To conclude, this study highlighted that cervical disc replacement with both the Bryan and Prestige LP discs not only preserved the motion at the operated level, but also maintained the normal motion at the adjacent levels. Under hybrid loading, the motion pattern of the spine with a TDR was closer to the intact motion pattern, as compared to the degenerative or fusion models. Also, in the presence of a pre-existing fusion, this study shows that an adjacent segment disc replacement is preferable to a second fusion.
Human intervertebral disc replacement is quickly becoming a superior substitute for cervical disc fusion as a surgical treatment for degenerative disc disease. The current disc implants share similar materials and show significant improvements over past designs. Scientific studies continue to evaluate the results of the implants compared to fusion, with the primary focus placed on the preservation of normal spine biomechanics with the articulating abilities of the implant versus absence of motion with fusion. This thesis investigated the biomechanical effects on the spine with eccentricity of the implant. More specifically, implantation at a location that is laterally offset from the midsagital axis, thus yielding misalignment to the patient's left or right from the geometric vertical axis. This study concentrates on the three main joints in the cervical spine and the load distribution on them due to a static axial loading case only. Three separate evaluations were used to compare results. A mechanical testing apparatus that simulates eccentric implantation was designed, built, and tested. Numerical and mathematical models of this apparatus completed the trio of evaluations. The results showed a characteristic that is linear. That is, minor offsets in the order of millimeters demonstrate significant increases in static loads on the facet furthest from the implant. A consideration of these results and research suggests that this could be the cause of long-term facet degeneration. The conclusion of this thesis suggests future research is needed to further understand this phenomenon, improve the surgical technique, or improve the implant, all in order to either better understand the biomechanical sacrifices with eccentric implantation or eliminate it all together.
This issue of Neurosurgery Clinics, guest edited by Dr. Domagoj Coric, provides an Update on Motion Preservation Technologies. This issue is one of four selected each year by our series consulting editors, Drs. Russell R. Lonser and Daniel K. Resnick. This issue discusses state-of-the-art indications, technique, devices, complications and evidence basis for motion preserving technologies in the cervical and lumbar spines. Topics covered in this issue will include: Cervical Total Disc Replacement: Indications and Technique, Cervical Total Disc Replacement: Off-label and Expanded Indications, Cervical Total Disc Replacement: FDA-approved Devices, Cervical Total Disc Replacement: Novel Devices, Cervical Spine Surgery: Arthroplasty versus Fusion versus Posterior Foraminotomy, Cervical Total Disc Replacement: Complications and Complication Avoidance, Cervical Total Disc Replacement: Long-term Outcomes, Biomechanics of Cervical Arthroplasty Devices, Adjacent-level Disease following Spinal Arthroplasty, Lumbar Total Disc Replacement: Current Usage, and Posterior Lumbar Facet Replacement and Arthroplasty.
Thieme congratulates Frank P. Cammisa on being chosen by New York magazine for its prestigious 'Best Doctors 2015' list. Dynamic Reconstruction of the Spine, Second Edition is the most up-to-date resource on the instrumentation, technologies, and fundamental science integral to achieving spine motion preservation and stabilization. It is a completely revised text that includes not only the latest technologies and surgical approaches, including MIS techniques, but also significantly more detail on the clinical biomechanics of the spine than the previous edition. Readers will appreciate the guidance this book provides on how to: successfully adopt new technology, find appropriate indications, address common safety and efficacy issues, and answer health economics questions for ethics committees and payers. Key Features: A substantial revision, with entirely new chapters in three quarters of the book, including a large section on basic as well as more advanced biomechanics topics Highly visual - contains 20% more figures than the previous edition Discusses and explains current advances in genetic and molecular technologies used to repair the spinal disc Includes an unbiased critique of the pro cons, clinical outcomes, and comparative outcomes of different devices This new edition is an indispensable reference for orthopedic surgeons, neurosurgeons, and radiologists, as well as residents and fellows seeking the latest information on the technologies used in spine motion preservation and stabilization.
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.
Anterior cervical disc fusion (ACDF) has been a treatment for degenerative disc disease for the last 50 years. ACDF, with a success rate of 95 percent, has been established as the primary method for treating disc disease. However, the fusion approach eliminates motion, which is philosophically different from technologies developed to treat other articulating joints. Subsequently, ACDF is believed to accelerate degeneration in spinal motion segments adjacent to the treated level and lead to cascading failures of the nearby discs. The desire to eliminate such cascading failures has prompted the development of an articulating cervical disc implant (ACDI). The objective of this research was to compare the mechanical behavior of a cervical spine specimen following ACDI with the mechanical behavior of the same specimen following ACDF. A mechanical testing device was developed to induce a controlled, pure moment loading scheme and to facilitate near physiological flexion-extension motion. The measures used to quantify the comparison were global kinematics, segmental kinematics, and intradiscal pressures. This study concluded the performance of the ACDI was at least equivalent to ACDF. Furthermore, this study suggested the ACDI promoted more energy absorption within the cervical spine and transferred less stress to adjacent discs at higher loads than the ACDF, but more tests are required to increase our confidence in this interesting possibility.
Over the past decade, there has been rapid growth in bioengineering applications in the field of spine implants. Spine Technology Handbook explains the technical foundation for understanding and expanding the field of spine implants, reviews the major established technologies related to spine implants, and provides reference material for developing and commercializing new spine implants. The editors, who have a track record of collaboration and editing technical books, provide a unified approach to this topic in the most comprehensive and useful book to date. Related website provides the latest information on spine technology including articles and research papers on the latest technology and development Major technologies reviewed include devices used for fusion (screws, plates, rods, and cages), disc repair and augmentation, total disc replacement, and vertebral body repair and augmentation Technology landscape, review of published/public domain data currently available, and safety and efficacy of technology discussed in detail
