Medical Specialties Commons^™

Ring And Peg Simulation For Minimally Invasive Surgical Robot, Evan Brown

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Surgical procedures utilizing minimally invasive laparoscopic techniques have shown less complications, better cosmetic results, and less time in the hospital than conventional surgery. These advantages are partially offset by inherent difficulties of the procedures which include an inverted control scheme, instrument clashing, and loss of triangulation. Surgical robots have been designed to overcome the limitations, the Da Vinci being the most widely used. A dexterous in vivo, two-armed robot, designed to enter an insufflated abdomen with a limited insertion profile and expand to perform a variety of operations, has been created as a less expensive, versatile alternative to the Da …

Ureteral Tunnel Length Versus Ureteral Orifice Configuration In The Determination Of Ureterovesical Junction Competence: A Computer Simulation Model, Carlos A. Villanueva, J. Tong, Carl A. Nelson, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Introduction The long-held belief that a ureteral re-implant tunnel should be five times the diameter of the ureter, as proposed by Paquin in 1959, ignores the effect of the orifice on the occurrence of reflux. In 1969, Lyon proposed that the shape of the ureteral orifice (UO) is more important than the intravesical tunnel. However, both theories missed quantitative evidence from principles of physics. The goal of the current study was to test Lyon’s theory through numerical models (i.e. to quantify the sensitivity of ureterovesical junction (UVJ) competence to intravesical tunnel length and to the UO).

Materials and methods The …

Tissue Stresses In Stented Coronary Arteries With Different Geometries: Effect Of The Relation Between Stent Length And Lesion Length, Xiang Shen, Song Ji, Yong-Quan Deng, Hong-Fei Zhu, Jia-Bao Jiang, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

In-stent restenosis after stent deployment remains an obstruction in the long-term benefits of stenting. This study sought to investigate the influence of the relation between stent length and lesion length on the mechanics of the arterial wall with different geometries, including straight and tapered vessels. Results showed that when the length of the stent was longer than the lesion length, the maximum stress in plaque and vessel increased as the length of stent increased. When the length of the stent was shorter than the lesion length, the vessel stress induced by stent inflation was lower; both ends of the stenosis …

Diffusion Modeling And Device Development For Peritoneal Membrane Oxygenation, Liana Hatoum

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Acute respiratory distress syndrome (ARDS) is a pulmonary disease that causes hypoxemia and respiratory failure. The mortality rate for ARDS ranges between 27% and 45%. Current treatments including mechanical ventilation and extracorporeal membrane oxygenation (ECMO) are often associated with high risk complications including barotrauma, infection, thrombosis, and hemorrhage. Alternative pulmonary support techniques are needed to improve the survival rate of patients suffering from ARDS. Previous studies introducing pure O₂ gas, perfluorocarbons and red blood cells into the intraperitoneal (IP) cavity have reported no effect or only a mild increase in oxygenation. Here we report peritoneal membrane oxygenation (PMO) using …

Exploring Oculomotor Trends In Collegiate Athletes, Brett Whorley, Julie A. Honaker

UCARE Research Products

Collaborative efforts to improve athlete safety without significantly hindering the rules of the games aim to develop a novel system to better measure and diagnose concussions. Provided that common signs of concussions include blurred vision, distant gaze, and dizziness, the Dizziness and Balance Disorders Lab at UNL believes that the simple oculomotor exam studied in this project may be applied to this procedure. Within the broader goal to better understand the causes, signs, symptoms, and prognosis of concussions, researchers desired to further investigate the results of this oculomotor test. The aim was to identify and interpret correlations between collegiate athlete …

Background Differences In Baseline And Stimulated Mmp Levels Influence Abdominal Aortic Aneurysm Susceptibility, Matthew A. Dale, Melissa K. Suh, Shijia Zhao, Trevor Meisinger, Linxia Gu, Vicki J. Swier, Devendra K. Agrawal, Timothy Greiner, Jeffrey S. Carson, B. Timothy Baxter, Wanfen Xiong

Department of Mechanical and Materials Engineering: Faculty Publications

Objective: Evidence has demonstrated profound influence of genetic background on cardiovascular phenotypes. Murine models in Marfan syndrome (MFS) have shown that genetic background-related variations affect thoracic aortic aneurysm formation, rupture, and lifespan of mice. MFS mice with C57Bl/6 genetic background are less susceptible to aneurysm formation compared to the 129/SvEv genetic background. In this study, we hypothesize that susceptibility to abdominal aortic aneurysm (AAA) will be increased in 129/SvEv mice versus C57Bl/6 mice. We tested this hypothesis by assessing differences in aneurysm size, tissue properties, immune response, and MMP expression.

Methods: Mice of C57Bl/6 or 129/SvEv background underwent AAA induction …

Feasibility Of Using Raman-Based Techniques For Breast Cancer Detection, Sara Mollamohammada

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Breast cancer is one of the common types of cancer among women all over the world. Early diagnosis is an effective way that improve the treatment process and gives the patients a better chance of survival. Many of the patients infected by breast cancer choose breast conservation surgery (BCS). However, some of those will be subjected to mastectomy, and many will have tumor recurrence as there is no precise technique to show the tumor margins. Raman-based methods are powerful techniques with potential to rapidly differentiate normal from tumor tissues and provides a solution to detect tumor margin. This is because …

A Sensorless Haptic Interface For Robotic Minimally Invasive Surgery, Baoliang Zhao

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Robotic minimally invasive surgery (R-MIS) has gained in popularity due to its advantages of improving the accuracy and dexterity of surgical interventions while minimizing trauma to the patient. However, because of the loss of direct contact with the surgical site, the surgeon cannot perceive tactile information, which may adversely affect surgical efficiency and/or efficacy. The lack of haptic feedback is regarded as a limiting factor in existing R-MIS technology.

To solve this problem, researchers have incorporated force sensors on the surgical tools to measure the tool-tissue interaction forces, and reproduce these forces at the surgeon console. However, the employment of …

Implementation And Validation Of Aortic Remodeling In Hypertensive Rats, Shijia Zhao, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

A computational framework was implemented and validated to better understand the hypertensive artery remodeling in both geometric dimensions and material properties. Integrating the stress-modulated remodeling equations into commercial finite element codes allows a better control and visualization of local mechanical parameters. Both arterial thickening and stiffening effects were captured and visualized. An adaptive material remodeling strategy combined with the element birth and death techniques for the geometrical growth were implemented. The numerically predicted remodeling results in terms of the wall thickness, inner diameter, and the ratio of elastin to collagen content of the artery were compared with and fine-tuned by …

Design And Development Of A Miniature In Vivo Surgical Robot With Distributed Motor Control For Laparoendoscopic Single-Site Surgery, Eric J. Markvicka

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Paradigm shifts in invasiveness, recovery time, cosmesis, and cost have been seen within the field of general surgery through major advances in surgical technology. Some of the most advanced types of general surgery now include Minimally Invasive Surgery (MIS), LaparoEndoscopic Single-Site (LESS) surgery, and Natural Orifice Translumenal Endoscopic Surgery (NOTES). One of the newest and rapidly developing catalysts is robotic platforms. Such platforms have improved ergonomics and control, increased workspace and dexterity, and have surpassed the efficacy of many non-robotic platforms such as traditional laparoscopic surgical tools. This thesis presents the design and development of a four-degree-of-freedom (4- DOF) miniature …

Towards Highly-Integrated Stereovideoscopy For In Vivo Surgical Robots, Jay Carlson

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

When compared to traditional surgery, laparoscopic procedures result in better patient outcomes: shorter recovery, reduced post-operative pain, and less trauma to incisioned tissue. Unfortunately, laparoscopic procedures require specialized training for surgeons, as these minimally-invasive procedures provide an operating environment that has limited dexterity and limited vision. Advanced surgical robotics platforms can make minimally-invasive techniques safer and easier for the surgeon to complete successfully. The most common type of surgical robotics platforms -- the laparoscopic robots -- accomplish this with multi-degree-of-freedom manipulators that are capable of a diversified set of movements when compared to traditional laparoscopic instruments. Also, these laparoscopic robots …

Production Of Recombinant Human Coagulation Factor Ix By Transgenic Pig, Weijie Xu

Department of Chemical and Biomolecular Engineering: Theses and Student Research

Hemophilia B is the congenital bleeding disorder caused by deficiency in functional coagulation factor IX (FIX) and about 28,000 patients worldwide in 2012. And current treatment is restricted to protein-replacement therapy, which required FIX concentrates for patients’ life-time. Approximately 1 billion units FIX were consumed in 2012. However, still about 70-80% patients, mostly in developing countries, received inadequate or no treatment because of the unavailable and/or unaffordable FIX concentrates. Considering safety reasons, e.g. transmission of blood-borne diseases, the recombinant human FIX (rFIX) is recommended other than the plasma-derived FIX. However, only one rFIX is currently available on the market. The …

Head Impact Exposure In Male And Female Collegiate Ice Hockey Players, Bethany J. Wilcox, Jonathan G. Beckwith, Richard M. Greenwald, Jeffrey J. Chu, Thomas W. Mcallister, Laura A. Flashman, Arthur C. Maerlender, Ann-Christine Duhaime, Joseph J. Crisco

Department of Psychology: Faculty Publications

The purpose of this study was to quantify head impact exposure (frequency, location and magnitude of head impacts) for individual male and female collegiate ice hockey players and to investigate differences in exposure by sex, player position, session type, and team. Ninety-nine (41 male, 58 female) players were enrolled and 37,411 impacts were recorded over three seasons. Frequency of impacts varied significantly by sex (males: 287 per season, females: 170, p < 0.001) and helmet impact location (p < 0.001) but not by player position (p = 0.088). Head impact frequency also varied by session type; both male and female players sustained more impacts in games than in practices (p < 0.001), however the magnitude of impacts did not differ between session types. There was no difference in 95th percentile peak linear acceleration between sexes (males: 41.6 g, females: 40.8 g), but 95th percentile peak rotational acceleration and HITsp (a composite severity measure) were greater for males than females (4424, 3409 rad/s2, and 25.6, 22.3, respectively). Impacts to the back of the helmet resulted in the greatest 95th percentile peak linear accelerations for males (45.2 g) and females (50.4 g), while impacts to the side and back of the head were associated with the greatest 95th percentile peak rotational accelerations (males: 4719, 4256 rad/sec², females: 3567, 3784 rad/sec², respectively). It has been proposed that reducing an individual’s head impact exposure is a practical approach for reducing the risk of …

On The Importance Of Modeling Stent Procedure For Predicting Arterial Mechanics, Shijia Zhao, Linxia Gu, Stacey R. Froemming

Department of Mechanical and Materials Engineering: Faculty Publications

The stent-artery interactions have been increasingly studied using the finite element method for better understanding of the biomechanical environment changes on the artery and its implications. However, the deployment of balloon-expandable stents was generally simplified without considering the balloon-stent interactions, the initial crimping process of the stent, its overexpansion routinely used in the clinical practice, or its recoil process. In this work, the stenting procedure was mimicked by incorporating all the above-mentioned simplifications. The impact of various simplifications on the stent-induced arterial stresses was systematically investigated. The plastic strain history of stent and its resulted geometrical variations, as well as …

Improving Health Care Quality And Safety: The Development And Assessment Of Laparoscopic Surgery Instrumentation, Practices And Procedures, Bernadette Mccrory

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Adverse events due to medical errors are a leading cause of death in the United States exceeding the mortality rates of motor vehicle accidents, breast cancer and AIDS. Improvements can and should be made to reduce the rates of preventable surgical errors since they account for nearly half of all adverse events within hospitals. Although minimally invasive surgery has proven patient benefits such as reduced postoperative pain and hospital stay, its operative environment imposes substantial physical and cognitive strain on the surgeon increasing the risk of error. In order to mitigate errors and protect patients, a multidisciplinary approach was taken …