Ni, J, Bongers, A, Chamoli, U, Bucci, J, Graham, P & Li, Y 2019, 'In Vivo 3D MRI Measurement of Tumour Volume in an Orthotopic Mouse Model of Prostate Cancer', CANCER CONTROL, vol. 26, no. 1.View/Download from: Publisher's site
Ramakrishna, VAS, Chamoli, U, Viglione, LL, Tsafnat, N & Diwan, AD 2018, 'Mild (not severe) disc degeneration is implicated in the progression of bilateral L5 spondylolysis to spondylolisthesis.', BMC musculoskeletal disorders, vol. 19, no. 1.View/Download from: UTS OPUS or Publisher's site
BACKGROUND:Spondylolytic (or lytic) spondylolisthesis is often associated with disc degeneration at the index-level; however, it is not clear if disc degeneration is the cause or the consequence of lytic spondylolisthesis. The main objective of this computed tomography based finite element modelling study was to examine the role of different grades of disc degeneration in the progression of a bilateral L5-lytic defect to spondylolisthesis. METHODS:High-resolution computed tomography data of the lumbosacral spine from an anonymised healthy male subject (26 years old) were segmented to build a 3D-computational model of an INTACT L1-S1 spine. The INTACT model was manipulated to generate four more models representing a bilateral L5-lytic defect and the following states of the L5-S1 disc: nil degeneration (NOR LYTIC), mild degeneration (M-DEG LYTIC), mild degeneration with 50% disc height collapse (M-DEG-COL LYTIC), and severe degeneration with 50% disc height collapse(S-COL LYTIC). The models were imported into a finite element modelling software for pre-processing, running nonlinear-static solves, and post-processing of the results. RESULTS:Compared with the baseline INTACT model, M-DEG LYTIC model experienced the greatest increase in kinematics (Fx range of motion: 73% ↑, Fx intervertebral translation: 53%↑), shear stresses in the annulus (Fx anteroposterior: 163%↑, Fx posteroanterior: 31%↑), and strain in the iliolumbar ligament (Fx: 90%↑). The S-COL LYTIC model experienced a decrease in mobility (Fx range of motion: 48%↓, Fx intervertebral translation: 69%↓) and an increase in normal stresses in the annulus (Fx Tensile: 170%↑; Fx Compressive: 397%↑). No significant difference in results was noted between M-DEG-COL LYTIC and S-COL LYTIC models. CONCLUSIONS:In the presence of a bilateral L5 spondylolytic defect, a mildly degenerate index-level disc experienced greater intervertebral motions and shear stresses compared with a severely degenerate index-level disc in ...
Ramakrishna, VAS, Chamoli, U, Viglione, LL, Tsafnat, N & Diwan, AD 2018, 'The Role of Sacral Slope in the Progression of a Bilateral Spondylolytic Defect at L5 to Spondylolisthesis: A Biomechanical Investigation Using Finite Element Analysis', Global Spine Journal, vol. 8, no. 5, pp. 460-470.View/Download from: UTS OPUS or Publisher's site
© The Author(s) 2017. Study Design: A biomechanical study using finite element analysis. Objectives: The main objective of this study was to investigate the role of sacral slope in the progression of a L5 bilateral spondylolytic defect to spondylolisthesis. Methods: A 3-dimensional model of lumbosacral spine was built using computed tomography (CT) data procured from an anonymized healthy male subject. The segmented CT data was manipulated to generate 3 more models representing L5 bilateral spondylolytic defect with normal sacral slope (SS), sacral slope increased by 10° (SS+10), and sacral slope decreased by 10° (SS-10). The 3D models were imported into finite element modelling software Strand7 for preprocessing, running nonlinear static solves, and postprocessing of the results. Results: Directional biomechanical instabilities were induced in the lumbosacral spine as a result of changes in the L5-S1 disc shape secondary to the changes in sacral slope. Compared with the normal L5 lytic model, wedging of the L5-S1 disc (SS+10) resulted in a significantly greater range of motion in flexion (18% ↑) but extension motion characteristics were similar. Conversely, flattening of the L5-S1 disc (SS-10) resulted in a significantly greater range of motion in extension (16% ↑) but flexion motion characteristics were similar to that of the normal L5 lytic model. Conclusions: Variations in sacral slope while preserving the L5-S1 mid-disc height and orientation of the L5 vertebra resulted in variations in the L5-S1 disc shape. The results suggest that for such extremities in the L5-S1 disc shape different pathomechanisms exist for the progression of the L5 lytic defect to spondylolisthesis.
Chamoli, U, Diwan, AD & Tsafnat, N 2014, 'Pedicle screw-based posterior dynamic stabilizers for degenerative spine: In vitro biomechanical testing and clinical outcomes', JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A, vol. 102, no. 9, pp. 3324-3340.View/Download from: Publisher's site
Chamoli, U, Chen, AS & Diwan, AD 2014, 'Re: Cook DJ, Yeager MS, Cheng BC. Interpedicular travel in the evaluation of spinal implants: an application in posterior dynamic stabilization. Spine 2012; 37: 923-31', SPINE, vol. 39, no. 11, pp. 921-921.View/Download from: Publisher's site
Parr, WCH, Chamoli, U, Jones, A, Walsh, WR & Wroe, S 2013, 'Finite element micro-modelling of a human ankle bone reveals the importance of the trabecular network to mechanical performance: New methods for the generation and comparison of 3D models', JOURNAL OF BIOMECHANICS, vol. 46, no. 1, pp. 200-205.View/Download from: UTS OPUS or Publisher's site
Aquilina, P, Chamoli, U, Parr, WCH, Clausen, PD & Wroe, S 2013, 'Finite element analysis of three patterns of internal fixation of fractures of the mandibular condyle', BRITISH JOURNAL OF ORAL & MAXILLOFACIAL SURGERY, vol. 51, no. 4, pp. 326-331.View/Download from: Publisher's site
Wroe, S, Chamoli, U, Parr, WCH, Clausen, P, Ridgely, R & Witmer, L 2013, 'Comparative Biomechanical Modeling of Metatherian and Placental Saber-Tooths: A Different Kind of Bite for an Extreme Pouched Predator', PLOS ONE, vol. 8, no. 6.View/Download from: Publisher's site
Oldfield, CC, McHenry, CR, Clausen, PD, Chamoli, U, Parr, WCH, Stynder, DD & Wroe, S 2012, 'Finite element analysis of ursid cranial mechanics and the prediction of feeding behaviour in the extinct giant Agriotherium africanum', JOURNAL OF ZOOLOGY, vol. 286, no. 2, pp. 163-170.View/Download from: Publisher's site
Parr, WCH, Wroe, S, Chamoli, U, Richards, HS, McCurry, MR, Clausen, PD & McHenry, C 2012, 'Toward integration of geometric morphometrics and computational biomechanics: New methods for 3D virtual reconstruction and quantitative analysis of Finite Element Models', JOURNAL OF THEORETICAL BIOLOGY, vol. 301, pp. 1-14.View/Download from: Publisher's site
Attard, MRG, Chamoli, U, Ferrara, TL, Rogers, TL & Wroe, S 2011, 'Skull mechanics and implications for feeding behaviour in a large marsupial carnivore guild: the thylacine, Tasmanian devil and spotted-tailed quoll', JOURNAL OF ZOOLOGY, vol. 285, no. 4, pp. 292-300.View/Download from: Publisher's site
Chamoli, U & Wroe, S 2011, 'Allometry in the distribution of material properties and geometry of the felid skull: Why larger species may need to change and how they may achieve it', JOURNAL OF THEORETICAL BIOLOGY, vol. 283, no. 1, pp. 217-226.View/Download from: Publisher's site