Luis Fernando Nicolini, Rafael Carreira Oliveira, Vitor Hugo Tramontini, Marx Ribeiro, Carlos Rodrigo de Mello Roesler, Eduardo Alberto Fancello
Anterior vertebral body tethering (VBT) is a promising technique for the treatment of adolescent idiopathic scoliosis. However, the segments directly treated with VBT can experience substantial loads resulting from the tether pretension, which may alter internal stresses and potentially compromise structures such as the intervertebral discs (IVDs) and facet joints. We aim to investigate the effects of tether within the VBT on the L1–L2 IVD stresses and contact forces of the facet joints, using an extensively calibrated and validated finite element model of the T10–S1 spine. The implant was inserted on the left side of the T10–L3 and tensioned up to 300 N representing the tether pretension applied during surgery and the case of the postoperative neutral position. Subsequently, the spine was tested under an external pure moment of 8 Nm. The tether pretension resulted in a significant increase in the IVD stresses. In the neutral position, a gradual increase in intervertebral pressure (IDP) at the center of the IVD of 0.094, 0.181, and 0.267 MPa was observed after applying forces of 100, 200, and 300 N to the tether, respectively. The contact force of the left facet joint also increased with pretension. It was 12.5 N for the native spine and gradually increased to 49.5, 82.0, and 100.9 N for tether pretensions of 100, 200, and 300 N, respectively, during extension. These results indicate that tether pretension is a key parameter that increases the internal stresses of the IVD and the contact forces of the facet joints at the implant side.
{"title":"The Effects of Vertebral Body Tethering on the Intervertebral Discs and Facet Joints: A Numerical Analysis","authors":"Luis Fernando Nicolini, Rafael Carreira Oliveira, Vitor Hugo Tramontini, Marx Ribeiro, Carlos Rodrigo de Mello Roesler, Eduardo Alberto Fancello","doi":"10.1002/cnm.70084","DOIUrl":"https://doi.org/10.1002/cnm.70084","url":null,"abstract":"<p>Anterior vertebral body tethering (VBT) is a promising technique for the treatment of adolescent idiopathic scoliosis. However, the segments directly treated with VBT can experience substantial loads resulting from the tether pretension, which may alter internal stresses and potentially compromise structures such as the intervertebral discs (IVDs) and facet joints. We aim to investigate the effects of tether within the VBT on the L1–L2 IVD stresses and contact forces of the facet joints, using an extensively calibrated and validated finite element model of the T10–S1 spine. The implant was inserted on the left side of the T10–L3 and tensioned up to 300 N representing the tether pretension applied during surgery and the case of the postoperative neutral position. Subsequently, the spine was tested under an external pure moment of 8 Nm. The tether pretension resulted in a significant increase in the IVD stresses. In the neutral position, a gradual increase in intervertebral pressure (IDP) at the center of the IVD of 0.094, 0.181, and 0.267 MPa was observed after applying forces of 100, 200, and 300 N to the tether, respectively. The contact force of the left facet joint also increased with pretension. It was 12.5 N for the native spine and gradually increased to 49.5, 82.0, and 100.9 N for tether pretensions of 100, 200, and 300 N, respectively, during extension. These results indicate that tether pretension is a key parameter that increases the internal stresses of the IVD and the contact forces of the facet joints at the implant side.</p>","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cnm.70084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144814946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Accurately predicting vertebral fracture risk in metastatic spines remains a critical challenge in clinical practice. This study developed and validated a QCT-based finite element analysis (QCT/FEA) approach to investigate the combined effects of baseline bone strength and tumor size on vertebral structural integrity. Areal bone mineral density (aBMD) was also calculated from QCT data to evaluate the reduction in bone density with increasing defect size. Nine cadaveric vertebral bodies were analyzed under varying tumor sizes (0%, 20%, 35%, and 50%). The results demonstrated a strong correlation between experimentally measured and computationally predicted failure forces (r = 0.97, p < 0.001) and aBMD values (r = 0.96, p < 0.001). Vertebral strength decreased linearly with increasing tumor size. Importantly, the study revealed that baseline vertebral strength plays a crucial role in fracture risk assessment, often surpassing the impact of tumor size alone. Tumor size reduced vertebral strength at a rate 84% faster than bone density (p = 0.009), highlighting a greater impact of tumor defects on bone fracture force than on bone density. These findings suggest that relying solely on tumor size for fracture risk prediction may be insufficient. Incorporating baseline bone strength into predictive models significantly enhances accuracy and reliability, providing valuable insights for clinical decision-making and personalized treatment strategies. This study underscores the importance of advanced computational tools in improving vertebral fracture risk assessment in metastatic spine cases.
在临床实践中，准确预测转移性脊柱骨折的风险仍然是一个关键的挑战。本研究开发并验证了基于QCT的有限元分析（QCT/FEA）方法，以研究基线骨强度和肿瘤大小对椎体结构完整性的综合影响。根据QCT数据计算面骨矿物质密度（aBMD），以评估骨密度随缺损尺寸增加而减少的情况。我们分析了9个不同肿瘤大小（0%、20%、35%和50%）的尸体椎体。结果表明，实验测量和计算预测的破坏力（r = 0.97, p < 0.001）与aBMD值（r = 0.96, p < 0.001）之间存在很强的相关性。椎体强度随肿瘤大小的增加呈线性下降。重要的是，该研究表明，基线椎体强度在骨折风险评估中起着至关重要的作用，通常超过肿瘤大小的单独影响。肿瘤大小降低椎体强度的速度比骨密度快84% (p = 0.009)，突出表明肿瘤缺陷对骨折力的影响大于对骨密度的影响。这些发现表明，仅仅依靠肿瘤大小来预测骨折风险可能是不够的。将基线骨强度纳入预测模型可显著提高准确性和可靠性，为临床决策和个性化治疗策略提供有价值的见解。这项研究强调了先进的计算工具在改善转移性脊柱病例椎体骨折风险评估中的重要性。
{"title":"Computational Assessment of Fracture Risk in Vertebral Bodies With Simulated Defects: The Role of Baseline Strength and Tumor Size","authors":"Mehran Fereydoonpour, Asghar Rezaei, Areonna Schreiber, Lichun Lu, Mariusz Ziejewski, Ghodrat Karami","doi":"10.1002/cnm.70081","DOIUrl":"https://doi.org/10.1002/cnm.70081","url":null,"abstract":"<div>\u0000 \u0000 <p>Accurately predicting vertebral fracture risk in metastatic spines remains a critical challenge in clinical practice. This study developed and validated a QCT-based finite element analysis (QCT/FEA) approach to investigate the combined effects of baseline bone strength and tumor size on vertebral structural integrity. Areal bone mineral density (aBMD) was also calculated from QCT data to evaluate the reduction in bone density with increasing defect size. Nine cadaveric vertebral bodies were analyzed under varying tumor sizes (0%, 20%, 35%, and 50%). The results demonstrated a strong correlation between experimentally measured and computationally predicted failure forces (<i>r</i> = 0.97, <i>p</i> < 0.001) and aBMD values (<i>r</i> = 0.96, <i>p</i> < 0.001). Vertebral strength decreased linearly with increasing tumor size. Importantly, the study revealed that baseline vertebral strength plays a crucial role in fracture risk assessment, often surpassing the impact of tumor size alone. Tumor size reduced vertebral strength at a rate 84% faster than bone density (<i>p</i> = 0.009), highlighting a greater impact of tumor defects on bone fracture force than on bone density. These findings suggest that relying solely on tumor size for fracture risk prediction may be insufficient. Incorporating baseline bone strength into predictive models significantly enhances accuracy and reliability, providing valuable insights for clinical decision-making and personalized treatment strategies. This study underscores the importance of advanced computational tools in improving vertebral fracture risk assessment in metastatic spine cases.</p>\u0000 </div>","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144811202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alessandra Aldieri, Chiara Garavelli, Luca Patruno, Marco Palanca, Marco Viceconti
Many proposed FE models to predict the vertebral risk of fracture consider single vertebrae only, neglecting the role of the intervertebral discs in load transmission and distribution across vertebrae. Inclusion of the intervertebral discs in multi-vertebrae models would allow more physiological boundary conditions. However, while CT allows material properties to be assigned to the vertebrae, no information about the discs is provided. Hence, the aim of this study was to build multi-level FE models uniquely based on CT data and validate them by comparing the predicted displacements and strains against the experimental measurements. One spine segment (T10-L1) was harvested from a human spine and tested in flexion-compression in the elastic regime. During the test, displacements and strains on the anterior surface were measured with digital image correlation. The FE model was built starting from the CT scan of that same spine segment. HU-based isotropic linear elastic properties were assigned to the vertebral bone. Five different combinations of hyperelastic material properties from the literature were assigned to the discs, modeling the nucleus pulposus and the anulus fibrosus separately. The boundary conditions replicated the flexion-compression test performed experimentally. Predicted displacements and strains on the vertebrae surfaces were compared against the measured displacements and strains. The model excellently predicted the displacement field (R2 = 0.92/0.99). On the other hand, different constitutive laws for the discs resulted in different principal strain distributions, which substantially differed from the experimental one, showing average relative errors higher than 34%. In conclusion, a different modeling approach should be adopted for the discs in CT-based multi-level FE models to achieve acceptable accuracy.
{"title":"Can Multi-Vertebral CT-Based Finite Element Models Accurately Predict Strains? An In Vitro Validation Study","authors":"Alessandra Aldieri, Chiara Garavelli, Luca Patruno, Marco Palanca, Marco Viceconti","doi":"10.1002/cnm.70085","DOIUrl":"https://doi.org/10.1002/cnm.70085","url":null,"abstract":"<p>Many proposed FE models to predict the vertebral risk of fracture consider single vertebrae only, neglecting the role of the intervertebral discs in load transmission and distribution across vertebrae. Inclusion of the intervertebral discs in multi-vertebrae models would allow more physiological boundary conditions. However, while CT allows material properties to be assigned to the vertebrae, no information about the discs is provided. Hence, the aim of this study was to build multi-level FE models uniquely based on CT data and validate them by comparing the predicted displacements and strains against the experimental measurements. One spine segment (T10-L1) was harvested from a human spine and tested in flexion-compression in the elastic regime. During the test, displacements and strains on the anterior surface were measured with digital image correlation. The FE model was built starting from the CT scan of that same spine segment. HU-based isotropic linear elastic properties were assigned to the vertebral bone. Five different combinations of hyperelastic material properties from the literature were assigned to the discs, modeling the nucleus pulposus and the anulus fibrosus separately. The boundary conditions replicated the flexion-compression test performed experimentally. Predicted displacements and strains on the vertebrae surfaces were compared against the measured displacements and strains. The model excellently predicted the displacement field (<i>R</i><sup>2</sup> = 0.92/0.99). On the other hand, different constitutive laws for the discs resulted in different principal strain distributions, which substantially differed from the experimental one, showing average relative errors higher than 34%. In conclusion, a different modeling approach should be adopted for the discs in CT-based multi-level FE models to achieve acceptable accuracy.</p>","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cnm.70085","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144810940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Barbara Wirthl, Paolo Decuzzi, Bernhard A. Schrefler, Wolfgang A. Wall
Heat-based cancer treatment, so-called hyperthermia, can be used to destroy tumour cells directly or to make them more susceptible to chemotherapy or radiation therapy. To apply heat locally, iron oxide nanoparticles are injected into the bloodstream and accumulate at the tumour site, where they generate heat when exposed to an alternating magnetic field. However, the temperature must be precisely controlled to achieve therapeutic benefits while avoiding damage to healthy tissue. We therefore present a computational model for nanoparticle-mediated hyperthermia treatment fully integrated into a multiphase porous-media model of the tumour and its microenvironment. We study how the temperature depends on the amount of nanoparticles accumulated in the tumour area and the specific absorption rate of the nanoparticles. Our results show that host tissue surrounding the tumour is also exposed to considerable doses of heat due to the high thermal conductivity of the tissue, which may cause pain or even unnecessary irreversible damage. Further, we include a lumped and a discrete model for the cooling effect of blood perfusion. Using a discrete model of a realistic microvasculature reveals that the small capillaries do not have a significant cooling effect during hyperthermia treatment and that the commonly used lumped model based on Pennes' bioheat equation may overestimate the effect: within the specific conditions analysed, the difference between lumped and discrete approaches is approximatively 0.75°C, which could influence the therapeutic intervention outcome. Such a comprehensive computational model, as presented here, can provide insights into the optimal treatment parameters for nanoparticle-mediated hyperthermia and can be used to design more efficient treatment strategies.
{"title":"Computational Modelling of Cancer Nanomedicine: Integrating Hyperthermia Treatment Into a Multiphase Porous-Media Tumour Model","authors":"Barbara Wirthl, Paolo Decuzzi, Bernhard A. Schrefler, Wolfgang A. Wall","doi":"10.1002/cnm.70074","DOIUrl":"https://doi.org/10.1002/cnm.70074","url":null,"abstract":"<p>Heat-based cancer treatment, so-called hyperthermia, can be used to destroy tumour cells directly or to make them more susceptible to chemotherapy or radiation therapy. To apply heat locally, iron oxide nanoparticles are injected into the bloodstream and accumulate at the tumour site, where they generate heat when exposed to an alternating magnetic field. However, the temperature must be precisely controlled to achieve therapeutic benefits while avoiding damage to healthy tissue. We therefore present a computational model for nanoparticle-mediated hyperthermia treatment fully integrated into a multiphase porous-media model of the tumour and its microenvironment. We study how the temperature depends on the amount of nanoparticles accumulated in the tumour area and the specific absorption rate of the nanoparticles. Our results show that host tissue surrounding the tumour is also exposed to considerable doses of heat due to the high thermal conductivity of the tissue, which may cause pain or even unnecessary irreversible damage. Further, we include a lumped and a discrete model for the cooling effect of blood perfusion. Using a discrete model of a realistic microvasculature reveals that the small capillaries do not have a significant cooling effect during hyperthermia treatment and that the commonly used lumped model based on Pennes' bioheat equation may overestimate the effect: within the specific conditions analysed, the difference between lumped and discrete approaches is approximatively 0.75°C, which could influence the therapeutic intervention outcome. Such a comprehensive computational model, as presented here, can provide insights into the optimal treatment parameters for nanoparticle-mediated hyperthermia and can be used to design more efficient treatment strategies.</p>","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cnm.70074","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144782528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pulsed Field Ablation (PFA) is an electroporation-based treatment modality to perform cardiac tissue ablations. Heart parenchyma is mainly constituted by elongated myocytes organized in fibers. This anisotropic morphology results in a preferential pathway for the electric current to flow along. Assuming conventional PFA modeling approaches in which lesions form where the electric field surpasses a threshold, such conductance anisotropy would result in relatively wide and shallow lesion morphologies when PFA applications are delivered with a focal monopolar catheter. Contrary to that, some recent preclinical data present narrow and deep elongated lesions. This study presents a multiscale simulation approach able to estimate electroporation treatment outcomes when applied in a highly anisotropic tissue such as the myocardium. In this work, a microscopic model was first implemented mimicking the conformation of the cardiac tissue. Longitudinal and transversal electric fields at different frequencies and magnitudes were applied to characterize the expected anisotropic behavior at the tissue level in terms of electric conductivity and expected membrane disruption due to electroporation. Second, the microscopic characterization was integrated into a macroscopic model of a focal ablation catheter in contact with the myocardial tissue to simulate the delivery of monopolar PFA treatments. The microscopic simulations results show that when low electric field magnitudes are applied, the induced membrane disruptions predominantly appear in fibers parallel to the electric field. However, at higher field magnitudes, a demarcated superior sensitivity is observed in perpendicular orientation. The integration of these anisotropic properties into the macroscopic model predicts width/depth ratios of 1.2 compared to the ratios of about 2 predicted with conventional modeling. In this work, the presented multiscale model and approach can predict relatively narrow and deep lesions, as observed preclinically.
{"title":"Computational Multiscale Modeling of Pulsed Field Ablation Considering Conductivity and Damage Anisotropy Reveals Deep Lesion Morphologies","authors":"Quim Castellvi, Antoni Ivorra","doi":"10.1002/cnm.70077","DOIUrl":"https://doi.org/10.1002/cnm.70077","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Pulsed Field Ablation (PFA) is an electroporation-based treatment modality to perform cardiac tissue ablations. Heart parenchyma is mainly constituted by elongated myocytes organized in fibers. This anisotropic morphology results in a preferential pathway for the electric current to flow along. Assuming conventional PFA modeling approaches in which lesions form where the electric field surpasses a threshold, such conductance anisotropy would result in relatively wide and shallow lesion morphologies when PFA applications are delivered with a focal monopolar catheter. Contrary to that, some recent preclinical data present narrow and deep elongated lesions. This study presents a multiscale simulation approach able to estimate electroporation treatment outcomes when applied in a highly anisotropic tissue such as the myocardium. In this work, a microscopic model was first implemented mimicking the conformation of the cardiac tissue. Longitudinal and transversal electric fields at different frequencies and magnitudes were applied to characterize the expected anisotropic behavior at the tissue level in terms of electric conductivity and expected membrane disruption due to electroporation. Second, the microscopic characterization was integrated into a macroscopic model of a focal ablation catheter in contact with the myocardial tissue to simulate the delivery of monopolar PFA treatments. The microscopic simulations results show that when low electric field magnitudes are applied, the induced membrane disruptions predominantly appear in fibers parallel to the electric field. However, at higher field magnitudes, a demarcated superior sensitivity is observed in perpendicular orientation. The integration of these anisotropic properties into the macroscopic model predicts width/depth ratios of 1.2 compared to the ratios of about 2 predicted with conventional modeling. In this work, the presented multiscale model and approach can predict relatively narrow and deep lesions, as observed preclinically.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cnm.70077","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144767848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Agnese Lucchetti, Levi G Juhl, Anna Corti, Alissa Zaccaria, Thomas Gries, Claudio Chiastra, Ted J Vaughan, Dario Carbonaro
Bioresorbable braided stents represent a promising solution for the treatment of peripheral artery disease, providing temporary mechanical support before gradually degrading into biocompatible byproducts. Previous studies have highlighted their lower mechanical performance compared to permanent metallic stents. However, their implantation in lower limb arteries remains unexplored, leaving uncertainty on whether their mechanical performance is sufficient for effective treatment. The aim of the present study was to evaluate the performance of a poly-l-lactic acid (PLLA) braided stent for the treatment of lower limb arteries through in silico analysis and compare it with that of a nickel-titanium (NiTi) device. A finite element (FE) model of the PLLA stent was implemented and validated against experimental bench test data. Subsequently, the mechanical characteristics of the PLLA device were compared to those of a NiTi stent, with identical geometrical features, through FE simulations of two bench tests (i.e., parallel plate compression and crimping tests). Finally, a virtual implantation procedure of both devices in a patient-specific lower limb artery was conducted by FE analysis, accounting for three different arterial wall conditions, to compare the stents' treatment performance. The FE analysis of the bench tests confirmed that the PLLA stent generated much lower force magnitudes than the NiTi device. Moreover, the virtual implantation procedure indicated the limited short-term performance of the PLLA stent for the treatment of peripheral artery disease in terms of risk for permanent deformations, low lumen gain, high values of incomplete stent apposition and a nonuniform distribution of contact pressure on the arterial wall.
{"title":"From Bench Testing to Virtual Implantation: A Comparative Study Between Poly-l-Lactic Acid and Nickel-Titanium Braided Stents.","authors":"Agnese Lucchetti, Levi G Juhl, Anna Corti, Alissa Zaccaria, Thomas Gries, Claudio Chiastra, Ted J Vaughan, Dario Carbonaro","doi":"10.1002/cnm.70078","DOIUrl":"10.1002/cnm.70078","url":null,"abstract":"<p><p>Bioresorbable braided stents represent a promising solution for the treatment of peripheral artery disease, providing temporary mechanical support before gradually degrading into biocompatible byproducts. Previous studies have highlighted their lower mechanical performance compared to permanent metallic stents. However, their implantation in lower limb arteries remains unexplored, leaving uncertainty on whether their mechanical performance is sufficient for effective treatment. The aim of the present study was to evaluate the performance of a poly-l-lactic acid (PLLA) braided stent for the treatment of lower limb arteries through in silico analysis and compare it with that of a nickel-titanium (NiTi) device. A finite element (FE) model of the PLLA stent was implemented and validated against experimental bench test data. Subsequently, the mechanical characteristics of the PLLA device were compared to those of a NiTi stent, with identical geometrical features, through FE simulations of two bench tests (i.e., parallel plate compression and crimping tests). Finally, a virtual implantation procedure of both devices in a patient-specific lower limb artery was conducted by FE analysis, accounting for three different arterial wall conditions, to compare the stents' treatment performance. The FE analysis of the bench tests confirmed that the PLLA stent generated much lower force magnitudes than the NiTi device. Moreover, the virtual implantation procedure indicated the limited short-term performance of the PLLA stent for the treatment of peripheral artery disease in terms of risk for permanent deformations, low lumen gain, high values of incomplete stent apposition and a nonuniform distribution of contact pressure on the arterial wall.</p>","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 8","pages":"e70078"},"PeriodicalIF":2.4,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12331417/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144800841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone scaffolds are artificial structures used to repair or reconstruct damaged bone tissue and restore its function. Various scaffold materials and structures have been studied, but few have assessed their behavior within anatomical geometries using 2D clinical CT data. Therefore, this study employed a computational approach to analyze the structural behavior of bone scaffolds composed of different materials and porous structures when implanted into a 2D model of the proximal femur derived from clinical-resolution CT images. In addition, this study investigated the relationship between the apparent elastic modulus of bone scaffolds and that of the surrounding bone. The results demonstrated that selecting appropriate materials and porous structures is essential for designing scaffolds with AEM values similar to those of native bone. Scaffolds with matching AEM effectively transferred and supported external loads, whereas those designed solely for high stiffness were less effective in load transmission. Notably, in the femoral head, the square and circular scaffolds made with NBM showed the smallest AEM differences from native bone: 0.93% and 8.27%, respectively. In the femoral neck, circular and triangular scaffolds made with PLDLLA/TCP exhibited the smallest differences of 39.38% and 11.00%. In the intertrochanter, honeycomb and triangular scaffolds made with NBM showed the smallest deviations: 24.51% and 33.00%, respectively. Among all combinations, the square-type scaffold with NBM also generated the highest internal strain energy in the femoral head (9.163 μJ), whereas the triangle scaffold with Bioglass/PLGA exhibited the lowest (0.091 μJ). These findings underscore the importance of tailoring scaffold stiffness to specific anatomical sites to optimize mechanical stimulation and promote bone regeneration.
{"title":"A Computational Approach to Investigate the Structural Behavior of Bone Scaffold-Implanted Proximal Femur in Routine Clinical Resolution","authors":"Jun Won Choi, Jung Jin Kim","doi":"10.1002/cnm.70072","DOIUrl":"https://doi.org/10.1002/cnm.70072","url":null,"abstract":"<div>\u0000 \u0000 <p>Bone scaffolds are artificial structures used to repair or reconstruct damaged bone tissue and restore its function. Various scaffold materials and structures have been studied, but few have assessed their behavior within anatomical geometries using 2D clinical CT data. Therefore, this study employed a computational approach to analyze the structural behavior of bone scaffolds composed of different materials and porous structures when implanted into a 2D model of the proximal femur derived from clinical-resolution CT images. In addition, this study investigated the relationship between the apparent elastic modulus of bone scaffolds and that of the surrounding bone. The results demonstrated that selecting appropriate materials and porous structures is essential for designing scaffolds with AEM values similar to those of native bone. Scaffolds with matching AEM effectively transferred and supported external loads, whereas those designed solely for high stiffness were less effective in load transmission. Notably, in the femoral head, the square and circular scaffolds made with NBM showed the smallest AEM differences from native bone: 0.93% and 8.27%, respectively. In the femoral neck, circular and triangular scaffolds made with PLDLLA/TCP exhibited the smallest differences of 39.38% and 11.00%. In the intertrochanter, honeycomb and triangular scaffolds made with NBM showed the smallest deviations: 24.51% and 33.00%, respectively. Among all combinations, the square-type scaffold with NBM also generated the highest internal strain energy in the femoral head (9.163 μJ), whereas the triangle scaffold with Bioglass/PLGA exhibited the lowest (0.091 μJ). These findings underscore the importance of tailoring scaffold stiffness to specific anatomical sites to optimize mechanical stimulation and promote bone regeneration.</p>\u0000 </div>","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 7","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuan Liu, Yuanfei Zhu, Junwen Yu, Shangting Wang, Ming Yang
Pulsatile blood flow has the potential to improve microcirculation perfusion and increase the oxygen transfer rate of the oxygenator. However, the specific effects of pulsatile blood flow parameters on the oxygen transfer rate remain unclear. A cross-scale simulation model for the oxygenator is established to investigate the relationship between the oxygen transfer rate of the oxygenator and the pulsatile blood flow parameters. This model comprises a macroscopic model for the oxygenator and a microscopic model for the hollow fiber membrane within the oxygenator. The macroscopic model is employed to calculate the oxygen transfer rate of the oxygenator under various pulsatile blood flow parameters, and a back propagation (BP) neural network is trained to extend the calculation result. The microscopic model for the hollow fiber membrane is employed to elucidate the mechanisms responsible for variations in the oxygen transfer rate. The simulation results demonstrate that at a blood flow rate of 1 L/min, the oxygen transfer rate is minimally affected by blood flow pulsation parameters. While under 2 L/min to 5 L/min, compared to steady blood flow, the oxygen transfer rate can be increased by 3% to 6% when pulsatile blood flow with a pulsation frequency below 0.5 Hz and a pulsation amplitude exceeding 80% is used. However, as the pulsatile frequency increases or the amplitude decreases, the oxygen transfer rate may approach or even fall below the levels achieved under steady-state blood flow conditions.
{"title":"Effect of Pulsatile Blood Flow Parameters on Membrane Oxygenator Performance: A Cross-Scale Simulation Study","authors":"Yuan Liu, Yuanfei Zhu, Junwen Yu, Shangting Wang, Ming Yang","doi":"10.1002/cnm.70076","DOIUrl":"https://doi.org/10.1002/cnm.70076","url":null,"abstract":"<div>\u0000 \u0000 <p>Pulsatile blood flow has the potential to improve microcirculation perfusion and increase the oxygen transfer rate of the oxygenator. However, the specific effects of pulsatile blood flow parameters on the oxygen transfer rate remain unclear. A cross-scale simulation model for the oxygenator is established to investigate the relationship between the oxygen transfer rate of the oxygenator and the pulsatile blood flow parameters. This model comprises a macroscopic model for the oxygenator and a microscopic model for the hollow fiber membrane within the oxygenator. The macroscopic model is employed to calculate the oxygen transfer rate of the oxygenator under various pulsatile blood flow parameters, and a back propagation (BP) neural network is trained to extend the calculation result. The microscopic model for the hollow fiber membrane is employed to elucidate the mechanisms responsible for variations in the oxygen transfer rate. The simulation results demonstrate that at a blood flow rate of 1 L/min, the oxygen transfer rate is minimally affected by blood flow pulsation parameters. While under 2 L/min to 5 L/min, compared to steady blood flow, the oxygen transfer rate can be increased by 3% to 6% when pulsatile blood flow with a pulsation frequency below 0.5 Hz and a pulsation amplitude exceeding 80% is used. However, as the pulsatile frequency increases or the amplitude decreases, the oxygen transfer rate may approach or even fall below the levels achieved under steady-state blood flow conditions.</p>\u0000 </div>","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 7","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Wiczenbach, L. Pachocki, W. Witkowski, B. Meronk, K. Wilde
<div> <p>This study introduced the development and validation of a transversely isotropic, visco-hyperelastic constitutive model for human spinal ligaments, implemented using the Finite Element Method (FEM). The model, incorporating a Neo-Hookean strain energy function for the isotropic matrix and a polynomial function for the anisotropic fibers, enriched with viscous aspects, was employed within the Ansys LS-Dyna environment. Infinite Impulse Response filtering techniques were integrated into the numerical analysis as a novel approach, aimed at refining the stability and computational efficiency of the simulations under various strain rates (<span></span><math> <semantics> <mrow> <mn>0.5</mn> <mspace></mspace> <msup> <mi>s</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> <annotation>$$ 0.5kern0.5em {mathrm{s}}^{-1} $$</annotation> </semantics></math>, <span></span><math> <semantics> <mrow> <mn>20</mn> <mspace></mspace> <msup> <mi>s</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> <annotation>$$ 20kern0.5em {mathrm{s}}^{-1} $$</annotation> </semantics></math>, <span></span><math> <semantics> <mrow> <mn>150</mn> <mspace></mspace> <msup> <mi>s</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> <annotation>$$ 150kern0.5em {mathrm{s}}^{-1} $$</annotation> </semantics></math>, and <span></span><math> <semantics> <mrow> <mn>300</mn> <mspace></mspace> <msup> <mi>s</mi> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </mrow> <annotation>$$ 300kern0.5em {mathrm{s}}^{-1} $$</annotation> </semantics></math>). This feature significantly mitigated numerical instabilities that could appear when an explicit time integration scheme was used with high strain rate scenarios, critical in modeling vehicular collisions. Material parameters of ligament tissues were acquired through nonlinear least squares fitting to low and high strain experimental data. A comparative analysis of the FEM results against analytical solutions demonstrated th
{"title":"On Implementation of a Finite Element Visco-Hyperelastic Material Model for Spinal Ligaments in Explicit Time Integration Method With an Infinite Impulse Response Filtering Technique","authors":"T. Wiczenbach, L. Pachocki, W. Witkowski, B. Meronk, K. Wilde","doi":"10.1002/cnm.70075","DOIUrl":"https://doi.org/10.1002/cnm.70075","url":null,"abstract":"<div>\u0000 \u0000 <p>This study introduced the development and validation of a transversely isotropic, visco-hyperelastic constitutive model for human spinal ligaments, implemented using the Finite Element Method (FEM). The model, incorporating a Neo-Hookean strain energy function for the isotropic matrix and a polynomial function for the anisotropic fibers, enriched with viscous aspects, was employed within the Ansys LS-Dyna environment. Infinite Impulse Response filtering techniques were integrated into the numerical analysis as a novel approach, aimed at refining the stability and computational efficiency of the simulations under various strain rates (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>0.5</mn>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ 0.5kern0.5em {mathrm{s}}^{-1} $$</annotation>\u0000 </semantics></math>, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>20</mn>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ 20kern0.5em {mathrm{s}}^{-1} $$</annotation>\u0000 </semantics></math>, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>150</mn>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ 150kern0.5em {mathrm{s}}^{-1} $$</annotation>\u0000 </semantics></math>, and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>300</mn>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ 300kern0.5em {mathrm{s}}^{-1} $$</annotation>\u0000 </semantics></math>). This feature significantly mitigated numerical instabilities that could appear when an explicit time integration scheme was used with high strain rate scenarios, critical in modeling vehicular collisions. Material parameters of ligament tissues were acquired through nonlinear least squares fitting to low and high strain experimental data. A comparative analysis of the FEM results against analytical solutions demonstrated th","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 7","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Platelet plug formation is a critical physiological response to vascular injury, serving as a cornerstone of primary hemostasis. Understanding and simulating this process are essential for advancing patient-specific treatments and interventions. However, achieving a balance between model accuracy and computational efficiency, in particular, for patient-specific scenarios, remains a challenge. In this work, we present a continuum-based approach for simulating platelet plug formation using adaptive mesh refinement, providing a novel solution in this field that enables both accuracy and computational feasibility. Indeed, it integrates a stabilized finite element method within the Variational Multiscale framework to model blood flow dynamics, treated as a non-Newtonian fluid, along with the transport of biochemical species such as platelets and agonists. The platelet plug is represented by an extra stress term in the Navier–Stokes equation, capturing its influence on local blood flow dynamics as a rigid body. A key feature is related to anisotropic mesh adaptation, enabling high-resolution representation of the evolving platelet plug boundary while drastically reducing computational cost. We validate the model against two-dimensional benchmarks under varying shear rates and apply it to a 3D scenario, demonstrating its scalability and precision in simulating thrombosis under complex hemodynamic conditions. The results highlight the model's unique capability to facilitate accurate and efficient patient-specific simulations, offering a transformative tool for advancing personalized medicine.
{"title":"A Continuum Approach With Adaptive Mesh Refinement for Platelet Plug Formation","authors":"Ugo Pelissier, Philippe Meliga, Elie Hachem","doi":"10.1002/cnm.70073","DOIUrl":"https://doi.org/10.1002/cnm.70073","url":null,"abstract":"<div>\u0000 \u0000 <p>Platelet plug formation is a critical physiological response to vascular injury, serving as a cornerstone of primary hemostasis. Understanding and simulating this process are essential for advancing patient-specific treatments and interventions. However, achieving a balance between model accuracy and computational efficiency, in particular, for patient-specific scenarios, remains a challenge. In this work, we present a continuum-based approach for simulating platelet plug formation using adaptive mesh refinement, providing a novel solution in this field that enables both accuracy and computational feasibility. Indeed, it integrates a stabilized finite element method within the Variational Multiscale framework to model blood flow dynamics, treated as a non-Newtonian fluid, along with the transport of biochemical species such as platelets and agonists. The platelet plug is represented by an extra stress term in the Navier–Stokes equation, capturing its influence on local blood flow dynamics as a rigid body. A key feature is related to anisotropic mesh adaptation, enabling high-resolution representation of the evolving platelet plug boundary while drastically reducing computational cost. We validate the model against two-dimensional benchmarks under varying shear rates and apply it to a 3D scenario, demonstrating its scalability and precision in simulating thrombosis under complex hemodynamic conditions. The results highlight the model's unique capability to facilitate accurate and efficient patient-specific simulations, offering a transformative tool for advancing personalized medicine.</p>\u0000 </div>","PeriodicalId":50349,"journal":{"name":"International Journal for Numerical Methods in Biomedical Engineering","volume":"41 7","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144657583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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