A 1DOF lower limb rehabilitation robot is presented for delivering leg extension therapy to bed-bound stroke patients. Such a compact and minimal system may be beneficial in terms of compatibility with pre-existing hospital equipment, ease-of-use, safety, and cost. A set of design criteria was created based on the literature and on previous field work at a local hospital. The device uses admittance control to apply assistive or resistive forces, and can also use haptic feedback to increase user engagement. A pilot study on six healthy participants was used to determine the feasibility of such a minimal system in administering assistance or resistance through the leg extension exercise. Results indicate that a single DOF is capable of decreasing trajectory error with assistance and increasing user effort with resistance. Observations confirm that the minimal system is effective; however, extending the robot with additional DOFs so that it can target multiple bed-bound exercises may help to increase therapy duration.

Noninvasive ventilator support such as bi-level positive airway pressure (BiPAP) or continuous positive airway pressure (CPAP) is often used for patients with obstructive sleep apnea or neuromuscular disorders, such as amyotrophic lateral sclerosis (ALS), where respiratory muscles are weakened. Current commercially available masks for BiPAP and CPAP are often cited as being ill-fitting and leaky, leading to poor quality of sleep or reduced usage of therapy. This project seeks to minimize leaks and maximize comfort by developing custom-fit masks. Patient faces are imaged using an in-house camera system to obtain a three-dimensional (3D) facial contour. Custom interfaces are generated based on this contour using interactive computer software. Using 3D printing to enable rapid tooling, these interfaces are produced in a skin-safe silicone and attached to an off-the-shelf (OTS) mask to create a custom mask. The methodology has been initially tested on five healthy subjects who underwent a two-night sleep study, one night with an OTS mask and one night with a custom-fit mask, to evaluate the leakage and comfort of the custom-fit mask compared to the OTS version. Subjects filled out a questionnaire asking them about mask comfort, leakage, and quality of sleep along with open-ended questions. While the custom-fit mask did not reduce the average measured leakage for subjects, subjects reported experiencing less leakage. Overall, results suggest that the custom-fit masks are more comfortable and tolerable than the provided OTS option. Subject feedback will be implemented into future masks that will be used in a clinical study.

Objective : Laparoscopic instruments with suction and irrigation functions often lead to tissue damage during removal of the aspirated tissues, owing to the presence of aspiration into the side holes of their catheters. To address this problem, we designed a novel irrigation-and-suction catheter and assessed its preclinical efficacy. Methods : We made structural improvements to the irrigation-suction catheter to prevent tissue aspiration through its side holes. We ran a simulation program to perform experimental assessments before printing out the catheter tip models using a three-dimensional (3D) printer. Model 1 was the control, and Models 2, 3, and 4 were the improved models. Using these, we performed 10 repetitions of 15-s suction followed by 15-s irrigation, for a total of 5 times per model. We recorded the number of aspirations that occurred through the side holes and analyzed each model using nonparametric methods. Results : Models 2 and 3 showed fewer aspirations because the velocity and pressure around their side holes were lower than those of Model 1; this was statistically significant. On the other hand, Model 4 had a lesser preventive effect against aspiration due to higher velocity and pressure around its side holes. Interpretation of Results : We confirmed that side-hole aspiration can be prevented with an internal structure that completely separates the irrigation and suction paths. Even if the irrigation and suction paths are not completely separated, adding a septal structure at the distal end of the catheter may prevent aspiration.

Obstructive sleep apnea (OSA) is an acute breathing disorder, which causes soft tissue inside the throat to collapse, thus blocking the airways while sleeping. This syndrome is usually treated by the supply of pressurized air delivered by a pump, which is connected to the patient via mouth and/or nose using a mask as an interface. While most of the literature on OSA is focused on the pressure pump and the therapy conditions (pressure, humidity, velocity, etc.) there has been an increased interest in the mask/interface as a key contributing factor to the treatment's effectiveness. Mask-related issues such as skin damage, allergic reactions, or air leaking due to poor fit can deter OSA patients from following this treatment. This study presents a preliminary evaluation of customized mask designs, which are tailored to specific wearer's facial contours. The development process includes the use of three-dimensional scanning/modeling/printing as an integrated workflow. Individual facial features have been digitally acquired and used to generate a custom device, which conforms to predefined facial landmarks of interest, which delimit the mask contour. A trial study was undertaken by recruiting two healthy volunteers for the fit and comfort evaluation of custom mask designs using a randomized fit test with a series of three-dimensional (3D) printed versus commercial standard mask. Results indicate that custom masks exhibit a higher level of comfort compared to conventional continuous positive airway pressure (CPAP) masks particularly on fit, contact pressure and comfort.

For most older adults, their own homes is the overwhelmingly preferred environment for living and growing older. However, for those living in homes with stairs, the difficulty and risk of injury in stair ascent/descent is a major challenge in their daily life, which may endanger the feasibility of such choice. In this paper, the authors present a novel assistive device, namely RailBot, to help mobility-challenged individuals (including frail older adults) to climb stairs more easily. Unlike the traditional elevators and stair lifts, the RailBot is a highly compact device that can be easily installed in existing stairways, allowing it to benefit a large number of individuals living in homes with stairs. Further, by assisting the users' stair climbing instead of carrying them upstairs, the RailBot enables and encourages the users to maintain and enhance their stair-climbing capabilities, and thus contributes to their long-term physical health. The design details of the RailBot prototype are presented, including the system configuration, the actuation mechanism of the mobile platform, as well as the intuitive control interface for start-stop control and speed regulation. After mounting the prototype in a real-world use environment, a small-scale human study was conducted, with the results clearly demonstrating the effectiveness of the RailBot assistance through the significant reduction of lower-limb muscle activities.

This paper presents the design and an experimental characterization of CADEL, a cable-driven elbow assisting device. The device design is presented to be portable and user-oriented solution and its kinematic model is formulated for functionality analysis. A first prototype and its experimental setup are discussed with the peculiarities of the novel solutions. Two operation modes are investigated with and without load in experimental testing. The performance characterization and feasibility are discussed referring to both the numerical and experimental results.

A commonly acknowledged barrier for the adoption of new computer-assisted orthopedic surgery (CAOS) technologies relates to a perceived long and steep learning curve. However, this perception has not been objectively tested with the consideration of surgeon-specific learning approaches. This study employed the cumulative sum control chart (CUSUM) to investigate individual surgeon's learning of CAOS technology by monitoring the stability of the surgical process regarding surgical time. Two applications for total knee arthroplasty (TKA) and two applications for total shoulder arthroplasty (TSA) provided by a modern CAOS system were assessed with a total of 21 surgeons with different levels of previous CAOS experience. The surgeon-specific learning durations identified by CUSUM method revealed that CAOS applications with “full guidance” (i.e., those that offer comprehensive guidance, full customization, and utilize CAOS-specific instrumentation) required on average less than ten cases to learn, while the streamlined application designed as a CAOS augmentation of existing mechanical instrumentation demonstrated a minimal learning curve (less than three cases). During the learning phase, the increase in surgical time was found to be moderate (approximately 15 min or less) for the “full guidance” applications, while the streamlined CAOS application only saw a clinically negligible time increase (under 5 min). The CUSUM method provided an objective and consistent measurement on learning, and demonstrated, contrary to common perception, a minimal to modest learning curve required by the modern CAOS system studied.

Robots utilize graspers for interacting with an environment. Conventional robotic graspers have difficulty conforming to objects of varied shape and exerting varying grasping forces. Variable stiffness soft robotic graspers provide these features but face issues such as slow response time, the requirement of external power packs for operation and low variation of stiffness. A variable stiffness compliant robotic grasper that is simple in design and operation would improve end effectors used in assistive robotics and prostheses for handling a wide array of objects. In this paper, we present the design of a novel variable stiffness compliant robotic grasper that can change its stiffness through structural transformations. Current designs utilizing structural transformations do not provide shape conformance while grasping objects. We propose a design for a soft robotic grasper using the concept of stability of truss structures. This design is capable of partially conforming to the surface of an object being grasped and can rapidly vary its stiffness utilizing compliant rotating elements embedded in the grasper jaws. The grasper behavior is modeled using finite element analysis (FEA) and validated experimentally. Our results demonstrate that structural transformation of flexible elements is a potential solution for achieving variable stiffness in a grasper.

This paper presents a legged and clamper-based capsule robot (CR) with active locomotion function. The CR utilizes the extension and contraction of the anchoring legs to expand the collapsed intestinal wall, crawl in the intestinal tract, and stand in large spaces such as the stomach and large intestine organs. The mechanical structure design, kinematic analysis, principle of locomotion, and force analysis of the CR are presented. The design concept and locomotion principles of the proposed CR are verified by a prototype with the diameter of 13 mm and length of 39 mm. Three experiments were conducted to test the locomotion performance of the proposed CR. In the experiments, the prototype successfully expands the collapsed phantom intestine, stands on the plane, and moves forward in transparent tube at a promising speed. Experimental results indicate that the CR has good locomotion capabilities.

This literature review was conducted to evaluate liver biopsy adequacy, including total core length (TCL), number of portal tracts (PT), fragmentation, and complication rates, as a function of needle type and gauge. A systematic electronic search was performed in the Web of Science and Google Scholar databases, according to the PRISMA statement. Eligible data, describing in vivo percutaneous ultrasound-guided human liver biopsy quality outcomes, were compared to adequacy criteria of the American Association for the Study of Liver Diseases (AASLD, TCL ≥ 20 mm, PT ≥ 11). An adequate mean number of PTs was found in 83% of biopsy needles assessed between 2012 and 2019, compared to 0% between 1998 and 2004. For TCL, this was 44% and 33%, respectively. Increasing the needle diameter enhanced TCL (result in 50% of included studies) and PT count (100%), and reduced fragmentation rates (75%), whereas no effect on pain or complications was found (83%). In total, five needle types achieved adequate PT counts, using 16 G (3×), 17 G (1×), or 18 G (1×) needles. Adequacy was reached using either a core needle biopsy (CNB, 3×) approach with one pass, or a fine needle aspiration (FNA, 2×) approach with two passes. The recommendations for biopsy adequacy can be met using 16/17 G FNA or 16/18 G CNB needles. Currently, many publications still present substandard liver biopsy quality outcomes. Although minimizing biopsy invasiveness is desirable, a decreased diameter or number of passes is ill-judged when reliability of biopsy outcomes is at stake.

Passive arm-assistive devices play an important role in the rehabilitation of patients with neuromuscular disorders or injuries by overcoming their motor deficit. Routine human activities such as feeding are not possible without the aid provided by one of these devices or by a caregiver. In this study, a body-powered assistive device was designed for feeding purposes using a compact spherical scissors mechanism and zero-free-length (ZFL) springs (rubber bands) to leverage the patient's residual biceps and healthy triceps function. This partially balanced and lightweight orthosis was also projected to accommodate the spring attachment points closer to the elbow joint center. The performance of the prototype was evaluated on a young adult with bilateral amyoplasia of the biceps due to arthrogryposis who could not initially reach the superior anterior aspect of the close-to-torso region of the reachable three-dimensional (3D) workspace (RWS). That was accomplished by measuring the anatomical RWS of the patient before and while wearing the device. The results show that the patient, with the assistance provided by the device, was able to attain positions in the frontal close-to-torso region of the body that included reaching her mouth, thus enabling independent feeding.

With advances in prosthetic technology, functional intent has extended past basic support toward providing increased dynamic ability for daily and athletic use. Addressing a disparity between universality and complexity in sport-grade and energy-storage-and-return (ESR) prostheses, this paper presents a pneumatic transtibial ankle prosthesis concept with semi-active control of ankle stiffness to adjust the prosthesis' properties for a wider range of gym exercises. Functional validation of the device falls under specific scenarios including the parallel back squat weightlifting exercise. The prosthesis features 30 deg sagittal ankle range of motion and provides wireless adjustment of static air pressure via a smartphone app to transition between the force and stiffness demands of walking and weightlifting. This pneumatic system includes a self-replenishing feature, providing a practical solution for the variable air pressure demands of athletics and everyday use. The mechanical, pneumatic, and control systems of the prosthesis are therefore described. Biomechanical tests including the back squat were conducted with one transtibial amputee subject. The resultant kinematic analysis validated the functional goals of the device, including an increased range of ankle rotation and variable stiffness across three different cylinder pressure settings. The kinetic profiles of the amputated leg and the natural leg also reveal an improvement in bilateral symmetry compared to a standard ESR prosthesis. This prosthesis concept has the potential to help persons with amputation participate in a wider range of activities, by improving the versatility of current ESR and sport prostheses.

Several studies have shown that chest compressions (CC) alone may produce in addition to blood circulation, a short-term passive ventilation. However, it is not clear whether high CC quality may produce in even greater amount of ventilation volumes. The aim of this study was to evaluate whether CC, using a new feedback device, can produce a substantial and sustainable passive volumes compared to standard CC. Thirty inexperienced volunteers performed CC for 2 min on a developed thoracic lung model and using a new feedback device. Participants were randomized into two groups that performed either CC with feedback first, followed by a trial without feedback, or vice versa. Efficient compression rate (correct CC rate and depth simultaneously) was significantly higher in feedback session (43.6% versus 25.5%; P = 0.006). As well, CC rate and depth efficiency were improved with feedback. Moreover, average tidal volumes and minute volumes that occurred during CC alone were significantly improved in feedback session (79.8 ± 5 ml versus 72.9 ± 7 ml) and (8.8 l/min versus 7.9 l/min), respectively (P < 0.001). Yet, no significant difference was found between the first and the 90th second interval (9.04 l/min versus 8.68 l/min, P = 0.163) in the feedback session. Conversely, a significant difference was evident after the first 15th seconds interval without feedback (8.77 l/min initially versus 8.38 l/min; P = 0.041). This study revealed that the new CPR feedback device improved CC quality in inexperienced volunteers. As well, the passive ventilation volumes were significantly increased and sustained when the device was used.

With the growing Accreditation Council for Graduate Medical Education (ACGME) regulations, studies have increasingly reported decreased technical proficiencies by clinical trainees. One major way programs have addressed this is by adopting proficiency through simulation training. One such crucial technique is radial artery line cannulation, an invasive procedure performed by trainees across multiple medical disciplines. The objective of this project was to design a high-fidelity, pulsatile, automated radial artery line simulation model that supports ultrasound (US) guided insertion and pressure transduction that could potentially be used for technical skill development and training purposes. A radial artery line simulation model was designed using a pulsatile, arterial circuit with an alginate silicone cast molded artificial hand that supported cannulation under US guidance. The radial arterial circuit pressure was transduced to display a simulated arterial waveform and pressure. Five radial artery lines were successfully cannulated under US guidance followed by pressure transduction. The results, although qualitative, demonstrate a proof of concept. Further studies are needed to determine if the radial artery simulation model can be used as an educational tool to help train medical professionals.

Instrument-assisted soft tissue mobilization (IASTM) tools are used during rehabilitative care for treatment of injuries to muscles, tendons, and ligaments. Many studies have quantified treatment application forces between tools and the patient. However, the effect of force on the clinician has not been studied even though research shows that clinicians experience discomfort and fatigue during treatment. This work presents a method to accurately measure the pressure profile between the IASTM tool handle and hand of the clinician. Flexible pressure indicating film was used to measure the pressure magnitude and distribution on the hand. These tests were performed at varying treatment application forces between 15 and 60 N, normal to the treatment surface. The tests were repeated, and forces were compared between 3D-printed designs. The pressure profile on the user was explored by changing aspects of the handle design. Results are analyzed and discussed as an effect of changing handle dimensions. As the diameter of the handle increased, the pressure magnitude decreased while the pressure distribution across the hand increased. Changing the contour of the handle further decreased the magnitude and increased the distribution. This procedure is not specific to the chosen tool and can be repeated for other tools.

This research sought to develop a fabricable prosthetic liner that could be fabricable, intuitive, and a cost-effective means of providing advanced prosthetics in developing settings. An affordable ethyl-vinyl-acetate roll-on (AERO) liner for permitting a total surface bearing suction socket design was created and provided to a single participant for in vivo outcome measurements. The liner was fabricated from locally produced low-density ethyl-vinyl-acetate (EVA) foam. A liner fabrication process was developed and described, and one participant was provided 3 mm and 6 mm AERO liner variants for outcome evaluations. Six-minute walk test, residual limb temperature, and socket comfort score (SCS) while in AERO liner were collected. Thirty-day step counts of AERO liner with prosthesis and thermoplastic elastomer (TPE) liner with prosthesis were collected. The results of in vivo evaluations indicate increased speed, slightly higher residuum temperature, and increased comfort of the 6 mm AERO liner. Pedometer tallied step counts for the AERO liner and TPE liner prostheses were similar. The 6 mm AERO liner provided the best comfort and function of the two thicknesses in liners, and step count data indicated that the volume of patient activity was similar to when wearing the TPE liner prosthesis. Roll-on fabricable low-cost liners offer an affordable means of providing total surface bearing suction prostheses for resource limited environments (RLE). A prosthetist or technician can use the existing skills and lab to create liners.

A new gene detection technique that is fast, inexpensive, and easy-to-use is urgently needed in hospitals, clinics, and laboratories without access to expensive equipments. The lack of a practical, minimally invasive, and economical method constitutes the main impediment to the promotion of genetic medicine in developing countries. Radiofrequency scattering parameters are an inexpensive gene sensor potentially capable of noninvasively identifying biological materials. They represent a quantitative value for the electromagnetic reflection/transmission characteristics of certain molecular markers in a given frequency domain. The S 21 parameter is the difference between the signal received and that transmitted. The aim of this study is to evaluate the S 21 transmittance parameters (magnitude and phase) as an indirect impedance measurement for detecting the label-free complementary deoxyribonucleic acid (cDNA) amplification of the 16S ribosomal subunit gene. S 21 values showed differences associated with distinct cDNA concentrations. Hence, this technique could possibly facilitate the design of an inexpensive, label-free, and easy-to-use gene sensor.

Postpartum hemorrhage (PPH) is the leading cause of maternal mortality worldwide, and effective interventions for addressing PPH are urgently needed. Uterine balloon tamponade (UBT) is a technique to control PPH. Commercially available UBT devices are expensive and frequently require imaging technology to ensure placement. Condom-catheter uterine tamponade (C-UBT) is a technique appropriate for low-resource settings. Testing of the C-UBT is needed to better understand and optimize this technique for use in a variety of clinical settings including low-resource contexts. We describe here the design, development, and bench-top validation of a reusable C-UBT device optimized for low-resource settings. The device was tested in three differently sized uterine models using a variety of condom balloon configurations. Intrauterine wall pressure application was measured to evaluate the device capacity to apply pressure of at least 90 mmHg, estimating the mean arterial pressure within the uterine vasculature. Bench-top experimental validation of pressure exerted in uterine models demonstrated the device's capability of reaching hemostatic pressure in uterine volumes ranging from 170 to 1740 mL. Device adaptability and versatility were shown through its ability to reach the target pressure of 90 mmHg in different uterine sizes by varying balloon parameters, including condom thickness and condom configuration. The results of this study show the potential of a low-cost, reusable C-UBT device optimized to treat PPH in a variety of clinical settings, including low-resource contexts.

Non-acid reflux is common in premature neonates. Current methods of diagnosing gastroesophageal reflux (GER) such as pH probes, multichannel impedance monitoring, X-rays, or endoscopy are either invasive or unable to diagnose non-acid reflux. Passage of a naso-esophageal tube is uncomfortable. Imaging studies are of short duration and may miss reflux entirely. Herein, we present proof of concept of a noninvasive accelerometric device that detects acid and non-acid reflux in premature infants. An accelerometer was taped over the subxiphoid process in patients suspected of having GER who were already scheduled for pH probe or multichannel impedance monitoring. The largest cohort was preterm infants, but term infants and toddlers were also studied. Low-frequency subaudible signals were obtained on a digital recorder (sampling rate 200 Hz) signals. Fast Fourier transforms graphically displayed the frequency and amplitude of signals. Data were then resampled at a rate of 60 Hz to create a spectrogram with a focused range of 0–30 Hz representing reflux-associated events. Proof of concept was attained through successful comparison with results from concurrent pH probes, multichannel impedance recordings, and ultrasound studies. We have thus validated accelerometry as a noninvasive method for assessing both acid and non-acid GER. The noninvasiveness of this diagnostic modality allows for repeated testing to assess the efficacy of anti-reflux medications, even when patients remain on antacids. This technology allows for more rational management of patients with GER and represents a major advance in the diagnosis and treatment of GER.

This study proposes an optically sensorized force-sensing tendon for minimally invasive surgical instruments. The tendon is composed of a high strength, polarization maintaining (PM) optical fiber with Bragg sensors (FBGs) that negate the cross-sensitivity of conventional FBGs. The PM-FBG fiber is locally reinforced with high stiffness Kevlar that enhances its load carrying capacity while enabling higher curvatures in tendon routing. The composite tendon has a mean diameter of ∼268 μ m which preserves the form-factor of instruments within this scope. Importantly, the tendons can improve the functionality of such tools by enabling local force and tissue-resistance estimation. This paper explores the performance of these sensorized tendons in terms of strength, stability, response under dynamic load, friction, and sensitivity as a force measuring tool within an 18 Ga articulate Nitinol (NiTi) cannula (a proxy for potential applications). Results reaffirm the potential of a bi-modal sensing and actuation component within instruments for robotic surgery.