Evaluation of Three Sources of Validity Evidence for a Laparoscopic Duodenal Atresia Repair Simulator

Purpose: Laparoscopic duodenal atresia (DA) repair is a relatively uncommon pediatric operation requiring advanced minimally invasive skills. Currently, there are no commercial simulators available that address surgeons' needs for refining skills associated with this procedure. The purposes of this study were (1) to create an anatomically correct, size-relevant model and (2) to evaluate the content validity of the simulator. Materials and Methods: Radiologic images were used to create an abdominal domain consistent with a full-term infant. Fetal bovine tissue was used to complete the simulator. Following Institutional Review Board exempt determination, 18 participants performed the simulated laparoscopic DA repair. Participants completed a self-report, six-domain, 24-item instrument consisting of 4-point rating scales (from 1=not realistic to 4=highly realistic). Validity evidence relevant to test content and response processes was evaluated using the many-facet Rasch model, and evidence of internal structure (inter-item consistency) was estimated using Cronbach's alpha. Results: The highest observed averages were for ?Value as a training and testing tool? (both observed averages=3.9), whereas the lowest ratings were ?Palpation of liver? (observed average=3.3) and ?Realism of skin? (observed average=3.2). The Global opinion rating was 3.2, indicating the simulator can be considered for use as is, but could be improved slightly. Inter-item consistency was high (α=0.89). Conclusions: We have successfully created a size-appropriate laparoscopic DA simulator. Participants agreed that the simulator was relevant and valuable as a learning/testing tool. Prior to implementing this simulator as a training tool, minor improvements should be made, with subsequent evaluation of additional validation evidence.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140148/1/lap.2014.0358.pd

Evaluation of Three Sources of Validity Evidence for a Synthetic Thoracoscopic Esophageal Atresia/Tracheoesophageal Fistula Repair Simulator

Purpose: Thoracoscopic esophageal atresia (EA)/tracheoesophageal fistula (TEF) repair is technically challenging. We have previously reported our experiences with a high-fidelity hybrid model for simulation-based educational instruction in thoracoscopic EA/TEF, including the high cost of the tissue for these models. The purposes of this study were (1) to create a low-cost synthetic tissue EA/TEF repair simulation model and (2) to evaluate the content validity of the synthetic tissue simulator. Materials and Methods: Review of the literature and computed tomography images were used to create computer-aided drawings (CAD) for a synthetic, size-appropriate EA/TEF tissue insert. The inverse of the CAD image was then printed in six different sections to create a mold that could be filled with platinum-cured silicone. The silicone EA/TEF insert was then placed in a previously described neonatal thorax and covered with synthetic skin. Following institutional review board?exempt determination, 47 participants performed some or all of a simulated thoracoscopic EA/TEF during two separate international meetings (International Pediatric Endosurgery Group [IPEG] and World Federation of Associations of Pediatric Surgeons [WOFAPS]). Participants were identified as ?experts,? having 6?50 self-reported thoracoscopic EA/TEF repairs, and ?novice,? having 0?5 self-reported thoracoscopic EA/TEF repairs. Participants completed a self-report, six-domain, 24-item instrument consisting of 23 5-point rating scales and one 4-point Global Rating Scale. Validity evidence relevant to test content and response processes was evaluated using the many-facet Rasch model, and evidence of internal structure (interitem consistency) was estimated using Cronbach's alpha. Results: A review of the participants' ratings indicates there were no overall differences across sites (IPEG versus WOFAPS, P=.84) or experience (expert versus novice, P=.17). The highest observed averages were 4.4 (Value of Simulator as a Training Tool), 4.3 (Physical Attributes?chest circumference, chest depth, and intercostal space), and 4.3 (Realism of Experience?fistula location). The lowest observed averages were 3.5 (Ability to Perform?closure of fistula), 3.7 (Ability to Perform?acquisition target trocar sites), 3.8 (Physical Attributes?landmark visualization), 3.8 (Ability to Perform?anastomosis and dissection of upper pouch), and 3.9 (Realism of Materials?skin). The Global Rating Scale was 2.9, coinciding with a response of ?this simulator can be considered for use in neonatal TEF repair training, but could be improved slightly.? Material costs for the synthetic EA/TEF inserts were less than $2 U.S. per insert. Conclusions: We have successfully created a low-cost synthetic EA/TEF tissue insert for use in a neonatal thoracoscopic EA/TEF repair simulator. Analysis of the participants' ratings of the synthetic EA/TEF simulation model indicates that it has value and can be used to train pediatric surgeons, especially those early in their learning curve, to begin to perform a thoracoscopic EA/TEF repair. Areas for model improvement were identified, and these areas will be the focus for future modifications to the synthetic EA/TEF repair simulator.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140150/1/lap.2014.0370.pd

Preliminary Evaluation of a Novel Thoracoscopic Infant Lobectomy Simulator

Purpose: Thoracoscopic lobectomy in infants requires advanced minimally invasive skills. Simulation-based education has the potential to improve complex procedural skills without exposing the patient to undue risks. The study purposes were (1) to create a size-appropriate infant lobectomy simulator and (2) to evaluate validity evidence to support or refute its use in surgical education. Materials and Methods: In this Institutional Review Board-exempt study, a size-appropriate rib cage for a 3-month-old infant was created. Fetal bovine tissue completed the simulator. Thirty-three participants performed the simulated thoracoscopic lobectomy. Participants completed a self-report, 26-item instrument consisting of 25 4-point rating scales (from 1=not realistic to 4=highly realistic) and a one 4-point Global Rating Scale. Validity evidence relevant to test content and response processes was evaluated using the many-facet Rasch model, and evidence of internal structure (inter-item consistency) was estimated using Cronbach's alpha. Results: Experienced surgeons (observed average=3.6) had slightly higher overall rating than novice surgeons (observed average=3.4, P=.001). The highest combined observed averages were for the domain Physical Attributes (3.7), whereas the lowest ratings were for the domains Realism of Experience and Ability to Perform Tasks (3.4). The global rating was 2.9, consistent with ?this simulator can be considered for use in infant lobectomy training, but could be improved slightly.? Inter-item consistency for items used to evaluate the simulator's quality was high (α=0.90). Conclusions: With ratings consistent with high physical attributes and realism, we successfully created an infant lobectomy simulator, and preliminary evidence relevant to test content, response processes, and internal structure was supported. Participants rated the model as realistic, relevant to clinical practice, and valuable as a learning tool. Minor improvements were suggested prior to its full implementation as an educational and testing tool.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140149/1/lap.2014.0364.pd

The assessment of visual behaviour and depth perception in surgery

Imperial Users onl

Bio-Inspired Multi-Spectral and Polarization Imaging Sensors for Image-Guided Surgery

Image-guided surgery (IGS) can enhance cancer treatment by decreasing, and ideally eliminating, positive tumor margins and iatrogenic damage to healthy tissue. Current state-of-the-art near-infrared fluorescence imaging systems are bulky, costly, lack sensitivity under surgical illumination, and lack co-registration accuracy between multimodal images. As a result, an overwhelming majority of physicians still rely on their unaided eyes and palpation as the primary sensing modalities to distinguish cancerous from healthy tissue. In my thesis, I have addressed these challenges in IGC by mimicking the visual systems of several animals to construct low power, compact and highly sensitive multi-spectral and color-polarization sensors. I have realized single-chip multi-spectral imagers with 1000-fold higher sensitivity and 7-fold better spatial co-registration accuracy compared to clinical imaging systems in current use by monolithically integrating spectral tapetal and polarization filters with an array of vertically stacked photodetectors. These imaging sensors yield the unique capabilities of imaging simultaneously color, polarization, and multiple fluorophores for near-infrared fluorescence imaging. Preclinical and clinical data demonstrate seamless integration of this technologies in the surgical work flow while providing surgeons with real-time information on the location of cancerous tissue and sentinel lymph nodes, respectively. Due to its low cost, the bio-inspired sensors will provide resource-limited hospitals with much-needed technology to enable more accurate value-based health care

Adenocarcinoma do Esófago - Abordagem Atual

Introdução O cancro do esófago é uma doença neoplásica agressiva, com uma incidência crescente e um prognóstico pobre. O adenocarcinoma e o carcinoma epidermóide são os dois tipos histológicos mais comummente associados a este cancro e compõem mais de 95% de todos os tumores esofágicos. O carcinoma epidermóide era anteriormente o tipo histológico predominante globalmente, enquanto o adenocarcinoma era raramente observável. No entanto, com o passar das décadas e a melhoria na qualidade de vida, a incidência do adenocarcinoma tem subido drasticamente no Ocidente, sendo responsável pela maioria dos cancros do esófago no Norte da Europa, América do Norte e Austrália. A doença do refluxo gastroesofágico é considerada preponente desta tendência epidemiológica; não-obstante exploram-se outras hipóteses causais menos bem-estabelecidas. Métodos Seguindo as guidelines SANRA, realizou-se uma revisão narrativa da literatura incidindo amplamente na temática do adenocarcinoma do esófago (epidemiologia, patofisiologia, fatores de risco, clínica, diagnóstico, estadiamento, tratamento e prognóstico). Recorreu-se a duas bases de dados de referências, a Medline e a ScienceDirect. Resultados Identificaram-se um total de 353 referências. Após exclusão de duplicados, artigos não disponíveis ou irrelevantes, analisaram-se qualitativamente 142 artigos. Discussão Toda a bibliografia atual considera o Esófago de Barret como o último estadio pré- invasivo na sequência metaplasia-displasia-neoplasia do adenocarcinoma do esófago, sendo assim o melhor preditor do risco de cancro. A vigilância dos pacientes com Esófago de Barrett oferece, assim, a oportunidade de deteção precoce do adenocarcinoma. As opções de tratamento incluem técnicas endoscópicas diretas, cirurgia de resseção, quimioterapia perioperatória e radioterapia preoperatória - sendo que a evidência recente de mais alta qualidade apoia a terapia multimodal e abordagens minimamente invasivas como o padrão de cuidados de saúde. Conclusão O corpo de conhecimento em torno do adenocarcinoma do esófago está maioritariamente bem descrito. Todavia, o prognóstico da doença permanece precário, que coloca o cancro esofágico no sexto lugar global de maior mortalidade.Introduction Esophageal cancer is an aggressive malignancy with an increasing incidence and a poor prognosis. Esophageal adenocarcinoma (EAC) and squamous cell carcinoma (SCC) are the two most common histologic types and make up over 95% of all esophageal malignant tumors. In the past, SCC was the predominating type, while EAC was a rarely seen condition. However, over time, as a result of better quality of life, the incidence of EAC has increased dramatically in Western countries, accounting for the majority of all esophageal cancers in Northern Europe, North America and Australia. Gastroesophageal reflux disease is consensually regarded as the main culprit. Regardless, we explore other less well-established hypothesis. Methods Following the SANRA guidelines, we performed a narrative review of literature regarding epidemiology, pathophysiology, risk factors, clinical manifestations, diagnosis, staging, treatment, and prognosis of Esophageal Adenocarcinoma. We used both Medline and ScienceDirect libraries. Results We identified a total of 353 records. After exclusion of duplicates, unavailable and non- relevant articles, we included 142 papers in our broad scope narrative review. Discussion All contemporary works consider Barrett's Esophagus (BE) as the last preinvasive stage in the metaplasia-dysplasia-neoplasia sequence of EAC, thus remaining the single best surrogate marker for cancer risk. BE surveillance offers the opportunity of early EAC diagnosis. Treatment options include novel direct endoscopic therapies, esophagectomy, perioperative chemotherapy and preoperative radiation therapy - with the most recent and highest-standard evidence pointing towards multimodality therapy & minimally invasive strategies as the standard of care. Conclusion The EAC landscape is for the most part well-described. Nevertheless, prognosis remains substandard and incidence is ever-increasing, which leads to esophageal cancer being the sixth most deadly worldwide

Intraoperative Endoscopic Augmented Reality in Third Ventriculostomy

In neurosurgery, as a result of the brain-shift, the preoperative patient models used as a intraoperative reference change. A meaningful use of the preoperative virtual models during the operation requires for a model update. The NEAR project, Neuroendoscopy towards Augmented Reality, describes a new camera calibration model for high distorted lenses and introduces the concept of active endoscopes endowed with with navigation, camera calibration, augmented reality and triangulation modules

Epälambertilaiset pinnat ja niiden haasteet konenäössä

This thesis regards non-Lambertian surfaces and their challenges, solutions and study in computer vision. The physical theory for understanding the phenomenon is built first, using the Lambertian reflectance model, which defines Lambertian surfaces as ideally diffuse surfaces, whose luminance is isotropic and the luminous intensity obeys Lambert's cosine law. From these two assumptions, non-Lambertian surfaces violate at least the cosine law and are consequently specularly reflecting surfaces, whose perceived brightness is dependent from the viewpoint. Thus non-Lambertian surfaces violate also brightness and colour constancies, which assume that the brightness and colour of same real-world points stays constant across images. These assumptions are used, for example, in tracking and feature matching and thus non-Lambertian surfaces pose complications for object reconstruction and navigation among other tasks in the field of computer vision. After formulating the theoretical foundation of necessary physics and a more general reflectance model called the bi-directional reflectance distribution function, a comprehensive literature review into significant studies regarding non-Lambertian surfaces is conducted. The primary topics of the survey include photometric stereo and navigation systems, while considering other potential fields, such as fusion methods and illumination invariance. The goal of the survey is to formulate a detailed and in-depth answer to what methods can be used to solve the challenges posed by non-Lambertian surfaces, what are these methods' strengths and weaknesses, what are the used datasets and what remains to be answered by further research. After the survey, a dataset is collected and presented, and an outline of another dataset to be published in an upcoming paper is presented. Then a general discussion about the survey and the study is undertaken and conclusions along with proposed future steps are introduced

Multi-Domain Adaptation for Image Classification, Depth Estimation, and Semantic Segmentation

The appearance of scenes may change for many reasons, including the viewpoint, the time of day, the weather, and the seasons. Traditionally, deep neural networks are trained and evaluated using images from the same scene and domain to avoid the domain gap. Recent advances in domain adaptation have led to a new type of method that bridges such domain gaps and learns from multiple domains. This dissertation proposes methods for multi-domain adaptation for various computer vision tasks, including image classification, depth estimation, and semantic segmentation. The first work focuses on semi-supervised domain adaptation. I address this semi-supervised setting and propose to use dynamic feature alignment to address both inter- and intra-domain discrepancy. The second work addresses the task of monocular depth estimation in the multi-domain setting. I propose to address this task with a unified approach that includes adversarial knowledge distillation and uncertainty-guided self-supervised reconstruction. The third work considers the problem of semantic segmentation for aerial imagery with diverse environments and viewing geometries. I present CrossSeg: a novel framework that learns a semantic segmentation network that can generalize well in a cross-scene setting with only a few labeled samples. I believe this line of work can be applicable to many domain adaptation scenarios and aerial applications

Optimal Port Placement And Automated Robotic Positioning For Instrumented Laparoscopic Biosensors

OPTIMAL SURGICAL PORT PLACEMENT AND AUTOMATED ROBOTIC POSITIONING FOR RAMAN AND OTHER BIOSENSORS by BRADY KING January 2011 Advisors: Dr. Abhilash Pandya, Dr. Darin Ellis, Dr. Le Yi Wang, and Dr. Greg Auner Major: Computer Engineering Degree: Doctor of Philosophy Medical biosensors can provide new information during minimally invasive and robotic surgical procedures. However, these biosensors have significant physical limitations that make it difficult to find optimal port locations and place them in vivo. This dissertation explores the application of robotics and virtual/augmented reality to biosensors to enable their optimal use in vivo. In the first study, human performance in the task of port placement was evaluated to determine if computer intervention and assistance was needed. Using a virtual surgical environment, we present a number of targets on one or more tissue surfaces. A human factors study was conducted with 20 subjects that analyzed the subject\u27s placement of a port with the goal of scanning as many targets as possible with a biosensor. The study showed performance to be less than optimal with significant degradation in several specific scenarios. In the second study, an automated intelligent port placement system for biosensor use was developed. Patient data was displayed in an environment in which a surgeon could indicate areas of interest. The system utilized biosensor physical limitations and provided the best port location from which the biosensor could reach the targets on a collision-free path. The study showed that it is possible to find an optimal port location for proper biosensor data capture. In the final study, a surgical robot was investigated for potential use in holding and positioning a biosensor in vivo. A full control suite was developed for an AESOP 1000, enabling the positioning of the biosensor without hand manipulation. It was found that the robot lacks the accuracy needed for proper biosensor utilization. Specific causes for the inaccuracies were identified for analysis and consideration in future robotic platforms. Overall, the results show that the application of medical robotics and virtual/augmented reality is able to overcome of the significant physical limitations inherent to biosensor design that currently limit their use in surgery. We conjecture that a complete system, with a more accurate robot, could be used in vivo. We believe that results taken from the individual studies will result in improvements to pre-operative port placement and robotic design