting collagen-binding integrins, supporting a role of cell-matrix adhesion in converting noxious mechanical stimuli in to pain signals. Further, neuronal mechanotransduction that initiates pain is found to involve the intracellular RhoA/Rho kinase ROCK. In vivo studies in the rat suggest that intra-articular ROCK likely contributes to the development of central sensitization and facet joint pain, possibly via neuropeptide-mediated synaptic transmission and spinal microglial activation. Collectively, these findings establish the role of collagen networks and fibers in translating macroscopic ligament stretch in to neuronal pain signals and identify mechanotransductive signaling cascades that have clinical relevance as possible treatment for trauma-induced facet pain

Haptics Rendering and Applications

There has been significant progress in haptic technologies but the incorporation of haptics into virtual environments is still in its infancy. A wide range of the new society's human activities including communication, education, art, entertainment, commerce and science would forever change if we learned how to capture, manipulate and reproduce haptic sensory stimuli that are nearly indistinguishable from reality. For the field to move forward, many commercial and technological barriers need to be overcome. By rendering how objects feel through haptic technology, we communicate information that might reflect a desire to speak a physically- based language that has never been explored before. Due to constant improvement in haptics technology and increasing levels of research into and development of haptics-related algorithms, protocols and devices, there is a belief that haptics technology has a promising future