Artificial materials including various kinds of polymers like polyurethanes are more and more widely used in different branches of science and also in biomedical engineering. The paper presents the process of creating a constitutive equation for a polyurethane nanocomposite which is considered to be hyper-elastic. The constitutive modelling was conducted within the range of application of the material as one of the components of lumbar intervertebral disc prosthesis. In the paper, the biomechanics of the lumbar spine and the most frequently applied intervertebral disc prostheses are described. Also a polyurethane nanocomposite as a new material to be applied in prostheses is presented. The way of formulating a constitutive equation by means of mathematical formulae is described. Four various hyper-elastic potential functions are considered, i.e., Ogden, Neo-Hookean, Yeoh and Mooney-Rivlin. On the basis of monotonic compression tests the best hyper-elastic model for the material considered was chosen and hyper-elastic constants were calibrated. Finally, the constitutive model was validated on the basis of FE analysis. The paper ends with a conclusion and presentation of further plans of research directed towards the development of a constitutive equation and its application in computer simulations by means of the finite element method.
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Int J Mol Sci
December 2024
Department of Anesthesiology, Laboratory and Clinical Research Institute for Pain, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
Metabolic dysfunction has been demonstrated to contribute to diabetic pain, pointing towards a potential correlation between glucose metabolism and pain. To investigate the relationship between altered glucose metabolism and neuropathic pain, we compared samples from healthy subjects with those from intervertebral disc degeneration (IVDD) patients, utilizing data from two public datasets. This led to the identification of 412 differentially expressed genes (DEG), of which 234 were upregulated and 178 were downregulated.
View Article and Find Full Text PDFJ Clin Med
December 2024
Pain Clinic, Mersin City Education and Research Hospital, Mersin 33343, Turkey.
Recurrent lumbar disc herniation (RLDH) refers to a lumbar disc herniation (LDH) that recurs at the same level, location, and side following surgical repair. This study aimed to evaluate the efficacy of transforaminal epidural steroid injection (TESI) and dorsal root ganglion pulsed radiofrequency (DRG PRF) therapy with and without caudal epidural steroid injection (CESI) for the treatment of lumbar radicular pain (LRP) associated with RLDH. This retrospective cohort study included 57 patients treated for RLDH in a hospital pain clinic between September 2022 and February 2024.
View Article and Find Full Text PDFCells
December 2024
Department of Surgery, Divisions of Orthopaedic and Neurosurgery, University of Toronto, 661 University Ave., Suite 13-1387, Toronto, ON M5G 0B7, Canada.
Pain and disability secondary to degenerative disc disease continue to burden the healthcare system, creating an urgent need for effective, disease-modifying therapies. Contemporary research has identified potential therapies that include protein-, cellular- and/or matrix-related approaches; however, none have yet achieved a meaningful clinical impact. The tissue-specific realities of the intervertebral disc create considerable therapeutic challenges due to the disc's location, compartmentalization, hypovascularization and delicate physiological environment.
View Article and Find Full Text PDFWe present a novel technique to approach far lateral lumbar pathologies using a bitubular, biportal endoscopic system and a paramedian approach. Background: Conventional approaches for lumbar far lateral discectomy range from open approaches to newer minimally invasive approaches such as tubular discectomy and single portal endoscopic discectomy. We present a case of a patient suffering with a left L3-4 and left L4-5 extraforaminal disc herniation who was treated successfully with a left sided bitubular, biportal endoscopic 2 level far lateral discectomy.
View Article and Find Full Text PDFNeurospine
December 2024
University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
To demonstrate the preoperative workup, surgical planning and execution of transforaminal endoscopic thoracic discectomy (TETD) for a giant calcified disc herniation. Surgeries for symptomatic thoracic disc herniations are rare and challenging. The main goal is to achieve sufficient decompression with minimal manipulation of the spinal cord.
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