published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed July 8, 2010). PDF text: xi, 200 p. : ill. (chiefly col.) ; 12 Mb. UMI publication number: AAT 3378560. Includes bibliographical references. Also available in microfilm and microfiche formats.

No description available.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed July 8, 2010). PDF text: xii, 156 p. : ill. (chiefly col.) ; 6 Mb. UMI publication number: AAT 3366042. Includes bibliographical references. Also available in microfilm and microfiche formats.

Surgical robotic systems and computer assisted surgery have revolutionized the delivery of surgical care by providing precision, accuracy and miniaturization of instrumentation unachievable with manual equipment and techniques. Despite advancements generated by these technologies, unmet challenges exist when working in the unstructured flexible environment of a surgical site. Current surgical robots are limited to preoperative surgical plans and minimal intraoperative sensory information due to inherent design limitations of these systems and lack of frameworks for utilization of real-time data. These limitations place restrictive burdens on surgeons for control with incomplete information on the robot, the surgical environment and their interaction. Acquisition and intelligent use of real-time intraoperative sensory information to augment current systems will result in a new generation of ``smart'' surgical robots that will enable surgeons to make strides in the complexity of techniques, precision, and overall capabilities of surgical procedures. These improvements will be made by adapting to the environment during teleoperation in order to make surgical slaves behave more reliably and safely. Improved intraoperative data integration will also allow autonomous performance of low level tasks, such as retraction, exploration of tissue margins, biopsy and suturing. This doctoral study seeks to advance methods and systems for addressing fundamental limitations of existing surgical robots by adding intraoperative intelligence based on mechanical sensory information. Interaction force data on the surgical slave unit can be acquired either through direct measurement by a dedicated force/torque sensor at the interaction site or indirect measurement of robot actuation forces. With interaction data, models of the environmental interaction can be constructed and novel control laws applied to modify the behavior of a robotic system to improve safety and surgical performance. In the first section of this dissertation, general algorithms for exploration and control in flexible environments are investigated for surgical robots with force sensing capabilities. Hybrid force-motion control and redundant coverage paths are described for exploration of the shape of a flexible environment. Based on localized excitation of tissue coupled with simultaneous force measurements, an algorithm for discrete tissue impedance estimates is presented and evaluated for adaptive exploration and segmentation of embedded features. The application of these algorithms for autonomous exploration and estimation are shown in flexible tissue models. In the second section of the dissertation, a framework for compliant motion control is presented for continuum surgical robots subject to unknown interactions with the environment. Through a mapping of unknown environmental interaction forces to a generalized description, joint level actuation force measurements serve as an input to a compliant motion controller that allows surgical slaves to actively comply with environmental forces. Un-modeled effects on the joint level forces are corrected via a feed-forward online estimate. Linear and non-linear regression techniques are evaluated for estimation and compensation of these model uncertainties. Conditions for the stability of the controller are defined and experimentally validated for complex multi-point robot-environmental interaction. Finally, the design and analysis of a novel telerobotic system is presented for minimally invasive surgery in deep surgical sites. The clinical requirements for a benchmark application in transurethral resection of bladder tumor and the design considerations for this system are described. Kinematic analysis of the dexterity at the surgical site and experimental evaluation of the manipulation capabilities of the system are presented in the context of representative clinical tasks. In summary, the algorithms and analysis presented in this dissertation constitute a methodology for collection and integration of sensory information toward the development and deployment of surgical robots with improved capabilities. The fundamental discoveries introduced will contribute to the development of a next generation of smart surgical robots that intelligently interact with the surgical environment leading to safer, faster, less invasive procedures with improved surgical outcomes.

Thesis (M.S.)--East Carolina University, 2009. / Presented to the faculty of the Department of Exercise and Sport Science. Advisor: Timothy P. Gavin. Title from PDF t.p. (viewed May 5, 2010). Includes bibliographical references.

No description available.

Radical prostatectomy is the main surgical treatment for prostate cancer and is associated with various short-term complications. Racial and ethnic minority patients have worse postoperative outcomes than White patients following prostate cancer surgery. One of the factors that may contribute to the racial differences in postoperative outcomes is the differential use of new medical technology of robot-assisted surgery (RAS) across racial and ethnic groups. Patients undergoing robot-assisted radical prostatectomy (RARP) have been shown to have reduced short-term complications, length of stay (LOS), and readmissions and comparable long-term survival compared with patients undergoing open radical prostatectomy (ORP). Previous studies demonstrated that racial and ethnic minority patients with prostate cancer were less likely to receive RARP than White patients. However, critical gaps remain in 1) understanding current evidence on racial and ethnic disparities related to RAS in pelvic cancer surgery thoroughly; 2) determining the impact of RARP on racial and ethnic disparities in postoperative outcomes among prostate cancer patients, and; 3) investigating the role of surgeons on the differential use of RARP across racial and ethnic groups. To address these gaps, this dissertation conducted a systematic review to comprehensively understand racial and ethnic disparities in the use of RAS in four major pelvic cancer treatments (prostate, uterine, bladder, and rectal cancers). Following the systematic review, empirical analyses were performed using linked New York State Cancer Registry and statewide discharge records to determine the contribution of RARP to racial and ethnic disparities in the short-term outcomes after prostate cancer surgery, including determining the presence and pattern of interaction between race/ethnicity and RARP use. Based on a multilevel framework, two important hypotheses were also tested to assess surgeons’ influence on the use of RARP across racial and ethnic groups through access to care and the process of care. The systematic review found consistent evidence that Black and Hispanic patients were less likely to receive RAS than White patients in all four pelvic cancer surgeries. There is a lack of formal assessment to determine the impact of RAS use on racial and ethnic disparities in postoperative outcomes. The systematic review also found that racial and ethnic minorities were less likely to receive treatment at RAS-performing or high-technology centers than White patients. But there is a paucity of research examining physician-level factors that may be related to differential use of RAS across racial and ethnic groups. The first empirical analysis detected a statistical interaction between race/ethnicity and procedure approach that was present on the additive scale but not on the multiplicative scale. Specifically, when undergoing RARP rather than ORP, non-Hispanic Black (NHB) and Hispanic men with prostate cancer, as compared to non-Hispanic White (NHW) men, experienced a greater reduction in the risk of adverse short-term outcomes of major events (NHB vs. NHW: RERI -0.32, 95% CI (-0.70,-0.01); Hispanic vs. NHW: RERI -0.28, 95% CI (-0.74,0.09)) and prolonged LOS (NHB vs. NHW: RERI -0.32, 95% CI (-0.70,-0.01); Hispanic vs. NHW: RERI -0.28, 95% CI(-0.74,0.09)) on the absolute risk (additive) scale. The second empirical analysis confirmed the two hypotheses related to surgeons’ role in the racial and ethnic disparities related to RARP use. First, NHB and Hispanic patients were more likely to be treated by surgeons who were low-RARP users (NHB vs. NHW: OR 1.73, 95% CI 1.58-1.90; Hispanic vs. NHW: OR 2.14, 95% CI 1.90-2.41) or by surgeons at non-RARP facilities (NHB vs. NHW: OR 4.26, 95% CI 3.45-5.27; Hispanic vs. NHW: OR 4.01, 95% CI 3.44-4.67) than NHW patients, supporting racial and ethnic disparities in access to care. Second, when treated by the same surgeon and having similar conditions, NHB and Hispanic patients were less likely to receive RARP than NHW patients (NHB vs. NHW: OR 0.73, 95% CI 0.59-0.91; Hispanic vs. NHW: OR 0.72, 95% CI 0.55-0.96), supporting racial and ethnic disparities in the process of care. In summary, this dissertation identified gaps in current literature and showed that NHB and Hispanic patients with prostate cancer were less likely to receive but benefitted more from RARP than NHW patients. Increasing equitable penetration of robot-assisted technology may help reduce racial disparities in patient outcomes after radical prostatectomy. This dissertation also revealed that NHB and Hispanic patients were less likely to be treated by high-RARP-use surgeons and less likely to receive RAPR when treated for similar conditions by the same surgeons than NHW patients. Addressing structural barriers faced by racial and ethnic minority patients during care-seeking and the process of care can help reduce disparities in RAS use.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Minimally Invasive Surgery (MIS) in human beings is performed by making small incisions in the abdominal region of the patient and inflating the abdominal cavity with CO2. This procedure enables the surgeon to manipulate long rigid surgical instruments inside the patient in order to perform the surgery. Unfortunately the current methods of insertion and assembly of MIS instruments limit the surgeon to only five (of a possible seven) Degrees of Freedom (DOF). Along with this, the surgeon’s movements are mirrored (called the Fulcrum effect) and scaled around the point of incision. Minimally invasive surgical robots attempt to alleviate these drawbacks by eliminating the Fulcrum effect, as well as improving dexterity and accuracy. These robots’ abilities to improve the surgeon’s hand-eye coordination, enables the surgeon to perform surgeries using their natural movements with reduced fatigue. As a result of this, the risk to both patient and surgeon is reduced. Existing MIS robotic systems are extremely expensive and large, and as a result they are not widely used. In this thesis a new, lower cost, seven DOF robotic manipulator is further developed. The thesis focuses on the external three DOF Secondary Slave Manipulator (SSM) and combines it with the Primary Slave Manipulator (PSM) that was developed by a previous Masters student. Tests done on the SSM showed that the manipulator has a minimum resolution of 0.7 ± 0.2 mm (mean ± standard deviation) on the shoulder joint’s yaw rotation and 0.5 ± 0.2 mm in pitch rotation. The linear actuator used for insertion has a minimum resolution of 0.2 ± 0.2 mm. A strength test was also conducted and showed that the manipulator is easily capable of producing a 10 N actuation force as required during Minimally Invasive Robotic Surgery (MIRS) procedures. In conclusion the complete system has potential as a viable alternative to the existing systems due to its accuracy and lower cost. Future work will include the development of a user interface and control system for the complete robot. / AFRIKAANSE OPSOMMING: Minimaal Indringende Chirurgie (MIC) op mense word uitgevoer deur klein insnydings in die pasiënt se buik te maak en dan die abdominale holte met CO2 te vul. Dit stel die chirurg in staat om lang, onbuigbare instrumente binne die pasiënt te manipuleer om sodoende die operasie uit te voer. Die manier waarop die MIC instrument ontwerp is en die pasiënt binnegaan, laat egter slegs vyf vryheidsgrade toe, terwyl die chirurg self sewe vryheidsgrade in sy handbewegings het. Verder veroorsaak hierdie instrumente ook dat die chirurg se aksies in spieëlbeeld vertolk word (Fulcrum effek) en geskaleer is. Chirurgiese robotika poog om hierdie nadele teen te werk deur die Fulcrum effek te verwyder, en ook om handvaardigheid en akkuraatheid te bevorder. Die robot se potensiaal om die chirurg se hand-oog koӧrdinasie te verbeter, maak dit moontlik vir die chirurg om op ’n meer natuurlike en gemaklike manier te werk te gaan en bring minder vermoeienis mee. Dit verminder die risiko’s vir beide die pasiënt en die chirurg. Bestaande robotiese stelsels is egter baie duur en groot, en word dus nie meer algemeen gebruik nie. In hierdie tesis word ‘n nuwe sewe-vryheidsgraad robotiese manipuleerder ontwikkel. Die tesis fokus op die eksterne drie-vryheidsgraad Sekondêre Slaaf Manipuleerder (SSM) en kombineer dit met die Primêre Slaaf Manipuleerder (PSM) wat deur ʼn vorige Meestersstudent ontwikkel is. Toetse wat uitgevoer is op die SSM het getoon dat dit ’n minimum resolusie van 0.7 ± 0.2 mm (gemiddeld ± standaard afwyking) op die skouer se afwyking en 0.5 ± 0.2 mm om die onderskeie skouer aslyne toon. Die linieêre aktueerder wat vir inlassing gebruik word het ’n minimum resolusie van 0.2 ± 0.2 mm. ’n Sterktetoets is uitgevoer en het getoon dat die manipuleerder maklik die nodige 10 N krag soos benodig in Minimaal Indringende Robotiese Chirurgie (MIRC) prosedures kan lewer. Ter afsluiting, die volledige stelsel het die potensiaal as lewensvatbare alternatief tot die bestaande stelsels vanweë die akkuraatheid en laer koste verbonde. Toekomstige navorsing kan moontlik die ontwikkeling van ʼn gebruikerkoppelvlak en beheerstelsel vir die volledige robot insluit.

Qi, Lin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.