Medicine and Health Sciences Commons^™

Microvascular Responsiveness To Cardiopulmonary Bypass, Michael O'Neil

Electronic Thesis and Dissertation Repository

Cardiopulmonary bypass can result in multiple organ failure due to mechanisms of ischemia reperfusion injury and the systemic inflammatory response syndrome. The primary objective of this thesis was to investigate and monitor the microvasculature in cardiac surgery patients using multiple methodologies and real-time monitoring techniques. The purpose of our first study was to determine whether pulsatile blood flow during bypass improves microvascular perfusion compared to non-pulsatile flow. We found that changes in sublingual mucosal microcirculation using orthogonal polarization spectral imaging correlate with indices of thenar muscle tissue oxygen saturation and its recovery during a vascular occlusion test using near-infrared spectroscopy …

Indocyanine Green Angiography In Pediatric Colorectal Surgery, Robin B. Wigen

Electronic Thesis and Dissertation Repository

Hirschsprung Disease (HD) and Anorectal Malformations (ARM) are congenital colorectal conditions that necessitate surgical correction via bowel resection with the creation of an anastomosis. Surgical complications, thought to be in part due to malperfusion of the bowel anastomosis, are frequent, as revealed by the retrospective review enclosed. Indocyanine Green Angiography (ICGA) is a process in which water-soluble dye (ICG) is used to assess perfusion of tissue, and it has been employed with success in adult populations to reduce rates of anastomotic leak during colorectal surgery. The systematic review conducted within confirms that this tool has not been extensively studied in …

Biomechanical Analysis Of Ligament Modelling Techniques And Femoral Component Malrotation Following Tka, Liam A. Montgomery

Electronic Thesis and Dissertation Repository

Previous studies have demonstrated that satisfaction and revision rates following total knee arthroplasty (TKA) are lower than those of comparable surgeries such as total hip replacements. A leading cause for these revisions is joint instability which may be due to improper ligament balancing or poorly aligned surgical implants. One of the methods used to investigate biomechanical forces and kinematics is computational modelling of the post-operative TKA knee.

A unique knee model was used to investigate the biomechanical and kinematic effects of ligament model complexity, as well as the effects of simulating ligament wrapping versus ignoring ligament wrapping. We then used …

The Effect Of Obesity On Revision Total Knee Arthroplasty: Functional Outcome, Ninety-Day Costs, Reoperations, Readmissions And Cost-Effectiveness, Mohamad Nasser Eddine

Electronic Thesis and Dissertation Repository

The demand for revision total knee arthroplasty (RTKA) is increasing due to obesity and an aging population. The purpose of this study is to evaluate the effect of different body mass index (BMI) categories on RTKA using a retrospective cohort analysis. The first part was to assess patients’ functionality post-RTKA. The second part was to determine the survival of RTKA and re-revision rate. The third part was to explore the complication and readmission rates, and to estimate the 90-day costs of RTKA. We found the most common indication for RTKA in super obese patients is infection, unlike other BMI categories, …

The Cost-Effectiveness Of A Midvastus Versus Standard Medial Parapatellar Surgical Approach For Total Knee Arthroplasty, Ishita Joshi

Electronic Thesis and Dissertation Repository

The minimally invasive midvastus (MMV) surgical approach for total knee arthroplasty (TKA) is a less invasive technique that has been proposed to accelerate recovery over standard TKA, however, advantages are not yet definitively established. We investigated the cost-effectiveness of MMV TKA versus the standard medial parapatellar (MPP) approach for TKA alongside a randomized controlled trial in patients with knee osteoarthritis. Patients reported resource use as well as indirect costs, and health outcomes were measured using the EQ-5D-5L and the Western Ontario and McMaster Universities Osteoarthritis Index over the 12-month study period. The results of our net benefit regression analysis suggest …

Predicting Dissatisfaction With Total Knee Arthroplasty, Joseph S. Munn

Electronic Thesis and Dissertation Repository

Total knee arthroplasty (TKA) is a common and effective treatment for end-stage osteoarthritis. However, approximately 20% of patients are consistently found to be dissatisfied or unsure of their satisfaction with their TKA at 1-year post-surgery. Two strategies for reducing dissatisfaction have appeared in the literature. The first aims to reduce the number of dissatisfied patients who will undergo surgery by identifying patients likely to be dissatisfied pre-surgery. The second aims to implement interventions that improve patient satisfaction by generating realistic expectations for outcomes and by association improving met expectations scores. It may be possible to improve the performance of these …

The Migration And Wear Of Reverse Total Shoulder Arthroplasty, Madeleine L. Van De Kleut

Electronic Thesis and Dissertation Repository

Reverse total shoulder arthroplasty (RTSA) inverts the ball and socket geometry of the shoulder. Though projected to become the most common shoulder replacement in the next decade, RTSA suffers from a high complication and revision rate, with implant loosening requiring revision. As the number of indications and demand from younger patients for RTSA continues to grow, there is the need to identify implant fixation techniques that promote longevity.

Radiostereometric analysis (RSA) is the current standard for measuring implant migration, which, if continuous in the first year postoperatively is highly predictive of later loosening and failure. RSA has also been used …

Does An Acute Achilles Tendon Rupture Become A Patient's Achilles Heel In The Long-Term?, Michaela Cm Khan

Electronic Thesis and Dissertation Repository

It is unknown if deficits in the involved limb following acute Achilles tendon rupture (AATR) persist in the long-term, or differ between patients treated operatively or non-operatively. This study investigated 43 patients 15±1 years post-AATR from a previous randomized controlled trial (RCT) that compared operative and non-operative treatment. Structural characteristics in the Achilles tendon and surrounding musculature were assessed using magnetic resonance imaging. We also performed physical examinations and evaluated performance-based and patient-reported outcomes. Overall, there were substantial differences between the involved and uninvolved limbs in most outcomes. Some outcomes improved over time from the initial RCT to the final …

Ultra-High Field Magnetic Resonance Imaging For Stereotactic Neurosurgery, Jonathan Lau

Electronic Thesis and Dissertation Repository

Stereotactic neurosurgery is a subspecialty within neurosurgery concerned with accurate targeting of brain structures. Deep brain stimulation (DBS) is a specific type of stereotaxy in which electrodes are implanted in deep brain structures. It has proven therapeutic efficacy in Parkinson’s disease and Essential Tremor, but with an expanding number of indications under evaluation including Alzheimer’s disease, depression, epilepsy, and obesity, many more Canadians with chronic health conditions may benefit. Accurate surgical targeting is crucial with millimeter deviations resulting in unwanted side effects including muscle contractions, or worse, vessel injury. Lack of adequate visualization of surgical targets with conventional lower field …

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 …

Investigating The Pathogenesis Of Staphylococcus Aureus In Periprosthetic Joint Infections, Santiago L. Iglesias

Electronic Thesis and Dissertation Repository

The most challenging complication after total joint replacement is the periprosthetic joint infection (PJI). Staphylococcus aureus is a commensal bacterium and a human pathogen. It is responsible for more than half of the PJI. We demonstrated that synovial fluid has antimicrobial properties against S. aureus and the iron restriction is one of the mechanisms used for the host to prevent bacterial growth, and is even able to increase killing of S. aureus. We have shown a clear role of transferrin as a restrictive factor in synovial fluid that functions by iron starving the bacteria and sensitizing them to killing …

Mechanical Properties Of Retrieved Highly Cross-Linked Polyethylene Acetabular Liners In Total Hip Arthroplasty, Gurpreet Singh

Electronic Thesis and Dissertation Repository

Highly cross-linked polyethylene (HXLPE) has replaced the conventional ultra-high-molecular-weight-polyethylene (UHMWPE) as the gold standard bearing surface in total hip arthroplasty (THA) due to superior wear characteristics and survivorship. However, HXLPE has demonstrated poorer mechanical properties, in vivo oxidation, and concerns of rim fractures. The purpose of this project was to study the mechanical properties at the rim of retrieved HXLPE acetabular liners.

We developed a simple technique for measurement of hardness at the rim of irradiated, remelted, HXLPE liners of a specific design. The effect of shelf time on mechanical properties of retrieved liners was determined and showed no correlation …

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 …

Surgical Approach In Total Hip Arthroplasty: Patient Outcomes And Impact On Costs, Stephen M. Petis

Electronic Thesis and Dissertation Repository

Total hip arthroplasty is often renowned as one of the most important surgical advances of the past century. Orthopaedic surgeons must choose a surgical approach to gain access to the hip joint in order to perform the reconstruction. There is debate in the literature as to which surgical approach optimizes patient outcomes, minimizes complications, and reduces costs to hospitals as a high volume procedure.

In the current studies, patient reported outcomes were compared at short-term follow-up using a prospective study design across the anterior, posterior, and lateral approach. A micro-costing method was used to acquire costs related to each procedure, …

Evaluating Human Performance For Image-Guided Surgical Tasks, Matthew Kenneth Kramers

Electronic Thesis and Dissertation Repository

The following work focuses on the objective evaluation of human performance for two different interventional tasks; targeted prostate biopsy tasks using a tracked biopsy device, and external ventricular drain placement tasks using a mobile-based augmented reality device for visualization and guidance. In both tasks, a human performance methodology was utilized which respects the trade-off between speed and accuracy for users conducting a series of targeting tasks using each device. This work outlines the development and application of performance evaluation methods using these devices, as well as details regarding the implementation of the mobile AR application. It was determined that the …

A Pilot Study To Investigate Concerns In Patients Undergoing Neck Dissection Surgery, Daniel Sundar Raj Arulananda Doss

Electronic Thesis and Dissertation Repository

Abstract:

This study investigates concerns in patients undergoing neck dissection surgery. Forty patients were recruited at Pre-surgery, Discharge and 1-month Post-surgery. The Patient Concerns Inventory - Level of Importance questionnaire (PCI-LOI), Shoulder Pain and Disability Index (SPADI), Neck Dissection Impairment Index (NDII) and the University of Washington - Quality of Life questionnaire (UWQOL) were used.

The study identified "Anxiety" at Pre-surgery and "Appearance" at Discharge and 1-month Post-surgery as the important patient concerns. Patients’ concerns were found to change over time. Support for cross-sectional convergent validity of the PCI-LOI was evidenced by significant correlations between the PCI-LOI and the UWQOL …

Complex Shoulder Instability: The Role Of The Latarjet Coracoid Transfer, Ryan Degen

Electronic Thesis and Dissertation Repository

Recurrent anterior shoulder instability is a common clinical entity often requiring surgical stabilization. Recurrence rates following soft-tissue stabilization procedures are moderately high and have been attributed to associated bony defects of either the glenoid or humeral head. Complex shoulder instability, defined as instability associated with bony defects around the shoulder, is a challenging clinical problem. The Latarjet coracoid transfer has been proposed as a treatment option and its resultant stabilizing effects have been explored in this biomechanical cadaver-based study.

For both glenoid and humeral head defects, the Latarjet coracoid transfer adequately stabilized the shoulder, outperforming other procedures often utilized for …