Traditional laparoscopic surgery continues to require significant training on the part of the surgeon before entering the operating room. Augmented Reality (AR) has been investigated for use in visual guidance in training and during surgery, but little work is available investigating the effectiveness of AR techniques in providing the user better awareness of depth and space. In this work we propose several 2D AR overlays for visual guidance in training for laparoscopic surgery, with the goal of aiding the user's perception of depth and space in that limiting environment. A pilot study of 30 subjects (22 male and 8 female) was performed with results showing the effect of the various overlays on subject performance of a path following task in the Computer Assisted Surgical Trainer (CAST-III) system developed in the Model Based Design Lab. Deviation, economy of movement, and completion time are considered as metrics. Providing a reference indicator for the nearest point on the optimal path is found to result in significant reduction (p < 0.05) in subject deviation from the path. The data also indicates a reduction in subject deviation along the depth axis and total path length with overlays designed to provide depth information. Avenues for further investigation are presented.

Background: Right ventricular failure is a serious complication after left ventricular assist device placement. Case Presentation: A 70-year-old male in decompensated heart failure with right ventricular failure after the placement of a left ventricular assist device. A single dual-lumen PROTEKDuo cannula was inserted percutaneously via the internal jugular vein to draw blood from the right atrium and return into the pulmonary artery using the CentriMag system, by passing the failing ventricle. The patient was successfully weaned from right ventricular assist device. Conclusions: In comparison to two-cannula conventional procedures, this right ventrivular assist device system improves patient rehabilitation and minimizes blood loss and risk of infection, while shortening procedure time and improving clinical outcomes in right ventricular failure.

Cryosurgery is the destruction of undesired biological tissues by freezing. Modern cryosurgery is frequently performed as a minimally-invasive procedure, where multiple hypodermic, needle-shaped cryoprobes are inserted into the target area to be treated. The aim of the cryosurgeon is to maximize cryoinjury within a target region, while minimizing damage to healthy surrounding tissues. There is an undisputed need for temperature-field reconstruction during minimally invasive cryosurgery to help the cryosurgeon achieve this aim. The work presented in this thesis is a part of ongoing project at the Biothermal Technology Laboratory (BTTL), to develop hardware and software tools to accomplish real-time temperature field reconstruction. The goal in this project is two-fold: (i) to develop the hardware necessary for miniature, wireless, implantable temperature sensors, and (ii) to develop mathematical techniques for temperature-field reconstruction in real time, which is the focus of the work presented in this thesis. To accomplish this goal, this study proposes a computational approach for real-time temperature-field reconstruction, combining data obtained from various sensing modalities such as medical imaging, cryoprobe-embedded sensors, and miniature, wireless, implantable sensors. In practice, the proposed approach aims at solving the inverse bioheat transfer problem during cryosurgery, where spatially distributed input data is used to reconstruct the temperature field. Three numerical methods have been developed and are evaluated in the scope of this thesis. The first is based on a quasi-steady approximation of the transient temperature field, which has been termed Temperature Field Reconstruction Method (TFRM). The second method is based on analogy between the fields of temperature and electrical potential, and is thus termed Potential Field Analogy Method (PFAM). The third method is essentially a hybrid of TFRM and PFAM, which has shown superior results. Each of these methods has been benchmarked against a full-scale finite elements analysis using the commercial code ANSYS. Benchmarking results display an average mismatch of less than 2 mm in 2D cases and less than 3 mm in 3D cases for the location of the clinically significance isotherms of -22°C and -45°C. In an advanced stage of numerical methods evaluation, they have been validated against experimental data, previously obtained at the BTTL. Those experiments were conducted on a gelatin solution, using proprietary liquid-nitrogen cryoprobes and a cryoheater to simulate urethral warming. The design of the experiment was aimed at creating a 2D heat-transfer problem. Validation results against experimental data suggest an average mismatch of less than 2 mm, for the hybrid of TFRM + PFAM method, which is of the order of uncertainty in estimating the freezing front location based on ultrasound imaging.

Quitosana é um biopolímero natural obtido a partir da desacetilação de quitina. Embora a quitosana já seja utilizada na Odontologia, seu papel sobre o substrato dentinário de dentes decíduos não está bem elucidado. Portanto, o objetivo do presente estudo foi avaliar o papel da incorporação do gel de quitosana a 2,5 % na dentina de dentes decíduos afetada por lesão de cárie. Dentes decíduos extraídos foram coletados e submetidos à indução de lesão de cárie artificial. Após teste de microdureza inicial (n=28), os dentes foram estratificados para receber gel de quitosana a 2,5%. A superfície dentinária hígida (n=3), dentina desmineralizada (n=3) e dentina biomodificada com gel de quitosana a 2,5% (n=3) foram submetidas à Espectroscopia de Energia Dispersiva de Raio-X (EDS) e Microscopia Eletrônica de Varredura (MEV). O teste de microdureza também foi realizado após a indução de lesão de cárie artificial e após a biomodificação da dentina. Os dados foram avaliados usando o teste paramétrico one-way ANOVA para medidas repetidas. A análise dos dados para EDS foi efetuada por meio de teste não paramétrico de Kruskal-Wallis seguido pelo ajuste dos valores de significância pela correção de Bonferroni para múltiplos testes, bem como por meio de estatística descritiva dos dados obtidos através da fórmula: Variável de estudo controle/ controle × 100. A biomodificação da dentina não alterou a microdureza da superfície dentinária (p=0,339). A porcentagem atômica de cálcio revelou diferenças estatisticamente significantes antre a dentina hígida e biomodificada com quitosana (p<0.022), assim como a porcentagem atômica de fósforo que se mostrou superior no grupo que sofreu a biomodificação. A MEV revelou um expressivo número de túbulos dentinários obliterados, porém com maior diâmetro. As imagens topográficas revelaram, ainda, uma superfície lisa e regular após a biomodificação. Embora a aplicação do gel de quitosana a 2,5% na dentina parcialmente desmineralizada em dentes decíduos não foi capaz de aumentar o valor de microdureza, a biomodificação gerou uma superfície dentinária apropriada para procedimentos restauradores adesivos / Chitosan is a natural biopolymer obtained from chitin deacetylation. Although chitosan is already used in dentistry, this role on the primary teeth dentin substrate is not well elucidated. So, the aim to this study was to evaluate the role of the 2.5% chitosan gel incorporation in primary caries-affected dentin teeth. Extracted primary teeth were collected and submitted to artificial caries induction. Teeth were stratified to receive 2.5% chitosan gel after dentin microhardness initial test (n= 28). Healthy dentin (n=3), demineralized dentin (n=3) and biomodified dentin with 2.5% chitosan gel (n=3) were submitted to Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM). Microhardness Test was performed too after artificial caries induction and after dentin biomodification. Data were evaluated using one-way ANOVA repeated measures parametric test. Data analysis for EDS was performed using non-parametric Kruskal-Wallis test followed by adjustment of significance values by Bonferroni correction for multiple tests, as well as by means of descriptive statistics of the data obtained using the formula: Study variable control/control × 100. Dentin biomodification did not alter the subsurface microhardness of dentin (p=0,339). The calcium atomic percentage showed statistically significant differences between healthy and biomodificated dentin (p<0.022) and too presented superior phosphorus atomic percentage. SEM revealed expressive number of dentinal tubules obliterated, but a larger diameter. Topographic images revealed a smooth and regular surface in biomodified dentin. Although 2.5% chitosan gel application on partially demineralized dentin in primary teeth was not able to increase microhardness, the biomodification generated an appropriate dentin surface for adhesive restorative procedures

"This thesis presents a single-slice based fast stereotactic registration and tracking technique along with a corresponding modular system for guiding robotic mechanism or interventional instrument to perform needle-based interventions under live MRI guidance. The system can provide tracking of full 6 degree-of-freedom (DOF) in stereotactic interventional surgery based upon a single, rapidly acquired cross-sectional image. The whole system is constructed with a modular data transmission software framework and mechanical structure so that it supports remote supervision and manipulation between a 3D Matlab tracking user interface (UI) and an existing MRI robot controller by using the OpenIGTLink network communication protocol. It provides better closed-loop control by implementing a feedback output interface to the MRI-guided robot. A new compact fiducial frame design is presented, and the fiducial is wrapped with a passive resonant coil. The coil resonates at the Larmor frequency for 3T MRI to enhance signal strength and enable for rapid imaging. The fiducial can be attached near the distal end of the robot and coaxially with a needle so as to visualize target tissue and track the surgical tool synchronously. The MRI-compatible design of fiducial frame, robust tracking algorithm and modular interface allow this tracking system to be conveniently used on different robots or devices and in different size of MRI bores. Several iterations of the tracking fiducial and passive resonant coils were constructed and evaluated in a Phillips Achieva 3T MRI. To assess accuracy and robustness of the tracking algorithm, 25 groups of images with different poses were successively scanned along specific sequence in and MRI experiment. The translational RMS error along depth is 0.271mm with standard deviation of 0.277mm for totally 100 samples. The overall angular RMS error is less than 0.426 degree with standard deviation of 0.526 degree for totally 150 samples. The passive resonant coils were shown to significantly increase signal intensity in the fiducial relative to the surroundings and provide for rapid imaging with low flip angles. "

" Sample cutting is an important minimally invasive medical procedure. Currently there are several types of medical devices used to cut a distal biological sample, for example, a video endoscope and TurboHawk Plaque Excision Systems. Directional Atherectomy (DA) with the TurboHawk Plaque Excision Systems is a catheter-based, minimally invasive treatment method for peripheral arterial disease (PAD). During a procedure, a catheter is directed toward an area of plaque buildup to remove the plaque from the body, restoring blood flow (Covidien, 2013). Endoscopy is an important procedure used in the medical field to study and diagnose different parts of a body without the need to undergo a major surgery. The major devices are a video endoscope with a flexible or rigid insertion tube and endoscopic therapy devices. Arrays of the devices, through the instrument channel in the insertion tube of endoscopes, to perform a variety of functions are offered. The biological sample cut is one of the important endoscopic therapies. Both of Directional Atherectomy and endoscopy procedures require a power transmission from the proximal tip of device to the distal end, where the cutter is located, for cutting a sample. However, the working length is up to meters, and the diameter of the devices is in millimeter scale in the minimally invasive surgery. Thus enough power transmitting to the distal end of the device for the biological sample cutting is crucial. This research presents the effort toward the investigation of the potential power mechanisms from the proximal tip to the cutter at the distal end of the device for rapid rotational cutting motion to improve the cutting efficiency and accuracy. In this thesis, the potential powering mechanisms including fluid, electrical, and torque coils are investigated. Since the transmission power is used for a rotational cutting action, and the cutting geometry has influence on the cutting power, thus this research also focuses on the analysis of the cutting geometry for the rotational sample cutting. The Hertz contact theory and von Mises yield criterion are used to find the influence of tool geometry on the material removing process, as well as Abaqus, a commercial FEM software, is used for the finite element analysis. Fiber-reinforced composite structures are the main characteristic of the representative biological sample, and their mechanical behavior is strongly influenced by the concentration and structural arrangement of constitute such as collagen and elastin. Researches show that the biological sample, for example, a soft biological sample, has hyperelastic properties and behave anisotropically, and there are a few publications about the plastic properties and cutting mechanics. Thus a linear elastic and linear plastic material model is defined for the finite element analysis of material removal. The analytical results and finite element results both show that as the tool rake angle increases or the tool angle decreases, the magnitude of cutting force decreases. A preliminary representative sample cutting experiment was conducted, and standard cutters with different cutting geometries were tested in order to find the characteristic of the biological sample cutting and the influence of tool geometry on the required cutting power. The experiments reveal the same conclusions as the analytical and finite element results. "

abstract: Minimally invasive surgery is a surgical technique that is known for its reduced patient recovery time. It is a surgical procedure done by using long reached tools and an endoscopic camera to operate on the body though small incisions made near the point of operation while viewing the live camera feed on a nearby display screen. Multiple camera views are used in various industries such as surveillance and professional gaming to allow users a spatial awareness advantage as to what is happening in the 3D space that is presented to them on 2D displays. The concept has not effectively broken into the medical industry yet. This thesis tests a multi-view camera system in which three cameras are inserted into a laparoscopic surgical training box along with two surgical instruments, to determine the system impact on spatial cognition, perceived cognitive workload, and the overall time needed to complete the task, compared to one camera viewing the traditional set up. The task is a non-medical task and is one of five typically used to train surgeons’ motor skills when initially learning minimally invasive surgical procedures. The task is a peg transfer and will be conducted by 30 people who are randomly assigned to one of two conditions; one display and three displays. The results indicated that when three displays were present the overall time initially using them to complete a task was slower; the task was perceived to be completed more easily and with less strain; and participants had a slightly higher performance rate. / Dissertation/Thesis / Masters Thesis Human Systems Engineering 2019

Robot-assisted minimally invasive surgery is used to perform intricate surgical tasks through small incisions using long, slender instruments. The miniaturization of these instruments is advantageous to both surgeon and patient because smaller instruments reduce trauma to surrounding tissue, decrease patient recovery times, and can be used in confined spaces otherwise inaccessible using larger instruments. However, miniaturization of existing designs is limited by friction between moving parts, the volume occupied by the end effector, and manufacturing and assembly constraints. The objective of this work is to develop and analyze concepts that can be used in robot-assisted needlescopic surgery. The concepts are intended for instrument shafts no larger than 3 mm in diameter. An ideal concept is one with large ranges of wrist and gripping motion. Concepts should also minimize friction and swept volume while maintaining a focus on manufacturability and ease of assembly. Multiple concepts were generated and evaluated using a tree classification scheme, proof-of-concept prototypes, and simplified mathematical models. Three unique concepts were further developed and tested—the Split CORE Grips, the Inverted Flexure Grips, and the Crossed Cylinders Wrist. The two grip concepts are instruments that incorporate one rotational degree of freedom and one gripping degree of freedom. The wrist concept incorporates two rotational degrees of freedom and could be coupled with a single DOF grip mechanism to form a functional instrument. In addition to concept development, a variety of fabrication techniques were investigated to better understand the challenges that arise when designing and fabricating devices at the 3 mm scale. To augment existing techniques, a novel fabrication technique was developed which uses layers of lithographically patterned carbon nanotube (CNT) composite material to form a 3D part. This method was used to prototype some of the designs at a 1:1 size scale.

Minimally invasive aesthetic medicine (MIAM) is a relatively new field, which lacks a clearly defined scope of practice. The purpose of this project was to clarify the scope of practice for nurse practitioners in MIAM in California. Without a clearly defined scope of practice, nurse practitioners are unable to practice to the full extent of their license which causes them to be underutilized and face liability issues. This project sought to answer the question: What is the scope of practice of the nurse practitioner in MIAM in the state of California? The model of professional nursing practice regulation was the model used to guide this project. Sources of evidence included case law that has emerged since 1983; reviewing documents from 3 state boards of nursing; and a survey of nurse practitioners who practice in the field of MIAM. The evidence was analyzed noting themes while determining what the legal backbone is for nurse practitioner's scope of practice in California. This project found that nurse practitioners in this field keep up to date in their knowledge, educate their patients, utilize methods to maintain competency, feel support in their environment, assess and refer to others when appropriate, and teach both staff and patients evidence-based practices. It also found that standardized procedures are the legal backbone to understanding the scope of practice in California. A scope of practice was developed based on the findings of this project which was then reviewed by an expert. It is recommended that nurse practitioners utilize their resources to obtain and maintain knowledge as well as learn what the standardized procedures are in their facility. The implications for clarifying the scope of practice will serve this population to fully utilize their capabilities and practice safely, as well as help to develop this relatively new field.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 234-239).