Realistic Simulation Model Research Articles

Improving surgical technical skills for emergency fixation of unstable pelvic ring fractures: an experimental study using a pelvic ring fracture simulator

BackgroundThe management of hemodynamically unstable pelvic ring injuries necessitates surgical intervention, often involving procedures such as external fixation and percutaneous screw placement. Given the infrequent performance of these procedures, regular training is imperative to ensure readiness for emergencies. Our pre- post simulation study aimed to adapt and validate a realistic simulation model for stabilizing unstable pelvic ring injuries, facilitating participants’ knowledge retention and procedural confidence enhancement.MethodsA standardized simulator of an unstable pelvic ring utilizing synthetic pelvic bones featuring complete disruption of the symphysis and sacroiliac joint was developed. Trauma surgeons of a level one academic hospital were invited to perform external fixation and emergency sacroiliac screw application under C-arm guidance. Prior to and following the simulation session, participants completed a subjective questionnaire assessing their confidence in emergency interventions on a 10-point Likert scale (10-LS). Objective parameters, such as intraoperative imaging quality, reduction accuracy, and the positioning of screws, wires, and external fixators, were also evaluated as secondary outcome measures.ResultsFifteen trauma surgeons (10 residents, 5 consultants) participated in the simulation over the course of one day. The mean total operation time was 20.34 ± 6.06 min, without significant differences between consultants and residents (p = 0.604). The confidence for emergency SI-Screw placement increased significantly after the simulator (10-LS: Before = 3.8 ± 3.08 vs. After = 5.67 ± 2.35; p = 0.002) as well as after external fixation (10-LS: Before = 3.93 ± 2.79 vs. After = 6.07 ± 2.52; p = 0.002). In addition, confidence in (intraoperative) pelvic imaging increased significantly (10-LS: Before = 4.60 ± 3.0 vs. After = 6.53 ± 2.39; p = 0.011). Overall, the model was rated as a realistic simulation of clinical practice (10-LS = 7.87 ± 1.13).ConclusionsOur unstable pelvis fracture model is a tool to practice emergency interventions such as external fixation and percutaneous techniques. Participants benefitted from this in terms of technical instrumentation as well as intraoperative imaging. Further studies are required to validate the objective benefits and improvements that participants undergo through frequent training.

A framework for modeling and simulating blockchain-based supply chain traceability systems

Traceability improves supply chain operations transparency, benefiting the overall performance and the end customer perception. Blockchain technology is a promising alternative to create robust traceability systems, as it promotes trust and supports information sharing based on data immutability. Despite the hype surrounding blockchain technology and the vast literature in the field, the effectiveness and efficiency of blockchain-based supply chain traceability systems remain uncertain across multiple industry sectors, due to the lack of empirical evidence. Considering its characteristics, simulation is a valuable tool to evaluate the performance of supply chain management processes and technology alternatives. However, a structured guide to support the building process of simulation models regarding blockchain in the supply chain is still missing, making it hard for modelers to create realistic simulation models. Thus, this work proposes a novel methodological framework with guidelines to develop HS models regarding supply chain traceability capable of integrating the main blockchain concepts for managerial purposes. Scenarios with different granularity levels may be designed through the combination of both discrete-event and agent-based simulation paradigms. The proposed approach integrates concepts and terminologies from foundational references, including the Supply Chain Operations Reference (SCOR) model and the Global Traceability Standard (GTS). In addition, it is anchored on the ADACOR holonic architecture for the agentification process. Following the Design Science Research methodology, a proof-of-concept application is presented, based on a real-scale industrial case of a lobster supply chain from Canada. Results obtained reflect the framework's versatility to assist the development of a hybrid simulation model, as traceability is explored through the perspectives of time to react, item separation, temporal screening, and blockchain participation rate.

Microwave Technique for Linear Skull Fracture Detection-Simulation and Experimental Study Using Realistic Human Head Models.

Microwave (MW) sensing is regarded as a promising technique for various medical monitoring and diagnostic applications due to its numerous advantages and the potential to be developed into a portable device for use outside hospital settings. The detection of skull fractures and the monitoring of their healing process would greatly benefit from a rapidly and frequently usable application that can be employed outside the hospital. This paper presents a simulation- and experiment-based study on skull fracture detection with the MW technique using realistic models for the first time. It also presents assessments on the most promising frequency ranges for skull fracture detection within the Industrial, Scientific and Medical (ISM) and ultrawideband (UWB) ranges. Evaluations are carried out with electromagnetic simulations using different head tissue layer models corresponding to different locations in the human head, as well as an anatomically realistic human head simulation model. The measurements are conducted with a real human skull combined with tissue phantoms developed in our laboratory. The comprehensive evaluations show that fractures cause clear differences in antenna and channel parameters (S11 and S21). The difference in S11 is 0.1-20 dB and in S21 is 0.1-30 dB, depending on the fracture width and location. Skull fractures with a less than 1 mm width can be detected with microwaves at different fracture locations. The detectability is frequency dependent. Power flow representations illustrate how fractures impact on the signal propagation at different frequencies. MW-based detection of skull fractures provides the possibility to (1) detect fractures using a safe and low-cost portable device, (2) monitor the healing-process of fractures, and (3) bring essential information for emerging portable MW-based diagnostic applications that can detect, e.g., strokes.

Numerical approach for the simulation of flow-induced noise around a structure with complex geometry: High-speed train bogie in a cavity

The bogie region is a significant source of aerodynamic noise on high-speed trains. Owing to its complex geometry and flow field, numerical simulations using computational fluid dynamics are especially challenging. The main challenge is to achieve a grid with adequate resolution, especially in the boundary layer, while ensuring computational affordability. This challenge is addressed here by employing a hybrid grid, integrating a structured hexahedral mesh near solid surfaces with an unstructured polyhedral mesh in the remaining volume. To limit the number of cells in the boundary layer region, the delayed detached eddy simulation method is adopted. Additionally, to achieve a further reduction in the cell count, the Reynolds number of the model is decreased by scaling down the model size and lowering the inflow speed. The hybrid grid generation and numerical settings are guided by validated simulations of flow over cylinders. A grid sensitivity study, conducted with a simplified half-width bogie model, reveals the meshing requirements for the full-width model. Aerodynamic results highlight the rear section of the cavity and bogie as primary noise sources, emphasizing the critical role of the detached shear layer from upstream components. Time-resolved surface pressure data are input into the Ffowcs Williams–Hawkings equation for far-field noise calculation. The results indicate that the sound energy is concentrated below 200 Hz in the full-scale model, with the cavity contributing more than the bogie. This study provides a practical numerical approach for simulating a structure with complex geometry, offering insights for realistic model simulations.

Black-box modeling of PMSG-based wind energy conversion systems based on neural ODEs

Abstract Integrating renewable energy sources like wind power into the power grid enhances the dynamic interactions among renewable energy-producing equipment, leading to new technological issues for the power grid. Modeling and simulation are essential to ensure the stability of the emerging power grid, but they require precise dynamic component modeling, which is often unavailable due to technical confidentiality and other factors. Conventional hardware-in-the-loop (HIL) simulation can accurately simulate the dynamics of a single renewable energy device, but not the complex dynamics of multiple devices. This research introduces a method that combines classical mechanism modeling and differential neural network modeling to create accurate wind turbine models utilizing equipment measurement data or HIL simulation data. A realistic wind turbine electromagnetic transient simulation model of a specific type is developed and validated by connecting it to the IEEE-39 node system, confirming the model’s accuracy.

Ex Vivo Porcine Model for Ureteral Stent Placement Training

Realistic simulation models for interventional radiology procedures are limited, including for placement of double-J ureteral stents (DJSs). Using a porcine kidney and empty saline bag (bladder), an ex vivo model aiming to improve operators’ knowledge and confidence in performing a DJS procedure was developed. Six faculty (J.W., J.L.) and 14 trainees (C.B.O.) successfully operated on the model. Mean results for faculty versus trainees were as follows: 2.2 (SD ± 1.5) versus 2.4 (SD ± 1.5) puncture attempts to access the collecting system (P = .78), 14.5 minutes (SD ± 4.8) versus 15.1 minutes (SD ± 6.0) for insertion time (P = .84), 7.3 minutes (SD ± 2.8) versus 10.3 minutes (SD ± 2.6) for exchange time (P = .04), 8.48 minutes (SD ± 2.0) versus 8.01 minutes (SD ± 2.6) for fluoroscopy time (P = .70), and 5.7 mGy (SD ± 1.6) versus 5.4 mGy (SD ± 2.0) for absorbed air kerma (P = .77). Self-assessed knowledge and confidence with DJS placement increased for all participants following model use.

Coupled natural-social water system in a subwatershed of the Tennessee River Basin

Regional water cycle systems are increasingly characterized by the dual effect of natural and social processes, which have profound impacts on global water security. However, accurately interpreting the changes in the coupled natural-social water system and identifying the driving factors pose significant challenges. Here, we attempted to model a coupled natural-social water system in the East Fork Poplar Creek (EFPC) watershed of the Tennessee River, United States. The study area features two social water cycle components: a local water transfer project and the Oak Ridge Wastewater Treatment Facility (ORWTF). We conducted the Soil and Water Assessment Tool (SWAT) modeling in the open-source light-weight QGIS software, with the synthesis of various climate and land use change scenarios in both historical periods (1980–2016) and future periods (2017–2050). We achieved more accurate and realistic model simulations when considering the social water cycle components, indicating that the social water cycle accounted for 13–18 % of the observed streamflow. Climate variation/change dominates natural runoff changes. Though land use and cover change (LUCC) had minimal effect on natural runoff, it had a profound impact on the process of runoff generation, i.e., surface runoff (RS) and subsurface runoff (RSS). Specifically, LUCC would be responsible for 152 % and 45 % of the changes in RS and RSS, respectively, in future periods. This study highlights the significance of artificial water discharge and withdrawal impacts on the water cycle and emphasizes the need for water resources management measures that fully consider natural-social hydrological processes.

Исследование сигнала внешнего магнитного поля асинхронного электродвигателя в режиме выбега

Currently, one of the important scientific tasks is the development and improvement of methods for non-destructive testing of asynchronous electric motors during operation. One of the promising areas of diagnostics is the use of an external magnetic field signal. However, its study in the run-down mode is not given due attention by the authors of scientific publications, despite a number of advantages of this signal. Therefore, the aim of this research is to confirm the possibility to record and study the signal of the radial component of the induction of the external magnetic field in the run-down mode of an asynchronous motor. So, the aim is relevant. The research is carried out using several test benches, real low-voltage and high-voltage asynchronous motors and a simulation model of an asynchronous electric motor designed in the Ansys software package. To process the signals, namely, to construct the frequency-time spectra of the external magnetic field in the run-down mode, the authors have used a program based on the Short Time Fourier Transform using the Flat-top window as a window function to more accurately determine the amplitudes of the harmonic components. During the research conducted on test benches, it has been found that the external magnetic field of the motor in the run-down mode will exist due to the phenomenon of residual magnetization. The possibility of modeling asynchronous motors considering residual magnetization has been proven and the reliability of the resulting model has been confirmed. The spectra of external magnetic field signals on real motors and simulation models in the run-down mode are presented. The external magnetic field signal in the run-down mode can be recorded both on simulation models and on real low-voltage and high-voltage asynchronous electric motors. During further research, it is planned to analyze the possibility of identifying faults in asynchronous motors using this signal.

Simulation of coronary fractional flow reserve and whole-cycle flow based on optical coherence tomography in individual patients with coronary artery disease

Computer simulations of coronary fractional flow reserve (FFR) based on coronary imaging have emerged as an attractive alternative to invasive measurements. However, most methods are proprietary and employ non-physiological assumptions. Our aims were to develop and validate a physiologically realistic open-source simulation model for coronary flow, and to use this model to predict FFR based on intracoronary optical coherence tomography (OCT) data in individual patients. We included patients undergoing elective coronary angiography with angiographic borderline coronary stenosis. Invasive measurements of coronary hyperemic pressure and absolute flow and OCT imaging were performed. A computer model of coronary flow incorporating pulsatile flow and the effect of left ventricular contraction was developed and calibrated, and patient-specific flow simulation was performed. Forty-eight coronary arteries from 41 patients were included in the analysis. Average FFR was 0.79 ± 0.14, and 50% had FFR ≤ 0.80. Correlation between simulated and measured FFR was high (r = 0.83, p < 0.001). Average difference between simulated FFR and observed FFR in individual patients was − 0.009 ± 0.076. Overall diagnostic accuracy for simulated FFR ≤ 0.80 in predicting observed FFR ≤ 0.80 was 0.88 (0.75–0.95) with sensitivity 0.79 (0.58–0.93) and specificity 0.96 (0.79–1.00). The positive predictive value was 0.95 (0.75–1.00) and the negative predictive value was 0.82 (0.63–0.94). In conclusion, realistic simulations of whole-cycle coronary flow can be produced based on intracoronary OCT data with a new, computationally simple simulation model. Simulated FFR had moderate numerical agreement with observed FFR and a good diagnostic accuracy for predicting hemodynamic significance of coronary stenoses.

Quantifying the stochastic component of epigenetic aging

DNA methylation clocks can accurately estimate chronological age and, to some extent, also biological age, yet the process by which age-associated DNA methylation (DNAm) changes are acquired appears to be quasi-stochastic, raising a fundamental question: how much of an epigenetic clock’s predictive accuracy could be explained by a stochastic process of DNAm change? Here, using DNAm data from sorted immune cells, we build realistic simulation models, subsequently demonstrating in over 22,770 sorted and whole-blood samples from 25 independent cohorts that approximately 66–75% of the accuracy underpinning Horvath’s clock could be driven by a stochastic process. This fraction increases to 90% for the more accurate Zhang’s clock, but is lower (63%) for the PhenoAge clock, suggesting that biological aging is reflected by nonstochastic processes. Confirming this, we demonstrate that Horvath’s age acceleration in males and PhenoAge’s age acceleration in severe coronavirus disease 2019 cases and smokers are not driven by an increased rate of stochastic change but by nonstochastic processes. These results significantly deepen our understanding and interpretation of epigenetic clocks.

Starting from Scratch: Experiences from Developing the First Vascular Anastomotic Training Program in North Macedonia Using the Porcine Thigh as a Simulation Model

AbstractMicrosurgical reconstruction constitutes a fundamental part of plastic and reconstructive surgery. It demands high dexterity and intricate technical skills. Its steep learning curve benefits from thorough training throughout residency, where using realistic simulation models in the appropriate sequence of complexity progression is essential in ensuring patient safety prior to progressing to a clinical setting. Commencing training on microvascular-like small diameter vessels could prove unsuitable and ineffective for inexperienced surgeons, however, the larger diameter neurovascular structures in the porcine thigh can provide excellent anastomotic training without compromising the animal tissue training sought after by residents. We present the results from implementing the first vascular anastomotic course in our country, where reconstructive theory was combined with simulated anastomotic training on the porcine thigh. Junior plastic surgery residents described acquiring comprehensive knowledge of reconstructive techniques and could successfully complete anastomoses, despite none to minimal previous experience. Using the porcine thigh should be encouraged as a start-up vascular anastomotic training tool as it provides realistic conditions and tissue handling training, and could improve quality of further training on microvascular structures.

Senning Procedure: Use of a 3D Printed, Silicone Molded Model for Surgical Training

The atrial switch is a technically complex procedure that requires considerable judgement and appreciation of the 3-dimensional anatomy of the heart. It is now rarely performed other than as part of the double-switch procedures for congenitally corrected transposition (ccTGA). Silicone moulded models based on 3D printed hearts are the latest, and most realistic simulation models for practicing and training in congenital heart surgery – and the atrial switch is an ideal substrate since the procedure is difficult to teach and rarely performed. The Senning procedure has become the most widely used type of atrial switch as it is associated with the best long term outcomes and freedom from baffle obstructions or leaks.

Dynamical subset sampling of quantum error-correcting protocols

Quantum error-correcting (QEC) stabilizer codes enable protection of quantum information against errors during storage and processing. Simulation of noisy QEC codes is used to identify the noise parameters necessary for advantageous operation of logical qubits in realistic quantum computing architectures. Typical quantum error-correction techniques contain intermediate measurements and classical feedback that determine the actual noisy circuit sequence in an instance of performing the protocol. Dynamical subset sampling enables efficient simulation of such nondeterministic quantum error-correcting protocols for any type of quantum circuit and incoherent noise of low strength. As an importance sampling technique, dynamical subset sampling allows one to effectively make use of computational resources to only sample the most relevant sequences of quantum circuits in order to estimate a protocol's logical failure rate with well-defined error bars. We demonstrate the capabilities of dynamical subset sampling with examples from fault-tolerant (FT) QEC. We show that, in a typical stabilizer simulation with incoherent Pauli noise of strength p=10−3, our method can reach a required sampling accuracy on the logical failure rate with two orders of magnitude fewer samples than direct Monte Carlo simulation. Furthermore, dynamical subset sampling naturally allows for efficient simulation of realistic multi-parameter noise models describing faulty quantum processors. It can be applied not only for QEC in the circuit model but any noisy quantum computing framework with incoherent fault operators including measurement-based quantum computation and quantum networks. Published by the American Physical Society 2024

Behavioural characteristics influencing walking speed of pedestrians over elevated facilities: A case study of India

Walking speed is an essential parameter used in determining pedestrians' walking behavioural characteristics, the performance of a pedestrian facility, the capacity of the system, and several traffic engineering policy-related applications. While several studies have focussed on understanding walking behavioural patterns over at-grade facilities, there is still a paucity of research on understanding the influence of pedestrians' individual and group behavioural characteristics on walking speed over elevated facilities. This study uses extensive video data collected from different foot-over bridges (FOBs) and skywalks to comprehensively understand walking speed characteristics and their variations over both elevated facilities. The results of the study demonstrated the importance of considering socio-demographic factors with the associative activities involved in walking, group characteristics, and land use type in the estimation of pedestrians’ walking speed. The outcome of the study results would provide relevant policy-related strategies to designers and planners for improving infrastructures, developing realistic crowd behavioural simulation models, and estimating overall crowd dynamics.

Novel Simulation Optimization Approach for Supply Chain Coordination and Management

The importance of supply chain management is paramount nowadays and this research seeks ways for better supply chain coordination. We present a roadmap for implementing true digital replicas of physical supply chains based on a disruptive simulation modeling approach. These digital replicas can enable the comparative evaluation of existing Just-In-Time (JIT) control policies for the first time without the unrealistic assumptions of existing studies in the literature. These realistic supply chain simulation models have the prospect of giving us better understanding of their behavior and of their complex dynamics. We provide guidelines for using the digital replicas and advanced optimization approaches to derive novel supply chain coordination policies pushing the field of JIT control beyond the state-of-the-art. An equally important contribution of this research is that it advances the field of hybrid discrete event-system dynamics (DES-SD) simulation with the prospect of pushing Systems Engineering to the next level. This research discusses theoretical foundations for mixing DES with SD simulation, and explores technical aspects and implementation details. The implications of this extent well beyond the supply chain field since both DES and SD have dozens of application areas including manufacturing, service systems and economics, social sciences, respectively. The paper is concluded with a discussion on the potential impact of the proposed approach including insights for practitioners, applicability of scientific results in industry and prerequisites for business process re-engineering.

A new device to treat ping-pong skull fractures: The hammer puller technique. A comparative analysis using a realistic simulation model.

This study aims to describe a new surgical technique for the treatment of ping-pong skull fractures and to evaluate its efficacy in a realistic simulation model compared to the dissector elevation technique. A total of 64 fractures were obtained using 16 model units, each with four fractures (two frontal and two parietal). The hammer puller technique was applied for left-sided fractures and the dissector technique for right-sided fractures. The variables evaluated were fracture repair time, fracture volume, fracture corrected volume, and fracture correction percentage. Fractures were separated into groups according to the surgical technique used (hammer or dissector) and the bone fractured (frontal or parietal). Statistical analysis was performed with Jamovi® software (version 2.3) using Student's t-test. A complete degree of fracture correction was achieved with both techniques, demonstrating a sufficient performance in the correction of the deformity. The hammer technique was shown to be faster in correcting frontal bone depressions with 20.1 ± 7.8 s compared to 31.3 ± 4.7 s for the dissector technique, P < 0.001. There was no statistically significant difference for parietal applications (P = 0.405). This study describes a new minimally invasive surgical technique for the treatment of ping-pong fractures. Comparative analysis showed that both techniques were equally effective but that the hammer puller technique was more efficient than the dissector elevation technique, especially for frontal bone fractures.

Parallelization of AMALGAM algorithm for a multi-objective optimization of a hydrological model

A calibration procedure is essential step to achieve a realistic model simulation particularly in hydrological model which simulates water cycle in the basin. This process is always faced with challenges due to selection of objective function and highly time-consuming. This study aimed to take advantage of parallel processing to accelerate the computations involved with simulation process of hydrologic model linked with the multi-objective optimization algorithm of AMALGAM for multi-site calibration of SWAT hydrologic model parameters. In order to illustrate how meaningful SWAT model calibration trade-off between the four objective functions involved in AMALGAM optimization program, the Pareto solution sets were provided. Furthermore, it is implemented a group of model runs with a number of cores involved (from one to eight) to demonstrate and evaluate the running of parallelized AMALGAM with taking advantages of “spmd” method to decrease the running time of the SWAT model. The results revealed the robustness of the method in reducing computational time of the parameter calibration significantly. This strategy with 4-objective functions focuses on high streamflow (Nash–Sutcliffe coefficient), low streamflow (Box–Cox transformed root–mean–square error), water balance (runoff coefficient error), and flashiness (slope of the flow duration curve error) provided an efficient tool to decide about the best simulation based on the investigated objective functions. This study also provides a strong basis for multi-objective optimization of hydrological and water quality models and its general analytical framework could be applied to other parts of the world.

Optimizing VANET Communication through Realistic Traffic Simulation

This article explores the optimization of communication in Vehicular Ad-Hoc Networks (VANETs) through the use of realistic traffic simulation in Raipur City, located in the state of Chhattisgarh. VANETs are a specialized type of Mobile Ad-Hoc Networks (MANETs) that enable vehicles to communicate with each other and with roadside infrastructure, improving road safety, traffic efficiency, and providing additional services. However, VANETs encounter challenges due to the dynamic nature of vehicular environments, including high mobility, intermittent connectivity, and varying traffic conditions. To address these challenges, this study proposes the Integration to Message Exchange (IME) method, which incorporates realistic traffic simulation into VANET communication optimization strategies. Realistic traffic simulation models vehicle behavior and interactions with the road network, considering factors such as traffic flow, congestion, and road conditions. By integrating this simulation into VANET communication optimization algorithms, the performance of the proposed IME method and other routing strategies is evaluated under realistic traffic scenarios. The results demonstrate that the IME method significantly improves message delivery rates and reduces message latency compared to the D-LAR and AODV routing methods. In comparison to the DLAR method, the IME method increases the packet delivery ratio by 4.82%, reduces end-to-end delay by 4.0%, increases throughput by 4.85%, decreases routing overhead by 8.79%, and normalizes routing load by 7.71%. The city of Raipur in Chhattisgarh is the geographical context for this research. Raipur is a rapidly growing urban area with diverse traffic patterns and road conditions. By conducting experiments and simulations in this specific setting, the findings of this study can directly address the challenges faced by VANETs in Raipur City.

Tests and dynamic simulation analysis of an automatic instrument

To better study the dynamic characteristics of an automatic instrument and establish a realistic simulation model of automatic instruments, this paper has carried out movement tests of crucial parts under fixed conditions and recoil tests and collected the speed-time and recoil-time curves. Based on ADAMS software, the virtual prototype model of the key parts of the instrument is established, and the dynamic simulation is carried out. The different simulation results are separately compared with the experimental data, which verifies the accuracy of the recoil simulation model and provides a reference for the optimal design and improvement of the automatic instrument.

First experience with Walrus balloon guide catheter in a whole-body flow model

PurposeFlow arrest using a balloon guide catheter (BGC) in mechanical thrombectomy (MT) due to large vessel occlusion has been associated with better outcomes. Known limitations of currently commercially available BGCs are incompatibility with large bore aspiration catheters (AC) and lack of distal flexibility. Walrus presents variable stiffness and compatibility with large bore AC. The goal of this study is to describe the first experience with Walrus in a realistic stroke simulation model.MethodsA full-length modular vascular model under physiological conditions was used. 8F+-Walrus inner-diameter (ID) 0.087in 95 cm combined with 6F-Sofia AC ID 0.070in 131 cm and an 8F-Flowgate2 BGC ID 0.084in 95 cm with a 5F-Sofia AC ID 0.055in 125 cm were used to perform aspiration MT. User surveys, access to target and occlusion site, technique, time of delivery, anatomical change, and catheter kick-back were assessed.ResultsSeven neuroradiologists with average of 10 years-experience in MT performed primary aspiration using the above-mentioned combinations in three different anatomies (N = 41). All operators would likely (29%) or very likely (71%) use again Walrus in combination with large bore AC and the majority (86%) found its navigability easier than with other BGCs. Time to reach final BGC position and catheter kick-back did not differ significantly among anatomies or catheter combinations (p > 0.05). However, Walrus was more likely to reach ICA petrous segment (p < 0.05) and intracranial occlusion with AC (p < 0.01).ConclusionThe Walrus combined with large bore AC presented significantly better distal access and navigability for primary aspiration in an in vitro stroke model.