The purpose of this study was to evaluate the wear and surface damage mechanisms of polyethylene in retrieved CHARITE total disc replacements. The retrieved implants showed evidence of adhesive/abrasive wear mechanisms in the central domed region of the implants. In addition, there was also evidence of macroscopic rim damage, including radial cracking, plastic deformation, and third body damage. The retrieved total disc replacements (TDRs) displayed surface damage observed previously in both hip and knee replacements. The information from this study will be useful for engineers seeking to adequately replicate long-term, clinically relevant damage modes of TDRs using in vitro testing methods.
Total disc replacement (TDR) was clinically introduced as an alternative to spinal fusion to relieve back pain, maintain mobility of the spine and eliminate the adverse side effects of fusion. More recently, gamma-inert-sterilized ultra-high molecular weight polyethylene (UHMWPE) TDR cores were introduced to replace historical gamma-air-sterilized cores in an effort to reduce UHMWPE wear debris and inflammation. In this study, both implant and periprosthetic tissue retrievals from patients with gamma-inert-sterilized TDRs were evaluated for in vivo performance and biological responses, respectively. As pain was the primary revision reason for all patients, the contributions of implant-related damage and tissue responses to the development of pain were also a focus of this investigation. After analyzing implants and tissues for 11 TDR patients, detectable UHMWPE wear debris was identified with corresponding macrophage infiltration in six patients with associated implant damage. Neither damage nor TDR bearing design, fixed vs mobile, influenced the amount, size and shape characteristics of wear particles. However, comparisons to a retrieval study of historical devices indicated that the number of UHMWPE particles generated from gamma-inert-sterilized devices were decreased by 99% (p=0.003) and were 50% rounder (p=0.003), confirming the improved wear resistance of the newer devices. Accordingly, periprosthetic tissue reactions were also substantially reduced. Prospective immunohistochemical investigations for these devices showed, for the first time, that UHMWPE wear-debris induced tissue reactions in the human lumbar spine can be linked to inflammation. First, inflammatory factors were elevated in TDR periprosthetic tissues (n=30) when compared to disc degenerative disease (DDD) patient tissues (n=3) from primary surgery and disc tissues (n=4) from normal autopsy patients with no history of lower back pain. The mean percent area of production for vascular endothelial growth factor (VEGF) (p=0.04), interleukin-1beta (IL-1[beta]), (p=0.01) and substance P (p=0.01) were significantly higher in TDR tissues when compared to tissues obtained from DDD patients. Although platelet derived growth factor-bb (PDGFbb) (p=0.14), tumor necrosis factor-alpha (TNF[alpha]) (p=0.06) and nerve growth factor (NGF) (p=0.19) were also increased in the TDR patient tissues, these increases were not significant. Compared to normal disc tissues, the mean percent area for all six factors was statistically increased in TDR tissues (at least p
This handbook is the most authoritative and up-to-date reference on spine technology written for practitioners, researchers, and students in bioengineering and clinical medicine. It is the first resource to provide a road map of both the history of the field and its future by documenting the poor clinical outcomes and failed spinal implants that contributed to problematic patient outcomes, as well as the technologies that are currently leading the way towards positive clinical outcomes. The contributors are leading authorities in the fields of engineering and clinical medicine and represent academia, industry, and international government and regulatory agencies. The chapters are split into five sections, with the first addressing clinical issues such as anatomy, pathology, oncology, trauma, diagnosis, and imaging studies. The second section, on biomechanics, delves into fixation devices, the bone implant interface, total disc replacements, injury mechanics, and more. The last three sections, on technology, are divided into materials, commercialized products, and surgery. All appropriate chapters will be continually updated and available on the publisher’s website, in order to keep this important reference as up-to-date as possible in a fast-moving field.
Joint replacement is a very successful medical treatment. However, the survivorship of the implants could be adversely affected due to the loss of materials in the form of particles or ions as the bearing surfaces articulate against earch other. The consequent tissue and immune response to the wear products, remain one of the key factors of their failure. Tribology has been defined as the science and technology of interacting surfaces in relative motion and all related wear products (e.g., particles, ions, etc.). Over the last few decades, in an attempt to understand and improve joint replacement technology, the tribological performance of several material combinations have been studied experimentally and assessed clinically. In addition, research has focused on the biological effects and long term consequences of wear products. Improvements have been made in manufacturing processes, precision engineering capabilities, device designs and materials properties in order to minimize wear and friction and maximize component longevity in vivo. This book investigates the in vivo and in vitro performance of the orthopaedic implants and their advanced bearings. Contributions are solicited from the researchers working in the field of biotribology and bioengineering
The third edition of Joint Replacement Technology provides a thoroughly updated review of recent developments in joint replacement technology. Joint replacement is a standard treatment for joint degradation and has improved the quality of life of millions of patients. Collaboration between clinicians and researchers is critical to its continued success and to meet the rising expectations of patients and surgeons.This edition covers a range of updated and new content, ranging from chapters on materials analysis and selection, to methodologies and techniques used for joint replacement and clinical challenges of replacing specific joints. Key topics include tribological considerations and experiments; challenges in joint bearing surfaces; cementless fixation techniques; healing responses to implants. Clinical challenges and perspectives are covered with the aid of case studies.Thanks to its widespread collaboration and international contributors, Joint Replacement Technology, Third Edition is useful for materials scientists and engineers in both academia and the biomedical industry. Chemists, clinicians, and other researchers in this area will also find this text invaluable. - This third edition provides an updated comprehensive review of recent developments in joint replacement technology - Reviews a range of specific joints, biological and mechanical issues and fixation techniques - Includes revised and new content, such as sections on regulatory affairs, AI techniques and 3D printing
Neurosurgery by Example: Key Cases and Fundamental Principles provides case-based, high yield content for the spine surgeon and neurosurgeons preparing for the American Board of Neurological Surgeons oral examination. It covers a wide array of spinal pathologies with their presentation, diagnosis, and treatment plans. Postoperative and complication management strategies are offered as well in order to prepare surgeons who can then provide comprehensive patient care for complex spine conditions.--Provided by publisher.
The challenge of treating complex spinal deformity often demands innovative solutions and greater skill than the initial surgical intervention; strategic planning is the critical element in successful surgical execution and outcome. Spinal Deformity: A Guide to Surgical Planning and Management, edited and written by the leading experts, is a landmark publication that provides critical information needed to safely plan, stage, and execute operations for the full range of complex spinal deformities. A Virtual Gold Mine of Information This book is an invaluable and practical tool for managing spinal deformities in your practice. Organized into four parts, it begins with a focus on recent advances in spine technology, starting with biomechanics, deformity classification, conservative management, and surgical indications. Subsequent chapters discuss technologic innovations, including spinal biologics, image guidance, and minimally invasive approaches for anterior and posterior spinal fusion. This introductory section is essential reading for the surgeon learning basic technique as well as for the experienced surgeon seeking to refine and enhance skills. The remaining parts focus on state-of-the-art surgical techniques for treating spinal deformity in the cervical spine, the thoracic spine, and the lumbosacral spine. Specific chapters have also been included on managing deformities at the cervicothoracic, thoracolumbar, and lumbosacropelvic junctions. In addition, both open and minimally invasive techniques are described. Organized with a consistent format, each technique chapter includes information on indications, planning and assessment, clinical problem solving, surgical technique, and postoperative care. A Who's Who of Spine Surgery The editors, Drs. Mummaneni, Lenke, and Haid; the part editors, Drs. Benzel, Kuklo, Resnick, and Shaffrey; and the contributors are world-renowned both neurosurgeons and orthopedic surgeons who have extensive experience in treating spinal deformity. Algorithms, Surgical Plans, and Tips and Tricks Aid in the Decision-Making Process Beautifully illustrated with step-by-step surgical technique, this book provides the practical advice, clinical nuances, and learning aids to assist you in the diagnosis and treatment of complex surgical deformities. Numerous imaging modalities are used to demonstrate the preoperative presentation as well as postoperative results. In addition, clinical problem-solving sections with treatment algorithms guide you in selecting the best surgical approach for each patient. Hundreds of case examples demonstrate the excellent results that can be achieved. To enhance the learning experience, an accompanying DVD with operative video is included.
The objective of this project is to develop a simplified, two-dimensional mathematical model of the lumbar spine for the purpose of studying the behavior the lumbar spine when affected by degenerative disc disease. Several hypothetical treatment options, including fusion and different types of artificial disc replacements (ADR) were examined. The cases presented consisted of three one-degree of freedom artificial discs, three two-degrees of freedom artificial discs, one ideal three-degrees of freedom artificial disc, a degenerated disc, a fused disc and a healthy spine. The equations of motion were generated for a healthy lumbar spine using Lagrange's equations and numerically integrated using Matlab®. Results were obtained for all cases at two different levels, L4-L5 and L5-S1 in response to an impulsive force of 100N applied at L3 in the posterior anterior direction. In the 1-DOF ADR cases at the L4-L5 level, the shear ADR performed better than the other two ADR, while at the L5-S1 level, the rotational ADR performed better than the other two ADR, and significantly better than the fused vertebrae case since it matched the behavior of the healthy spine much more closely. All the other 1-DOF ADR provided little or no improvement when compared to the fused case. In the 2-DOF ADR cases, the shear rotational ADR behaved very similarly to the healthy spine when implanted at both levels, L4-L5 and L5-S1, showing a behavior that varied by less than 1% in the posterior anterior direction and flexion extension rotation and less than 10% in the axial displacement when compared to the behavior of a healthy spine. Overall, the results of this thesis indicate that implanting an artificial disc to replace a damaged disc offers more benefits for the spine than fusion since this allows the spine to behave closer to the natural healthy spine, and hence most likely cause less damage to adjacent discs.
