Engineering Commons^™

Remote Navigation And Contact-Force Control Of Radiofrequency Ablation Catheters, Daniel Gelman

Electronic Thesis and Dissertation Repository

Atrial fibrillation (AF), the most common and clinically significant heart rhythm disorder, is characterized by rapid and irregular electrical activity in the upper chambers resulting in abnormal contractions. Radiofrequency (RF) cardiac catheter ablation is a minimally invasive curative treatment that aims to electrically correct signal pathways inside the atria to restore normal sinus rhythm. Successful catheter ablation requires the complete and permanent elimination of arrhythmogenic signals by delivering transmural RF ablation lesions contiguously near and around key cardiac structures. These procedures are complex and technically challenging and, even when performed by the most skilled physician, nearly half of patients undergo …

Evaluation Of Individual Finger Forces During Activities Of Daily Living In Healthy Individuals And Those With Hand Arthritis, Michael Riddle

Electronic Thesis and Dissertation Repository

Hand-Osteoarthritis (H-OA) leads to pain, loss of grip strength, and decreased hand function. Current treatment for H-OA involves joint protection programs (JPP) which seek to reduce joint loading during activity. The use of wearable technology to measure hand forces during activity has the potential to determine the effectiveness of JPP. The objective of this thesis was to develop and validate a method of directly measuring finger forces during the performance of activities of daily living, and then use that system to measure the envelope of hand forces during activity in healthy individuals and in patients with H-OA. A commercially-available capacitive …

Development Of A Force-Based Ream Vector Measurement System For Glenoid Reaming Simulation, David Axford

Electronic Thesis and Dissertation Repository

Glenoid reaming is a technically challenging step during total shoulder arthroplasty surgery that may be improved through frequent practice and exposure to simulation training. At our institution, a vibration haptic glenoid reaming simulator is being developed that simulates the vibrations felt during glenoid reaming. This thesis presents the development of a force-based reamer vector measurement system that allows the simulator to measure the user’s net applied force and reamer angle of approach. This capability allows for the simulation of eccentric reaming maneuvers commonly used to adjust the glenoid orientation. The system error was characterized and evaluated using a robot to …

Tissue Equivalent Gellan Gum Gel Materials For Clinical Mri And Radiation Dosimetry, Pawel Brzozowski

Electronic Thesis and Dissertation Repository

Hydrogels contain high amount of water allowing their use as surrogates to human tissues with specific properties that can be tuned by additives. Gellan gum is a gel-forming material of interest and is a replacement for other common gelling agent with limited use as a tissue phantom. Therefore, this thesis examines the application of gellan gum gels as a novel magnetic resonance imaging (MRI) phantom with a design of experiments model to obtain tunable properties. The analysis was extended to include mechanical and electrical properties with a separate design of experiment. Gels doped with synthesized superparamagnetic iron oxide nanoparticles (SPIONs) …

Tibiotalar Arthrodesis: Development Of A Novel Jig And Alignment Guide, Adam Mathew Ropchan

Electronic Thesis and Dissertation Repository

Tibiotalar arthrodesis is a surgical procedure, used for the treatment of end-stage ankle arthrosis and instability. There are dozens of described procedures in the literature, all with varying rates of success. Two of the most common reasons for reoperation in tibiotalar arthrodesis are nonunion and infection; few studies have established any associations between patient/surgical factors and reoperation for nonunion and infection.

The first part of this thesis focuses on determining the rate of reoperation to the ipsilateral lower limb and if any patient/surgical factors are associated with reoperation for nonunion and infection. The second part of this thesis turns attention …

Investigation And Validation Of Imaging Techniques For Mitral Valve Disease Diagnosis And Intervention, Claire Vannelli

Electronic Thesis and Dissertation Repository

Mitral Valve Disease (MVD) describes a variety of pathologies that result in regurgitation of blood during the systolic phase of the cardiac cycle. Decisions in valvular disease management rely heavily on non-invasive imaging. Transesophageal echocardiography (TEE) is widely recognized as the key evaluation technique where backflow of high velocity blood can be visualized under Doppler. In most cases, TEE imaging is adequate for identifying mitral valve pathology, though the modality is often limited from signal dropout, artifacts and a restricted field of view. Quantitative analysis is an integral part of the overall assessment of valve morphology and gives objective evidence …

A Biomechanical And Physiological Signal Monitoring System For Four Degrees Of Upper Limb Movement, Allison R. Goldman

Electronic Thesis and Dissertation Repository

A lack of adherence to prescribed physical therapy regimens in improper healing results in poor outcomes for those affected by musculoskeletal disorders (MSDs) of the upper limb. Societal and psychological barriers to proper adherence can be addressed through the system presented in this work consisting of the following components: an ambulatory biosignal acquisition sleeve, an electromyography (EMG) based motion repetition detection algorithm, and the design of a compatible capacitive EMG acquisition module.

The biosignal acquisition sleeve was untethered, unobtrusive to motion, contained only modular components, and collected biomechanical and physiological sensor data to form full motion profiles of the following …

Electrospun Collagen Fibers For Tissue Regeneration Applications, Ying Li

Electronic Thesis and Dissertation Repository

Tissue engineering aims to regenerate damaged and deceased tissue by combining cells with scaffold made from an appropriate biomaterial and providing a conducive environment to guide cell growth and the formation or regeneration of new tissue or organ. While collagen, an important material of the extracellular matrix (ECM), is a natural choice as a scaffold biomaterial, the conducive environment can only be created by having the ability to control the geometry, organization, structural and mechanical properties of the scaffold. Moreover, degradability and degradation rate control of the scaffold has to be taken into consideration too. In this work, we aim …

Development Of Image-Based Surgical Planning Software For Bone-Conduction Implants, Carlos D. Salgado

Electronic Thesis and Dissertation Repository

The BONEBRIDGE bone-conduction device is used to treat conductive and mixed hearing losses. The size of its floating mass transducer (FMT) can preclude implantation in certain anatomies, necessitating comprehensive surgical planning. Current techniques are time consuming and difficult to transfer to the operating room. The objective of this thesis was to develop software for calculating skull thickness to the dura mater to find locations for the FMT and to the first air cells which guarantee sufficient bone for the implant screws to grasp. Temporal bone computed tomography (CT) images were segmented and processed and custom Matlab code was written to …

Dynamic Calibration Of Emg Signals For Control Of A Wearable Elbow Brace, Taylor Stanbury

Electronic Thesis and Dissertation Repository

Musculoskeletal injuries can severely inhibit performance of activities of daily living. In order to regain function, rehabilitation is often required. Assistive devices for use in rehabilitation are an avenue explored to increase arm mobility by guiding therapeutic exercises or assisting with motion. Electromyography (EMG), which are the muscle activity signals, may be able to provide an intuitive interface between the patient and the device if appropriate classification models allow smart systems to relate these signals to the desired device motion.

Unfortunately, there is a gap in the accuracy of pattern recognition models classifying motion in constrained laboratory environments, and large …

Evaluating Devices For The Measurement Of Auditory-Evoked Fetal Movement, Patrick Gatutsi

Electronic Thesis and Dissertation Repository

Determining normal and abnormal fetal function in utero in order to better predict which fetuses are at risk for adverse outcome is critical. However, the medical imaging tools that could assist with diagnosis are very expensive and rarely available in the developing world. In this study, we developed a prototype audio-motio-tachograph (AMTG), which measures fetal movements through the recording of abdominal wall deformations and tested it in Rwanda. First, we showed that AMTG detected fetal signals and that fetuses respond to complex acoustic stimuli. In order to improve the sensitivity of the device, we then measured whole abdominal wall deformations …

An In-Silico Assessment Of Stemless Shoulder Arthroplasty: From Ct To Predicted Bone Response, Jacob M. Reeves

Electronic Thesis and Dissertation Repository

Despite the emergence of stemless humeral implants that utilize short fixation features to gain purchase solely in the metaphysis, the literature contains little information regardingthe morphology and mechanical properties of the humerus’ proximal trabecular-canal, and how stemless implants impact bone response. The present work employs in-silicotools, including CT-based and Finite Element (FE) methods, to define parameters that may influence stemless implant design.

The density and morphology of the proximal humerus were assessed using CT-derived point clouds of the trabecular-canal. Bone density was found to diminish 15-20mm beneath the humeral head resection and was greater peripherally. The depth, path and bounding …

Augmented Reality Ultrasound Guidance In Anesthesiology, Golafsoun Ameri

Electronic Thesis and Dissertation Repository

Real-time ultrasound has become a mainstay in many image-guided interventions and increasingly popular in several percutaneous procedures in anesthesiology. One of the main constraints of ultrasound-guided needle interventions is identifying and distinguishing the needle tip from needle shaft in the image. Augmented reality (AR) environments have been employed to address challenges surrounding surgical tool visualization, navigation, and positioning in many image-guided interventions. The motivation behind this work was to explore the feasibility and utility of such visualization techniques in anesthesiology to address some of the specific limitations of ultrasound-guided needle interventions. This thesis brings together the goals, guidelines, and best …

The Kinematic And Biomechanical Effects Of Bracing On The Rehabilitation Of The Lcl Injured Elbow, Sara M. Banayan

Electronic Thesis and Dissertation Repository

Lateral collateral ligament (LCL) injuries are often treated non-operatively or with surgical repair. If instability persists, hinged elbow orthoses (HEOs) are often recommended. However, these orthoses are designed as a straight hinge, which does not account for the native carrying angle of the elbow. A custom HEO was designed to adjust the orthosis valgus angulation to measure in vitro elbow kinematics and biomechanics. An in vitro study investigated the effect of HEO valgus angulation during simulated active and passive flexion, in the vertical dependent and varus positions, with the forearm pronated and supinated. In the vertical dependent position, the orthosis …

Development Of Force-Space Navigation For Surgical Robotics, Corey Daniel Smith

Electronic Thesis and Dissertation Repository

Surgical robotics have been used for many years in orthopaedic procedures in the hip and knee. Robots tend to offer high accuracy and repeatability but add increased cost, complexity, time, and workflow disruption. This work outlines the design and development of a surgical robot that navigates using force feedback. Flexible components tether the patient to the robot and reaction loads are measured allowing the robot to “feel” its way around the pre-operative plan. Differences calculated between measured and desired loads are converted to Cartesian corrections that the robot used to navigate. The robot was tested first using simple square paths …

Embedded Smart-Polymer Sensor Arrays For Elucidating Load Distributions In Orthopaedic Implants, Carolina Micolini

Electronic Thesis and Dissertation Repository

The long-term outcomes of orthopaedic joint implants are only beginning to be understood, making it imperative to monitor the contact loads across the entire implant interface. This capability will elucidate the force transmission and distribution mechanisms exhibited by these implants in-service over time. This study explores the design and implementation of 3D-printed smart-polymer force sensor arrays, consisting of piezoresistive polyaniline (PANI) structures embedded within a polymeric parent phase. This unique multi-material additive manufacturing process was then employed to realize transducers embedded in the humeral component of a replacement prosthetic device conventionally used to restore the functionality of the shoulder joint. …

Optical Fibre-Based Force Sensing Needle Driver For Minimally Invasive Surgery, Pouya Soltani Zarrin

Electronic Thesis and Dissertation Repository

Minimally invasive surgery has been limited from its inception by insufficient haptic feedback to surgeons. The loss of haptic information threatens patients safety and results in longer operation times. To address this problem, various force sensing systems have been developed to provide information about tool–tissue interaction forces. However, the provided results for axial and grasping forces have been inaccurate in most of these studies due to considerable amount of error and uncertainty in their force acquisition method. Furthermore, sterilizability of the sensorized instruments plays a pivotal role in accurate measurement of forces inside a patient's body. Therefore, the objective of …

Design, Implementation And Control Of A Robotic Platform For Post-Stroke Upper- And Lower-Limb Rehabilitation, Vahid Mehrabi

Electronic Thesis and Dissertation Repository

Stroke is the primary cause of permanent disabilities worldwide. Hemiparesis and hemiplegia (the most common consequences of stroke) are the decreases in motor-functionality of the brain on one side of the body which will affect the daily life activities of the patient. There are several challenges with the current state of delivering rehabilitation services such as limitations on the number of the clinics, financial resources needed for providing rehabilitation, associated costs of transportation, and human resources. To overcome the issues related to conventional ways of delivering therapy, different robotic systems have been developed to benefit healthcare systems and patient with …

A 3d Us Guidance System For Permanent Breast Seed Implantation: Development And Validation, Justin Michael

Electronic Thesis and Dissertation Repository

Permanent breast seed implantation (PBSI) is a promising breast radiotherapy technique that suffers from operator dependence. We propose and have developed an intraoperative 3D ultrasound (US) guidance system for PBSI.

A tracking arm mounted to a 3D US scanner registers a needle template to the image. Images were validated for linear and volumetric accuracy, and image quality in a volunteer. The tracking arm was calibrated, and the 3D image registered to the scanner. Tracked and imaged needle positions were compared to assess accuracy and a patient-specific phantom procedure guided with the system.

Median/mean linear and volumetric error was ±1.1% and …

Design And Evaluation Of Neurosurgical Training Simulator, Trinette L. Wright

Electronic Thesis and Dissertation Repository

Surgical simulators are becoming more important in surgical training. Consumer smartphone technology has improved to allow deployment of VR applications and are now being targeted for medical training simulators. A surgical simulator has been designed using a smartphone, Google cardboard 3D glasses, and the Leap Motion (LM) hand controller. Two expert and 16 novice users were tasked with completing the same pointing tasks using both the LM and the medical simulator NeuroTouch. The novice users had an accuracy of 0.2717 bits (SD 0.3899) and the experts had an accuracy of 0.0925 bits (SD 0.1210) while using the NeuroTouch. Novices and …

Development Of An Active Finger Motion Simulator: With In-Vitro Assessments Of Tendon Loads And Joint Kinematics, Mohammad Haddara

Electronic Thesis and Dissertation Repository

Musculoskeletal injuries of the finger far outnumber those of other joints, and while in-vitro motion simulators are useful for studying joint biomechanics and evaluating surgical repairs, considerably less simulator development has been reported for the finger compared to other joints. Replication of active musculoskeletal movement during in-vitro testing has been shown to be more representative of in-vivo motion patterns, and closed-loop motion controllers are the current state-of-the-art for in-vitro kinematics studies. However, an in-vitro motion simulator with closed-loop tendon load control and simultaneous tendon excursion control has not yet been reported for the finger. This thesis outlines the design and …

Functional Design And Analysis Of A Linked Shoulder Prosthesis, Emily West

Electronic Thesis and Dissertation Repository

Persistent shoulder instability following joint arthroplasty remains a concern with mixed outcomes following clinical and surgical intervention. Thus, a linked universal joint implant was developed and functionally analyzed. A virtual model of the linked implant was developed and implanted in a 3D bony specimen to measure the available circumduction range of motion. Stresses in the implant were estimated using finite element analysis based on joint loads during activities of daily life. The glenoid fixation stress was evaluated using finite element analysis.

The implant was capable of restoring normal range of motion, and withstanding expected joint loads without yield or fatigue …

Force Sensing Surgical Grasper With Folding Capacitive Sensor, Dave Bp Tripp

Electronic Thesis and Dissertation Repository

Minimally-invasive surgery (MIS) has brought many benefits to the operating room, however, MIS procedures result in an absence of force feedback, and surgeons cannot as accurately feel the tissue they are working on, or the forces that they are applying. One of the barriers to introducing MIS instruments with force feedback systems is the high cost of manufacturing and assembly. Instruments must also be sterilized before every use, a process that can destroy embedded sensing systems. An instrument that can be disposed of after a single use and produced in bulk at a low cost is desirable. Printed circuit micro-electro-mechanical …

Real-Time Membrane Puncture Detection Using Force Sensors For Micro-Injections In Phantoms, Szymon Kowal

Electronic Thesis and Dissertation Repository

Micro-manipulators provide tools for researchers to improve workflow in common preclinical and clinical applications. Following drug delivery injections where drugs did not reach their target will squander research time, experimental animals and other resources. An ultrasound-guided robot developed at Robarts Research Institute was revised to implement closed-loop force feedback to compensate for tissue deformation during micro-interventions. Force sensors can detect puncture events as the needle penetrates tissue membranes, thereby reducing damage to surrounding tissues by preventing the needle from overshooting its target. Changing the angle of injection determined that the range of detectable forces during injections into tissue-mimicking phantoms suggests …

Assessment Of The Non-Linear Stress-Strain Characteristics Of Poly (Vinyl Alcohol) Cryogel, Mojdeh Zakeri

Electronic Thesis and Dissertation Repository

Creation of tissue-mimicking constructs is of great importance in the field of biomedical engineering. Poly (vinyl Alcohol) (PVA) is a biomaterial capable of simulating a wide range of geometries and mechanical properties of biological tissues. It is nontoxic, biocompatible, and easy to produce. PVA can be physically crosslinked by repeated cycles of freezing and thawing. The final product of this process is called PVA cryogel (PVA-C). The mechanical properties of PVA-C can be accurately controlled by changing PVA molecular weight, PVA concentration, and number and duration of freeze/thaw cycles (FTC). In this study, the stress-strain behavior of PVA cryogel was …

Design Of Radio-Frequency Arrays For Ultra-High Field Mri, Ian R O Connell

Electronic Thesis and Dissertation Repository

Magnetic Resonance Imaging (MRI) is an indispensable, non-invasive diagnostic tool for the assessment of disease and function. As an investigational device, MRI has found routine use in both basic science research and medicine for both human and non-human subjects.

Due to the potential increase in spatial resolution, signal-to-noise ratio (SNR), and the ability to exploit novel tissue contrasts, the main magnetic field strength of human MRI scanners has steadily increased since inception. Beginning in the early 1980’s, 0.15 T human MRI scanners have steadily risen in main magnetic field strength with ultra-high field (UHF) 8 T MRI systems deemed to …

The Role Of Scapular Morphology In Reverse Shoulder Arthroplasty, Ashish Gupta

Electronic Thesis and Dissertation Repository

Baseplate fixation in a reverse shoulder arthroplasty depends on adequate bone stock. In cases of severe glenoid bone loss and revision shoulder arthroplasty, deficiency of the glenoid vault compels the surgeon to attain screw fixation in the three columns of the scapula. The relationship of these columns demonstrated that the coracoid is closer to the lateral scapular pillar in females than in males. Significant gender dimorphism exists between the orientations of the three columns. The gender dimorphism is further evaluated by anthropometric measurements of the scapular body and the glenoid. The clinical significance lies in the ability to reconstruct the …

Miniature Implantable Telemetry System For Pressure-Volume Cardiac Monitoring, Kyle G. Fricke

Electronic Thesis and Dissertation Repository

Safety Pharmacology is becoming an increasingly important field to pharmaceutical companies in order to determine if medical treatments (drugs) are safe for use in human subjects. In the pre-clinical phase, test models, most commonly small rodents, undergo various gene alterations to affect, for example, their cardiovascular system in order to emulate human diseases. Pharmaceutical companies rely on these models to determine the drug efficacy and to ensure minimal side effects and safety for human subjects. Currently, no fully implantable left-ventricle pressure--volume (PV) telemetry systems have been implemented for Safety Pharmacology assessment applications. A fully implantable PV telemetry system would not …

Low Frequency Bio-Electrical Impedance Mammography And Dielectric Measurement, Seyyed Hesabgar

Electronic Thesis and Dissertation Repository

Assessment of electrical impedance of biological tissues at low frequencies offers a great potential for a safe, simple, and low-cost medical breast imaging techniques such as mammography. As such, in this dissertation a mammography method which uses tissue electrical impedance to detect breast malignancies was developed. The dissertation also introduces a new technique for measuring the dielectric properties of biological tissues at low frequencies. The impedance mammography technique introduced in this study is founded on the assumption that dielectric values of breast malignancies are significantly higher than the dielectric values of normal breast tissues. While previous studies have shown that …

Neurosurgical Ultrasound Pose Estimation Using Image-Based Registration And Sensor Fusion - A Feasibility Study, Utsav Pardasani

Electronic Thesis and Dissertation Repository

Modern neurosurgical procedures often rely on computer-assisted real-time guidance using multiple medical imaging modalities. State-of-the-art commercial products enable the fusion of pre-operative with intra-operative images (e.g., magnetic resonance [MR] with ultrasound [US] images), as well as the on-screen visualization of procedures in progress. In so doing, US images can be employed as a template to which pre-operative images can be registered, to correct for anatomical changes, to provide live-image feedback, and consequently to improve confidence when making resection margin decisions near eloquent regions during tumour surgery.

In spite of the potential for tracked ultrasound to improve many neurosurgical procedures, it …