Applied Sciences

Research

17 pages, 1977 KiB

Open AccessArticle

Assessing the Structural Performance of Biodegradable Capsules

by Harri Hakula

Appl. Sci. 2023, 13(16), 9232; https://doi.org/10.3390/app13169232 - 14 Aug 2023

Viewed by 565

Biodegradable materials pose challenges over all aspects of computational mechanics. In this study, the focus is on the resulting domain uncertainty. Model structures or devices are shells of revolution subject to random variation of the outer surface. The novelty of the proposed computational [...] Read more.

Biodegradable materials pose challenges over all aspects of computational mechanics. In this study, the focus is on the resulting domain uncertainty. Model structures or devices are shells of revolution subject to random variation of the outer surface. The novelty of the proposed computational approach is the possibility to restrict the variation to specific parts of the structure using a posteriori filtering, which is applied to the random process whose realisations are the profiles of the shells. The dimensionally reduced stochastic elasticity problems are solved using a collocation method where every realisation is discretised separately. The collocation scheme is validated against standard Monte Carlo. The reliability of the simulations is further confirmed via a posteriori error estimates that are computed using the same collocation scheme. The quantities of interest on the nominal domain are the expected displacement fields and their variances. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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16 pages, 2740 KiB

Open AccessArticle

Revisiting the Role of Knee External Rotation in Non-Contact ACL Mechanism of Injury

by Carla F. Santos, Ricardo Bastos, Renato Andrade, Rogério Pereira, Marco P. L. Parente, Renato Natal Jorge and João Espregueira-Mendes

Appl. Sci. 2023, 13(6), 3802; https://doi.org/10.3390/app13063802 - 16 Mar 2023

Cited by 1 | Viewed by 2529

Abstract

An anterior cruciate ligament (ACL) tear is a severe sports injury that often occurs in young athletes. Besides the strong cumulative evidence on noncontact ACL tears, the injury mechanism (especially the contribution of external rotation) is still not well understood. The present work [...] Read more.

An anterior cruciate ligament (ACL) tear is a severe sports injury that often occurs in young athletes. Besides the strong cumulative evidence on noncontact ACL tears, the injury mechanism (especially the contribution of external rotation) is still not well understood. The present work aims to evaluate which knee kinetics result in higher ACL stress and strain. A finite element model of the ACL was developed with a detailed geometry; the two distinct bundles (anteromedial and posterolateral) and the surrounding connective tissue were modelled based on medical anatomic measures and images. The model was validated using computational and cadaveric external data. Sixteen simulations were performed using different combinations of moments and axial loads applied to the knee model as boundary conditions. The results demonstrated that the peak stress (11.00 MPa) and strain (0.048) occurred at the midportion of the anteromedial bundle with the higher values being obtained under a combined knee valgus, flexion, tibial external rotation and high axial load. Anterior load showed low sensitivity in ACL stress and strain peaks. The tibial external rotation showed a higher contribution to the peak ACL stress and strain as compared to internal rotation. These results reinforce the role of axial load and highlight the importance of external rotation on ACL stress and strain, which may be suggestive of the ACL tear mechanism. The role of external rotation is often neglected and should be further explored in future cadaveric and experimental studies. The findings of this study provide data-driven insights to optimize the indications for prevention, diagnosis and treatment of ACL injuries in clinical practice and contribute to raising awareness of the injury mechanism among all relevant stakeholders. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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13 pages, 5947 KiB

Open AccessCommunication

Numerical Study of Tympanosclerosis Including Its Effect on Human Hearing

by Fernanda Gentil, Marco Parente, Carla Santos, Bruno Areias and Renato Natal Jorge

Appl. Sci. 2023, 13(3), 1665; https://doi.org/10.3390/app13031665 - 28 Jan 2023

Viewed by 1825

Abstract

Tympanosclerosis is an abnormal disorder of the middle ear or only the eardrum (i.e., myringosclerosis) in which there are calcium deposits. Normally, it is caused by recurrent middle ear infections. In this work, a 3D finite element model of the ear was developed, [...] Read more.

Tympanosclerosis is an abnormal disorder of the middle ear or only the eardrum (i.e., myringosclerosis) in which there are calcium deposits. Normally, it is caused by recurrent middle ear infections. In this work, a 3D finite element model of the ear was developed, simulating different cases of tympanosclerosis. Through this model, the magnitude and the phase angle of the umbo and stapes displacement were obtained. The middle ear sound transfer function was determined for a stimulus of 80, 90 and 100 dB SPL, in a frequency range between 100 Hz and 10 kHz, applied on the outer surface of the eardrum in the external auditory canal. Depending on the tympanosclerosis affected area, the main conclusion is that worse results (leading to hearing loss) occur when all of the ossicular chain is affected. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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10 pages, 4118 KiB

Open AccessArticle

Application of a Novel Attachable Magnetic Nerve Stimulating Probe in Intraoperative Lumbar Pedicle Screw Placement: A Porcine Model Study

by Tae Sik Goh, Sung-Chan Shin, Hyun-Keun Kwon, Eui-Suk Sung, Se Bin Jun, Byung-Joo Lee and Jung Sub Lee

Appl. Sci. 2021, 11(17), 7801; https://doi.org/10.3390/app11177801 - 25 Aug 2021

Viewed by 2160

Abstract

Pedicle screw instrumentation is a fundamental technique in lumbar spine surgery. However, several complications could occur when placing a pedicle screw, the most serious being damage to the neural structures. We developed an attachable magnetic nerve stimulating probe used for triggered electromyography (t-EMG) [...] Read more.

Pedicle screw instrumentation is a fundamental technique in lumbar spine surgery. However, several complications could occur when placing a pedicle screw, the most serious being damage to the neural structures. We developed an attachable magnetic nerve stimulating probe used for triggered electromyography (t-EMG) to avoid these. This study aimed to investigate the efficacy of this probe for intraoperative neuromonitoring (ION) during lumbar pedicle screw placement in a porcine model. Forty pedicle screws were inserted bilaterally into the pedicles of the fourth and fifth lumbar vertebrae of five pigs; 20 were inserted typically into the pedicle without nerve damage (Group A), and the other 20 were inserted through the broken medial wall of the pedicle to permit contact with the neural structures (Group B). We measured the triggered threshold for pedicle screw placement through the conventional nerve probe and our newly developed magnetic probe. There was no significant difference in the triggered threshold between the two instruments (p = 0.828). Our newly developed magnetic stimulating probe can be attached to a screwdriver, thus preventing real-time screw malpositioning and making it practical and equally safe. This probe could become indispensable in revision spine surgeries with severe adhesions or endoscopic spine surgeries. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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17 pages, 6220 KiB

Open AccessArticle

Analysis of Different Stop-Jumping Strategies on the Biomechanical Changes in the Lower Limbs

by Huiyu Zhou, Datao Xu, Chaoyi Chen, Ukadike Chris Ugbolue, Julien S. Baker and Yaodong Gu

Appl. Sci. 2021, 11(10), 4633; https://doi.org/10.3390/app11104633 - 19 May 2021

Cited by 11 | Viewed by 2830

Abstract

The stop-jumping task is one of the most important technical actions in basketball. A previous study showed 70% probability of non-contact ACL injuries during stop-jumping tasks. Therefore, the present study aimed to investigate the differences in lower extremity biomechanical changes between the rear [...] Read more.

The stop-jumping task is one of the most important technical actions in basketball. A previous study showed 70% probability of non-contact ACL injuries during stop-jumping tasks. Therefore, the present study aimed to investigate the differences in lower extremity biomechanical changes between the rear foot as the initial contact area to terminate the jump (SJR) and the fore foot as the initial contact area to also terminate the jump (SJF) during the horizontal landing during a stop-jumping phase. In total, 25 male amateur Ningbo University basketball athletes from China were recruited for this study. The participants were asked to jump vertically by using two different stop-jumping strategies. Kinematic and kinetics data were amassed during a stop-jumping task. Statistical parametric mapping (SPM) analysis was used to find the differences between SJR and SJF. Our results indicated that the change of different ankle range of motion caused significantly different values for knee angle (p < 0.001), velocity (p = 0.003) (p = 0.023) (p < 0.001), moment (p = 0.04) (p < 0.001), (p = 0.036) and power (p = 0.015) (p < 0.001) during the stop-jumping phase and the horizontal landing phase. The same biomechanical parameters of the hip joint were also significantly different for hip angle (p < 0.001), moment (p = 0.012) (p < 0.001) (p < 0.001), and power (p = 0.01) (p < 0.001) (p < 0.001). These findings indicate that altering the primary contact at the ankle angle might effectively reduce the risk of a knee injury. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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18 pages, 4252 KiB

Open AccessArticle

Numerical Evaluation of Spinal Stability after Posterior Spinal Fusion with Various Fixation Segments and Screw Types in Patients with Osteoporotic Thoracolumbar Burst Fracture Using Finite Element Analysis

by Cheol-Jeong Kim, Seung Min Son, Sung Hoon Choi, Tae Sik Goh, Jung Sub Lee and Chi-Seung Lee

Appl. Sci. 2021, 11(7), 3243; https://doi.org/10.3390/app11073243 - 5 Apr 2021

Cited by 7 | Viewed by 2499

Abstract

The aim of this study was to analyze the spinal stability and safety after posterior spinal fusion with various fixation segments and screw types in patients with an osteoporotic thoracolumbar burst fracture based on finite element analysis (FEA). To realize various osteoporotic vertebral [...] Read more.

The aim of this study was to analyze the spinal stability and safety after posterior spinal fusion with various fixation segments and screw types in patients with an osteoporotic thoracolumbar burst fracture based on finite element analysis (FEA). To realize various osteoporotic vertebral fracture conditions on T12, seven cases of Young’s modulus, namely 0%, 1%, 5%, 10%, 25%, 50%, and 100% of the Young’s modulus, for vertebral bones under intact conditions were considered. Four types of fixation for thoracolumbar fracture on T12 (fixed with T11-L1, T10-T11-L1, T11-L1-L2, and T10-T11-L1-L2) were applied to the thoracolumbar fusion model. The following screw types were considered: pedicle screw (PS) and cortical screw (CS). Using FEA, four motions were performed on the fixed spine, and the stress applied to the screw, peri-implant bone (PIB), and intervertebral disc (IVD) and the range of motion (ROM) were calculated. The lowest ROM calculated corresponded to the T10-T11-L1-L2 model, while the closest to the intact situation was achieved in the T11-L1-L2 fixation model using PS. The lowest stress in the screw and PB was detected in the T10-T11-L1-L2 fixation model. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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14 pages, 5603 KiB

Open AccessArticle

Comparative Study of Aortic Wall Stress According to Geometric Parameters in Abdominal Aortic Aneurysms

by Ji-Hun You, Chung Won Lee, Up Huh, Chi-Seung Lee and Dongman Ryu

Appl. Sci. 2021, 11(7), 3195; https://doi.org/10.3390/app11073195 - 2 Apr 2021

Cited by 2 | Viewed by 2088

Abstract

In abdominal aortic aneurysm (AAA), the rupture of the aortic tissue is directly related to wall stress. Thus, the investigation of maximum wall stress is a necessary procedure to predict the aortic rupture in AAA. In this study, computational simulations were performed to [...] Read more.

In abdominal aortic aneurysm (AAA), the rupture of the aortic tissue is directly related to wall stress. Thus, the investigation of maximum wall stress is a necessary procedure to predict the aortic rupture in AAA. In this study, computational simulations were performed to investigate the correlation between peak wall stress (PWS) and AAA geometry. The Holzapfel model and various orientations of the collagen fibers and thicknesses of the layers of the aorta were employed in the simulation. The material constants used in the Holzapfel model were estimated from the examination and analysis of the biaxial tensile test results of the normal abdominal aorta and AAA. The aneurysm diameter, height, neck angle, and iliac angle were selected as geometric factors affecting the AAA rupture. In addition, a simulation scenario was conceived and created based on the measurement results using the computed tomography data of patients with AAA. Accordingly, the correlation between the PWS and AAA geometry was estimated. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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Graphical abstract

11 pages, 3512 KiB

Open AccessCommunication

Estimation of the Abduction/Adduction Movement of the Metacarpophalangeal Joint of the Thumb

by Néstor J. Jarque-Bou, Margarita Vergara and Joaquín L. Sancho-Bru

Appl. Sci. 2021, 11(7), 3158; https://doi.org/10.3390/app11073158 - 1 Apr 2021

Cited by 3 | Viewed by 2201

Abstract

Thumb opposition is essential for grasping, and involves the flexion and abduction of the carpometacarpal and metacarpophalangeal joints of the thumb. The high number of degrees of freedom of the thumb in a fairly small space makes the in vivo recording of its [...] Read more.

Thumb opposition is essential for grasping, and involves the flexion and abduction of the carpometacarpal and metacarpophalangeal joints of the thumb. The high number of degrees of freedom of the thumb in a fairly small space makes the in vivo recording of its kinematics a challenging task. For this reason, along with the very limited independence of the abduction movement of the metacarpophalangeal joint, many devices do not implement sensors to measure such movement, which may lead to important implications in terms of the accuracy of thumb models. The aims of this work are to examine the correlation between thumb joints and to obtain an equation that allows thumb metacarpophalangeal abduction/adduction movement to be estimated from the other joint motions of the thumb, during the commonest grasps used during activities of daily living and in free movement. The correlation analysis shows that metacarpophalangeal abduction/adduction movement can be expressed mainly from carpometacarpal joint movements. The model thus obtained presents a low estimation error (6.29°), with no significant differences between grasps. The results could benefit most fields that do not typically include this joint movement, such as virtual reality, teleoperation, 3D modeling, prostheses, and exoskeletons. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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10 pages, 3137 KiB

Open AccessArticle

Efficacy of Iopamidol for Sealing an Injured Thoracic Duct: Pilot Experiments in a Large Animal

by Hyo Yeong Ahn, Seunghwan Song, Up Huh, Il Jae Wang, Jung Seop Eom and Dong-Man Ryu

Appl. Sci. 2020, 10(23), 8424; https://doi.org/10.3390/app10238424 - 26 Nov 2020

Viewed by 1736

Abstract

Chylothorax can be spontaneously healed by lymphangiography using lipiodol, but pulmonary or systemic embolization is a potential complication. We determined the efficacy of iopamidol for treating chylous leakage in an animal model. Twelve pigs were randomly divided into two groups. After inducing thoracic [...] Read more.

Chylothorax can be spontaneously healed by lymphangiography using lipiodol, but pulmonary or systemic embolization is a potential complication. We determined the efficacy of iopamidol for treating chylous leakage in an animal model. Twelve pigs were randomly divided into two groups. After inducing thoracic duct damage, pigs from groups A and B were injected with iopamidol and lipiodol, respectively. At 5, 10, and 30 min after damage induction, the drug effects were monitored by video-assisted thoracoscopy and lymphangiography. In vitro, chyle samples from the pigs were incubated with iopamidol and lipiodol. The damaged thoracic duct was harvested and examined using microscopy. In group A, four and two pigs did not show chylous leakage after 5 and 10 min, respectively. In group B, none showed chylous leakage after 5 min. Nevertheless, the p value was 0.46, and there was no statistically significant difference between groups A and B. In vitro, both iopamidol- and lipiodol-treated chyle samples adhered after 5 min and solidified at 30 min. Our findings confirmed that the damaged thoracic duct was clogged with an amorphous proteinaceous material (iopamidol). Therefore, iopamidol is potentially a new therapeutic agent for chylous leakage. Thoracic duct embolization failures or systemic embolization risks from lipiodol injection may be avoided by injecting iopamidol via the thoracic duct, and this warrants further investigation. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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17 pages, 4057 KiB

Open AccessArticle

Computational Fluid Dynamics Study of Superselective Intra-arterial Chemotherapy for Oral Cancer: Flow Simulation of Anticancer Agent in the Linguofacial Trunk

by Hiroaki Kitajima, Toshinori Iwai, Yasuharu Yajima and Kenji Mitsudo

Appl. Sci. 2020, 10(21), 7496; https://doi.org/10.3390/app10217496 - 25 Oct 2020

Cited by 1 | Viewed by 2516

Abstract

Superselective intra-arterial chemotherapy (SSIAC) for oral cancer can deliver a higher concentration of anticancer agent into a tumor-feeding artery than intravenous systemic chemotherapy. However, the agent distribution between the lingual artery and facial artery (FA) is not clear in SSIAC for patients with [...] Read more.

Superselective intra-arterial chemotherapy (SSIAC) for oral cancer can deliver a higher concentration of anticancer agent into a tumor-feeding artery than intravenous systemic chemotherapy. However, the agent distribution between the lingual artery and facial artery (FA) is not clear in SSIAC for patients with the linguofacial trunk. The agent distribution in the SSIAC method was investigated using computational fluid dynamics (CFD). Ten three-dimensional vessel models were created from CT images of two patients with oral cancer (patients A and B) with the linguofacial trunk. Catheter models were combined with vessel models to mimic intra-arterial infusion, and the agent flow was analyzed. In patient A models, the agent distribution varied depending on the catheter tip position in the linguofacial trunk, while all anticancer agents flowed into the FA only in patient B models. This study revealed that the behavior of the agent in the common trunk is determined by the blood flow field which depends on the topography of the vessels in each patient. Therefore, the catheter tip position should be changed according to the vessel topography to deliver anticancer agents into the tumor-feeding artery. Moreover, CFD can be a useful method to predict the agent flow for each patient before SSIAC. Full article

(This article belongs to the Special Issue Recent Developments and Emerging Trends in Biomechanics)

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