ORCID Profile
0000-0001-8377-5343
Current Organisations
Queensland University of Technology
,
Queensland University of Technology (QUT)
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Timber, Pulp and Paper | Manufacturing Engineering | Manufacturing Processes and Technologies (excl. Textiles) | Petroleum and Reservoir Engineering
ANZSRC Socio-Economic Objective (SEO)
Wood, Wood Products and Paper not elsewhere classified | Oil and Gas Extraction | Fabricated Metal Products not elsewhere classified |
Related Links
Publications
Toward Patient Specific Models of Pediatric IVDs: A Parametric Study of IVD Mechanical Properties
Publisher: Frontiers Media SA
Date: 15-02-2021
DOI: 10.3389/FBIOE.2021.632408
Abstract: Patient specific finite element (FE) modeling of the pediatric spine is an important challenge which offers to revolutionize the treatment of pediatric spinal pathologies, for ex le adolescent idiopathic scoliosis (AIS). In particular, modeling of the intervertebral disc (IVD) is a unique challenge due to its structural and mechanical complexity. This is compounded by limited ability to non-invasively interrogate key mechanical parameters of a patient's IVD. In this work, we seek to better understand the link between mechanical properties and mechanical behavior of patient specific FE models of the pediatric lumbar spine. A parametric study of IVD parameter was conducted, coupled with insights from current knowledge of the pediatric IVD. In particular, the combined effects of parameters was investigated. Recommendations are made toward areas of importance in patient specific FE modeling of the pediatric IVD. In particular, collagen fiber bundles of the IVD are found to dominate IVD mechanical behavior and are thus recommended as an area of primary focus for patient specific FE models. In addition, areas requiring further experimental research are identified. This work provides a valuable building block toward the development of patient specific models of the pediatric spine.
Quantifying Anterior Chest Wall Deformity in Adolescent Idiopathic Scoliosis: Correlation With Other Deformity Measures and Effects of Anterior Thoracoscopic Scoliosis Surgery
Publisher: Springer Science and Business Media LLC
Date: 05-2019
DOI: 10.1016/J.JSPD.2018.09.069
Abstract: Retrospective cohort study. This study investigated how anterior chest wall deformity is affected by thoracoscopic anterior scoliosis fusion (TASF) surgery in adolescent idiopathic scoliosis patients. We aimed to determine correlations pre- and postoperatively with other clinical and radiological scoliosis measures. Scoliosis surgery aims to halt progression of the deformity, and to reduce its severity. Currently, deformity correction is clinically measured in terms of Cobb angle and rib hump (RH) however, a significant cosmetic concern for patients is anterior chest wall deformity. Pre- and postoperative CT scans of 28 female, Lenke type 1 patients with a mean preoperative Cobb angle of 50.2° ± 7.1° were retrieved from the Research Group's surgical database. Using ImageJ, 3D reconstructions of the thorax were created. Two observers measured the anterior chest wall deformity as a chest wall angle (CWA) and posterior deformity as a posterior apical deformity angle (PDA). We investigated pre- to postoperative changes in CWA, PDA, RH, and Cobb angle as well as their interrelationship. All deformity parameters (Cobb angle, RH, CWA, and PDA) showed statistically significant improvement post TASF. Correlation was found between RH and Cobb angle pre- and postoperatively, Cobb angle and CWA preoperatively and between postoperative change in Cobb angle and CWA. No relationship was found between CWA and RH or PDA. Anterior chest wall deformity is independent from the posterior chest wall measures RH and PDA, indicating that the anterior chest wall deformity is not reflected in the posterior rib cage. The correlation between Cobb angle and CWA indicates that the deformity in the spine and the deformity in the ribs are related, and shows that the anterior chest wall deformity is improved post thoracoscopic anterior scoliosis fusion surgery as the lateral deviation of the spine is corrected. Level III.
Morphological changes in the respiratory system: an MRI investigation of differences between the supine and left lateral decubitus positions
Publisher: Informa UK Limited
Date: 26-04-2021
Are coupled rotations in the lumbar spine largely due to the osseo-ligamentous anatomy?—A modeling study
Publisher: Informa UK Limited
Date: 02-2008
DOI: 10.1080/10255840701552143
Abstract: Prior studies have found that primary rotations in the lumbar spine are accompanied by coupled out-of-plane rotations. However, it is not clear whether these accompanying rotations are primarily due to passive (discs, ligaments and facet joints) or active (muscles) spinal anatomy. The aim of this study was to use a finite element (FE) model of the lumbar spine to predict three-dimensional coupled rotations between the lumbar vertebrae, due to passive spinal structures alone. The FE model was subjected to physiologically observed whole lumbar spine rotations about in vivo centres of rotation. Model predictions were validated by comparison of intra-discal pressures and primary rotations with in vivo measurements and these showed close agreement. Predicted coupled rotations matched in vivo measurements for all primary motions except lateral bending. We suggest that coupled rotations accompanying primary motions in the sagittal (flexion/extension) and transverse (axial rotation) planes are primarily due to passive spinal structures. For lateral bending the muscles most likely play a key role in the coupled rotation of the spine.
A Preliminary Sensitivity Study of Vertebral Tethering Configurations Using a Patient-Specific Finite Element Model of Idiopathic Scoliosis
Publisher: Springer International Publishing
Date: 2020
Biomaterial science meets computational biology
Publisher: Springer Science and Business Media LLC
Date: 18-04-2015
DOI: 10.1007/S10856-015-5518-Z
Abstract: There is a pressing need for a predictive tool capable of revealing a holistic understanding of fundamental elements in the normal and pathological cell physiology of organoids in order to decipher the mechanoresponse of cells. Therefore, the integration of a systems bioengineering approach into a validated mathematical model is necessary to develop a new simulation tool. This tool can only be innovative by combining biomaterials science with computational biology. Systems-level and multi-scale experimental data are incorporated into a single framework, thus representing both single cells and collective cell behaviour. Such a computational platform needs to be validated in order to discover key mechano-biological factors associated with cell-cell and cell-niche interactions.
Quantifying Muscle Size Asymmetry in Adolescent Idiopathic Scoliosis Using Three-dimensional Magnetic Resonance Imaging
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-07-2023
DOI: 10.1097/BRS.0000000000004715
Abstract: This is a case-control study of prospectively collected data. To quantify paraspinal muscle size asymmetry in adolescent idiopathic scoliosis (AIS) and determine if this asymmetry is i) greater than observed in adolescent controls with symmetrical spines and ii) positively associated with skeletal maturity using Risser grade, scoliosis severity using the Cobb angle, and chronological age in years. AIS is a three-dimensional deformity of the spine which occurs in 2.5-3.7% of the Australian population. There is some evidence of asymmetry in paraspinal-muscle activation and morphology in AIS. Asymmetrical paraspinal muscle forces may facilitate asymmetrical vertebral growth during adolescence. An asymmetry index [Ln(concave/convex volume)] of i) deep and ii) superficial paraspinal-muscle volumes, at the level of the i) major curve apex (Thoracic 8-9 th vertebral level) and ii) lower-end vertebrae ( LEV , Thoracic 10-12 th vertebral level), was determined from 3D Magnetic Resonance Imaging (MRI) of 25 adolescents with AIS (all right thoracic curves), and 22 healthy controls (convex=left) all female, 10-16 years. Asymmetry index of deep paraspinal-muscle volumes was greater in AIS (0.16±0.20) than healthy spine controls (-0.06±0.13) at the level of the apex ( P .01, linear mixed-effects analysis), but not LEV ( P .05). Asymmetry index was positively correlated with Risser grade (r=0.50, P .05) and scoliosis Cobb angle (r=0.45, P .05), but not age (r=0.34, P .05). There was no difference in the asymmetry index of superficial paraspinal muscle volumes between AIS and controls ( P .05). The asymmetry of deep apical paraspinal-muscle volume in AIS at the scoliosis apex is greater than that observed at equivalent vertebral levels in controls and may play a role in the pathogenesis of AIS.
Intra-operative measurement of applied forces during anterior scoliosis correction
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.CLINBIOMECH.2016.10.014
Abstract: Spinal instrumentation and fusion for the treatment of scoliosis is primarily a mechanical intervention to correct the deformity and halt further progression. While implant-related complications remain a concern, little is known about the magnitudes of the forces applied to the spine during surgery, which may affect post-surgical outcomes. In this study, the compressive forces applied to each spinal segment during anterior instrumentation were measured in a series of patients with Adolescent Idiopathic Scoliosis. A force transducer was designed and retrofit to a routinely used surgical tool, and compressive forces applied to each segment during surgery were measured for 15 scoliosis patients. Cobb angle correction achieved by each force was measured on intra-operative fluoroscope images. Relative changes in orientation of the screw within the vertebra were also measured to detect intra-operative screw plough. Intra-operative forces were measured for a total of 95 spinal segments. The mean applied compressive force was 540N (SD 230N, range 88N-1019N). There was a clear trend for higher forces to be applied at segments toward the apex of the scoliosis. Fluoroscopic evidence of screw plough was detected at 10 segments (10.5%). The magnitude of forces applied during anterior scoliosis correction vary over a broad range. These forces do reach magnitudes capable of causing intra-operative vertebral body screw plough. Surgeons should be aware there is a risk for tissue overload during correction, however the clinical implications of intra-operative screw plough remain unclear. The dataset presented here is valuable for providing realistic input parameters for in silico surgical simulations.
Changes in femur stress after hip resurfacing arthroplasty: Response to physiological loads
Publisher: Elsevier BV
Date: 05-2007
DOI: 10.1016/J.CLINBIOMECH.2006.12.002
Abstract: Hip resurfacing arthroplasty is being increasingly considered as an alternative to total hip arthroplasty in young, active patients. Hip resurfacing arthroplasty is reported to preserve the normal joint mechanics. However, there is concern, in the short term, due to frequent occurrence of femoral neck fractures. We evaluated changes in femoral mechanics after hip resurfacing arthroplasty. We used an experimentally validated, distributed material finite element model of a cadaveric femur before and after hip resurfacing arthroplasty. Bone stiffness and strength values representing normal, elderly and osteoporotic bone were used. For a physiological load case, bone strains were compared with literature values for total hip arthroplasty and a risk of fracture scalar calculated. The changes in peak stresses after hip resurfacing arthroplasty were low in relation to the failure strength of bone and the fracture risk was low. The intact and implanted finite element models showed bone strains after hip resurfacing arthroplasty were closer to the intact condition than after total hip arthroplasty. The bone stresses predicted after resurfacing in both the normal and aged femoral neck were not sufficient to be a potential cause of fracture.
The Effect of Soft Tissue Properties on Spinal Flexibility in Scoliosis
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2009
The mechanical response of the ovine lumbar anulus fibrosus to uniaxial, biaxial and shear loads
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.JMBBM.2009.09.002
Abstract: Analytical and computational models of the intervertebral disc (IVD) are commonly employed to enhance understanding of the biomechanics of the human spine and spinal motion segments. The accuracy of these models in predicting physiological behaviour of the spine is intrinsically reliant on the accuracy of the material constitutive representations employed to represent the spinal tissues. There is a paucity of detailed mechanical data describing the material response of the reinforced-ground matrix in the anulus fibrosus of the IVD. In the present study, the 'reinforced-ground matrix' was defined as the matrix with the collagen fibres embedded but not actively bearing axial load, thus incorporating the contribution of the fibre-fibre and fibre-matrix interactions. To determine mechanical parameters for the anulus ground matrix, mechanical tests were carried out on specimens of ovine anulus, under unconfined uniaxial compression, simple shear and biaxial compression. Test specimens of ovine anulus fibrosus were obtained with an adjacent layer of vertebral bone/cartilage on the superior and inferior specimen surface. Specimen geometry was such that there were no continuous collagen fibres coupling the two endplates. S les were sub ided according to disc region - anterior, lateral and posterior - to determine the regional inhomogeneity in the anulus mechanical response. Specimens were loaded at a strain rate sufficient to avoid fluid outflow from the tissue and typical stress-strain responses under the initial load application and under repeated loading were determined for each of the three loading types. The response of the anulus tissue to the initial and repeated load cycles was significantly different for all load types, except biaxial compression in the anterior anulus. Since the maximum applied strain exceeded the damage strain for the tissue, experimental results for repeated loading reflected the mechanical ability of the tissue to carry load, subsequent to the initiation of damage. To our knowledge, this is the first study to provide experimental data describing the response of the 'reinforced-ground matrix' to biaxial compression. Additionally, it is novel in defining a study objective to determine the regionally inhomogeneous response of the 'reinforced-ground matrix' under an extensive range of loading conditions suitable for mechanical characterisation of the tissue. The results presented facilitate the development of more detailed and comprehensive constitutive descriptions for the large strain nonlinear elastic or hyperelastic response of the anulus ground matrix.
The development of a modular design workflow for 3D printable bioresorbable patient-specific bone scaffolds to facilitate clinical translation
Publisher: Informa UK Limited
Date: 05-09-2023
Effects of geometric individualisation of a human spine model on load sharing: neuro-musculoskeletal simulation reveals significant differences in ligament and muscle contribution
Publisher: Springer Science and Business Media LLC
Date: 05-01-2023
DOI: 10.1007/S10237-022-01673-3
Abstract: In spine research, two possibilities to generate models exist: generic (population-based) models representing the average human and subject-specific representations of in iduals. Despite the increasing interest in subject specificity, in idualisation of spine models remains challenging. Neuro-musculoskeletal (NMS) models enable the analysis and prediction of dynamic motions by incorporating active muscles attaching to bones that are connected using articulating joints under the assumption of rigid body dynamics. In this study, we used forward-dynamic simulations to compare a generic NMS multibody model of the thoracolumbar spine including fully articulated vertebrae, detailed musculature, passive ligaments and linear intervertebral disc (IVD) models with an in idualised model to assess the contribution of in idual biological structures. In idualisation was achieved by integrating skeletal geometry from computed tomography and custom-selected muscle and ligament paths. Both models underwent a gravitational settling process and a forward flexion-to-extension movement. The model-specific load distribution in an equilibrated upright position and local stiffness in the L4/5 functional spinal unit (FSU) is compared. Load sharing between occurring internal forces generated by in idual biological structures and their contribution to the FSU stiffness was computed. The main finding of our simulations is an apparent shift in load sharing with in idualisation from an equally distributed element contribution of IVD, ligaments and muscles in the generic spine model to a predominant muscle contribution in the in idualised model depending on the analysed spine level.
Patient‐specific computational biomechanics for simulating adolescent scoliosis surgery: Predicted vs clinical correction for a preliminary series of six patients
Publisher: Wiley
Date: 10-12-2010
DOI: 10.1002/CNM.1422
Development of a multi-scale finite element model of the osteoporotic lumbar vertebral body for the investigation of apparent level vertebra mechanics and micro-level trabecular mechanics
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1016/J.MEDENGPHY.2010.04.006
Abstract: Osteoporotic spinal fractures are a major concern in ageing Western societies. This study develops a multi-scale finite element (FE) model of the osteoporotic lumbar vertebral body to study the mechanics of vertebral compression fracture at both the apparent (whole vertebral body) and micro-structural (internal trabecular bone core) levels. Model predictions were verified against experimental data, and found to provide a reasonably good representation of the mechanics of the osteoporotic vertebral body. This novel modelling methodology will allow detailed investigation of how trabecular bone loss in osteoporosis affects vertebral stiffness and strength in the lumbar spine.
Are coupled rotations in the lumbar spine largely due to the osseo-ligamentous anatomy? – A modelling study
Publisher: Informa UK Limited
Date: 04-2008
Patient-Customized Theatre Mattress Supports for Spinal Surgery: A Pilot Study Presenting a Novel Engineering Virtual Design and Manufacturing Technique
Publisher: ASME International
Date: 02-03-2022
DOI: 10.1115/1.4053604
Abstract: Optimal patient positioning for spine surgery is vital for surgical success and the minimization of complications intra- ostoperatively. In patients with complex comorbidities, commercially available surgical positioning equipment is inadequate. To overcome this, a novel method was developed to create custom-fit patient-specific theater mattresses for patients undergoing spine surgery. An innovative digital workflow involving three-dimensional (3D) surface scanning, 3D simulation, and computer-aided design was developed to manufacture customized theater supports with patient-specific requirements. These supports offered the surgeon an enhanced ability to relieve load bearing on prominent anatomical features or where desired, to tailor the support surface to the patient's anatomy for lengthy surgery. The bespoke theater mattress was evaluated by whether the support resulted in a complication-free surgery. Using this new workflow, case ex les for two patients with complex comorbidities were described. The spine surgeon and anesthetist reported the patient-specific custom mattresses were fit as per the required design, provided sufficient clearance around anatomical prominences and areas that required to be unloaded, had sufficient clearance for the anesthetic method and cannulation, provided excellent surgical access and stability during surgery, and postoperatively no soft tissue overload over bony prominence and implanted devices. Positive patient outcomes after successful lengthy surgical interventions were associated with these patient-specific, contoured mattress supports. Future projects will seek to utilize this technology for other types of surgeries and intra-operative positioning requirements, and for a broader demographic of patients in both the pediatric and adult setting.
Accuracy of 3D surface scanners for clinical torso and spinal deformity assessment
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.MEDENGPHY.2018.11.004
Abstract: Externally visible deformities are cosmetic features of great concern for Adolescent Idiopathic Scoliosis (AIS) patients. Current assessment techniques for AIS do not fully encompass the external deformity. A non-invasive method capable of capturing superficial anatomy, such as 3D scanning, would enable better qualitative and quantitative evaluation of cosmesis. This study aimed to quantify the accuracy of commonly available scanners, in assessing posterior asymmetry in AIS. The technique of 3D surface deviation analysis was proposed as a suitable method for comparing the models created by each scanner. Eight plaster cast moulds manufactured to create braces for AIS patients were used as test s les. Four 3D scanners were selected: Solutionix RexScan CS+ Artec Eva Microsoft Kinect V1 iPhone with 123D Catch App. These scanners were selected from those available as representative of a range of scanning technologies. Each cast was scanned and 3D models created. A simulated rib hump measurement was obtained and the surface-to-surface deviations between the Solutionix scan and all other scans were determined. The Solutionix scanner is a metrology scanner of very high quality and so it was selected as the reference. Surface-to-surface deviations were calculated in the positive and negative directions separately to specifically identify size and volume inaccuracies created by the scans. Surface deviations showed excellent agreement between the Solutionix and the Eva with deviations of +0.17 ± 0.17 mm (Eva regions larger) and -0.20 ± 0.32 mm (Eva regions smaller) (mean±SD). The Kinect showed lower agreement (+1.58 ± 1.50 mm and -0.58 ± 0.58 mm). The iPhone scans were not able to be scaled to the correct size, so were excluded. Rib hump measurements with all scanners were within clinical measurement variability (±4.9 deg) of the known values. These commercially available 3D scanners are capable of imaging torso shape in 3D and deriving clinically relevant external deformity measures. The non-invasive 3D topographic information provided can be used to improve assessment of torso shape in spinal deformity patients.
Quantifying Typical Progression of Adolescent Idiopathic Scoliosis
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 13-09-2023
Towards determining soft tissue properties for modelling spine surgery: current progress and challenges
Publisher: Springer Science and Business Media LLC
Date: 25-12-2011
DOI: 10.1007/S11517-011-0848-6
Abstract: Current complication rates for adolescent scoliosis surgery necessitate the development of better surgical planning tools to improve outcomes. Here we present our approach to developing finite element models of the thoracolumbar spine for deformity surgery simulation, with patient-specific model anatomy based on low-dose pre-operative computed tomography scans. In a first step towards defining patient-specific tissue properties, an initial 'benchmark' set of properties were used to simulate a clinically performed pre-operative spinal flexibility assessment, the fulcrum bending radiograph. Clinical data for ten patients were compared with the simulated results for this assessment and in cases where these data differed by more than 10%, soft tissue properties for the costo-vertebral joint (CVJt) were altered to achieve better agreement. Results from these analyses showed that changing the CVJt stiffness resulted in acceptable agreement between clinical and simulated flexibility in two of the six cases. In light of these results and those of our previous studies in this area, it is suggested that spinal flexibility in the fulcrum bending test is not governed by any single soft tissue structure acting in isolation. More detailed biomechanical characterisation of the fulcrum bending test is required to provide better data for determination of patient-specific soft tissue properties.
A multiscale road map of cancer spheroids – incorporating experimental and mathematical modelling to understand cancer progression
Publisher: The Company of Biologists
Date: 2013
DOI: 10.1242/JCS.123836
Abstract: Computational models represent a highly suitable framework, not only for testing biological hypotheses and generating new ones but also for optimising experimental strategies. As one surveys the literature devoted to cancer modelling, it is obvious that immense progress has been made in applying simulation techniques to the study of cancer biology, although the full impact has yet to be realised. For ex le, there are excellent models to describe cancer incidence rates or factors for early disease detection, but these predictions are unable to explain the functional and molecular changes that are associated with tumour progression. In addition, it is crucial that interactions between mechanical effects, and intracellular and intercellular signalling are incorporated in order to understand cancer growth, its interaction with the extracellular microenvironment and invasion of secondary sites. There is a compelling need to tailor new, physiologically relevant in silico models that are specialised for particular types of cancer, such as ovarian cancer owing to its unique route of metastasis, which are capable of investigating anti-cancer therapies, and generating both qualitative and quantitative predictions. This Commentary will focus on how computational simulation approaches can advance our understanding of ovarian cancer progression and treatment, in particular, with the help of multicellular cancer spheroids, and thus, can inform biological hypothesis and experimental design.
An FE investigation simulating intra-operative corrective forces applied to correct scoliosis deformity
Publisher: Springer Science and Business Media LLC
Date: 16-05-2013
Parametric equations to represent the profile of the human intervertebral disc in the transverse plane
Publisher: Springer Science and Business Media LLC
Date: 21-08-2007
DOI: 10.1007/S11517-007-0242-6
Abstract: Computational and finite element models of the spine are used to investigate spine and disc mechanics. Subject specific data for the transverse profile of the disc could improve the geometric accuracy of these models. The current study aimed to develop a mathematical algorithm to describe the profile of the disc components, using subject-specific data points. Using data points measured from pictures of human intervertebral discs sectioned in the transverse plane, parametric formulae were derived that mapped the outer profile of the anulus and nucleus. The computed anulus and nucleus profile were a similar shape to the discs from which they were derived. The computed total disc area was similar to the experimental data. The nucleus:disc area ratios were sensitive to the data points defined for each disc. The developed formulae can be easily implemented to provide patient specific data for the disc profile in computational models of the spine.
Nonlinear finite element analysis of anular lesions in the L4/5 intervertebral disc
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/J.JBIOMECH.2007.01.007
Abstract: Degenerate intervertebral discs exhibit both material and structural changes. Structural defects (lesions) develop in the anulus fibrosus with age. While degeneration has been simulated in numerous previous studies, the effects of structural lesions on disc mechanics are not well known. In this study, a finite element model (FEM) of the L4/5 intervertebral disc was developed in order to study the effects of anular lesions and loss of hydrostatic pressure in the nucleus pulposus on the disc mechanics. Models were developed to simulate both healthy and degenerate discs. Degeneration was simulated with either rim, radial or circumferential anular lesions and by equating nucleus pressure to zero. The anulus fibrosus ground substance was represented as a nonlinear incompressible material using a second-order polynomial, hyperelastic strain energy equation. Hyperelastic material parameters were derived from experimentation on sheep discs. Endplates were assumed to be rigid, and annulus lamellae were assumed to be vertical in the unloaded state. Loading conditions corresponding to physiological ranges of rotational motion were applied to the models and peak rotation moments compared between models. Loss of nucleus pulposus pressure had a much greater effect on the disc mechanics than the presence of anular lesions. This indicated that the development of anular lesions alone (prior to degeneration of the nucleus) has minimal effect on disc mechanics, but that disc stiffness is significantly reduced by the loss of hydrostatic pressure in the nucleus. With the degeneration of the nucleus, the outer innervated anulus or surrounding osteo-ligamentous anatomy may therefore experience increased strains.
Evaluating the Change in Axial Vertebral Rotation Following Thoracoscopic Anterior Scoliosis Surgery Using Low-Dose Computed Tomography
Publisher: Springer Science and Business Media LLC
Date: 05-2017
DOI: 10.1016/J.JSPD.2016.12.003
Abstract: In recent years, there has been increasing appreciation of the need to treat scoliosis as a three-dimensional deformity. Assessment of surgical strategies and outcomes should consider not only the coronal plane correction but also derotation of the transverse plane deformity that can affect trunk appearance. This study included a cohort of 29 female adolescent idiopathic scoliosis patients who received thoracoscopic single rod anterior fusion (TASF) surgery. This study used pre- and postoperative low-dose computed tomographic (CT) scans to accurately measure apical axial vertebral rotation (AVR). The pre- and postoperative values for clinically measured coronal Cobb correction and rib hump correction as well as AVR were compared to determine whether these values improved postoperatively. There are no conflicts of interest to report for authors of this investigation. As expected, statistically significant reductions in coronal Cobb angle (mean preoperative Cobb 51°, reducing to 24° at the two-year follow-up) and rib hump (mean preoperative rib hump 15°, reducing to 7° at two-year follow-up) were achieved. The mean reduction in apical AVR measured using CT was only 3° (mean preoperative AVR 16°, reducing to 13° at two-year follow-up), which was statistically but not clinically significant. Significant correlations were found between Cobb angle and rib hump, between Cobb angle and AVR, and between AVR and rib hump, suggesting that patients with greater coronal Cobb correction also achieve better derotation with this surgical procedure. The historical low-dose CT data set permitted detailed three-dimensional assessment of the deformity correction that is achieved using thoracoscopic anterior spinal fusion for progressive adolescent idiopathic scoliosis.
Relative Roles of Cortical and Trabecular Thinning in Reducing Osteoporotic Vertebral Body Stiffness: A Modeling Study
Publisher: Springer Berlin Heidelberg
Date: 2009
Biomechanics of the human intervertebral disc: A review of testing techniques and results.
Publisher: No publisher found
Date: 2017
DOI: 10.1016/J.JMBBM.2017.01.037
Abstract: Many experimental testing techniques have been adopted in order to provide an understanding of the biomechanics of the human intervertebral disc (IVD). The aim of this review article is to amalgamate results from these studies to provide readers with an overview of the studies conducted and their contribution to our current understanding of the biomechanics and function of the IVD. The overview is presented in a way that should prove useful to experimentalists and computational modellers. Mechanical properties of whole IVDs can be assessed conveniently by testing 'motion segments' comprising two vertebrae and the intervening IVD and ligaments. Neural arches should be removed if load-sharing between them and the disc is of no interest, and specimens containing more than two vertebrae are required to study 'adjacent level' effects. Mechanisms of injury (including endplate fracture and disc herniation) have been studied by applying complex loading at physiologically-relevant loading rates, whereas mechanical evaluations of surgical prostheses require slower application of standardised loading protocols. Results can be strongly influenced by the testing environment, preconditioning, loading rate, specimen age and degeneration, and spinal level. Component tissues of the disc (anulus fibrosus, nucleus pulposus, and cartilage endplates) have been studied to determine their material properties, but only the anulus has been thoroughly evaluated. Animal discs can be used as a model of human discs where uniform non-degenerate specimens are required, although differences in scale, age, and anatomy can lead to problems in interpretation.
Development of a biaxial compression device for biological samples: Preliminary experimental results for a closed cell foam
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.JMBBM.2008.10.011
Abstract: Biological tissues are subjected to complex loading states in vivo and in order to define constitutive equations that effectively simulate their mechanical behaviour under these loads, it is necessary to obtain data on the tissue's response to multiaxial loading. Single axis and shear testing of biological tissues is often carried out, but biaxial testing is less common. We sought to design and commission a biaxial compression testing device, capable of obtaining repeatable data for biological s les. The apparatus comprised a sealed stainless steel pressure vessel specifically designed such that a state of hydrostatic compression could be created on the test specimen while simultaneously unloading the s le along one axis with an equilibrating tensile pressure. Thus a state of equibiaxial compression was created perpendicular to the long axis of a rectangular s le. For the purpose of calibration and commissioning of the vessel, rectangular s les of closed cell ethylene vinyl acetate (EVA) foam were tested. Each s le was subjected to repeated loading, and nine separate biaxial experiments were carried out to a maximum pressure of 204 kPa (30 psi), with a relaxation time of two hours between them. Calibration testing demonstrated the force applied to the s les had a maximum error of 0.026 N (0.423% of maximum applied force). Under repeated loading, the foam s le demonstrated lower stiffness during the first load cycle. Following this cycle, an increased stiffness, repeatable response was observed with successive loading. While the experimental protocol was developed for EVA foam, preliminary results on this material suggest that this device may be capable of providing test data for biological tissue s les. The load response of the foam was characteristic of closed cell foams, with consolidation during the early loading cycles, then a repeatable load-displacement response upon repeated loading. The repeatability of the test results demonstrated the ability of the test device to provide reproducible test data and the low experimental error in the force demonstrated the reliability of the test data.
Development and validation of a semi-automated measurement tool for calculating consistent and reliable surface metrics describing cosmesis in Adolescent Idiopathic Scoliosis
Publisher: Springer Science and Business Media LLC
Date: 05-04-2023
DOI: 10.1038/S41598-023-32614-4
Abstract: Adolescent Idiopathic Scoliosis (AIS) is a 3D spine deformity that also causes ribcage and torso distortion. While clinical metrics are important for monitoring disorder progression, patients are often most concerned about their cosmesis. The aim of this study was to automate the quantification of AIS cosmesis metrics, which can be measured reliably from patient-specific 3D surface scans (3DSS). An existing database of 3DSS for pre-operative AIS patients treated at the Queensland Children’s Hospital was used to create 30 calibrated 3D virtual models. A modular generative design algorithm was developed on the Rhino-Grasshopper software to measure five key AIS cosmesis metrics from these models—shoulder, scapula and hip asymmetry, torso rotation and head-pelvis shift. Repeat cosmetic measurements were calculated from user-selected input on the Grasshopper graphical interface. InterClass-correlation (ICC) was used to determine intra- and inter-user reliability. Torso rotation and head-pelvis shift measurements showed excellent reliability ( 0.9), shoulder asymmetry measurements showed good to excellent reliability ( 0.7) and scapula and hip asymmetry measurements showed good to moderate reliability ( 0.5). The ICC results indicated that experience with AIS was not required to reliably measure shoulder asymmetry, torso rotation and head-pelvis shift, but was necessary for the other metrics. This new semi-automated workflow reliably characterises external torso deformity, reduces the dependence on manual anatomical landmarking, and does not require bulky/expensive equipment.
Characterization of progressive changes in pedicle morphometry and neurovascular anatomy during growth in adolescent idiopathic scoliosis versus adolescents without scoliosis
Publisher: Springer Science and Business Media LLC
Date: 17-06-2020
Effects of surgical joint destabilization on load sharing between ligamentous structures in the thoracic spine: A finite element investigation
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.CLINBIOMECH.2011.05.004
Abstract: In vitro investigations have demonstrated the importance of the ribcage in stabilizing the thoracic spine. Surgical alterations of the ribcage may change load-sharing patterns in the thoracic spine. Computer models are used in this study to explore the effect of surgical disruption of the rib-vertebrae connections on ligament load-sharing in the thoracic spine. A finite element model of a T7-8 motion segment, including the T8 rib, was developed using CT-derived spinal anatomy for the Visible Woman. Both the intact motion segment and the motion segment with four successive stages of destabilization (discectomy and removal of right costovertebral joint, right costotransverse joint and left costovertebral joint) were analyzed for a 2000 Nmm moment in flexion/extension, lateral bending and axial rotation. Joint rotational moments were compared with existing in vitro data and a detailed investigation of the load sharing between the posterior ligaments carried out. The simulated motion segment demonstrated acceptable agreement with in vitro data at all stages of destabilization. Under lateral bending and axial rotation, the costovertebral joints were of critical importance in resisting applied moments. In comparison to the intact joint, anterior destabilization increases the total moment contributed by the posterior ligaments. Surgical removal of the costovertebral joints may lead to excessive rotational motion in a spinal joint, increasing the risk of overload and damage to the remaining ligaments. The findings of this study are particularly relevant for surgical procedures involving rib head resection, such as some techniques for scoliosis deformity correction.
Material properties of human lumbar intervertebral discs across strain rates
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.SPINEE.2019.07.012
Abstract: The use of finite element (FE) methods to study the biomechanics of the intervertebral disc (IVD) has increased over recent decades due to their ability to quantify internal stresses and strains throughout the tissue. Their accuracy is dependent upon realistic, strain-rate dependent material properties, which are challenging to acquire. The aim of this study was to use the inverse FE technique to characterize the material properties of human lumbar IVDs across strain rates. A human cadaveric experimental study coupled with an inverse finite element study. To predict the structural response of the IVD accurately, the material response of the constituent structures was required. Therefore, compressive experiments were conducted on 16 lumbar IVDs (39±19 years) to obtain the structural response. An FE model of each of these experiments was developed and then run through an inverse FE algorithm to obtain subject-specific constituent material properties, such that the structural response was accurate. Experimentally, a log-linear relationship between IVD stiffness and strain rate was observed. The material properties obtained through the subject-specific inverse FE optimization of the annulus fibrosus (AF) fiber and AF fiber ground matrix allowed a good match between the experimental and FE response. This resulted in a Young modulus of AF fibers (-MPa) to strain rate (ε˙, /s) relationship of YMAF=31.5ln(ε˙)+435.5, and the C These material properties can be used to improve the accuracy, and therefore predictive ability of FE models of the spine that are used in a wide range of research areas and clinical applications. Finite element models can be used for many applications including investigating low back pain, spinal deformities, injury biomechanics, implant design, design of protective systems, and degenerative disc disease. The accurate material properties obtained in this study will improve the predictive ability, and therefore clinical significance of these models.
Development of a Computer Simulation Tool for Application in Adolescent Spinal Deformity Surgery
Publisher: Springer Berlin Heidelberg
Date: 2010
Change in Lung Volume Following Thoracoscopic Anterior Spinal Fusion Surgery
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 15-06-2017
Determining a reliably visible and inexpensive surface fiducial marker for use in MRI: a research study in a busy Australian Radiology Department
Publisher: BMJ
Date: 08-2019
DOI: 10.1136/BMJOPEN-2018-027020
Abstract: Single-use commercial surface fiducial markers are used in clinical imaging for a variety of applications. The current study sought to find a new, reliably visible, easily sourced and inexpensive fiducial marker alternative for use with MRI. Five commonly requested MRI sequences were determined (three-dimensional (3D) T1-weighted, T1 coronal, 3D T2-weighted, T2 fat suppressed, proton density), to examine the visibility of 18 items (including a commercial fiducial marker). Clinical 3T MRI scanner in an Australian Tertiary Hospital and an Australian University Biomedical Engineering research group. 18 marker alternatives were scanned using five common MRI sequences. Images were reformatted to obtain both an image through the mid-height of each marker and a maximum intensity z-projection image over the volume of the marker. Variations in marker intensity were profiled across each visible marker and a visibility rating defined. Outcome measures were based on quantitative assessment of a clear intensity contrast ratio between the marker and the adjacent tissue and a qualitative assessment of visibility via a 3-point scale. The fish oil capsule, vitamin D capsule, paint ball pellet, soy sauce sushi tube and commercial markers were typically visible to a high quality on all the imaging sequences and demonstrated a clear differential in intensity contrast against the adjacent tissue. Other common items, such as plasticine ‘play doh’ and a soft ‘Jelly baby’ sweet, were surprise candidates, demonstrating high-quality visibility and intensity contrast for the 3D T1-weighted sequence. Depending on the basis for referral and MRI sequence chosen, four alternative fiducial markers were determined to be inexpensive, easily sourced and consistently visible. Of these, the vitamin D capsule provided an excellent balance between availability, size, cost, usability and quality of the visualised marker for all the commonly used MRI sequences analysed.
Coupled rotations in the lumbar spine—are these a consequence of passive spinal anatomy?
Publisher: WIT Press
Date: 05-09-2007
DOI: 10.2495/BIO070091
A subject-specific FEM to predict deep tissue mechanical stresses when supine: Development of efficient contact interfaces using Shared Topology
Publisher: Elsevier BV
Date: 05-2022
DOI: 10.1016/J.JBIOMECH.2022.111085
Abstract: Prior studies have demonstrated Finite Element (FE) analysis is a useful tool when analysing the complex interplay of tissue and body loads which act through the human pelvis in a subject lying supine. The computational accuracy and efficiency of FE models that contain complex non-linear geometric interfaces between different anatomical and tissue regions can be compromised by superfluous node interactions and contact penetrations. This study proposes a method for the development of efficient contact definitions using shared topology. The Shared Topology Finite Element Model (FEM) resulted in a 37% reduction in solution time compared to an equivalent FEM defined with Bonded contact. At all tissue interfaces, contact penetration occurred in the Bonded FEM, with subsequent under-prediction of peak compressive strains and stresses by 1-7% compared to the Shared Topology FEM. Simulating supine lying of a 19-year-old male, the Shared Topology FEM predicted peak compressive stress in the muscle interfacing the sacrum of 29.4 kPa, and peak compressive strain of 50%. The proposed methodology can be applied for any medical imaging derived FEM where there are multiple congruent 3D geometries with negligible sliding across interfaces.
Predicting spinal column profile from surface topography via 3D non-contact surface scanning
Publisher: Public Library of Science (PLoS)
Date: 23-03-2023
DOI: 10.1371/JOURNAL.PONE.0282634
Abstract: 3D Non-Contact surface scanning (3DSS) is used in both biomechanical and clinical studies to capture accurate 3D images of the human torso, and to better understand the shape and posture of the spine–both healthy and pathological. This study sought to determine the efficacy and accuracy of using 3DSS of the posterior torso, to determine the curvature of the spinal column in the lateral lying position. A cohort of 50 healthy adults underwent 3DSS and Magnetic Resonance Imaging (MRI) to correlate the contours of the external spine surface with the internal spinal column. The correlation analysis was composed of two phases: (1) MRI vertebral points vs MRI external spine surface markers and (2) MRI external spine surface markers vs 3DSS external spine surface markers. The first phase compared the profiles of fiducial markers (vitamin capsules) adhered to the skin surface over the spinous processes against the coordinates of the spinous processes–assessing the linear distance between the profiles, and similarity of curvature, in the sagittal and coronal planes. The second phase compared 3DSS external spine surface markers with the MRI external spine surface markers in both planes, with further qualitative assessment for postural changes. The distance between the MRI vertebral points and MRI external spine surface markers showed strong statistically significant correlation with BMI in both sagittal and coronal planes. Kolmogorov-Smirnov (KS) tests showed similar no significant difference in curvature, k, in almost all participants on both planes. In the second phase, the coronal 3DSS external spine surface profiles were statistically different to the MRI external spine surface markers in 44% of participants. Qualitative assessment showed postural changes between MRI and 3DSS measurements in these participants. These study findings demonstrate the utility and accuracy of using anatomical landmarks overlaid on the spinous processes, to identify the position of the spinal bones using 3DSS. Using this method, it will be possible to predict the internal spinal curvature from surface topography, provided that the thickness of the overlaying subcutaneous adipose layer is considered, thus enabling postural analysis of spinal shape and curvature to be carried out in biomechanical and clinical studies without the need for radiographic imaging.
Engineering the perfect mattress: The influence of substrate mechanics on deep tissue stresses in supine
Publisher: Elsevier BV
Date: 12-2023
Sequential MRI reveals vertebral body wedging significantly contributes to coronal plane deformity progression in adolescent idiopathic scoliosis during growth
Publisher: Springer Science and Business Media LLC
Date: 25-05-2020
Load-induced changes in the diffusion tensor of ovine anulus fibrosus: A pilot MRI study
Publisher: Wiley
Date: 07-11-2017
DOI: 10.1002/JMRI.25531
Abstract: To assess the feasibility of diffusion tensor imaging (DTI) for evaluating changes in anulus fibrosus (AF) microstructure following uniaxial compression. Six axially aligned s les of AF were obtained from a merino sheep disc two each from the anterior, lateral, and posterior regions. The s les were mechanically loaded in axial compression during five cycles at a rate and maximum compressive strain that reflected physiological conditions. DTI was conducted at 7T for each s le before and after mechanical testing. The mechanical response of all s les in unconfined compression was nonlinear. A stiffer response during the first loading cycle, compared to the remaining cycles, was observed. Change in diffusion parameters appeared to be region-dependent. The mean fractional anisotropy increased following mechanical testing. This was smallest in the lateral (2% and 9%) and largest in the anterior and posterior s les (17-25%). The mean average diffusivity remained relatively constant (<2%) after mechanical testing in the lateral and posterior s les, but increased (by 5%) in the anterior s les. The mean angle made by the principal eigenvector with the spine axis in the lateral s les was 73° and remained relatively constant (<2%) following mechanical testing. This angle was smaller in the anterior (55°) and posterior (47°) regions and increased by 6-16° following mechanical testing. These preliminary results suggest that axial compression reorients the collagen fibers, such that they become more consistently aligned parallel to the plane of the endplates. 1 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017 :1723-1735.
Understanding how axial loads on the spine influence segmental biomechanics for idiopathic scoliosis patients: A magnetic resonance imaging study
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.CLINBIOMECH.2015.11.007
Abstract: Segmental biomechanics of the scoliotic spine are important since the overall spinal deformity is comprised of the cumulative coronal and axial rotations of in idual joints. This study investigates the coronal plane segmental biomechanics for adolescent idiopathic scoliosis patients in response to physiologically relevant axial compression. In idual spinal joint compliance in the coronal plane was measured for a series of 15 idiopathic scoliosis patients using axially loaded magnetic resonance imaging. Each patient was first imaged in the supine position with no axial load, and then again following application of an axial compressive load. Coronal plane disc wedge angles in the unloaded and loaded configurations were measured. Joint moments exerted by the axial compressive load were used to derive estimates of in idual joint compliance. The mean standing major Cobb angle for this patient series was 46°. Mean intra-observer measurement error for endplate inclination was 1.6°. Following loading, initially highly wedged discs demonstrated a smaller change in wedge angle, than less wedged discs for certain spinal levels (+2,+1,-2 relative to the apex, (p<0.05)). Highly wedged discs were observed near the apex of the curve, which corresponded to lower joint compliance in the apical region. While in idual patients exhibit substantial variability in disc wedge angles and joint compliance, overall there is a pattern of increased disc wedging near the curve apex, and reduced joint compliance in this region. Approaches such as this can provide valuable biomechanical data on in vivo spinal biomechanics of the scoliotic spine, for analysis of deformity progression and surgical planning.
Patient-Specific Modeling of Scoliosis
Publisher: Springer Berlin Heidelberg
Date: 2011
DOI: 10.1007/8415_2011_97
The effect of soft tissue properties on overall biomechanical response of a human lumbar motion segment: a preliminary finite element study
Publisher: WIT Press
Date: 05-09-2007
DOI: 10.2495/BIO070101
Predicting spinal profile using 3D non-contact surface scanning: Changes in surface topography as a predictor of internal spinal alignment
Publisher: Public Library of Science (PLoS)
Date: 26-09-2019
Investigating the change in three dimensional deformity for idiopathic scoliosis using axially loaded MRI
Publisher: Elsevier BV
Date: 06-2012
DOI: 10.1016/J.CLINBIOMECH.2011.12.004
Abstract: Adolescent idiopathic scoliosis is a complex three-dimensional deformity, involving a lateral deformity in the coronal plane and axial rotation of the vertebrae in the transverse plane. Gravitational loading plays an important biomechanical role in governing the coronal deformity, however, less is known about how they influence the axial deformity. This study investigates the change in three-dimensional deformity of a series of scoliosis patients due to compressive axial loading. Magnetic resonance imaging scans were obtained and coronal deformity (measured using the coronal Cobb angle) and axial rotations measured for a group of 18 scoliosis patients (Mean major Cobb angle was 43.4°). Each patient was scanned in an unloaded and loaded condition while compressive loads equivalent to 50% body mass were applied using a custom developed compressive device. The mean increase in major Cobb angle due to compressive loading was 7.4° (SD 3.5°). The most axially rotated vertebra was observed at the apex of the structural curve and the largest average intravertebral rotations were observed toward the limits of the coronal deformity. A level-wise comparison showed no significant difference between the average loaded and unloaded vertebral axial rotations (intra-observer error=2.56°) or intravertebral rotations at each spinal level. This study suggests that the biomechanical effects of axial loading primarily influence the coronal deformity, with no significant change in vertebral axial rotation or intravertebral rotation observed between the unloaded and loaded condition. However, the magnitude of changes in vertebral rotation with compressive loading may have been too small to detect given the resolution of the current technique.
The Use of EOS Imaging to Assess Curve Magnitude Changes in Adolescent Idiopathic Scoliosis Undertaking Brace Management
Publisher: Acta Scientific Publications Pvt. Ltd.
Date: 04-2022
Geometric sensitivity of patient-specific finite element models of the spine to variability in user-selected anatomical landmarks
Publisher: Informa UK Limited
Date: 21-11-2013
DOI: 10.1080/10255842.2013.843673
Abstract: Software to create in idualised finite element (FE) models of the osseoligamentous spine using pre-operative computed tomography (CT) data-sets for spinal surgery patients has recently been developed. This study presents a geometric sensitivity analysis of this software to assess the effect of intra-observer variability in user-selected anatomical landmarks. User-selected landmarks on the osseous anatomy were defined from CT data-sets for three scoliosis patients and these landmarks were used to reconstruct patient-specific anatomy of the spine and ribcage using parametric descriptions. The intra-observer errors in landmark co-ordinates for these anatomical landmarks were calculated. FE models of the spine and ribcage were created using the reconstructed anatomy for each patient and these models were analysed for a loadcase simulating clinical flexibility assessment. The intra-observer error in the anatomical measurements was low in comparison to the initial dimensions, with the exception of the angular measurements for disc wedge and zygapophyseal joint (z-joint) orientation and disc height. This variability suggested that CT resolution may influence such angular measurements, particularly for small anatomical features, such as the z-joints, and may also affect disc height. The results of the FE analysis showed low variation in the model predictions for spinal curvature with the mean intra-observer variability substantially less than the accepted error in clinical measurement. These findings demonstrate that intra-observer variability in landmark point selection has minimal effect on the subsequent FE predictions for a clinical loadcase.
Thermal Effects of Cement Mantle Thickness for Hip Resurfacing
Publisher: Elsevier BV
Date: 04-2008
DOI: 10.1016/J.ARTH.2007.02.015
Abstract: Hybrid hip resurfacing arthroplasty with uncemented acetabular and cemented femoral fixation is increasingly becoming popular as an alternative to total hip arthroplasty. There is concern about femoral neck fractures, and long-term survival has not yet been demonstrated. Thermal necrosis may be an important factor for neck fracture and will affect the viability of the femoral bone. This cadaveric study investigated the thermal effect of thick (1.5 mm, n = 3) and thin (0.5 mm, n = 3) cement mantles 5 thermocouples were used to record temperature at the femoral bone/cement interface during hip resurfacing arthroplasty. The highest recorded temperatures were significantly higher when a thick cement mantle is used (45.4 degrees C), compared to a thin cement mantle (32.7 degrees C). To reduce the potential for thermal necrosis, the thin cement mantle technique is recommended.
Dynamics of Population Activity in Rat Sensory Cortex: Network Correlations Predict Anatomical Arrangement and Information Content
Publisher: Frontiers Media SA
Date: 06-07-2016
Is There Asymmetry Between the Concave and Convex Pedicles in Adolescent Idiopathic Scoliosis? A CT Investigation
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2017
SpheroidSim—Preliminary evaluation of a new computational tool to predict the influence of cell cycle time and phase fraction on spheroid growth
Publisher: Wiley
Date: 11-09-2018
DOI: 10.1002/BTPR.2692
Abstract: There is a relative paucity of research that integrates materials science and bioengineering with computational simulations to decipher the intricate processes promoting cancer progression. Therefore, a first-generation computational model, SpheroidSim, was developed that includes a biological data set derived from a bioengineered spheroid model to obtain a quantitative description of cell kinetics. SpheroidSim is a 3D agent-based model simulating the growth of multicellular cancer spheroids. Cell cycle time and phases mathematically motivated the population growth. SpheroidSim simulated the growth dynamics of multiple spheroids by in idually defining a collection of specific phenotypic traits and characteristics for each cell. Experimental data derived from a hydrogel-based spheroid model were fit to the predictions providing insight into the influence of cell cycle time (CCT) and cell phase fraction (CPF) on the cell population. A comparison of the number of active cells predicted for each analysis showed that the value and method used to define CCT had a greater effect on the predicted cell population than CPF. The model predictions were similar to the experimental results for the number of cells, with the predicted total number of cells varying by 8% and 12%, respectively, compared to the experimental data. SpheroidSim is a first step in developing a biologically based predictive tool capable of revealing fundamental elements in cancer cell physiology. This computational model may be applied to study the effect of the microenvironment on spheroid growth and other cancer cell types that demonstrate a similar multicellular clustering behavior as the population develops. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1335-1343, 2018.
Vertebral body tethering for idiopathic scoliosis: a systematic review and meta-analysis
Publisher: Springer Science and Business Media LLC
Date: 11-07-2023
DOI: 10.1007/S43390-023-00723-9
Abstract: Vertebral body tethering (VBT) is a recent procedure to correct and reduce spinal curves in skeletally immature patients with adolescent idiopathic scoliosis (AIS). The purpose of this systematic review and meta-analysis is to determine the expected curve reduction and potential complications for adolescent patients after VBT. PubMed, Embase, Google Scholar and Cochrane databases were searched until February 2022. Records were screened against pre-defined inclusion and exclusion criteria. Data sources were prospective and retrospective studies. Demographics, mean differences in Cobb angle, surgical details and complication rates were recorded. Meta-analysis was conducted using a random-effects model. This systematic review includes 19 studies, and the meta-analysis includes 16 of these. VBT displayed a statistically significant reduction in Cobb angle from pre-operative to final (minimum 2 years) measurements. The initial mean Cobb angle was 47.8° (CI 95% 42.9–52.7°) and decreased to 22.2° (CI 95% 19.9–24.5°). The mean difference is − 25.8° (CI 95% − 28.9–22.7) ( p 0.01). The overall complication rate was 23% (CI 95% 14.4–31.6%), the most common complication was tether breakage 21.9% (CI 95% 10.6–33.1%). The spinal fusion rate was 7.2% (CI 95% 2.3–12.1%). VBT results in a significant reduction of AIS at 2 years of follow-up. Overall complication rate was relatively high although the consequences of the complications are unknown. Further research is required to explore the reasons behind the complication rate and determine the optimal timing for the procedure. VBT remains a promising new procedure that is effective at reducing scoliotic curves and preventing spinal fusion in the majority of patients. Systematic review of Therapeutic Studies with evidence level II–IV.
Deep Learning-Based Automatic Segmentation for Reconstructing Vertebral Anatomy of Healthy Adolescents and Patients With Adolescent Idiopathic Scoliosis (AIS) Using MRI Data
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
A semiautomatic method to identify vertebral end plate lesions (Schmorl's nodes)
Publisher: Elsevier BV
Date: 07-2015
DOI: 10.1016/J.SPINEE.2015.04.027
Abstract: There are differences in the definitions of end plate lesions (EPLs), often referred to as Schmorl's nodes, that may, to some extent, account for the large range of reported prevalence (3.8%-76%). The purpose of this study was to develop a technique to measure the size, prevalence, and location of EPLs in a consistent manner. This study proposed a method using a detection algorithm that was applied to five adolescent females (average age, 15.1 [range, 13.0-19.2] years) with idiopathic scoliosis (average major Cobb angle, 60° [range, 55°-67°]). Existing low-dose, computed tomography scans were segmented semiautomatically to extract three-dimensional morphology of each vertebral end plate. Any remaining attachments to the posterior elements of adjacent vertebrae or end plates were then manually sectioned. An automatic algorithm was used to determine the presence and position of EPLs. End plate lesions were identified in 15 of the 170 (8.8%) end plates analyzed with an average depth of 3.1 mm. Eleven of the 15 EPLs were seen in the lumbar spine. The algorithm was found to be most sensitive to changes in the minimum EPL gradient at the edges of the EPL. This study describes an imaging analysis technique for consistent measurement of the prevalence, location, and size of EPLs. The technique can be used to analyze large populations without observer errors in EPL definitions.
Effect of modular neck variation on bone and cement mantle mechanics around a total hip arthroplasty stem
Publisher: Elsevier BV
Date: 03-2009
DOI: 10.1016/J.CLINBIOMECH.2008.12.010
Abstract: Total hip arthroplasty carried out using cemented modular-neck implants provides the surgeon with greater intra-operative flexibility and allows more controlled stem positioning. In this study, finite element models of a whole femur implanted with either the Exeter or with anew cemented modular-neck total hip arthroplasty (separate, neck and stem components) were developed.The changes in bone and cement mantle stress/strain were assessed for varying amounts of neck offset and version angle for the modular-neck device for two simulated physiological load cases: walking and stair climbing. Since the Exeter is the gold standard for polished cemented total hip arthroplasty stem design, bone and cement mantle stresses/strains in the modular-neck finite element models were compared with finite element results for the Exeter. For the two physiological load cases, stresses and strains in the bone and cement mantle were similar for all modular-neck geometries. These results were comparable to the bone and cement mechanics surrounding the Exeter. These findings suggest that the Exeter and the modular neck device distribute stress to the surrounding bone and cement in a similar manner. It is anticipated that the modular-neck device will have a similar short-term clinical performance to that of the Exeter, with the additional advantages of increased modularity.
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Industrial Transformation Training Centres - Grant ID: IC180100008
Start Date: 07-2019
End Date: 06-2025
Amount: $3,981,223.00
Funder: Australian Research Council
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