Biomimetic Lumbar Artificial Intervertebral Disc

Biomimetic lumbar Artificial intervertebral pho zero(prenominal)raph recordRapid Prototyping of a Biomimetic Lumbar Artificial Intervertebral Disc for Total Disc fill-in ArthroplastyAbstractIntervertebral books (IVDs) are batty tissues that provide flexibility to the vertebral column by transmitting and distributing the large slews that act on the spine. retroversion of any of the IVD components may cause low back inconvenience oneself (LBP) in a significant amount of the worlds population due to salmagundi in the good disks mechanics. IVD arthroplasty or total criminal record replacement (TDR) is an alter(a) to spinal fusion by allowing some movement to be constructd to the patient. alive counterfeit book replacements ( supports) have not the same properties of a nervous strain biological IVDs, and may cause notwithstanding complications such as metallosis, osteolysis, and set dislodgement. certainly, there exist no emboldens that allow the same wave of motion , mechanised performance, and comparable life span to a biological IVD. This projects seeks to hold a mushy and flexible biomimetic precaution with equivalent mechanical properties by rapid prototyping to be able to personalize the constitute to suit the anatomic characteristics of each individual.BackgroundThe spinal column provides rigidity and stability to the bod it is divided into 4 distinct spinal regions cervical (C1 C7), thoracic (T1 T12), lumbar (L1 L5), and sacral (S1 S5). Each section of the spine is composed of osseous elements called vertebrae scattered by intervertebral discs (IVD) attached to the surfaces of the vertebral bodies. IVDs are composed of soft tissue with three main components the gelatinous nucleus pulposus (NP) at the centre, the ring concentric collagen layers of the annulus fibrosus (AF), and the cartilaginous endplates that attach the NP and the AF to the vertebral bodies. Degene hind endion of any of these soft tissues will cause the mec hanical behaviour of the entire disc to change 1. In particular, degeneration of the nucleus pulposus causes the loss of osmotic pressure and hydration. Consequently, the fluid exchange is reduced and affects the tissues cellular function and disc height diminution. Producing as a result an increase in disc instability and impingement of the roots of the spine triggering discogenic torture 2 3.IVD degeneration in any of the spinal regions directly contributes to instability, axial back pain 3. The strongest coalition forces that affect the components of the spine are experienced at the height of the lumbar-sacral regions (L4-L5 and L5-S1) 4 5 6 a good deal resulting in lumbar or low back pain (LBP) 3. LBP is the imprimatur most frequent reason for a medical intervention in the the States 7, affecting an estimated 80% 6 of the worlds population at some heighten of their lives with an estimated economic impact of approximately $100 billion in the USA 8 9, and 12 billion in the UK 10 per annum.While surgery is not the scratch line choice to treat discogenic pain, it is considered after a six month flow rate of conservative pain management fails to ease the patients pain 3 6. Surgical options for LBP take dynamic stabilization, spinal fusion, and total disc replacement (TDR) surgery 3 6. TDR is an alternative treatment that may be employ in some patients kind of of spinal fusion 3 it consists removing the damaged IVD and employ a mechanical blind to replace it and restore movement to the affected zone 1 3 11. This method aims to restore movement to the spine and prevent early degeneration and disease of contiguous segments that may be caused by the load and motion redistribution of a amalgamated spinal segment 3 12 TDR has a significantly reduced surgery time, shorter postoperative recuperation, improved patient recovery, and acceptable level of morbidity 3 11 13. Among the most used artificial intervertebral discs (AIDs) commercially acquirable now include Charite artificial discs (Depuy, Johnson and Johnson) 14 13, ProDisc-L (DePuy Synthes) 3 13.Statement of the ProblemAIDs are more comm sole(prenominal) do from hard materials, such as metals, ceramics and hard polymers 11 13 15, but these experience conk out and may even result in metallosis, osteolysis and imbed dislodgement 11 16 Current technologies consist mostly of superposed metallic plates with an otherwise core material playing as the nucleus pulposus. The surfaces of the implants connected to the vertebras may lead to the formation of nasty bonds that cause clashing movements between the plate and core materials hinder the implant-bone embrasure. In reality, these AIDs have limited mobility compared to recipe biological IVDs, and may further deteriorate the patients condition by dislodging from the vertebral bodies or releasing junk from the wear and friction of the implant 11 17. Flexible AIDs made from polymeric materials have been deemed as unable to su stain the high mechanical loads of the spine 15.Shikinami et al pioneered a flexible 3D woven textile AID made form bioinert ultrahigh molecular weight polyethylene (UHMWPE) 16. Their AID consisted of mimicking the collagenous fibre arrangement of a normal biological IVD using a triaxial fibre arrangement able to exhibit similar mechanical properties to a forgiving IVD however, they acknowledged that wear debris occurred at the bone-implant interface in vitro and their fixation method could cause direct bonding to the vertebral bodes or cause fibrous connective tissues to cover the interface 17. The Bonassar meeting at Cornell University have devised a composite AID made form TE-TDR and ovine AF and NP cell. After being implanted in the rat caudal lumbar spine for six months, it was shown to maintain adequate disc height (78%) and ECM deposition into the vertebral bodies and endplate. Nevertheless, this composite AID was only tested axially and it is not known if such composite w ould be able to resist bending and torsion 18.More recently, a coalesced deposition modelling (FDM) 3D printed composite TE-TDR PCL scaffold was created to replicate a rabbit IVD 19. Their results show that their model exhibited higher compressive stiffness than that of a military man IVD and prove that personalised implants created by rapid prototyping are promising in the future. However, their proposed implant does not mimic the internal structure of a normal biological IVD. Thus far, there are no commercial AID implants that cater to the unique anatomical features of each individual. Furthermore, current soft AID implants being investigated have the following concerns these seldom mimic the radially alternating lamellas of the AF, have been thoroughly tested in the six degrees of freedom that the human spine endures, or promote appropriate implant vertebral body integration. investigate ObjectivesThe guiding research question is Would a 3D printed soft biomimetic AID be abl e to have the same mobility and mechanical properties of a normal biological IVD? This involves the following specific objectivesTo create an accurate 3D printed biomimetic implant mimicking the radially alternating lamellas of the annulus fibrosus.Assess the implants endurance and drop resistance.To promote cellular integration of the implants top and bottom surfaces into the vertebral bodies without hindering the implants performance.Compare the biomimetic implant to commercially available AIDs implants.MethodologyThe research plan will proceed in two phases. During the world-class phase, 1) I will collect anthropometric data to generate a geometrically accurate IVD model from CT/MRI databases using Materialise Mimics (Materialise NV). From this model, 2) I will create a detent model of a biomimetic IVD implant mimicking the AF lamellas , and 3) perform FEA on the model to determine if the chosen materials will be able to sustain the in vivo loads a natural IVD experiences. In this first phase, I will also perform FEA analysis of commercially available artificial disc implants and compare them to our biomimetic IVD implant. The final step of the first phase is to 3D print the biomimetic model and if needed 4) optimize it to paper for any warping or curling of the material, or any other defects caused by the rapid prototyping.During the second phase, 5) I will test implant wear, endurance, and other mechanical properties and 6) biocompatibility and osseous integration to the top and bottom surfaces of the biomimetic IVD and respect cellular attachment to the vertebras. I will also 7) compare our biomimetic IVD to commercially available artificial discs such as Charite (Depuy, Johnson and Johnson) and ProDisc-L (DePuy Synthes).Tentative TimelinePhase 1 GreenPhase 2 Blue201820192020 nightfallSpringFallSpringFallSpringFallFinalize project comment1) Anthropometric data acquisition2) Biomimetic CAD model of IVD implant.3) FEA analysis of CAD model4) 3D print ing optimization of model5) Mechanical test of 3D printed model6) Biocompatibility and integration of biomimetic IVD implant7) Comparison to commercially available TDR implants8) Preparing Thesis and DefenseDefense XReferences1D. H. Cortes and D. M. Elliot, The Intervertebral Disc Overview of Disc Mechanics, in The Intervertebral Disc, Springer-Verlag Wien, 2014, pp. 17-31.2S. M. Richardson, A. J. Freemont and J. A. Hoyland, Pathogenesis of Intervertebral Disc Degeneration, in The Intervertebral Disc, Springer-Verlag Wien, 2014, pp. 177-200.3D. G. Sueki and B. 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