Acta of bioengineering and biomechanics最新文献

Purpose: There is a need to create objective and reproducible tool for assessing the quality of infant movements. It's substantially important to detect movement disorders in infants as early as possible. The study aimed to evaluate the reproducibility of kinesiological measurements of spontaneous movements performed by 51 infants (aged 6 to 15 weeks) recorded three times for two consecutive days using OSESEC computer analysis algorithms by determining numerical values of parameters, i.e., speed, acceleration, direction, and movement trajectory. Methods: The study group consisted of 51 infants. The diagnostic method of Prechtl was used for qualitative assessment. The quantitative assessment was based on the use of a OSESEC system. Numerical values for all movement parameters were determined, and the data obtained in the study were used for statistical analysis. Results: Analysis including movement parameter values on three consecutive recordings for the same infant revealed no statistically significant differences in location ( p = 0.073), range ( p = 0.557), shape ( p = 0.289), mean acceleration ( p = 0.124) and mean speed ( p = 0.767). This confirms the reproducibility of measurements of the proposed parameters of the objectification of spontaneous infant movements. Conclusions: The interpretability and accuracy of the presented parameters were proved. All parameters estimation is fully automated. Further research and testing requires a larger study group to create an objective diagnostic device for infants.

Purpose: Microwave ablation is a minimally invasive thermal modality for cancer treatment with high survival and low recurrence rates. Despite the unquestionable benefits of microwave ablation, the interaction between the medical instruments and the tissue may cause damage to the healthy tissue around the tumor. Such damages can be removed by clarifying the conditions for their development. In addition to clinical methods, computer simulations have become very effective tools for optimizing microwave ablation performance. Methods: The study was focused on the determination of the optimal input power for complete microwave tumor ablation with an ade-quate safety margin avoiding injury to the surrounding healthy tissue. In three-dimensional simulations, the liver tumor model was based on a real tumor (1.74 cm × 2.40 cm × 1.43 cm) from the 3D-IRCADb-01 database. Calculations were performed for a 10-slot antenna proven to achieve a higher degree of ablation zone localization than a standard single-slot antenna. The temperature-dependent dielectric and thermal properties of healthy and tumoral liver tissue, blood perfusion, and water content were included in the model. Results: The obtained simulation results revealed that the proper choice of input power ensures that necrotic tissue is mainly located in the tumor with minimal damage to the surrounding healthy tissue. Conclusions: This study may represent a step forward in the planning of individual microwave ablation treatment for each patient.

Purpose: The purpose of this work is to present a multivariate analysis of the kinematics of an upper limb rehabilitation robot. Comparing multiple concepts of kinematic chains makes it possible to identify advantages and disadvantages and, as a consequence, choosing the optimal solution to create a physical device. Such actions shall contribute towards automation of the rehabilitation process, bringing benefits to both therapists and patients in comparison with conventional rehabilitation. Methods: Multivariate analysis of kinematics was performed on the basis of three concepts of the kinematic chain of an exoskeleton, enabling the rehabilitation of both right and left upper limb within the area of the shoulder joint, elbow joint and wrist. The kinematic chain allows the performance of simple and complex movements. Results: The results of the conducted multivariate kinematic analysis define specific movements and angular ranges, which may be performed while applying one of the proposed concepts of the robot design. The results made it possible to determine the optimum solution to the kinematic diagram and construction design, which best satisfy the expectations for effective rehabilitation. Conclusions: The analysis of the kinematic diagram concept of the exoskeleton should be done in relation to its design (construction form). Considering the obtained parameters, it is necessary to find an optimum concept and wisely manoeuvre the values, in order to avoid a situation in which one significant parameter influences another, equally important one. It is noteworthy that the introduction of changes into particular segments of the kinematic chain often has a significant impact on other segments.

Purpose: The paper shows a preliminary study of the basic strength parameters of printed parts made of biocompatible polymers with ceramic layers applied to increase the strength of the tool cutting surface. Methods: The specimens were made from different materials and using different 3D printing technologies and the working surfaces that will eventually form the cutting element of the tool were coated with Al₂O₃. Gloss tests were conducted, properties of the coating, a scratch test of the coated surface, also evaluated surface to-pography. Results: Based on the conducted research, it was found that polymeric materials are characterized by sufficient strength and can be used for disposable tools, however, the use of thin layers of Al₂O₃ significantly increases the surface strength parameters, which may have a significant impact on the reliability and durability of the tools. The polymer surface covered with an Al₂O₃ layer is characterised by increased scratch resistance ranging from 24% to 75% depending on the core material and printing technology. The gloss of the surfaces is disproportionately low compared to currently used metal tools, which indicates that they can be used in endoscopic procedures. Conclusions: Based on the conducted research, it was found that the use of thin layers of Al₂O₃ covering polymer 3D prints is an excellent way to increase strength parameters such as scratch resistance, tribological parameters and light reflections arising on the surface as a result of endoscopic lighting are disproportionately small compared to metallic biomaterials. This gives great hope for using polymer 3D prints for personalised neurosurgical tools.

Purpose: Iliac vein stenting is the primary treatment for patients with iliac vein compression syndrome (IVCS). However, post-stent placement, patients often experience in-stent restenosis and thrombosis. Despite this, the role of lower limb movements in the functioning of stents and veins in IVCS patients remains unclear. This study aimed to address this knowledge gap by developing a computational model using medical imaging techniques to simulate IVCS after stent placement. Methods: This research used a patient-specific model to analyze the effects of lower extremity exercises on hemodynamics post-stent placement. We conducted a comprehensive analysis to evaluate the impact of specific lower limb movements, including hip flexion, ankle movement and pneumatic compression on the hemo-dynamic characteristics within the treated vein. The analysis assessed parameters such as wall shear stress (WSS), oscillatory shear index (OSI), and residence time (RRT). Results: The results demonstrated that hip flexion significantly disrupts blood flow dynamics at the iliac vein bifurcation after stenting. Bilateral and left hip flexion were associated with pronounced regions of low WSS and high OSI at the iliac-vena junction and the stent segment. Additionally, active ankle exercise (AAE) and intermittent pump compression (IPC) therapy were found to enhance the occurrence of low WSS regions along the venous wall, potentially reducing the risk of thrombosis post-stent placement. Consequently, both active joint movements (hip and ankle) and passive movements have the potential to influence the local blood flow environment within the iliac vein after stenting. Conclusions: The exploration of the impact of lower limb movements on hemodynamics provides valuable insights for mitigating adverse effects associated with lower limb movements post iliac-stenting. Bilateral and left hip flexions negatively impacted blood flow, increasing thrombosis risk. However, active ankle exercise and intermittent pump compression therapies effectively improve the patency.

Purpose: This study aimed to evaluate the biomechanical response or load transfer on the osteoporotic L1 vertebra under torsional loading. Methods: To achieve this goal, a numerical model of osteoporotic vertebra in various trabecular bone degenerations was developed and tested. The mechanical behavior of the model was represented taking into account the anisotropic properties of the cancellous bone, which provided a more realistic mechanical picture of the biological subsystem. To ensure the reliability of osteoporotic degradation, the thinning of cortical bone and the appearance of gaps between trabecular bone and cortical bone were also taken into account when creating the models. Results: Finite element (FE) analysis showed that the deformations of cortical bone thinning and detachment of the cortical bone from the trabecular tissue lead to local instability of the vertebra. As a result, the cortical bone of a vertebra loses its load-bearing capacity, even if the strength limit is not reached. Conclusions: The results obtained allow us to state that taking into account the thinning of the trabeculae, which creates voids, is extremely important for load-bearing capacity of osteoporotic vertebrae. However, a limitation of this study is the lack of experimental data to ensure consistency with the computer simulation results.

Purpose: Drownings are a societal phenomenon occurring worldwide, hence the importance of rescue skills, including directly towing a victim to a safe place. The purpose of this study was to evaluate the most effective towing techniques based on kinematic parameters, considering different types of drowning cases, for their recommendation for widespread use in water rescue. Methods: The research involved 18 water lifeguards aged 18-25 years. The evaluation included speed tests in towing a mannequin over a distance of 50 m using the Extended Arm Tow (EAT), Double Armpit Tow (DAT), "Sailor" Technique Tow (STT) and with a rescue tube (RT), accompanied by video recording to measure in the designated measurement area the number of cyclic paddling movements by the lower limbs, angles of the body attack, towing velocity, and its decrease during towing. Results: Number of cyclic paddling movements by the lower limbs, towing with a RT was considered the most beneficial, and least beneficial was the DAT. In the DAT, the lifeguard swam with the smallest body angle, in contrast to the STT, where this angle was the largest. The effect of the number of cyclic paddling movements and the body angle by the lifeguard was the velocity, with the highest value recorded in towing using a RT; in other techniques, velocity were similar. Conclusions: Institutions associated with water rescue should recommend towing using a RT for direct rescue actions in the water, as its use shortens the time, while simultaneously increasing safety for both the rescuer and the victim.

Purpose: This study aimed to explore the impact of different landing methods on leg movement ability and the relationship between various parameters of leg movement. Methods: This work parameters including stride, contact time, flight time, duty factor, stride angle, vertical stiffness, leg stiffness and peak vertical ground reaction force. Thirty healthy subjects voluntarily participated in this study. In this experiment, each subject was required to perform two tests on a treadmill (using a speed of 10 km/h and 160 spm) (The interval between two experiments is 7 days). In the first test, subjects used RFS. In the second test, FFS was used. A high-speed video camera was used to collect the images and the Kwon3D motion analysis suite was used to process the images in this experiment. Results: The findings of this study revealed that runners employing the forefoot strike FFS method exhibited several favorable characteristics in contrast to those using the rearfoot strike RFS method. These included shorter contact time, longer flight time, reduced duty cycle, increased stride angle and heightened leg stiffness. Additionally, peak vertical ground reaction forces were significantly elevated in females. Conclusions: While rear foot strike RFS demonstrates a notable enhancement in leg stiffness among female runners with low leg stiffness, it concurrently leads to a significant increase in peak vertical ground reaction force and imposes a greater load on the legs. However, this phenomenon is not observed among male participants.

Purpose: Shoelace tightness is an important factor that may influence basketball players' performance and injury risk during shuttle slip movement. This study aimed to examine the effects of shoelace tightness on shoelace tension, lower limb kinematics and kinetics, and subjective perception in basketball players. Methods: Sixteen male college basketball players performed lateral shuffle movements with their dominant foot landing on a force plate under three shoelace tightness conditions (loose, comfortable and tight). A motion capture system and a force plate were used to measure lower limb kinematics and kinetics, respectively. A customized wireless shoelace tension system was used to measure shoelace tension at three locations on the dorsum of the foot. Visual analogue scales were used to assess perceived comfort, foot pressure and in-shoe displacement. Results: Shoelace tension increased with shoelace tightness (loose: 13.56 ± 6.21 N, comfortable: 16.14 ± 5.35 N, tight: 21.25 ± 6.19 N) and varied with shoelace position (front: 20.19 ± 5.99 N, middle: 13.71 ± 5.59 N, rear: 17.04 ± 6.95 N). Shoelace tightness also affected some of the ankle joint kinematics and kinetics as well as the subjective ratings of foot pressure and in-shoe displacement ( p < 0.05). The loose shoelace increased the ankle inversion angle, while the comfortable shoelace decreased the knee negative power. The tight shoelace increased the perceived foot pressure and reduced the inshoe movement ( p < 0.05). Conclusions: Shoelace tightness could significantly affect lower limb biomechanics and subjective perception during lateral shuffle in basketball. Basketball footwear designers should consider the incorporation of multiple shoelaces or zonal lacing systems to allow athletes to fine-tune the tension across different areas of the foot.

Purpose: Finite element analysis is frequently used for lumbar spine biomechanical analysis. The primary scope of this work is to illustrate, using finite element analysis, how the biomechanical behavior of the transforaminal lumbar interbody fusion (TLIF), along with a novel combination of the interspinous process device (IPD) and pedicle screws, improves lumbar spine stability. Methods: In this study, unilateral pedicle screw fixation (UPSF) and bilateral pedicle screw fixation (BPSF) were used. Four FE models were developed using ANSYS software, as follows: (1) Intact model; (2) TLIF with "U"-shaped Coflex-F IPD (UCF); (3) TLIF with Coflex-F and UPSF (UCF + UPSF); (4) TLIF with Coflex-F and BPSF (UCF + BPSF). The intact model was subjected to four pure moments (10 Nm), and the results were validated with previous literature data. The intact model results correlated well with the literature data, and the model was validated. Three surgical models were subjected to 7.5 Nm four pure moments, flexion (FL), extension (ET), lateral bending (LB), and axial rotation (AR) and a 280N follower load. Results: The surgical model results were compared with the intact model. The comprehensive analysis results show the UCF + BPSF surgical model gave a good advantage on range of motion, cage stress, Coflex-F stress and endplate stress compared among the two models. Conclusion: This study proposes that the UCF + BPSF system helps to reduce the stress on the implant and adjacent endplates and gives very good stability to the lumbar spine under the various static loading conditions.