Medical Specialties Commons^™

Monitoring Intraventricular Hemorrhage In Preterm Infants, Lilian Mn Kebaya

Electronic Thesis and Dissertation Repository

Germinal Matrix-Intraventricular hemorrhage (GMH-IVH) remains a significant cause of adverse neurodevelopmental outcomes in preterm infants. Current management options for GMH-IVH rely on serial 2-dimensional cranial ultrasound (2D cUS) ventricular measurements and clinical signs. A need exists for reliable biomarkers to aid in the early detection of posthemorrhagic ventricular dilatation (PHVD) and cerebral palsy (CP). We incorporated 3-dimensional cranial US (3D cUS) and functional infrared spectroscopy (fNIRS) to monitor ventricle volumes (VV) and spontaneous functional connectivity (sFC) in preterm infants with GMH-IVH. Infants with severe GMH-IVH who underwent cerebrospinal fluid diversion showed larger VV, which correlated with decreased sFC. Our findings …

Development Of An On-Call Assessment Tool For Competency-Based Surgical Training, Eric C. Mitchell

Electronic Thesis and Dissertation Repository

Introduction: A central tenet of competency-based medical education is formative assessment of trainees. There are no assessments examining resident competence on-call, despite this being a significant component of resident training and characterized by less supervision compared to daytime.

Methods: A national survey was conducted to evaluate the state of assessment in Canadian Plastic and Reconstructive Surgery programs. An on-call assessment tool was developed based on a consensus group and was piloted over six months. Validity of the tool was examined through qualitative and quantitative methods.

Results: There were 63 tools completed across ten residents and seven staff physicians. Tool reliability …

Noninvasive Quantification Of Tissue Sodium Concentration In The Kidney Disease Spectrum Using 23na Magnetic Resonance Imaging, Fabio R. Salerno

Electronic Thesis and Dissertation Repository

Chronic kidney disease (CKD), especially when requiring kidney replacement therapy (hemodialysis (HD) and peritoneal dialysis (PD)), is associated with extracellular water expansion with increased total body sodium. Sodium can also be accumulated in tissues independently of extracellular water. Sodium-23 magnetic resonance imaging (²³Na MRI) can quantify the concentration of sodium nuclei in tissues. Applied to the human leg, quantification of tissue sodium concentrations mainly at the skin and muscle level is possible. We hypothesized that increased tissue sodium concentrations exert toxic effects in CKD and dialysis. We aimed to (1) compare tissue sodium concentrations in adults, children and …

Severe Lower Extremity Trauma In Ontario: A Linked Population-Based Analysis, Stephanie M. Kim

Electronic Thesis and Dissertation Repository

Open tibia fractures (OTF) are a management challenge. Admission to a trauma center (TC) and a coordinated approach to bony fixation and soft-tissue reconstruction (STR) have been shown to improve outcomes. The objective of this study was to describe patients who had OTF in Ontario and analyze their outcomes. Linked population data pertaining to patients who had OTF between the years 2009-2020 were examined. Demographic information, admission location, and management course were collected. 4240 patients were found. The mean age was 47, and majority were males. Patients admitted to TC had greater proportion of having Injury Severity Score >15, and …

Comparison Of Hip Navigation System Accuracy In Direct Anterior Approach, Jeremy Loh

Electronic Thesis and Dissertation Repository

Introduction

Malposition of the acetabular component has been thought to have an influence on increasing increase the risk instability, impingement, and ultimately revision surgery. Hip navigation technology has been developed to provide the surgeon with real time intraoperative metrics to make critical decisions in implant placement. The goal of this study was to compare the accuracy of acetabular component positioning in direct anterior approach hip replacements using conventional fluoroscopy only technique, fluoroscopic image dependent navigation, and imageless navigation.

Methods

A retrospective data collection and prospective analysis was conducted for this study. After sample size calculations, fifty patients were collected for …

A Long-Term Follow-Up Of The Stability Study: Multicenter Rct Comparing Anterior Cruciate Ligament Reconstruction With And Without Lateral Extra-Articular Tenodesis In Individuals At High Risk Of Graft Failure, Katelyn M. Inch

Electronic Thesis and Dissertation Repository

One hundred and ninety-six patients at the Fowler Kennedy Sport Medicine Clinic (FKSMC) undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) were randomized as part of the multi-center STABILITY study to receive either an isolated ACLR or ACLR with a lateral extra-articular tenodesis (LET). The STABILITY study followed these patients up to two years postoperative, and a long-term follow-up protocol was initiated afterwards. Eighty-two patients from this center were seen at three, five and seven years postoperative as part of a long-term follow-up. Our primary outcome was a composite outcome of instability and graft failure. Secondary outcomes included patient-reported outcome measures …

Exploration Of The Pathophysiological Mechanisms Underlying Hemodialysis Associated Cardiac Ischemic Injury, Lisa Yun Jeong Hur

Electronic Thesis and Dissertation Repository

Hemodialysis (HD) provides life-saving treatment in individuals with kidney failure. However, HD is associated with poor quality of life and extremely high mortality rates mainly caused by cardiovascular disease due to heart failure and sudden cardiac death. Standard pharmacological treatment developed within the non-kidney disease community are largely ineffective in HD patients because of the difference in pathophysiology of cardiovascular mortality. HD treatment causes hypotension and recurrent ischemic injury to multiple vascular beds including the heart, leading to heart failure. These injuries can be abrogated by improving the patient’s tolerability of the treatment. To apply interventions that may improve hemodynamic …

The Clinical Value Of Oculomotor Assessments Across The Continuum Of Concussion, Dillon Richards

Electronic Thesis and Dissertation Repository

Concussions are complex conditions that are difficult to manage medically. Variations in symptom presentation, intricate neurophysiological processes, and the availability of a variety of possible assessment tools may contribute to this complexity. Clinicians must use a broad approach, employing both subjective symptom assessment and objective assessments to confirm a diagnosis and/or monitor progression and recovery. Oculomotor function after concussion may be an important indicator of injury, given the interconnectedness of oculomotor function, vestibulo-ocular and visual systems, and even cognition. Oculomotor function may be assessed objectively or indirectly using patient-reported symptom checklists as part of subjective assessments. One way of objectively …

Total Hip Arthroplasty In Young Patients, Aaron G. Chen

Electronic Thesis and Dissertation Repository

Total hip arthroplasty (THA) is the gold standard in treatment of hip arthritis yet is often avoided in young patients due to concerns of inferior survivorship. We aim to explore the role of THA in young patients and assess whether these historical concerns are valid in contemporary THA by presenting the results of: (1) a systematic review and meta-analysis of the current literature, (2) a retrospective database review, and (3) a retrospective population-based study. We found excellent long-term survivorship with modern THA in young patients, demonstrating greater than 90% revision-free survival up to 15 years. Factors that may increase risk …

Decompression Vs. Decompression And Fusion In Cauda Equina Syndrome Secondary To Massive Lumbar Disc Herniation, Ruheksh Raj

Electronic Thesis and Dissertation Repository

Posterior spinal surgery through either a decompression or additional fusion procedure is the widely accepted standard of care for patients presenting with cauda equina syndrome (CES) secondary to massive disc herniation. A plethora of literature has been published regarding post- surgical outcome, particularly in regards to improvement of lower sacral nerve symptoms in relation to timing of surgery. There is a paucity of data with regards to long term clinical outcomes in patients between the decompression and decompression and fusion groups. We initially hypothesized was that there would be no longer term clinical differences in outcome between the two groups, …

Multimorbidity And Cognition Among Canadian Older Adults: A Three-Decade Perspective, Juan Camilo Vargas Gonzalez

Electronic Thesis and Dissertation Repository

Background: Scarce information exists about whether the relationship between multimorbidity and cognitive decline has changed over the past decades.

Objectives: 1) To summarize knowledge about the association of multimorbidity and cognitive decline by performing a systematic review. 2) To estimate the association between multimorbidity in two cohorts selected three decades apart. 3)To identify which multimorbidity combinations have the strongest associations with cognitive decline 4) To identify protective factors that reduce the risk of cognitive decline in the presence of multimorbidity.

Methods: We performed a systematic review following the PRISMA statement. We then addressed objectives 2-4 by analyzing data from two …

Technical Adaptations For Cardiac Sodium Mri, Taylor L. Marcus

Electronic Thesis and Dissertation Repository

Cardiac sodium (Na⁺) MRI has the potential to unveil relationships between chronic kidney disease (CKD) and cardiovascular disease (CVD). Unfortunately, this modality requires many technical adaptations before it’s possible to extract and compare image data between individuals. This study investigated whether cardiac electrocardiogram (ECG) gating could improve image quality, and whether a uniform phantom could increase signal uniformity if a surface coil is used to acquire the image. Healthy participants were imaged with a custom-built surface coil and 3.0-T MR system. Cardiac gated images presented with a decreased signal-to-noise ratio (SNR), but intensity correction significantly increased image signal …

Multi-Scale Computational Modeling Of Coronary Blood Flow: Application To Fractional Flow Reserve., Jermiah Joseph

Electronic Thesis and Dissertation Repository

Introduction. Fractional flow reserve (FFR) is presently an invasive coronary clinical index. Non-invasive CT imaging combined with computational coronary flow modelling may reduce the patient’s burden of undergoing invasive testing.

Research statement. The ability to obtain information of the hemodynamic significance of detected lesions would streamline decision making in escalation to invasive angiography.

Methods. A reduced order (lumped parameter) model of the coronary vasculature was further developed. The model was used in the assessment of the roles of structure and function on the FFR. Sophisticated methods were used to elicit numerical

solutions. Further, CT imaging (n = …

Determination Of The Protective Capacity Of Hand Wraps In Combat Athletes Using Force Analysis, Eva M. Gusnowski

Electronic Thesis and Dissertation Repository

Upper extremity injuries are common in combat athletes, and are highest in the hand/wrist. Although protective hand gear is used, there is a paucity of research investigating its effectiveness. This study addressed this knowledge gap by measuring the level of force transmitted to the hand during striking using two types of hand wraps. This prospective cross over study included six combat athletes. A load cell was placed over the proximal phalanges/metacarpophalangeal joints and was used to measure sustained peak force during striking while covered with either standard linear or gel-reinforced hand wraps and boxing gloves. The gel reinforced wraps consistently …

Role Of Decorin At The Fetal-Maternal Interface, Chidambra D. Halari

Electronic Thesis and Dissertation Repository

The human placenta is an invasive tumor-like structure, this invasion being physiological. A subset of placental trophoblast called extra-villous trophoblast invades the uterine decidua and remodels uterine arteries into low-resistance, high-flow tubes to permit adequate flow of maternal blood to nourish the fetus. A poor extra-villous trophoblast invasion and uterine arterial remodeling can lead to fetal growth restriction and a serious pregnancy-associated maternal disease preeclampsia. Decorin, a leucine-rich proteoglycan produced by uterine decidual cells restrains multiple trophoblast functions: self-renewal and differentiation of trophoblast stem cells, migration, invasion, proliferation and endovascular differentiation. Additionally, decidual overproduction of decorin was associated with preeclampsia, …

Biomechanical Characterization Of Semi-Rigid Constructs And The Potential Effect On Proximal Junctional Kyphosis In The Thoracic Spine, Chloe Cadieux

Electronic Thesis and Dissertation Repository

Long spinal fusions are the mainstay of treatment in adult spinal deformity; however, proximal junctional kyphosis (PJK) is a common and potentially catastrophic complication that can occur following this procedure. It has been hypothesized that using semi-rigid constructs at the superior aspect of the instrumentation may decrease this complication. The objective of this thesis was to determine if there is a biomechanical advantage between various semi-rigid constructs utilized in long spinal fusions to help decrease the risk of PJK. Nine human cadaveric spines (T1 – T12) instrumented with the standard all-pedicle-screw construct (APS) were compared to various semi-rigid constructs including …

The Molecular Landscape Of Early-Stage Breast Cancer With Lymph Node Metastasis, Farhad Ghasemi

Electronic Thesis and Dissertation Repository

Axillary lymph nodes (ALNs) are the primary site of metastasis in breast cancer, and their involvement has implications in disease staging, prognostication, and treatment decisions. A non-invasive modality of assessing the risk of ALN metastasis can improve care in patients with early-stage breast cancer by omitting the morbidity and costs associated with axillary surgery.

This thesis explores the molecular landscape of early-stage breast cancers with ALN metastasis and shows the potential of tumour molecular signatures in predicting ALN involvement. After a systematic review of the literature, we use data from The Cancer Genome Atlas (TCGA) to develop molecular signatures correlated …

Myeloarchitectonic Maps Of Cat Auditory Cortex, Austin Robertson

Electronic Thesis and Dissertation Repository

The cerebral cortex contains myriad cortical areas that differ in structure, function, and connectivity. Current methods of delineating cortical structures and their subregions are insufficient for in vivo applications, either being highly invasive or requiring a detailed knowledge of a region’s tuning properties. To address this, we seek to establish a structural biomarker capable of delineating the cortex that possesses a non-invasive correlate. We explore myelin as a potential candidate by evaluating its efficacy in parcellating the feline auditory cortex through the generation of depthwise myelin density profiles for each of the 13 auditory cortical subregions. Our analyses revealed significant …

Feasibility And Clinical Value Of 3-Dimensional Myocardial Deformation Analysis By Computed Tomography In Transcatheter Aortic Valve Replacement Patients, Mohamad Rabbani

Electronic Thesis and Dissertation Repository

Purpose: Multi-phase computed tomography angiography (CTA) for the pre-procedural planning of TAVR presents a unique opportunity to assess 3D myocardial biomechanics. This study aimed to assess the feasibility and predictive utility of 3D myocardial deformation analysis (3D-MDA) based principal strain to predict heart failure or death following TAVR using pre-procedural, multi-phase computed tomography angiography (CTA) datasets.

Methods: Two hundred and five patients undergoing pre-TAVR multi-phase gated CTA followed by successful TAVR were retrospectively identified. Whole heart 3D mesh chamber models were generated followed by 3D-MDA of the left ventricle (LV) to determine global LV minimum principal strain (minPS) for endocardial, …

Effectiveness Of Machine Learning Classifiers For Cataract Screening, Ronald Cheung

Electronic Thesis and Dissertation Repository

Cataract is the leading cause of blindness and vision loss globally. The implementation of artificial intelligence (AI) in the healthcare industry has been on the rise in the past few decades and machine learning (ML) classifiers have shown to be able to diagnose patients with cataracts. A systematic review and meta-analysis were conducted to assess the diagnostic accuracy of these ML classifiers for cataracts currently published in the literature. Retrieved from nine articles, the pooled sensitivity was 94.8% and the specificity was 96.0% for adult cataracts. Additionally, an economic analysis was conducted to explore the cost-effectiveness of implementing ML to …

Quantitative Mri And 3d-Printing For Monitoring Periprosthetic Joint Infection, Greg Hong

Electronic Thesis and Dissertation Repository

Joint replacements are becoming increasingly commonplace with over 130,000 joint arthroplasties being performed annually in Canada. Although joint replacement surgery is highly successful, implants do occasionally fail and need to be replaced via costly and difficult revision surgery. Periprosthetic joint infection (PJI) has recently become the leading reason for revision of both hip and knee replacements, which is unfortunate because PJI is difficult to diagnose and treat effectively; diagnosis is made particularly difficult by the lack of established non-invasive (imaging) means of evaluating PJI. This thesis aims to demonstrate that magnetic resonance imaging (MRI) has potential for diagnosing and monitoring …

Developing Artificial Intelligence And Machine Learning To Support Primary Care Research And Practice, Jacqueline K. Kueper

Electronic Thesis and Dissertation Repository

This thesis was motivated by the potential to use "everyday data", especially that collected in electronic health records (EHRs) as part of healthcare delivery, to improve primary care for clients facing complex clinical and/or social situations. Artificial intelligence (AI) techniques can identify patterns or make predictions with these data, producing information to learn about and inform care delivery. Our first objective was to understand and critique the body of literature on AI and primary care. This was achieved through a scoping review wherein we found the field was at an early stage of maturity, primarily focused on clinical decision support …

Anticancer Effects And Mechanisms Of Cfi-400945 And Radiation In Breast Cancer, Sierra M. Pellizzari

Electronic Thesis and Dissertation Repository

Breast cancer is a leading cause of death in women and development of new treatments is essential. Polo-like Kinase 4 (PLK4) controls centriole duplication and its inhibition by CFI-400945 induces genomic instability and aneuploidy. Radiation therapy (RT) also induces aneuploidy leading to cell death, although development of radioresistance is common. We hypothesized that CFI-400945 and RT act synergistically in breast cancer. Colony formation assays identified synergistic anticancer effects of CFI-400945 and RT, with combinatorial effects also observed for RT with either siRNA inhibition of PLK4 or with the PLK4 inhibitor Centrinone B. This suggests that the antiproliferative effect of these …

The Biomechanical Effects Of Glenoid And Humeral Lateralization On The Rotator Cuff Muscles In Reverse Total Shoulder Arthroplasty, Yousif Atwan

Electronic Thesis and Dissertation Repository

The utilization of reverse total shoulder arthroplasty (RTSA) has continued to increase as its clinical indications expand. The optimization of the rotator cuff function in the setting of RTSA is poorly understood and poor outcomes are associated with lack of external and internal rotation function. The purpose of this study is to evaluate the role of implant parameters on rotator cuff tendon excursion and moment arms in the setting of RTSA.

Using a cadaveric based model, a custom designed modular RTSA system was implanted that allowed for incremental changes to glenoid and humeral lateralization. Using a shoulder simulator and optical …

Shockwave Lithotripsy Of Upper Urinary Tract Calculi - Outcomes Of A Multicentre International Prospective Observational Study, Fernanda C. Gabrigna Berto

Electronic Thesis and Dissertation Repository

Introduction

Shockwave lithotripsy (SWL) is a surgical procedure used in urolithiasis treatment. Several factors can influence its results. This study aims to evaluate “real-world” success rates and identify predictors of treatment success in patients undergoing SWL.

Methods

Adult patients undergoing SWL for urolithiasis at three institutions in Canada and Oman were prospectively enrolled. Treatment success after a maximum of two SWL sessions was assessed by post-operative imaging. Logistic regression assessed for predictors of treatment success.

Results

Between May 2021 and February 2022, 271 patients were prospectively enrolled. Overall success rate was 46.1% after one SWL session, and 58.3% after two …

The Role Of Urinary Modulators In The Development Of Infectious Kidney Stones, Brendan Wallace

Electronic Thesis and Dissertation Repository

The pathogenesis of infectious kidney stones is poorly understood, while equally unclear is the role of urinary modulators and bacteria. An experimental model was created and utilized to test a variety of urinary modulators and bacterial strains commonly associated with struvite and calcium phosphate stones to evaluate their potential roles in influencing crystal formation. Modulators such as acids, citrate, and osteopontin had strong inhibitory effects on infectious crystal formation while the remaining modulators had neutral, mixed, or positive effects. Lastly, it was determined that the presence of urease may not directly lead to calcium phosphate and struvite stones in all …

Breast Augmentation: The Current Landscape, Khalifa Sh. Al-Ghanim

Electronic Thesis and Dissertation Repository

Primary breast augmentation is one of the most common surgeries performed by plastic surgeons. Breast augmentation, since its inception in 1895, has become a multimillion-dollar industry. Today, the two most common methods include implant-based and fat graft augmentation. Implant-based augmentation includes the use of silicone or saline prosthesis to enhance breast volume or shape. With fat grafting, a patient’s fat is harvested, processed, and injected into the breast to achieve the desired result. This thesis aims to outline the current literature on both methods of breast augmentation, review patient reported outcomes, as well as a proposed clinical trial to gain …

Development Of A Novel Rodent Model Of Radiation-Induced Implant Capsular Contracture, Tanya Delyzer

Electronic Thesis and Dissertation Repository

Radiation-induced implant capsular contracture is a challenging complication of post-mastectomy breast reconstruction. The objective of this thesis was to establish a novel rodent model that replicates the critical properties of this complication. Retired breeder female Sprague-Dawley rats underwent surgery with custom smooth silicone implants placed under the right 4^th mammary fat pad. Half these rats received 26Gy of ionizing radiation to the implant and fat pad. Radiated implants had both higher Baker grades of capsular contracture and Kumar scores denoting radiation-induced fibrosis. Irradiated capsules showed increased Masson’s trichrome staining and significantly higher hydroxyproline to total protein ratio compared to …

The Molecular Mechanisms Of Hepatic Mitochondrial Dysfunction In Growth-Restricted Offspring With Hyperlipidemia, Shelby L. Oke

Electronic Thesis and Dissertation Repository

Intrauterine growth restriction (IUGR) is a pathological condition characterized by low birth weight and poor organ development. Growth of the fetal liver is often compromised at the expense of other vital organs, thereby leading to hepatic dyslipidemia in the affected offspring. As such, epidemiological studies suggest an inverse relationship between birth weight and long-term metabolic health, while the occurrence of postnatal catch-up growth can exacerbate this relationship. Animal studies have shown that IUGR offspring exhibit impaired mitochondrial function, which likely contributes to the later development of metabolic pathologies. That said, the molecular mechanisms by which mitochondria are affected remain unknown. …

Evaluating The Utility Of S100a7 In Identifying Oral Dysplastic Lesions That Will Progress To Oral Squamous Cell Carcinoma, Jeff Soparlo

Electronic Thesis and Dissertation Repository

Title: Evaluating the utility of S100A7 in identifying oral dysplastic lesions that will progress to oral squamous cell carcinoma Introduction: Recently, S100A7 has been shown to be a potential useful marker for identifying oral lesions at risk of transformation from dysplasia to squamous cell carcinoma. Our hypothesis is that high S100A7 protein expression predicts the transformation of oral epithelial dysplasia to malignancy. The objective of our study is to semi-quantitatively evaluate the level of S100A7 expression in dysplastic lesions which have transformed into oral squamous cell carcinoma using immunohistochemistry, and correlate these results with other methods of analysis including the …