A técnica cirúrgica endoscópica transluminal por orifícios naturais (NOTES) envolve o acesso à cavidade abdominal através de uma perfuração intencional de uma víscera (p.ex. estômago, reto, vagina, bexiga urinária) com um endoscópio flexível para acessar a cavidade abdominal e realizar uma exploração intra-abdominal. O presente estudo teve por objetivo verificar a viabilidade de se realizar a técnica cirúrgica endoscópica transvaginal híbrida em éguas para a exploração da cavidade abdominal posicionados em estação e distribuídos em dois grupos conforme o acesso laparosópico pelo flanco direito ou esquerdo e pela incisão do saco fundo vaginal à esquerda da cérvix na posição horária de 9 horas ou à direita da cérvix na posição horária de 3 horas. O abdômen foi explorado sob visualização endoscópica utilizando um endoscópio flexível de 2 metros por 14 mm de diâmetro. A incisão vaginal foi realizada sob visualização indireta pelo laparoscópio acessado via flanco. Foram utilizados 6 éguas hígidas e 1 égua com histórico de lesão abdominal por arma de fogo. Os animais foram submetidos a jejum alimentar de 24 a 36 horas, distribuídos em dois grupos. No grupo 1 foram incluídos animais que foram acessado o flanco esquerdo para a introdução do laparoscópico e realizado a incisão do saco vaginal à esquerda da cérvix, enquanto no grupo 2, o acesso do flanco para a introdução abdominal do laparoscópio foi pelo lado direito e a incisão vaginal à direita da cérvix. Os animais foram sedados com a combinação de cloridrato de xilazina e butorfanol e para dessensibilização cutânea e muscular realizada no flanco esquerdo e direito e a execução da epidural baixa foi utilizada lidocaína. A técnica cirurgia realizada foi a cirurgia endoscópica transluminal híbrida pelo acesso vaginal utilizando uma cânula vaginal que permitiu a introdução do endoscópio flexível e facilitando a passagem para o lado contralateral da incisão vaginal do endoscópio flexível para realizar a visualização da cavidade abdominal. Foi possível visualizar em todos os animais o diafragma, o estômago, o lobo hepático esquerdo, direito e processo caudato, o baço, projeções do rim esquerdo e direito, o cólon menor, o ovário esquerdo e direito, o ligamento largo do útero, o corno uterino e as tubas uterinas esquerda e direita, o duodeno, a base do ceco, o cólon dorsal direito e as alças do intestino delgado. Não foi identificadoo forame epiplóico, o pâncreas, o reto e a bexiga em nenhum dos animais do estudo. O procedimento endoscópico transvaginal híbrido para a exploração da cavidade abdominal em éguas hígidas não evidenciou dificuldade em sua execução nem complicações pós-cirúrgicas, sendo viável nos dois diferentes grupos propostos, como também auxiliou no diagnóstico de lesões intra-abdominais em uma égua causadas por arma The natural orifice translumenal endoscopic surgery (NOTES) technique involves the access to the abdominal cavity through an intentional perforation of a viscus (i.e. stomach, rectus, vagina, urinary bladder) with an endoscope in order to access the abdominal cavity and perform an intra-abdominal exploration. Until now, abdominal surgery in horses using minimally invasive techniques has been performed through laparoscopy. The objective of this study was to confirm the availability to perform the hybrid transvaginal endoscopic surgery technique in mares in order to explore the abdominal cavity in the standing position. The mares were divided in two groups according to the laparoscopic access through the left or right flank. / The natural orifice translumenal endoscopic surgery (NOTES) technique involves the access to the abdominal cavity through an intentional perforation of a viscus (i.e. stomach, rectus, vagina, urinary bladder) with an endoscope in order to access the abdominal cavity and perform an intra-abdominal exploration. Until now, abdominal surgery in horses using minimally invasive techniques has been performed through laparoscopy. The objective of this study was to confirm the availability to perform the hybrid transvaginal endoscopic surgery technique in mares in order to explore the abdominal cavity in the standing position. The mares were divided in two groups according to the laparoscopic access through the left or right flank. An incision was performed on the posterior vaginal fornix on the left side of the cervix in a 9 o’clock position or on the right side of the cervix on a 3 o’clock position. The abdomen was explored under endoscopic visualization using a 2 meters long flexible endoscope by 14 mm in diameter. The vaginal incision accessed via flank was performed under indirect visualization using a laparoscope. Six healthy mares and one mare with the history of abdominal lesion by gun fire were used. The horses were subjected to fasting from 24 to 36 hours and they were divided in two groups according to the laparoscopic access through the flank and vaginal incision. In group 1, horses were accessed on the left flank to the introduction of the laparoscope and it was performed an incision on the vaginal fornix in the left side of the cervix. In group 2, the access of the flank to the abdominal introduction of the laparoscope was through the left side and the vaginal incision in the left side of the cervix. The horses were sedated using a combination of xylazine chloride and butorphanol. Lidocaine was used for skin and muscular anesthesia on the left and right flank and for the execution of low epidural. The surgery technique used was the hybrid NOTES through the vaginal access using a vaginal cannula which allowed the introduction of the flexible endoscope making it rigid and the passage of the endoscope to the contralateral side of the vaginal incision to visualize the abdominal cavity. In all the animals of the experiment, it was possible to see the diaphragm, stomach, left, right and caudate liver lobe, spleen, left and right kidney projection, small colon, left and right ovaries, broad ligament of the uterus, uterine horn and right and left uterine tubes, duodenum, base of the cecum, left dorsal colon, and bowel loops of the small intestine. There were not identified foramen epiploicum, pancreas, rectus, and bladder in none of the animals in the experiment. The hybrid transvaginal endoscopic procedure for the exploration of the abdominal cavity in healthy mares did not demonstrate difficulties in its execution not even post-surgery complications. The procedure was considered viable in both different proposed groups.

Introduction: As the number of minimally invasive technologies increases in the field of thoracic surgery, so have the number of learning curve analyses performed for these innovations. Variation in learning curve methodology makes between-study comparisons and evidence syntheses difficult. Furthermore, poorly described and reported learning curve analyses make the results difficult to apply to different clinical settings. The objective of this systematic review is to characterize the variability in the methods used to construct and describe learning curves, with the goal of identifying shortcomings and potential areas for improvement in this line of research. Methods: A search of Ovid Medline, Ovid Embase, EBSCO CINAHL, and Web of Science was performed. Studies of learning curves of anatomical lung resection operations in adult patients published in the English language were eligible for inclusion. Two reviewers independently assessed studies for eligibility, and extracted relevant data. Results: The search yielded 56 articles eligible for inclusion in the present review. A variety of methods were used to construct the learning curve, with chronological grouping of cases being the most commonly used technique in 22 (39.29%) studies, followed by the cumulative sum method, employed in 21 (37.50%) studies. A total of 15 unique metrics were used for learning curve analyses; operative time was the most common metric, used in 39 (69.64%) studies. A large proportion of studies failed to provide details on learning curve parameters such as competency thresholds, surgeon’s prior experience, case complexity, and learning curve definition. Considerable heterogeneity was found in the methods and reporting standards of learning curve evaluations in minimally invasive thoracic surgery. Conflicts of Interest: None. Funding Source: Boris Family Centre for Robotic Surgery. / Thesis / Master of Science (MSc)

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Yes / Recovering high-quality 3D point clouds from monocular endoscopic images is a challenging task. This paper proposes a novel deep learning-based computational framework for 3D point cloud reconstruction from single monocular endoscopic images. An unsupervised mono-depth learning network is used to generate depth information from monocular images. Given a single mono endoscopic image, the network is capable of depicting a depth map. The depth map is then used to recover a dense 3D point cloud. A generative Endo-AE network based on an auto-encoder is trained to repair defects of the dense point cloud by generating the best representation from the incomplete data. The performance of the proposed framework is evaluated against state-of-the-art learning-based methods. The results are also compared with non-learning based stereo 3D reconstruction algorithms. Our proposed methods outperform both the state-of-the-art learning-based and non-learning based methods for 3D point cloud reconstruction. The Endo-AE model for point cloud completion can generate high-quality, dense 3D endoscopic point clouds from incomplete point clouds with holes. Our framework is able to recover complete 3D point clouds with the missing rate of information up to 60%. Five large medical in-vivo databases of 3D point clouds of real endoscopic scenes have been generated and two synthetic 3D medical datasets are created. We have made these datasets publicly available for researchers free of charge. The proposed computational framework can produce high-quality and dense 3D point clouds from single mono-endoscopy images for augmented reality, virtual reality and other computer-mediated medical applications.

Irreversible electroporation (IRE) is a non-thermal tissue ablation modality in which electrical pulses are used to generate targeted disruption of cellular membranes. Clinically, IRE is administered by inserting one or more needles within or around a region of interest, then applying a series of short, high amplitude pulsed electric fields (PEFs). The treatment effect is dictated by the local field magnitude, which is quite high near the electrodes but dissipates exponentially. When cells are exposed to fields of sufficient strength, nanoscale "pores" form in the membrane, allowing ions and macromolecules to rapidly travel into and out of the cell. If enough pores are generated for a substantial amount of time, cell homeostasis is disrupted beyond recovery and cells eventually die. Due to this unique non-thermal mechanism, IRE generates targeted cell death without injury to extracellular proteins, preserving tissue integrity. Thus, IRE can be used to treat tumors precariously positioned near major vessels, ducts, and nerves. Since its introduction in the late 2000s, IRE has been used successfully to treat thousands of patients with focal, unresectable malignancies of the pancreas, prostate, liver, and kidney. It has also been used to decellularize tissue and is gaining attention as a cardiac ablation technique. Though IRE opened the door to treating previously inoperable tumors, it is not without limitation. One drawback of IRE is that pulse delivery results in intense muscle contractions, which can be painful for patients and causes electrodes to move during treatment. To prevent contractions in the clinic, patients must undergo general anesthesia and temporary pharmacological paralysis. To alleviate these concerns, high-frequency irreversible electroporation (H-FIRE) was introduced. H-FIRE improves upon IRE by substituting the long (~100 µs) monopolar pulses with bursts of short (~1 µs) bipolar pulses. These pulse waveforms substantially reduce the extent of muscle excitation and electrochemical effects. Within a burst, each pulse is separated from its neighboring pulses by a short delay, generally between 1 and 5 µs. Since its introduction, H-FIRE burst waveforms have generally been constructed simply by choosing the duration of constitutive pulses within the burst, with little attention given to this delay. This is quite reasonable, as it has been well documented that pulse duration plays a critical role in determining ablation size. In this dissertation, we explore the role of these latent periods within burst waveforms as well as their interaction with other pulse parameters. Our central hypothesis is that tuning the latent periods will allow for improved ablation size with reduced muscle contractions over traditional waveforms. After gaining a simple understanding of how pulse width and delay interact in vitro, we demonstrate theoretically that careful tuning of the delay within (interphase) and between (interpulse) bipolar pulses in a burst can substantially reduce nerve excitation. We then analyze how pulse duration, polarity, and delays affect the lethality of burst waveforms toward determining the most optimal parameters from a clinical perspective. Knowing that even the most ideal waveform will require slightly increased voltages over what is currently used clinically, we compare the clinical efficacy of two engineered thermal mitigation strategies to determine what probe design modifications will be needed to successfully translate H-FIRE to the clinic while maintaining large, non-thermal ablation volumes. Finally, we translate these findings in two studies. First, we demonstrate that burst waveforms with an improved delay structure allow for enhanced safety and larger ablation volumes in vivo. And finally, we examine the efficacy of H-FIRE in spontaneous canine liver tumors while also comparing the ablative effect of H-FIRE in tumor and non-neoplastic tissue in a veterinary clinical setting. / Doctor of Philosophy / Cancer is soon to become the most common cause of death in the United States. In 2023, approximately 2 million new cases of cancer will be diagnosed, leading to roughly 650 thousand lost lives. Interestingly, about half of newly diagnosed cancers are caught in the early stages before the disease has spread throughout the body. With effective local intervention, these patients could potentially be cured of their malignancy. Surgical removal of the tumor is the gold standard, but it is often not possible due to tumor location, patient comorbidities, or organ health status. In some instances, focal thermal ablation with radiofrequency or microwave energy can be performed when resection is not possible. These treatments entail the delivery of thermal energy through a needle electrode, which causes local tissue damage through coagulation (cooking) of the tissue. However, thermal ablation destroys tissue indiscriminately, meaning that any nearby blood vessels or neural components will also be damaged, which precludes thousands of patients from treatment each year. Irreversible electroporation (IRE) was introduced to overcome these challenges and provide a treatment option for patients diagnosed with otherwise untreatable tumors. IRE uses pulsed electric fields to generate nanoscale pores in cell membranes, which lead to a homeostatic imbalance and cell death. Because IRE is a membrane-based effect, it does not rely on thermal effects to generate cellular injury, which allows it to be administered to tumors that are adjacent to critical tissue structures such as major nerves and vasculature. Though IRE opened the door to treating otherwise inoperable tumors, procedures are technically challenging and require specialized anesthesia protocols. High-frequency irreversible electroporation (H-FIRE) was introduced by our group roughly a decade ago to simplify the procedure through the use of an alternate pulsing strategy. These higher frequency pulses offer several advantages such as limiting muscle contractions and reducing the risk of cardiac interference, both of which were concerns with IRE. However, H-FIRE ablations have been limited in size, and there is limited knowledge regarding the optimal pulsing strategy needed in order to maximize the ratio of therapeutic benefits to undesirable side effects like muscle stimulation and Joule heating. In this dissertation, we sought to understand how different pulse parameters affect these outcomes. Using a combination of computational, benchtop, and in vivo experiments, we comprehensively characterized the behavior of user-tunable pulse parameters and identified optimal methods for constructing H-FIRE protocols. We then translated our findings in a proof-of-principle study to demonstrate the ability of newly introduced waveform designs to increase ablation size with H-FIRE. Overall, this dissertation improves our understanding of how H-FIRE waveform selection affects clinical outcomes, introduces a new strategy for maximizing therapeutic outcomes with minimal side effects, and provides a framework for selecting parameters for specific applications.

Introduction: During laparoscopic surgery, surgeons may experience prolonged periods without fluid intake, which might impact surgical performance, yet there are no objective data investigating this issue. Therefore, the aim of this study was to elucidate the effect of prolonged dehydration on laparoscopic surgical performance and tissue handling. - Methods: A total of 51 laparoscopic novices participated in a single-center, open-label, prospective randomized cross-over trial. All participants were trained to proficiency using a standardized laparoscopic training curriculum. Afterward, all participants performed four different laparoscopic tasks twice, once after 6 h without liquid intake (dehydrated group) and once without any restrictions (control group). Primary endpoints were tissue handling defined by force exertion, task time, and error rate. The real hydration status was assessed by biological parameters, like heart rate, blood pressure, and blood gas analysis. - Results: 51 laparoscopic novices finished the curriculum and completed the tasks under both hydrated and dehydrated conditions. There were no significant differences in mean non-zero and peak force between the groups. However, dehydrated participants showed significantly slower task times in the Peg transfer task (hydrated: 139.2 s vs. dehydrated: 147.9 s, p = 0.034) and more errors regarding the precision in the laparoscopic suture and knot task (hydrated: 15.7% accuracy rate vs. dehydrated: 41.2% accuracy rate, p < 0.001). - Conclusion: Prolonged periods of dehydration do not appear to have a substantial effect on the fundamental tissue handling skills in terms of force exertion among surgical novices. Nevertheless, the observed impact on speed and precision warrants attention.

INTRODUÇÃO: Tem-se afirmado que a via de acesso minimamente invasiva na artroplastia total de joelho (ATJ) por não agredir o músculo quadríceps femoral permite reabilitação mais precoce. A fim de verificar a influência da preservação do aparelho extensor no ato cirúrgico, avaliou-se a força da musculatura extensora e flexora do joelho em pacientes submetidos à ATJ por duas vias de acesso diferentes. MÉTODOS: Este estudo comparou, no período de janeiro de 2005 a julho de 2006, os valores de torque máximo e de trabalho total obtidos por dinamometria isocinética aos seis meses de pós-operatório. Foram avaliados 12 indivíduos submetidos à ATJ por via de acesso minimamente invasiva e 8 indivíduos submetidos à ATJ por via de acesso transquadricipital. RESULTADOS: A análise estatística dos valores de torque máximo e de trabalho total absolutos e corrigidos pelo peso corporal não demonstrou diferença entre os dois grupos. CONCLUSÃO: Não há diferença de força da musculatura extensora e flexora do joelho aos seis meses de cirurgia. / INTRODUCTION: It has been stated that for total knee arthroplasty (TKA), the minimally invasive approach permits earlier rehabilitation because it is not prejudicial for the femoral quadriceps muscle. To verify the influence of preserving the extensor apparatus during surgery, strength of the knee extension and flexion muscles was evaluated in patients submitted to TKA with different approaches. METHODS: The values of maximum torque and total work obtained by isokinetic dynamometry six months after surgery were compared for the MIS group of 12 individuals submitted to TKA by the minimally invasive surgical approach and the Control group of eight others submitted to TKA by the transquadricipital approach, between January 2005 and July 2006. RESULTS: Statistical analysis of the absolute values of maximum torque and total work corrected by body weights did not show a difference between the two groups. CONCLUSION: There was no difference in the extension and flexion strength of the knee muscles six months after surgery.

INTRODUÇÃO: Tem-se afirmado que a via de acesso minimamente invasiva na artroplastia total de joelho (ATJ) por não agredir o músculo quadríceps femoral permite reabilitação mais precoce. A fim de verificar a influência da preservação do aparelho extensor no ato cirúrgico, avaliou-se a força da musculatura extensora e flexora do joelho em pacientes submetidos à ATJ por duas vias de acesso diferentes. MÉTODOS: Este estudo comparou, no período de janeiro de 2005 a julho de 2006, os valores de torque máximo e de trabalho total obtidos por dinamometria isocinética aos seis meses de pós-operatório. Foram avaliados 12 indivíduos submetidos à ATJ por via de acesso minimamente invasiva e 8 indivíduos submetidos à ATJ por via de acesso transquadricipital. RESULTADOS: A análise estatística dos valores de torque máximo e de trabalho total absolutos e corrigidos pelo peso corporal não demonstrou diferença entre os dois grupos. CONCLUSÃO: Não há diferença de força da musculatura extensora e flexora do joelho aos seis meses de cirurgia. / INTRODUCTION: It has been stated that for total knee arthroplasty (TKA), the minimally invasive approach permits earlier rehabilitation because it is not prejudicial for the femoral quadriceps muscle. To verify the influence of preserving the extensor apparatus during surgery, strength of the knee extension and flexion muscles was evaluated in patients submitted to TKA with different approaches. METHODS: The values of maximum torque and total work obtained by isokinetic dynamometry six months after surgery were compared for the MIS group of 12 individuals submitted to TKA by the minimally invasive surgical approach and the Control group of eight others submitted to TKA by the transquadricipital approach, between January 2005 and July 2006. RESULTS: Statistical analysis of the absolute values of maximum torque and total work corrected by body weights did not show a difference between the two groups. CONCLUSION: There was no difference in the extension and flexion strength of the knee muscles six months after surgery.

Numerous studies have demonstrated the potential efficacy of percutaneous image-guided interventions over open surgical interventions. The conventional image-guided procedures are limited by the freehand technique, requiring mental 3D registration and hand-eye coordination for needle placement. The outcomes of these procedures are associated with longer duration and increased patient discomfort with high radiation exposure. Previously, a static image overlay system was proposed for aiding needle interventions. Certain drawbacks associated with the static system limited the clinical translation. To overcome the ergonomic issues and longer calibration duration associated with static system, an adjustable image overlay system was proposed. The system consisted of monitor and semi-transparent mirror, attached together to an articulated mobile arm. The 90-degree mirror-monitor configuration was proposed to improve the physician access around the patient. MicronTracker was integrated for dynamic tracking of the patient and device. A novel method for auto-direct calibration of the virtual image overlay plane was proposed. Due to large mechanical structure, the precise movement was limited and consumed useful space in the procedure room. A mobile image overlay system with reduced system weight and smaller dimensions was proposed to eliminate the need for mechanical structure. A tablet computer and beamsplitter were used as the display device and mirror respectively. An image overlay visualization module of the 3D Slicer was developed to project the correct image slice upon the tablet device. The system weight was reduced to 1 kg and the image overlay plane tracking precision (0.11mm STD=0.05) was similar to the printed physical markers. The auto-calibration of the image overlay plane can be done in two simple steps, away from the patient table and without additional phantom. Based on the successful pre-clinical testing of the previous static system, the mobile image overlay system with reduced weight, increased tracking precision and easier maneuverability, can be possibly hand-held by the physician to explore the image volume over the patient and be used for a wide range of procedures. The mobile image overlay system shall be classified as Class II device as per FDA regulations, do not require extensive verification and validation efforts and further improves the commercialization opportunities. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2014-06-26 18:51:03.958