Annals of Biomedical Engineering最新文献

Purpose: Biomechanical parameters of the temporomandibular joint (TMJ), such as joint contact forces and intra-articular stresses, are suggested to contribute to the development of temporomandibular joint disorders, but are impractical to measure. In this study, we present a computational framework for evaluating these parameters by integrating a function assessment system and a patient-specific modeling approach.

Methods: The pipeline consists of acquiring patients' functional and morphological data and developing combined multibody dynamics and finite-element (MBD-FE) models for simulating their specific biting tasks. We demonstrate the approach in a pre-/post-orthognathic surgery scenario and present the measured and simulated outputs.

Results: In a three-patient cohort of one Class I control and two surgical patients (one Class II and one Class III patient), surgery was accompanied by functional changes such as increased bite force capacity and shifts in muscle-usage during unilateral first premolar clenching that brought the surgical cases closer to the control case. Also, morphological measurements showed postoperative adaptations in condylar size and joint space. Simulations demonstrated that contralateral joint forces exceeded ipsilateral forces during unilateral biting and predicted regions of concentrated disc stress that coincided with regions of reduced joint gap and poorer articular congruency, highlighting how morphology-function interactions shape local mechanics.

Conclusion: By unifying individualized functional inputs and subject-specific geometries, the framework provides a practical basis for patient-tailored assessment of biomechanical parameters and decision support in TMJ care.

Purpose: Peripheral artery disease (PAD) predominantly affects the lower extremities, where complex biomechanical deformations during limb flexion contribute to disease progression and treatment failure. While human and cadaver studies have characterized these deformations, preclinical device testing requires large-animal models that replicate human arterial anatomy and biomechanics. Swine are commonly used, yet their biomechanical comparability to humans remains poorly defined.

Methods: We performed a detailed morphometric and biomechanical analysis of the external iliac (EIA), superficial femoral (SFA), and popliteal (PA) arteries in 20 Yucatan and 16 domestic swine using computed tomography angiography. Arteries were evaluated in straight and flexed limb postures to assess diameters, lengths, axial compression, tortuosity, bending angles, and inscribed sphere radii. Breed-specific effects of age and weight were also analyzed.

Results: Porcine arterial dimensions closely matched human lower extremity vessels. EIA diameters (4.9-7.2 mm) corresponded to human SFA, porcine SFA (4.1-5.9 mm) approximated human PA, and porcine PA (3.0-4.7 mm) resembled human tibial arteries. Segment lengths supported use of multiple devices. Flexion induced 12-33% axial compression, mimicking worst-case human scenarios. Tortuosity increased distally, and bending characteristics in porcine PAs aligned with human data. In Yucatan swine, vessel diameters were stable with age and weight, while domestic swine exhibited greater variability. Flexion-induced compression and tortuosity were not influenced by age or weight.

Conclusion: Swine are well-suited for modeling the geometry and biomechanics of human lower extremity arteries. Their anatomical compatibility and ability to replicate physiologic deformations make them valuable models for preclinical testing of PAD therapies and vascular devices.

The complexities of bone architecture, with its hierarchical organization and varying spatiotemporal scales, necessitate advanced modeling techniques to capture its mechanical behavior precisely. This review aims to highlight recent trends in capturing the multiscale nature of bone using two primary computational approaches: classical and data-driven frameworks. Each class is assessed regarding its versatility in achieving scale dimensions, modeling complex behavior, integrating biological data, and balancing computational efficiency and interpretability. In addition, hybrid techniques have been shown to offer future avenues for promising robust and generalizable modeling. Therefore, particular attention has been given to the synergy between these techniques. A hierarchical decision matrix is proposed to translate this review into actionable guidance, shedding light on the selection or combination of appropriate techniques based on specific application contexts, such as data availability, modeling objectives, and computational constraints. This review aims to serve as both a state-of-the-art synthesis and a practical reference for future advancements in multiscale bone biomechanics.

Purpose: Understanding how the neuromuscular system adapts to increasing force demands is essential for characterizing compensatory motor control. This study investigated force-dependent reconfiguration of muscle and cortical functional networks during isometric upper-limb tasks.

Methods: Twelve healthy participants performed isometric elbow flexion at 30%, 50%, and 70% of maximal voluntary contraction (MVC). Surface electromyography (sEMG) from eight upper-limb muscles and electroencephalography (EEG) from 21 scalp electrodes were recorded concurrently. Directed functional connectivity was estimated using generalized partial directed coherence (GPDC), and graph-theoretical metrics-average global efficiency (AGE), average clustering coefficient (ACC), and average path length (APL)-were computed separately for muscle and cortical networks.

Results: In the muscle network, a significant main effect of force level was observed. Compared with 30% MVC, AGE increased by 12.24% ( $P=0.043$ ) and APL decreased by 17.14% ( $P=0.031$ ) at 70% MVC, while ACC increased by 44.64% ( $P=0.018$ ). In the EEG beta band, AGE increased by 8.12% ( $P=0.048$ ) and APL decreased by 12.34% ( $P=0.036$ ) at 70% MVC relative to 30% MVC. Gamma band changes were limited or non-significant across conditions.

Conclusion: These results demonstrate systematic, force-dependent reconfiguration of both muscle and cortical functional networks during isometric force production. Rather than indicating improved performance or neural plasticity, the observed network changes suggest shifts in coordination strategies as force demands increase. The present framework provides quantitative network metrics that can be extended to clinical and longitudinal studies in future work.

Purpose: Assessment of muscle coordination during cycling can provide insight into motor control strategies and movement efficiency. This study evaluated muscle synergy patterns as indicators of neuromuscular coordination in the lower limbs across three power levels of cycling (LPL = Lowest Power Level, MPL = Middle Power Level, HPL = Highest Power Level).

Methods: Twenty recreational cyclists performed a graded cycling test on a stationary bicycle ergometer. Electromyography (EMG) was recorded bilaterally from seven lower-limb muscles and muscle synergies were extracted using non-negative matrix factorization. The Synergy Index (SI) and Synergy Coordination Index (SCI) were calculated to assess muscle coordination patterns.

Results: Four muscle synergies were identified consistently across power levels, with changes in synergy composition and activation timing correlated with increasing muscular demands. At the dominant hip, SI remained consistent across power levels (0.50 ± 0.11 at LPL, 0.56 ± 0.15 at MPL, 0.54 ± 0.15 at HPL). At the dominant knee, SI decreased with increasing power (0.47 ± 0.07 at LPL to 0.34 ± 0.05 at HPL; p < 0.01, η_p² = 0.51). At the dominant ankle, SI increased with increasing power (0.19 ± 0.09 at LPL to 0.27 ± 0.10 at HPL; p < 0.01, η_p² = 0.41). The SCI increased with increasing power level (0.08 ± 0.04 at LPL, 0.13 ± 0.08 at MPL, 0.24 ± 0.11 at HPL; p < 0.01, Kendall's W = 0.59).

Conclusion: These findings provide insight into how the central nervous system modulates its response to increasing mechanical demands. Combining synergy indices offers a promising approach to assess motor control, inform rehabilitation, and optimize performance in cycling tasks.

Purpose: Atherosclerotic vascular disease remains a leading cause of morbidity and mortality worldwide. Current treatments such as angioplasty, stenting, and atherectomy are invasive and limited by restenosis, thrombosis, and incomplete long-term efficacy. Pulsed field ablation (PFA), a nonthermal electroporation-based modality, has demonstrated safety in other cardiovascular applications, but it has not been applied for the treatment of endoluminal vascular diseases. We investigated whether pulsed electric fields could be delivered within the coronary artery and if PFA could selectively ablate the cellular components of atherosclerotic plaques.

Methods: An endoluminal bipolar PFA probe was fabricated using a balloon catheter with flexible electrodes and evaluated in potato and ex vivo porcine hearts. The electrical conductivities of human atherosclerotic plaques were derived from previous impedance measurements for patient-specific multi-tissue and single-cell electroporation modeling. PFA was then evaluated for selective decellularization within an electrical conductivity-matched 3D fibrotic atherosclerosis tissue mimic using high concentrations of human macrophages and aggregated oxidized low-density lipoproteins, encapsulated within a collagen matrix.

Results: Endoluminal probe positioning and high-voltage pulsed electric field delivery feasibility was established within the porcine left coronary arteries, with susequent potato lesions experiments demonstrating maximum ablations (6.99 cm²) and current (13 A) with equal treatment parameters. The multi-tissue model then indicated that endoluminal PFA can effectively cover > 95% of severe and thick plaques with irreversible electroporation, with single-cell modeling supporting the electroporation of foam cells within the plaque. The 3D atherosclerosis mimic validated the ability of PFA to completely ablate the foam cells with fibrotic tissue at > 1000 V/cm.

Conclusions: This study provides practical demonstration of PFA for the treatment of atherosclerotic vascular disease. By combining experimental validation with computational modeling, we establish proof-of-concept that endoluminal PFA can selectively ablate diseased cells while preserving extracellular architecture, laying the groundwork for future translational development of this therapy.

Current research in predicting traumatic brain injury risk focuses on the relationship between head impacts and the likelihood of white matter damage, often overlooking the role of neurovascular coupling in the injury response. To fill this gap, we combined biomechanical and neurodynamic principles to simulate alterations to large-scale resting-state brain activity following head impacts. We simulated cortical neural activity with a network of Kuramoto phase oscillators, using structural connectivity to define coupling and a vascular-informed local resource term to capture neurovascular coupling. By combining the neurodynamic model with a brain mechanics model, we investigated two mechanistic pathways of network dysfunction: (1) white matter damage, reflected in degrading network edges, and (2) local tissue oxygenation decline, reflected in adjusting the resource term at each network node. We simulated 53 real-world head impacts using a vasculature template to evaluate the changes in simulated functional connectivity (FC) and neural dynamics relative to injury outcomes (concussion vs. no concussion). To assess vascular variability, simulations were repeated across 41 individual vasculature maps. Our results show simulated FC changes (measured by Pearson's correlation) consistently correlated well with injury outcomes, regardless of injury mechanism (AUC = 0.89 and 0.90), However, the two injury models yielded distinct FC patterns as indicated by graph metrics. Vascular variability substantially influenced how injury affected FC, with some brains exhibiting resilience to synchrony disruption depending on their vascular structure. These findings offer testable insight into the neurovascular mechanism of brain dysfunction after TBI and have important implications for individualized protection and treatment.

Purpose: Low back pain associated with whole-body vibration (WBV) exposure remains a significant health concern, yet the biomechanical mechanisms linking WBV to spinal loads are incompletely understood. Prior computational studies often relied on simplified assumptions, such as static muscle activation patterns and constrained lumbar joint rotations, limiting the fidelity of dynamic spinal load predictions. To address these gaps, this study aims to establish and validate a muscle-driven lumbar spine model that integrates nonlinear mechanical properties of intervertebral joints and an adaptive feedback control strategy.

Methods: A hybrid inverse-forward dynamics framework, integrated with a robust adaptive proportional-integral-derivative (PID)-based control algorithm providing closed-loop feedback tracking, dynamically allocated muscle excitations to stabilize lumbar posture under vertical vibration without artificial rotational constraints. The effects of muscle activations and vibration frequency on spinal biomechanical loads and biodynamic responses were also investigated.

Results: Validations against in vivo intradiscal pressure and erector spinae electromyography showed good agreement (r > 0.9). For biodynamic responses, seat-to-head transmissibility was used to set the pelvis-seat interface properties, and apparent mass was predicted with favorable agreement. A preliminary analysis of frequency effects revealed peak spinal loads near resonance. Active muscle control considerably altered resonance frequencies (4.5 Hz vs. 5 Hz in passive models) and reduced vibration transmissibility while increasing lumbar compressive loads at resonance, highlighting a critical trade-off between vibration mitigation and spinal biomechanical stress.

Conclusion: By addressing limitations in resolving dynamic muscle recruitment and joint-level loads, this work provides a validated framework for evaluating vibration-induced spinal biomechanics, offering insights into injury pathways and informing ergonomic interventions.

Purpose: The growing demand for functional tissues and organs has driven advances in tissue engineering, particularly through 3D bioprinting. However, the mechanical stress associated with extrusion can compromise cell viability, limiting its clinical applicability. This study aimed to evaluate the viability of mature osteoblast-like cells (SaOS-2) in alginate-based bioinks supplemented with different platelet concentrates, platelet-rich plasma (PRP), platelet-poor plasma (PPP), platelet-rich fibrin (PRF), and injectable PRF (iPRF) to identify formulations that enhance cell survival post-printing.

Methods: Bioinks composed of alginate and varying concentrations (10% and 20%) of platelet concentrates were prepared and characterized rheologically. SaOS-2 cells were embedded in the bioinks and printed using extrusion-based 3D bioprinting. Printed scaffolds were analyzed for cell viability using the LIVE/DEAD assay and confocal microscopy at 24, 48, and 72 hours post-printing.

Results: Rheological analysis confirmed the printability of constructs containing 10% PPP, 10% PRF, and 20% PRF. Cell viability exceeded 58% at 24 hours and 80% at 48 hours across all tested bioinks. Notably, PRF-containing constructs demonstrated viability recovery up to 86% at 72 hours, suggesting a protective and regenerative role.

Conclusion: PRF-enriched bioinks significantly improve cell viability after extrusion and enhance the physical integrity of bioprinted scaffolds. These results support the potential of PRF-based bioinks as promising candidates for clinically relevant bone tissue engineering applications.