Implanting Left ventricular assist devices (LVADs) can be life saving therapies that improve life expectancy for the patients that receive it. The target patient population suffer from end-stage heart failure and are therefore susceptible to morbidities arising from a less than ideal surgical implantation. Importantly, the graft that carries the blood from the LVAD pump to the aorta needs to be sized accordingly so as to not cause any compounding complications. The current typical surgical method, is to perform a visual estimation at the time of implantation. This present study proposes a computational tool that utilizes pre-procedural imaging to better calculate the personalized, ideal, LVAD graft length.

Total hip replacement is a widespread medical procedure, with over 300,000 surgeries performed each year in the US alone. The vast majority of total hip replacements utilize press fit fixation, where the implant cup is physically impacted into the patient’s acetabular cavity. Successful seating of the implant requires a delicate balance between inserting the implant deep enough to obtain sufficient primary stability, while avoiding fracture of bone, which causes pain, complications during recovery, and revision surgery. To improve patient outcomes, this surgical field needs assistive technologies that can measure the forces applied during press fit fixation, and provide real-time feedback to guide how much force to apply, and when to stop applying additional forces. The development of such technology, however, requires a greater understanding of the forces experienced at the implant-acetabular cup interface, and the resulting cup insertion and implant stability. Here, we present a preliminary study of acetabular cup insertion into bone proxy samples. We find that as the magnitude of force on the acetabular cup increases, the cup displacement and axial extraction force increase linearly and then plateau. For repeated impacts of a given force, cup insertion and force experienced in bone increase correspondingly and reach a plateaued value over certain number of impacts, which represents rate of insertion. These finding suggest the plausibility of a feedback mechanism that utilizes measured force patterns in bone, implant/bone interface, and impaction tool in relation to rate of insertion to infer optimal primary implant stability in arthroplasty.

Traumatic brain injury (TBI) has been considered a precarious health issue especially within the military population. Research has shown that early treatment of TBI could reduce possible neurocognitive injury. However, the nature of military triage has created challenges for early TBI detection. Intracranial pressure (ICP), which is used as a biomarker of outcomes in TBI, is not only expensive to measure but is also invasive and requires specialized surgical and procedural skills. Episcleral venous pressure (EVP) was proven to be a good alternative biomarker to ICP. However, the current technology in measuring EVP is not portable, and requires a skilled operator with a slit-lamp for testing. Moreover, the measurement is highly subjective and depends on the operator’s skill and technique. Therefore, there is a critical need for alternative technology for non-clinical TBI diagnosis. In this paper, we present an improved venomanometer design for measuring EVP in the field.

Open Reduction and Internal Fixation (ORIF) of scapula fractures have increased in numbers recently. This is due to better functional outcomes achieved post-ORIF than non-operative management techniques. In South Africa, there is only one available supplier for anatomical contoured scapula plates used in the ORIF. This study examines the fit of these plates on the bony topology of fifty healthy scapula. It was observed that the short medial body plate performed the best in adhering to the bone topology followed by the short acromion plate. The glenoid plate and the long acromion and body plates were not adequately designed to fit their intended regions on the scapula. In conclusion, this study highlights the drawbacks in design of current commercial plates available for ORIF of scapula. Further studies are needed in order to evaluate the quantitative-fit performance of these plates on fracture scapula surfaces.

Acute Myocardial Infarction (AMI) is the leading cause of worldwide death and disability, and approximately 720,000 Americans will experience an AMI in 2018. Studies have shown that rapid hypothermia therapy (< 35°C) before reperfusion in patients with AMI can reduce infarct size by 37%. Localized therapeutic hypothermia has proven the potential to cool heart tissue rapidly following AMI, 3°C in 5 minutes. Using digital imaging software and the finite volume method we analyzed temperature distributions in six patient-specific LCX artery models. A mock circulatory loop was used to determine the exiting temperatures of a standard 7 Fr catheter with flow rates ranging from 9.1 ml/min to 88.9 ml/min for input into our model. The said flow rates were fed into our model using 0.45 W and 128.4 W of cooling, respectively. Our work showed typical exit temperatures were between 35.8°C and 36.9°C using a 29.2 ml/min catheter infusion flow rate in all six heart models. Additionally, results of this study indicate that biovariability in patient-specific vascular structures significantly impacts Therapeutic Hypothermia (TH) treatment methods. These results indicate that further research is needed to examine more accurate physiological effects, such as pulsatile flow. Future models will be used to provide insight to guide more efficient TH device designs and operational parameters to optimize patient outcomes following AMI.

Legg-Calvé-Perthes disease (LCPD) is a painful pediatric hip condition caused by an idiopathic disruption of blood flow to the femoral head. The bone subsequently becomes necrotic and fragile. This can result in significant femoral head deformity, leading to pain and early degeneration of the hip. Severity of avascular involvement of the femoral head correlates with long-term outcomes, including hip arthritis and replacement. Preclinical models present extreme cases of the disease and do not represent the spectrum of LCPD seen clinically. A virtual model was developed to explore advancing the preclinical model through new methods of visualizing the data. Overall, three opportunities to advance the preclinical model and our understanding of LCPD are presented.

The use of computational modeling and 3D printing to assist in the procedural planning process for the correction of complex congenital heart malformations is becoming the standard of care. However, the use of this technology in planning the placement of ventricular support devices in pediatric patients with non-compaction has been significantly less common. We present the use of a series of models to help guide the sizing and positioning of both the inflow and outflow cannulae in a patient with left ventricular failure as an example of how these technologies can help improve patient outcomes and reduce procedural times.

This paper presents the design and fabrication of a textile-based soft Electromyography (EMG) sensor and machine-learning-based methods to detect muscle spasticity. The textile EMG sensor is flexible, foldable, stretchable, washable for multiple times, and easily customizable to meet the heterogeneous needs of SCI individuals. The machine learning algorithms that can estimate the muscle status and the performance of functional ADLs by classification of function ADLs and the detection of muscle spasticity. The soft textronic sensors, its intelligent machine learning algorithms, and biofeedback-based rehabilitation has the potential to enable home-based rehabilitation and encourage more manipulation for function ADLs and independence in SCI and stroke individuals.

Needle-based surgical procedures for diagnostic and therapeutic purposes such as biopsy and brachytherapy has significantly contributed in minimally invasive surgeries. Percutaneous interventions demand precise navigation of surgical needles in soft tissue. Active needle steering increases the target placement accuracy, and consequently improves the clinical outcome. In this work, a novel 3D steerable active surgical needle with three Shape Memory Alloy (SMA) actuators is proposed. The actuation capabilities of SMAs were used to realize a 3D motion at the needle tip. The feasibility of 3D steerability was demonstrated through active control of multiple SMA actuators.

Robot assisted surgery has been widely accepted by the medical community. Surgeons utilize robots in many different procedures worldwide. However, cardiothoracic surgeons do not regularly use robotic tools to aid them in performing even simple, catheter based procedures such as cardiac ablation or mapping. Some cardiac Monophasic Action Potentials (MAPs) and ablation catheters require a specific window of force to either effectively characterize or scar cardiac tissue. This is challenging to maintain through the cardiac cycle, so the application of a constant force is not a trivial task for surgeons. Robotic assistance to control the force applied to a catheter through ablation and mapping procedures is needed to improve the outcome for patients. The purpose of this work is to develop a single degree of freedom robot that controls the force applied to a beating swine heart. Rather than trying to predict the motion and timing of the heartbeat, or tracking its movement this robot senses and reacts to the force produced by the myocardium. Through the cardiac cycle, the robot applies a constant force to the surface of a beating heart. The kinematics of the cardiac tissue were characterized by utilizing piezoelectric transducers. Hardware to control the catheter motion was designed to fit most commercially available devices. The controller was designed by first building a mathematical model using measured data, and then a control law was implemented considering the heartbeat as disturbances to the system. Finally, testing was completed with dry runs, and in situ and ex-vivo testing in the Visible Heart ® Laboratory.

Laparoscopic surgery offers multiple clinical advantages over open surgical procedures. The rise in adoption of laparoscopic surgery brings with it unique human factors challenges for surgeons and device developers. The design of laparoscopic surgical tools requires specialized human factors analysis and ergonomic considerations to overcome these challenges. Often, this necessary ergonomic design refinement is a secondary effort after proof-of-concept engineering prototypes demonstrate technological feasibility. In this paper, the evaluation and redesign of an engineering proof-of-concept multimodal hand tool, is presented. The baseline design, a three-in-one laparoscopic hand tool for liver resection, merged three distinct devices into one integrated solution for dissection, vessel sealing, and tissue cautery. The work described herein evolves the initial prototype using a multifaceted human factors analysis and design process. This included the use of operating room and laboratory contextual inquiry, simulated use studies, anthropometric underlays, an iterative design process, and expert reviews. The revised design reduced ulnar deviation based on directed hand position via design, provided dual grip options, added over-molded interaction points, incorporated end-effector rotation, and implemented a new handle and controls layout based on anthropometric underlays. The outcome reinforces the notion that human factors and industrial design principles are required elements of a successful user centered design process.

Cerebrospinal fluid shunts for the treatment of hydrocephalus fail at a rate of 40% within the first year. The importance of this problem is supported by one institution’s analysis of neurosurgical 30-day readmissions with CSF shunt failure only second to brain tumor readmissions. Hospital shunt related costs have been estimated at $1.4 to $2 billion annually. The majority of these costs are attributable to shunt failures based on the number of revisions out of the total numbers of annual shunt procedures. The technical innovation of this project is a low cost, low risk and easy to implement CSF shunt design change compatible with current protocols. The proposed product is an innovative distal catheter to minimize the need for revision surgery due to obstruction (also referred to as occlusion). This is accomplished with a dual lumen catheter (current distal catheters are single lumen) consisting of a primary lumen and a secondary lumen providing redundant functionality in the event ofprimary lumen occlusion thereby eliminating the need for surgical shunt revision. 40% of shunts fail within the year after implant and distal catheter obstruction accounts for up to 24% of failures. Though less prevalent than proximal catheter occlusion, incidence of distal catheter occlusion is significant and improved reliability would reduce costs and improve patient outcomes by lowering the number of revisions.

In this study, we focus on validating the accuracy of the previously developed software, which reconstructs thoracic rib cage and thoracic volume in 3D. This software is applied in spine deformity patients to help doctors monitor and follow spine curvature and the thoracic volume variation. Five users were recruited to perform usability testing for the developed software. The usability testing shows that the performance of the thoracic volume reconstruction via our software meets the criterion set by the American Thoracic Society, which recommends an acceptable error of ±3% for the respiratory measurement. In addition, the user operation results were analyzed through a two-way analysis of variance (ANOVA), without replication, statistical method. The outcome indicates the reconstruction accuracy of the software is satisfactory. In the reproducibility study, the result shows that the performance of the developed software is superior to previous literature and the reconstruction is clinically relevant.

Aortic aneurysm is a common disorder which is due to weakening of the aortic wall [1]. Aneurysm rupture is a potentially life threatening complication [2]. The stent graft implantation is one of the potential alternatives for treating patients at high risk for an open surgical procedure. The short-term outcome for stent implantation is promising; however, as with any medical procedure, this has potential limitations such as side branch occlusion, device malfunctions, dilatation at the proximal portion and the so called ‘endoleak’. An endoleak is the persistent blood flow into and within the aneurysmal sac after endovascular repair (i.e. the blood leaks around the endograft which is supposed to have sealed off the entry of blood around it and can be classified into 5 categories[3]). Type I (inadequate seal) and III (graft mechanical failure) endoleaks, characterized by direct communication between systemic and aneurysm sac compartments, pose higher risk of aneurysm rupture and are therefore aggressively treated [4]. Despite advances in the treatment of aneurysm, we believe that there is a still great need for a medical device that can improve patient outcomes.

Colorectal surgery is widely performed to re-establish the bowel, the part of which is removed because of diverticulitis, intestinal polyps, inflammatory bowel and cancer. Stapled anastomosis is a highly standardized technique and considered the standard of care. However, complications like leakage, stenosis and postoperative bleeding cannot be completely avoided [1,2]. There is limited understanding of the impact of staplers on tissue and basic mechanics of tissue stapling. According to the previous research, compression, staple height, tissue thickness, tissue compressibility, and tissue type have an effect on the patient outcomes [3]. Hence, we conducted this prospective study to analyze the effect of staple height on tissue damage and compression pressure. An attempt was made to determine the relationship between the tissue height and the optimal closed staple height.

For more than 27 years, implanted vagus nerve stimulation (VNS) devices, with electric current outputs in the 1 to 3.5 mA range, have been developed for many health care applications, including epilepsy and heart disease [1]. Mechanical compression approaches for VNS were administered under surgical conditions, using forceps, in the 1800’s [2]. Outcomes such as Electrocardiogram (ECG) data, blood pressure (BP), and heart rate (HR) were evaluated. Also, non-invasive (NI) mechanical compression of the vagus nerve for various nervous system disorders using hand, thumb, finger and belt pressure was popular in the 1800’s [3]. Cyberonics (now LivaNova) received the first FDA clearance for a surgically implanted electrical VNS device to treat refractory epilepsy in 1997.

Exoskeleton based rehabilitation for post-stroke recovery is being aggressively pursued due to unavailability of adequate number of caregivers and huge investment for the manual treatment [1]. The structural framework for providing different training exercises is not similar for all exoskeletons and there is no standardized protocol for rehabilitation following stroke [2]. Various approaches have been undertaken to come up with customized exoskeleton design for implementing a specific type of exercise. Though a few exoskeletons have proved to be beneficial in terms of clinical outcomes, there is still a long way to go before a useful rehabilitation device becomes acceptable to the users. After reviewing the 46 exoskeletons (commercial or prototypes) [3], two key requirements can be considered for the design of an exoskeleton; the structural parameter which decides the size, weight and the ease of control and the other is the nature of rehabilitation therapy which defines the type and intensity of the exercises performed during training.

Nearly half of individuals with stroke experience some form of long-term disability and stroke is one of the main causes of wheelchair use in the United States [1]. Early rehabilitation in the acute phase of stroke has been shown critical to promoting motor plasticity and patient outcomes. However, research shows that only 32% of the time during inpatient rehabilitation is spent in active therapy, while the rest of the time is spent on other activities around the ward [2]. For walking impairment, it is especially important for patients to experience similar force loading and practice the patterning of gait in order to recover [3]. However, in a typical therapy session focused on gait rehabilitation patients only will take about 300 steps on average. This is far below what has been thought needed for humans to learn how to walk [4].

Stent implantation is widely used to treat blocked lumen. Stents were meshed structure made of polymers and metal alloys, including stainless steel, cobalt chrome and nitinol [1]. Clinical studies had demonstrated that stents helped to scaffold the diseased lesion up to one year when tissue adapted to the stented environment [2]. However, the permanently implanted stents inside artery were associated with complications such as stent fracture, tissue inflammation, in-stent restenosis and thrombosis [3]. Currently, biodegradable stents are attracting more attention due to its potential long-term efficacy in treating blocked lumens. The detailed characterizations of biodegradable stents are essential for the desired clinical outcomes.

Episcleral venous pressure (EVP) refers to the pressure in the episcleral veins. It is used by scientists in glaucoma physiology and pharmacology research to study the parameters of aqueous humor dynamics as part of the Goldmann equation [1]. The episcleral veins drain into the superior ophthalmic vein which drains into the cavernous sinus. Our previous work in a pig model [2] shows for the first time that EVP is an excellent non-invasive quantitative marker for intracranial pressure (ICP) estimation (high ICP leads to high intracranial venous pressure and high EVP). Intracranial pressure (ICP) is an important marker of outcomes in traumatic brain injury. There is an unfulfilled civilian and military need for a non-invasive ICP measurement modality. EVP could serve as a quantitative ICP biomarker, measurable by personnel with different skill levels for remote acute triage in battlefields and other urgent situations.