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  • 刊频： Quarterly
  • NLM标题： J Med Device
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  • 1.

    【2hr】Design and Experimental Evaluation of a Vertical Lift Walker for Sit-to-Stand Transition Assistance

    包量

    机译 立式起步辅助垂直升降助行器的设计与实验评估
    摘要：A walker capable of providing vertical lift support can improve independence and increase mobility of individuals living with spinal cord injury (SCI). Using a novel lifting mechanism, a walker has been designed to provide sit-to-stand assistance to individuals with partially paralyzed lower extremity muscles. The design was verified through experiments with one individual with SCI. The results show the walker is capable of reducing the force demands on the upper and lower extremity muscles during sit-to-stand transition compared to standard walkers. The walker does not require electrical power and no grip force or harness is necessary during sit-to-stand operation, enabling its use by individuals with limited hand function. The design concept can be extended to aid other populations with lower extremity weakness.
  • 2.

    【2hr】Effects of Microneedle Design Parameters on Hydraulic Resistance

    包量

    机译 微针设计参数对水力阻力的影响
    摘要：Microneedles have been an expanding medical technology in recent years due to their ability to penetrate tissue and deliver therapy with minimal invasiveness and patient discomfort. Variations in design have allowed for enhanced fluid delivery, biopsy collection, and the measurement of electric potentials. Our novel microneedle design attempts to combine many of these functions into a single length of silica tubing capable of both light and fluid delivery terminating in a sharp tip of less than 100 microns in diameter. This manuscript focuses on the fluid flow aspects of the design, characterizing the contributions to hydraulic resistance from the geometric parameters of the microneedles. Experiments consisted of measuring the volumetric flow rate of de-ionized water at set pressures (ranging from 69-621 kPa) through a relevant range of tubing lengths, needle lengths, and needle tip diameters. Data analysis showed that the silica tubing (~150 micron bore diameter) adhered to within ±5% of the theoretical prediction by Poiseuille’s Law describing laminar internal pipe flow at Reynolds numbers less than 700. High hydraulic resistance within the microneedles correlated with decreasing tip diameter. The hydraulic resistance offered by the silica tubing preceding the microneedle taper was approximately 1-2 orders of magnitude less per unit length, but remained the dominating resistance in most experiments as the tubing length was >30 mm. These findings will be incorporated into future design permutations to produce a microneedle capable of both efficient fluid transfer and light delivery.
  • 3.

    【2hr】Two-dimensional FSI simulation of closing dynamics of a tilting disc mechanical heart valve

    包量

    机译 倾斜盘式机械心脏瓣膜关闭动力学的二维FSI模拟
    摘要：The fluid dynamics during valve closure resulting in high shear flows and large residence times of particles has been implicated in platelet activation and thrombus formation in mechanical heart valves. Our previous studies with bi-leaflet valves have shown that large shear stresses induced in the gap between the leaflet edge and the valve housing results in relatively high platelet activation levels whereas flow between the leaflets results in shed vortices not conducive to platelet damage. In this study we compare the result of closing dynamics of a tilting disc valve with that of a bi-leaflet valve. The two-dimensional fluid-structure interaction analysis of a tilting disc valve closure mechanics is performed with a fixed grid Cartesian mesh flow solver with local mesh refinement, and a Lagrangian particle dynamic analysis for computation of potential for platelet activation. Throughout the simulation the flow remains in the laminar regime and the flow through the gap width is marked by the development of a shear layer which separates from the leaflet downstream of the valve. Zones of re-circulation are observed in the gap between the leaflet edge and the valve housing on the major orifice region of the tilting disc valve and are seen to be migrating towards the minor orifice region. Jet flow is observed at the minor orifice region and a vortex is formed which sheds in the direction of fluid motion as observed in experiments using PIV measurements. The activation parameter computed for the tilting disc valve, at the time of closure was found to be 2.7 times greater than that of the bi-leaflet mechanical valve and was found to be in the vicinity of the minor orifice region mainly due to the migration of vortical structures from the major to the minor orifice region during the leaflet rebound of the closing phase.
  • 4.

    【2hr】Numerical Investigation of Coil Configurations That Provide Ultra-High Packing Density of Saccular Aneurysms

    包量

    机译 提供囊状动脉瘤超高堆积密度的线圈构型的数值研究
    摘要：BackgroundThe long-term outcome of endovascular coiling of cerebral aneurysms is directly related to the packing density at time of treatment. In general, the highest packing density achievable is only about 45% due to the quasi-random distribution of currently available coils within aneurysms. We investigated whether packing densities could be maximized via more ordered coil configurations.
  • 5.

    【2hr】Design of a Catheter-Based Device for Performing Percutaneous Chordal-Cutting Procedures

    包量

    机译 基于导管的用于执行经皮弦切手术的设备的设计
    摘要：This paper focuses on the design and implementation of a percutaneous catheter-based device to provide physicians with an externally controlled tool capable of manipulating and cutting specific chordae tendinae within the hear to alleviate problems associated with some forms of mitral valve regurgitationt. In the United States alone, approximately 500,000 people develop ischemic or functional MR per year, and the chordae tendinae cutting procedure and device are needed because many patients do not have the required level of health necessary to survive open-heart surgery. A deterministic design process was used to generate several design concepts and then evaluate and compare each concept based on a set of functional requirements. A final concept to be alpha prototyped was then chosen, further developed, and fabricated. Experiments showed that the design was capable of locating and grabbing a chord and that ultrasound imaging is a viable method for navigating the device inside of the human body. Once contact between the chord and an RF ablator tip was confirmed, the chord was successfully ablated.
  • 6.

    【2hr】Automating skeletal expansion: An implant for distraction osteogenesis of the mandible

    包量

    机译 自动骨骼扩张：下颌骨成骨的植入物
    摘要：BackgroundDistraction osteogenesis (DO) is a technique of bone lengthening that makes use of the body’s natural healing capacity. An osteotomy is created and a rigid distraction device is attached to the bone. After a latency period, the device is activated 2–4 times per day for a total of 1 mm/day of bone lengthening. This technique is used to correct a variety of congenital and acquired deformities of the mandible, midface and long bones. To shorten the treatment period and to eliminate the complications of patient activation of the device, an automated continuous distraction device would be desirable. It has been reported that continuous distraction generates adequate bone with lengthening at a rate of 2 mm/day, thereby reducing the treatment time.
  • 7.

    【2hr】Optimizing Design With Extensive Simulation Data: A Case Study of Designing a Vacuum-Assisted Biopsy Tool

    包量

    机译 利用大量的仿真数据优化设计：以设计真空辅助活检工具为例
    摘要：Design by Dragging (DBD) [1] is a virtual design tool, which displays three-dimensional (3D) visualizations of many simulation results obtained by sampling a large design space and ties this visual display together with a new user interface. The design space is explored through mouse-based interactions performed directly on top of the 3D data visualizations. Our previous study [1] introduced the realization of DBD with a simplistic example of biopsy needle design under a static bending force. This paper considers a realistic problem of designing a vacuum-assisted biopsy (VAB) needle that brings in more technical challenges to include dynamic tissue reaction forces, nonlinear tissue deformation, and progressive tissue damage in an integrated visualization with design suggestions. The emphasis is placed on the inverse design strategy in DBD, which involves clicking directly on a stress (or other output field parameter) contour and dragging it to a new (usually preferable) position on the contour. Subsequently, the software computes the best fit for the design variables for generating a new output stress field based on the user input. Three cases demonstrated how the inverse design can assist users in intuitively and interactively approaching desired design solutions. This paper illustrates how virtual prototyping may be used to replace (or reduce reliance on) purely experimental trial-and-error methods for achieving optimal designs.
  • 8.

    【2hr】A Novel Macroscale Acoustic Device for Blood Filtration

    包量

    机译 一种新型的血液过滤宏观声学装置
    摘要：Retransfusion of a patient's own shed blood during cardiac surgery is attractive since it reduces the need for allogeneic transfusion, minimizes cost, and decreases transfusion related morbidity. Evidence suggests that lipid micro-emboli associated with the retransfusion of the shed blood are the predominant causes of the neurocognitive disorders. We have developed a novel acoustophoretic filtration system that can remove lipids from blood at clinically relevant flow rates. Unlike other acoustophoretic separation systems, this ultrasound technology works at the macroscale, and is therefore able to process larger flow rates than typical micro-electromechanical system (MEMS) scale acoustophoretic separation devices. In this work, we have first demonstrated the systematic design of the acoustic device and its optimization, followed by examining the feasibility of the device to filter lipids from the system. Then, we demonstrate the effects of the acoustic waves on the shed blood; examining hemolysis using both haptoglobin formation and lactate dehydrogenase release, as well as the potential of platelet aggregation or inflammatory cascade activation. Finally, in a porcine surgical model, we determined the potential viability of acoustic trapping as a blood filtration technology, as the animal responded to redelivered blood by increasing both systemic and mean arterial blood pressure.
  • 9.

    【2hr】Integrating Cadaver Needle Forces Into a Haptic Robotic Simulator

    包量

    机译 将尸体针力集成到触觉机器人模拟器中
    摘要：Accurate force simulation is essential to haptic simulators for surgical training. Factors such as tissue inhomogeneity pose unique challenges for simulating needle forces. To aid in the development of haptic needle insertion simulators, a handheld force sensing syringe was created to measure the motion and forces of needle insertions. Five needle insertions were performed into the neck of a cadaver using the force sensing syringe. Based on these measurements a piecewise exponential needle force characterization, was implemented into a haptic central venous catheterization (CVC) simulator. The haptic simulator was evaluated through a survey of expert surgeons, fellows, and residents. The maximum needle insertion forces measured ranged from 2.02 N to 1.20 N. With this information, four characterizations were created representing average, muscular, obese, and thin patients. The median survey results showed that users statistically agreed that “the robotic system made me sensitive to how patient anatomy impacts the force required to advance needles in the human body.” The force sensing syringe captured force and position information. The information gained from this syringe was able to be implemented into a haptic simulator for CVC insertions, showing its utility. Survey results showed that experts, fellows, and residents had an overall positive outlook on the haptic simulator's ability to teach haptic skills.
  • 10.

    【2hr】Development and Feasibility of a Robotic Laparoscopic Clipping Tool for Wound Closure and Anastomosis

    包量

    机译 腹腔镜机器人闭合伤口吻合工具的开发与可行性
    摘要：This paper reports the design, development, and initial evaluation of a robotic laparoscopic clipping tool for single manipulator wound closure and anastomosis (tubular reconnection). The tool deploys biodegradable clips and clasps with the goal of (i) integrating grasping and suturing into a single device for single hand or manipulator use, (ii) applying the equivalent of interrupted sutures without the need of managing suture thread, and (iii) allowing for full six degrees-of-freedom (DOFs) laparoscopic control when mounted on a robot arm. The specifications, workflow, and detailed design of the robotic laparoscopic tool and injection molded bio-absorbable T shaped clip and locking clasp are reported. The clipping tool integrates forceps to grab and stabilize tissue and a clip and clasp applier to approximate and fixate the tissue. A curved needle is advanced on a circular needle path and picks up and drags clips through tissue. The clip is then tightened through the tissue and a clasp is clamped around the clip, before the clip is released from the needle. Results of several bench test runs of the tool show: (a) repeatable circular needle drive, (b) successful pick-up and deployment of clips, (c) successful shear of the clip to release the clip from the needle, and (d) closure of clasp on clip with an average of 2.0 N holding force. These data indicate that the robotic laparoscopic clipping tool could be used for laparoscopic wound closure and anastomosis.
  • 11.

    【2hr】Design and Evaluation of a Robotic Device for Automated Tail Vein Cannulations in Rodent Models

    包量

    机译 啮齿动物模型中自动尾静脉插管机器人设备的设计和评估
    摘要：Preclinical testing in rodent models is a ubiquitous part of modern biomedical research and commonly involves accessing the venous bloodstream for blood sampling and drug delivery. Manual tail vein cannulation is a time-consuming process and requires significant skill and training, particularly since improperly inserted needles can affect the experimental results and study outcomes. In this paper, we present a miniaturized, robotic medical device for automated, image-guided tail vein cannulations in rodent models. The device is composed of an actuated three degrees-of-freedom (DOFs) needle manipulator, three-dimensional (3D) near-infrared (NIR) stereo cameras, and an animal holding platform. Evaluating the system through a series of workspace simulations and free-space positioning tests, the device exhibited a sufficient work volume for the needle insertion task and submillimeter accuracy over the calibration targets. The results indicate that the device is capable of cannulating tail veins in rodent models as small as 0.3 mm in diameter, the smallest diameter vein required to target.
  • 12.

    【2hr】Design and Fabrication of a Low-Cost Three-Dimensional Bioprinter

    包量

    机译 低成本三维生物打印机的设计与制作
    摘要：Three-dimensional (3D) bioprinting offers innovative research vectors for tissue engineering. However, commercially available bioprinting platforms can be cost prohibitive to small research facilities, especially in an academic setting. The goal is to design and fabricate a low-cost printing platform able to deliver cell-laden fluids with spatial accuracy along the X, Y, and Z axes of 0.1 mm. The bioprinter consists of three subassemblies: a base unit, a gantry, and a shuttle component. The platform utilizes four stepper motors to position along three axes and a fifth stepper motor actuating a pump. The shuttle and gantry are each driven along their respective horizontal axes via separate single stepper motor, while two coupled stepper motors are used to control location along the vertical axis. The current shuttle configuration allows for a 5 mL syringe to be extruded within a work envelope of 180 mm × 160 mm × 120 mm (X, Y, Z). The shuttle can easily be reconfigured to accommodate larger volume syringes. An attachment for a laser pen is located such that printing material may be light-activated pre-extrusion. Positional fidelity was established with calipers possessing a resolution to the nearest hundredth millimeter. The motors associated with the X and Y axes were calibrated to approximately 0.02 mm per motor impulse. The Z axis has a theoretical step distance of ∼51 nm, generating 0.04% error over a 10 mm travel distance. The A axis, or pump motor, has an impulse distance of 0.001 mm. The volume extruded by a single impulse is dictated by the diameter of the syringe used. With a 5 mL syringe possessing an inner diameter of 12.35 mm, the pump pushes as little as 0.119 μL. While the Z axis is tuned to the highest resolution settings for the motor driver, the X, Y, and A axes can obtain higher or lower resolution via physical switches on the motor drivers.
  • 13.

    【2hr】Effects of Sterilization on Shape Memory Polyurethane Embolic Foam Devices

    包量

    机译 灭菌对形状记忆聚氨酯栓塞泡沫装置的影响
    摘要：Polyurethane shape memory polymer (SMP) foams have been developed for various embolic medical devices due to their unique properties in minimally invasive biomedical applications. These polyurethane materials can be stored in a secondary shape, from which they can recover their primary shape after exposure to an external stimulus, such as heat and water exposure. Tailored actuation temperatures of SMPs provide benefits for minimally invasive biomedical applications, but incur significant challenges for SMP-based medical device sterilization. Most sterilization methods require high temperatures or high humidity to effectively reduce the bioburden of the device, but the environment must be tightly controlled after device fabrication. Here, two probable sterilization methods (nontraditional ethylene oxide (ntEtO) gas sterilization and electron beam irradiation) are investigated for SMP medical devices. Thermal characterization of the sterilized foams indicated that ntEtO gas sterilization significantly decreased the glass transition temperature. Further material characterization was undertaken on the electron beam (ebeam) sterilized samples, which indicated minimal changes to the thermomechanical integrity of the bulk foam and to the device functionality.
  • 14.

    【2hr】The Role of Simulation in the Design of a Semi-Enclosed Tubular Embolus Retrieval

    包量

    机译 模拟在半封闭管状栓塞取回设计中的作用
    摘要：A numerical analysis of a semi-enclosed tubular mechanical embolus retrieval device (MERD) for the treatment of acute ischemic stroke (AIS) is presented. In this research, the finite element analysis (FEA) methodology is used to evaluate mechanical performance and provide suggestions for optimizing the geometric design. A MERD fabricated from nickel–titanium alloy (Nitinol) tubing is simulated and analyzed under complex in vivo loading conditions involving shape-setting, crimping, deployment, and embolus retrieval. As a result, the peak strain of the shape-setting procedure is proved to be safe for the device pattern. However, the MERD shows poor mechanical behavior after crimping into a catheter, because the peak crimping strain obtains a value of 12.1%. The delivery and deployment step demonstrates that the artery wall has little risk of serious injuries or rupture. In addition, the process of simulation of embolus retrieval and device system migration inside the cerebral artery lumen provides useful information during the design process.
  • 15.

    【2hr】Design of a Magnetic Resonance Imaging Guided Magnetically Actuated Steerable Catheter

    包量

    机译 磁共振成像引导的电磁操纵导管的设计
    摘要：This paper presents design optimization of a magnetic resonance imaging (MRI) actuated steerable catheter for atrial fibrillation ablation in the left atrium. The catheter prototype, built over polymer tubing, is embedded with current-carrying electromagnetic coils. The prototype can be deflected to a desired location by controlling the currents passing through the coils. The design objective is to develop a prototype that can successfully accomplish the ablation task. To complete the tasks, the catheter needs to be capable of reaching a set of desired targets selected by a physician on the chamber and keeping a stable contact with the chamber surface. The design process is based on the maximization of the steering performance of the catheter by evaluating its workspace in free space. The selected design is validated by performing a simulation of an ablation intervention on a virtual model of the left atrium with a real atrium geometry. This validation shows that the prototype can reach every target required by the ablation intervention and provide an appropriate contact force against the chamber.
  • 16.

    【2hr】Statistical Shape Modeling for Cavopulmonary Assist Device Development: Variability of Vascular Graft Geometry and Implications for Hemodynamics

    包量

    机译 辅助肺辅助装置开发的统计形状建模：血管移植物几何的变异性及其对血流动力学的影响
    摘要：Patients born with a single functional ventricle typically undergo three-staged surgical palliation in the first years of life, with the last stage realizing a cross-like total cavopulmonary connection (TCPC) of superior and inferior vena cavas (SVC and IVC) with both left and right pulmonary arteries, allowing all deoxygenated blood to flow passively back to the lungs (Fontan circulation). Even though within the past decades more patients survive into adulthood, the connection comes at the prize of deficiencies such as chronic systemic venous hypertension and low cardiac output, which ultimately may lead to Fontan failure. Many studies have suggested that the TCPC’s inherent insufficiencies might be addressed by adding a cavopulmonary assist device (CPAD) to provide the necessary pressure boost. While many device concepts are being explored, few take into account the complex cardiac anatomy typically associated with TCPCs. In this study, we focus on the extra cardiac conduit vascular graft connecting IVC and pulmonary arteries as one possible landing zone for a CPAD and describe its geometric variability in a cohort of 18 patients that had their TCPC realized with a 20mm vascular graft. We report traditional morphometric parameters and apply statistical shape modeling to determine the main contributors of graft shape variability. Such information may prove useful when designing CPADs that are adapted to the challenging anatomical boundaries in Fontan patients. We further compute the anatomical mean 3D graft shape (template graft) as a representative of key shape features of our cohort and prove this template graft to be a significantly better approximation of population and individual patient’s hemodynamics than a commonly used simplified tube geometry. We therefore conclude that statistical shape modeling results can provide better models of geometric and hemodynamic boundary conditions associated with complex cardiac anatomy, which in turn may impact on improved cardiac device development.
  • 17.

    【2hr】pneuRIPTM: A Novel Respiratory Inductance Plethysmography Monitor

    包量

    机译 pneuRIPTM：新型的呼吸感应心律描记仪
    摘要：Objective pulmonary function (PF) evaluation is essential for the diagnosis, monitoring, and management of many pediatric respiratory diseases as seen in the emergency room, intensive care, and outpatient settings. In this paper, the development and testing of a new noninvasive PF instrument, pneuRIPTM, which utilizes respiratory inductance plethysmography (RIP) are discussed. The pneuRIPTM hardware includes a small circuit board that connects to the RIP bands and measures and wirelessly transmits the band inductance data to any designated wirelessly connected tablet. The software provides indices of respiratory work presented instantaneously in a user-friendly graphical user interface on the tablet. The system was tested with ten normal children and compared with an existing system, Respitrace (Sensormedics, Yorba Linda, CA), under normal and loaded breathing conditions. Under normal breathing, the percentage differences between the two systems were 2.9% for labored breathing index (LBI), 31.8% for phase angle (Φ), 4.8% for percentage rib cage (RC%), and 26.7% for respiratory rate (BPM). Under loaded breathing, the percentage differences between the two systems were 1.6% for LBI, 4.1% for Φ, 8.5% for RC%, and 52.7% for BPM. For LBI, Φ, and RC%, the two systems were in general agreement. For BPM the pneuRIPTM is shown to be more accurate than the respitrace when compared to manually counting the breaths: 13.2% versus 36.4% accuracy for normal breathing and 16.9% versus 60.7% accuracy for breathing under load, respectively.
  • 18.

    【2hr】Hydraulic Robotic Surgical Tool Changing Manipulator

    包量

    机译 液压机器人手术工具更换机械手
    摘要：Natural orifice transluminal endoscopic surgery (NOTES) is a surgical technique to perform “scarless” abdominal operations. Robotic technology has been exploited to improve NOTES and circumvent its limitations. Lack of a multitasking platform is a major limitation. Manual tool exchange can be time consuming and may lead to complications such as bleeding. Previous multifunctional manipulator designs use electric motors. These designs are bulky, slow, and expensive. This paper presents design, prototyping, and testing of a hydraulic robotic tool changing manipulator. The manipulator is small, fast, low-cost, and capable of carrying four different types of laparoscopic instruments.
  • 19.

    【2hr】Particulate Release From Nanoparticle-Loaded Shape Memory Polymer Foams

    包量

    机译 纳米颗粒状形状记忆聚合物泡沫的颗粒释放
    摘要：Highly porous, open-celled shape memory polymer (SMP) foams are being developed for a number of vascular occlusion devices. Applications include abdominal aortic and neurovascular aneurysm or peripheral vascular occlusion. A major concern with implanting these high surface area materials in the vasculature is the potential to generate unacceptable particulate burden, in terms of number, size, and composition. This study demonstrates that particulate numbers and sizes in SMP foams are in compliance with limits stated by the most relevant standard and guidance documents. Particulates were quantified in SMP foams as made, postreticulation, and after incorporating nanoparticles intended to increase material toughness and improve radiopacity. When concentrated particulate treatments were administered to fibroblasts, they exhibited high cell viability (100%). These results demonstrate that the SMP foams do not induce an unacceptable level of risk to potential vascular occlusion devices due to particulate generation.
  • 20.

    【2hr】Novel Device For Removal of Blot Clot Obstructions in Drainage Tubes

    包量

    机译 消除引流管血栓阻塞的新型装置
    摘要：Medical drains frequently become obstructed requiring removal or re-intervention. Currently, there is no widely accepted practice for maintaining drain patency. A simple device to remove obstructions from medical drains may have significant benefit. We manufactured a prototype drain clot extractor (DCE) for extracting obstructions. Fresh nonanticoagulated swine blood was instilled within drainage tubes of 16, 20, and 32 French (n = 2 for each size) to generate a 4 cm blood clot. The operator was then equipped with a 0.035 in. guidewire (GW) and given 2.5 min to attempt removal while blinded. Similarly, the operator was equipped with the DCE. Volumes removed were determined by volume displacement and by drain size and method of removal. Comparison of DCE to GW by analysis of variance and means comparison using Tukey were used for statistical analysis. The DCE facilitated mechanical removal of obstructions for 16, 20, and 32 French drainage tubes. Volumes removed: 16 French (GW mean 10% volume, DCE mean 70% volume p = 0.02); 20 French (GW mean 12.5% volume, DCE mean 75% volume p = 0.01); 32 French (GW mean 37.5% volume, DCE mean 100% volume p = 0.01). DCE volume removal had no dependence on drain size (p > 0.05). This device may have utility for reducing morbidity from early drain discontinuation or replacement. Further in vivo and clinical studies are needed to determine the safety, feasibility, and efficacy of this device as tool for removing medical drainage obstructions.
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