Intranasal drug delivery is an attractive route to noninvasively achieve a rapid therapeutic effect, avoid first pass metabolism, and bypass the blood brain barrier. However, the types of drugs that can be administered by this route has been limited, in part, by device technology. Herein, we describe a pneumatic nasal spray device that is capable of mixing liquid and solid components of a drug formulation as part of the actuation process during dose administration. The ability to store a nasal spray drug formulation as two separate components can be leveraged to solve a variety of stability issues that would otherwise preclude intranasal administration. Examples of drugs that could be delivered intranasally by utilizing this two-part formulation strategy include biomolecules that are unstable in solution and low solubility drugs that can be rendered into metastable supersaturated solutions. A proof of concept nasal spray device prototype was constructed to demonstrate that a liquid and solid can be rapidly mixed and atomized into a spray in a single action. The primary breakup distance and angle of the spray cone were measured as a function of the function of the propellant gas pressure.

In the U.S. alone, 7.5 million individuals have survived stroke, traumatic brain injury, and spinal cord injury, and over a million new patients are diagnosed every year [1]. Most of these patients will need gait rehabilitation. Body weight supported gait training is a widely used rehabilitation therapy to improve gait function [2]. Commonly, a physical therapist provides assistance using a gait belt to support the patient. Sometimes two or three therapists may be needed for severely impaired patients. Bodyweight supported treadmill training uses a harness attached to an overhead lift to support body weight [2], however harness systems often cause discomfort and may take significant time to set up and take down. Lite Run Corporation has developed a system for the treatment of patients with gait and balance difficulties that uses differential air pressure inside a specially designed suit to reduce up to 50 percent of a patient’s body weight. The suit facilitates patient ambulation using technology like that in astronaut spacesuits to achieve comfort and flexibility. Potential benefits include longer therapy sessions due to greater comfort and greater unweighting, as well as the therapeutic benefits of being upright and walking for subjects unable to stand independently. The suit is used in conjunction with the Gait Trainer device shown in Figure 1 which provides air pressure to the suit and support for the patient. Gait Trainer features include: 1) electro-mechanical and pneumatic controls to support the suit and patient when rising from sitting to standing and ambulating during therapy — so that a single therapist can safely transfer a patient from a wheelchair and practice gait therapy; 2) an open design that permits access to patient’s body and legs by the therapist; 3) a compact profile that provides easy maneuverability; 4) a “base spread” function that permits positioning close to a patient when seated in wheel chair, bed or therapy table. Together these features provide safety and stability for the patient and reduced physical burden on the therapist. The objectives for the current study were to establish the safety and feasibility of the Gait Trainer, validate user design requirements, and to test the hypothesis that the rate of perceived exertion when using the device is significantly less than during unaided walking therapy.

Getting dressed is a universally performed daily activity, and has a substantial impact on a person’s well-being. Choosing appropriate outfits to wear is important, as clothes protect a person from elements in the environment, and act as a barrier against harsh surfaces [1]. Studies have shown strong correlation between clothing choices and perceptions of sociability, emotional stability, and impression formation (e.g., [2]). This activity, however, can be difficult for some individuals, as they may lack the required reasoning and judgement required [3]. They include children with intellectual and learning disabilities [4] (e.g., Down syndrome [5], dyspraxia [6], autism spectrum disorder [7]), and older adults suffering from dementia including Alzheimer’s disease [8,9], or HIV-associated neurocognitive disorders [10]. In this paper, we present the development of a novel autonomous robotic clothing recommendation system to provide appropriate clothing options, which are personalized to a user’s wardrobe. This research expands on our previous work on socially assistive robots providing assistance with other daily activities, including meal eating [11] and playing Bingo games [12]. Currently, a few smartphone applications exist for providing outfit choices (e.g., [13,14]); however, unlike our proposed system, they are fashion-focused and not able to adapt online to a user’s preferences. Furthermore, by utilizing a socially assistive robot, we provide a more engaging interaction. We utilize the small Nao social robot, Leia, to guide and interact with a user in order to obtain information regarding his/her preferences, the activity for which the clothing will be worn, as well as the environment in which the activity will take place in order to make outfit recommendations, Fig. 1.

Maintaining upright stance is a complex process, it requires appropriate functioning of a postural control system which consists of inputs from somatosensory, vestibular, musculoskeletal, and proprioceptive systems as well as from several brain regions [1–4]. A concussion is defined as a brain injury caused due to unexpected acceleration/deceleration of the head causing temporary alteration of brain function and it is a prevalent source of injury to football athletes [1]. With the altered function of the brain, the ability to maintain postural equilibrium becomes challenging due to the inability of individuals to respond promptly to stressors, thus, making maintenance of postural equilibrium rather difficult for individuals with a concussion. Effects of concussion on postural ability are shown to last up to three days post injury [5]. Postural stability test, therefore, can be performed to make a valid return to play (RTP) decision, pre-mature RTP is shown to have been catastrophic due to its potential to permanently impair previously affected region/functioning [1,5]. Postural sway data (center of pressure, COP) is traditionally analyzed to study the postural control. Therefore, COP can provide critical information regarding individual’s ability to maintain upright stance post injury. A more sensitive concussion assessment tool based on electroencephalogram (EEG) is used to accurately track effects of concussion [6]. However, sophisticated electrode placement requirement inhibits its immediate applicability. In current preliminary research, we attempt to differentiate athletes with a history of concussion (experimental) from healthy (control) using postural data. In order to do so, a concept of empirical mode decomposition (EMD) was adopted. EMD has shown evidence in the literature to infer vital information pertaining to the complex underlying physiological phenomenon [4, 7–8]. In the current research, the resultant COP (COPr) was decomposed into its finite set of band-limited signals termed as intrinsic mode functions (IMFs) [8], a set of linear and nonlinear features were extracted from COPr and its IMfs. Lastly, a test of significance was conducted to infer the potential of postural data for differentiating concussed from healthy athletes.

Most commercially available lower-limb prostheses are designed for walking, not for standing. The Minneapolis VA Health Care System has developed a bimodal prosthetic ankle-foot system with distinct modes for walking and standing [1]. With this device, a prosthesis user can select standing or walking mode in order to maximize standing stability or walking functionality, depending on the activity and context. Additionally, the prosthesis was designed to allow for an “automatic mode” to switch between standing and walking modes based on readings from an onboard Inertial Measurement Unit (IMU) without requiring user interaction to manually switch modes. A smartphone app was also developed to facilitate changing between walking, standing and automatic modes. The prosthesis described in [1] was used in a pilot study with 18 Veterans with lower-limb amputations to test static, dynamic, and functional postural stability. As part of the study, 17 Veterans were asked for qualitative feedback on the bimodal ankle-foot system (Table 1). The majority of participants (82%) expressed an interest in having an automatic mode. The participants also indicated that the automatic mode would need to reach walking mode on their first step and to lock the ankle quickly once the standing position was achieved. When asked about how they wanted to control the modes of the prosthesis, 82% wanted to use a physical switch and only 12% wanted to use a smartphone app. The results indicated that the following major design changes would be needed: 1) A fast and accurate automatic mode 2) A physical switch for mode changes This paper describes the use of machine learning algorithms to create an improved automatic mode and the use of stakeholder feedback to design a physical switch for the bimodal ankle-foot system.

The traditional spinal surgery is often conducted by hand operation with the help of navigation system which is combined with medical image. Although a veteran surgeon has a good adaptability during surgeries, it will tend to decrease along with the increase in surgery time which causes fatigues and leads to low qualities. Many surgical robots have been developed to assist surgeons in operation, and some of them approved by doctors or researchers are DaVinci (Intuitive Surgical, America) [1], Renaissance (Mazor Robotics, Israel), etc. These robot systems have enhanced the accuracy of operation; however, the adaptabilities are still weakened at the same time. During the pedicle screw drilling, surgeons can well adapt to the spine movements mainly caused by respiration, while it is difficult for these robots to adapt to the movements, indicating that the accuracy might drop in the actual application. Respiratory compensation system is aimed to keep the region of operation stable or reduce the amplitude of fluctuation [2]. The rests of paper introduced the respiratory compensation system and its control algorithm based on infrared tracking data, and experiments were conducted to analyze the accuracy and stability.

Peripheral neuropathy (PN), commonly caused by diabetes mellitus, is a debilitating condition that currently affects approximately 20 million Americans. Chronic symptoms of PN often involve pain and weakness of the lower limbs, with eventual sensation loss on the plantar surfaces of the feet. According to epidemiological studies, reduced foot sole sensation has been linked to decreased standing stability [1] and an increased risk of falling [2]. Consequently, cost-effective interventions are needed to improve balance and mobility in this population. A growing body of research suggests that vibrotactile cues delivered to sensate areas of the lower limb may be an effective way to provide information about foot sole pressure to PN patients who experience poor balance control. Indeed, sensory substitution devices that provide vibrotactile feedback have been shown to aid in balance and improve postural control in various patient populations [3–7]. However, none of these technologies have been based on measurements of foot pressure nor have they been used as a balance prosthesis. The goal of this study was to investigate the effect of a new external lower-limb sensory prosthesis, the Walkasins™, on the balance and gait of individuals with PN who experience balance problems [8]. Walkasins™ consist of two parts: a leg unit and a foot pad (Figure 1). The leg unit wraps around the lower leg of the user and contains electronics for reading foot pad pressure signals, a microprocessor, and four vibrating motors that provide gentle tactile sensory cues to the front, back, medial, and lateral surfaces of the user’s leg. These cues reflect real-time foot pressure information at a location above the ankle where skin sensation is still present. The leg unit has a power button, two status LEDs, and a reset button (not shown in Figure 1). Power is supplied by a rechargeable internal battery. The foot pad is a thin consumable sole insert that can be cut to size and fit into a regular shoe. The foot pad connects to the leg unit through a physical cable. In this study, subjects performed gait and balance assessments with and without the Walkasins™ turned on in order to determine its short-term effects.

Monophasic action potentials (MAPs) have long been used as a means to study the focal electrical activity of the myocardium. [1, 2] Upon the application of adequate contact force, the signals provide important insights into focal depolarization and repolarization, activation timing, and focal arrhythmic behaviors. [3–6] Within our laboratory we have developed an isolated physiologic, four-chamber working, large mammalian heart model (the Visible Heart ® methodology) to study cardiac devices and their interactions with the myocardium. [7] Through the use of a modified Krebs-Henseleit buffer, we can uniquely visualize the device-tissue interface: in this study, the placement of catheters. The purpose of this study was two-fold. First, we demonstrated the long term stability of MAP recordings in an in situ swine model. Second, we showed the relationship between MAPs recorded from in vitro and in situ preparations of each specimen.

The human ankle plays a major role in locomotion as it the first major joint to transfer the ground reaction torques to the rest of the body while providing power for locomotion and stability. One of the main causes of the ankle impedance modulation is muscle activation [1, 2], which can tune the ankle’s stiffness and damping during the stance phase of gait. The ankle’s time-varying impedance is also task dependent, meaning that different activities such as walking at different speeds, turning, and climbing/descending stairs would impose different profiles of time-varying impedance modulation. The impedance control is commonly used in the control of powered ankle-foot prostheses; however, the information on time-varying impedance of the ankle during the stance phase is limited in the literature. The only previous study during the stance phase, to the best of the authors knowledge, reported the human ankle impedance at four points of the stance phase in dorsiflexion-plantarflexion (DP) [1] during walking. To expand previous work and estimate the impedance in inversion-eversion (IE), a vibrating platform was fabricated (Fig. 1) [3]. The platform allows the ankle impedance to be estimated at 250 Hz in both DP and IE, including combined rotations in both degrees of freedom (DOF) simultaneously. The results can be used in a 2-DOF powered ankle-foot prosthesis developed by the authors, which is capable of mimicking the ankle kinetics and kinematics in the frontal and sagittal planes [4]. The vibrating platform can also be used to tune the prosthesis to assure it properly mimics the human ankle dynamics. This paper describes the results of the preliminary experiments using the vibrating platform on 4 male subjects. For the first time, the time-varying impedance of the human ankle in both DP and IE during walking in a straight line are reported.

Patellofemoral complications remain the single largest reason for knee related clinical visits. Yet, robust clinical treatment remains a challenge [1]. To establish causal relationships and understand joint behavior, a complimentary approach utilizing simulation and experimentation may offer valuable insight. Simulation can be confirmed with experimental data and can also be exploited in a predictive capacity. For example, the medial patellofemoral ligament (MPFL) is a clinically relevant structure due to its role in patellofemoral stabilization [2]. MPFL reconstruction, which can be explored in a simulation framework, often utilizes a relatively stiff semitendinosus or gracilis tendon autograft [3]. The procedure is accepted to address patients with chronic patellar instability [4]. While joint stability may be achieved with such an approach, the underlying cartilage loading, and potential long term effects, are unknown. Previous simulation results found sensitivity in cartilage pressures during MPFL reconstruction [4], and these findings may be corroborated using a higher fidelity evaluation of clinically relevant factors. In the context of developing a general patellofemoral simulation framework, the goal of this study was to evaluate the effects of reconstructed MPFL zero force reference (“slack”) length on predicted joint mechanics across a range of potential values. To support the predictive simulation results, a preliminary model validation was also performed against specimen-specific in vitro joint mechanics.

Total knee arthroplasty (TKA) prostheses are semi-constrained artificial joints. A particular prosthesis design should have a level of femorotibial constraint that matches the device’s clinical indication. For example, a cruciate retaining (CR) TKA prosthesis is indicated for patients who have a fully functioning posterior cruciate ligament (PCL), while a CR-Constrained (CRC) prosthesis that compensates for PCL function by increasing sagittal conformity to offer additional anterior stability might be indicated for those who do not.

Evaluating the risk of endograft migration is important for long-term durability of endovascular aneurysm repair (EVAR) technique. In this paper we apply a step-wise coupled finite element approach to evaluate the risk of endograft migration in representative aorta models subjected to in-vivo hemodynamic displacement forces. Device stability is observed to be a strong function of aortic geometry (tortuosity, proximal fixation) with increased tortuosity or lower proximal fixation leading to greater risk of device migration.

Posterolateral corner (PLC) injury of the knee causes varus and posterolateral rotatory instability. The anatomy of the PLC has been reported in the literature but the importance of PLC reconstruction has only recently been established and ideal reconstruction techniques are still in development. The native function of the PLC is to restrain varus and external rotation. Reconstruction methods should properly restore these functions without overconstraining the joint. Several reconstructions for PLC injury have been reported but with concerns of iatrogenic neurovascular injury, fibular head cutout, and restoration of the knee kinematics. To address these concerns, a new cross fibula tunnel method was developed that may have lower risk of iatrogenic nerve injury and fibula head cutout. The purpose of this study was to verify the stability of this technique using a PLC deficient knee.

Objective: Long term clinical data showed that lumbar fusion for Lumbar spinal stenosis (LSS) and lumbar disc degeneration (LDD) therapy could change the loads of disc and articular facet and increase the motion of adjacent segments which lead to facet arthropathy and adjacent level degeneration. This study is to design and analyze an interspinous process device (IPD) that could prevent adjacent level degeneration in the LSS and LDD therapy. Method: The IPD was designed based on anatomical parameters measured from 3D CT images directly. The IPD was inserted at the validated finite element model of the mono-segmental L3/L4. The biomechanical performance of a pair of interbody fusion cages and a paired pedicel screws were studied to compare with the IPD. The model was loaded with the upper body weight and muscle forces to simulate five loading cases including standing, compression, flexion, extension, lateral bending and axial rotation. Results: The interbody fusion cage induced serious stress concentration on the surface of vertebral body, has the worst biomechanical performance among the three systems. Pedicle screws and interbody fusion cage could induce stress concentration within vertebral body which leads to vertebral compression fracture or screw loosening. Regarding to disc protection, the IPD had higher percentage to share the load of posterior lumbar structure than the pedicel screws and interbody fusion cage. Conclusion: IPD has the same loads as pedicle screw-rod which suggests it has a good function in the posterior stability. While the IPD had much less influence on vertebral body. Furthermore, IPD could share the load of intervertebral discs and facet joints to maintain the stability of lumbar spine.

The properties of implant materials used in humans may have important influences on the outcomes of clinical treatments. Recently, titanium and titanium alloys have been extensively employed as in-vivo implant materials, due to their generally favorable biocompatibility, high resistance to corrosion, and relatively low cost. On the other hand, even when using chemically identical materials, the biocompatibility of an implant or its stability depends heavily on its surface structure, as well as the thickness and properties of the surface oxide film. As the characteristics of the implant surface have been reported to play an important role in the in-vivo reactions of implants, a great deal of interest has recently been focused on different surface treatment methods. Currently, there are a variety of methods with which titanium implant surfaces are treated. The anodizing method is an electrochemical technique, which forms a rough, thick oxidized capsule with nanotubular structures on the implant surface. To increase the biocompatibility and bone regeneration and to improve the current shortcomings of Ti and Ti alloy (Ti6Al4V)implants, we applied a uniquely fabricated nanotubular coating over the surface of such implants.

Glenohumeral joint stability is provided by complex interaction between the passive (bony geometry, capsule, and ligaments) and active (muscles) stabilizers [1]. The functional roles of geometry, capsule, ligaments, and muscles have been evaluated by sequential cutting studies [2–4] or direct measurements [5–7]. However these isolated function of individual stabilizer does not replicate in vivo glenohumeral joint biomechanics where the joint stability is controlled by interaction between passive and active stabilizers. Direct measurement device instrumentation on the soft tissue do not allow entire capsular strain measurement during rotational range of motion. Sequential cutting of the soft tissue can result in alteration in the synergy of passive and active stabilizers. To replicate in vivo interaction between passive and active stabilizers it is required to minimize the measurement device instrumentation on the glenohumeral joint capsule while the joint stability is provided by both passive and active stabilizers. Therefore, the objective of this study was to quantify the simultaneous contribution of the capsule and muscles using a geometry-driven biomechanical analysis.

Vertically unstable fractures of the pelvis are uncommon high-energy injuries. There exist various methods of fixation for posterior pelvic ring injuries such as anterior plating, tension band-plating, trans-iliac bars, spinopelvic fixation, and iliosacral (IS) screws. Recent literature supports that triangular osteosynthesis (spinopelvic fixation) provides superior fixation strength compared to traditionally placed IS screw fixation. The theoretical advantage of triangular osteosynthesis fixation is that this technique combines unilateral spinopelvic distraction osteosynthesis for vertical stabilization with ipsilateral iliosacral screw fixation for horizontal stabilization, thereby providing biplanar stability. While spinopelvic fixation provides biplanar biomechanical stability there are inherent risks of spinal instrumentation, including neurologic injury from malpositioned pedicle screws, hardware loosening or breakage, local infection, wound dehiscence, hardware prominence requiring removal, and predisposition of spinal arthritis. Iliosacral screws are thought to be advantageous in that they can be applied percutaneously or as an open procedure, potentially limit soft tissue dissection, and minimize blood loss. However, IS screw fixation alone has been associated with fixation failure in unstable vertical shear pelvic fractures. There exists a vertical shear repair technique that has been used in revisional and non-union cases, which utilizes trans-sacral screws to stabilize vertical shear fractures. This trans-sacral technique provides biplanar stability and can be implemented without spinal instrumentation. The purpose of this study was to compare the structural integrity of trans-sacral (TS) versus triangular osteosynthesis (TO) in an unstable sacral fracture model.

Injury to the cervical spine can be debilitating injury. Fracture the Dens of the C1-C2 motion segment can lead to gross instability of the cervical spine and neurological deficit. It is important to achieve stability operatively. Posterior fusion is considered by some to be a relatively safe operation compared to other procedures. Any spinal surgery which relies on boney stabilization post-operatively must provide a sufficiently small amount of movement initially to allow bone consolidation and healing.

The process of using activities of daily living to evaluate the performance of implantable devices under physiological loading conditions has been researched [1,2,3,4]. In particular, long-term stability of hip-implants, as related to fatigue, have been evaluated using normal walking [1,2,4], sit to stand [1], stair climbing [2,4], and combinations of everyday activities [3]. Current methods that utilize estimated physiological loading conditions are traditionally used as pass/fail tests to identify whether a particular design performs to a set of minimum specifications for long-term use. Such tests are also traditionally limited to a small number of physiologically representative loading conditions (i.e. walking, stair climbing, sit-to-stand).

Unstable thoracolumbar burst fractures are serious injuries and their management remains controversial. Some authors advocate the use of short-segment posterior instrumentation (SSPI) for certain burst fractures which offers several benefits including preservation of motion segments; however, clinical studies have shown mixed results. Whether crosslinks contribute sufficient stability to this construct has not been determined, therefore the objective of this study was to evaluate the biomechanical characteristics of short-segment posterior instrumentation, with and without crosslinks, in an unstable human burst fracture model.