Zielsetzung: In dieser Studie wurde an 15 gesunden Rindern die Methode der Thorakoskopie erprobt mit dem Ziel, eine Grundlage für den weiteren Einsatz dieses Verfahrens am bovinen Thorax zu schaffen. Im Mittelpunkt standen die Entwicklung einer geeigneten Untersuchungstechnik und die Beschreibung der endoskopisch dargestellten, im Pleuraspalt gelegenen Organe sowie möglicher pathologischer Befunde. Weiterhin galt es Komplikationen zu ermitteln und anhand der Erfahrungen aus diesem Versuch Indikationen für den Einsatz dieses minimal-invasiven Verfahrens beim Rind zu formulieren. Methodik: Alle Tiere wurden einer links- und rechtsseitigen Thorakoskopie jeweils mit und ohne intrapleurale Insufflation von Kohlenstoffdioxid über einen interkostalen Zugang unterzogen. Im Rahmen des Versuches fanden folglich vier Thorakoskopien je Rind und insgesamt 60 Thorakoskopien mit einer Wartezeit von 24 Stunden zwischen den einzelnen Untersuchungen statt. Die Untersuchungen erfolgten am im Zwangsstand fixierten, lokal anästhesierten Tier. Der endoskopische Zugang lag stets auf Höhe des Tuber coxae und variierte vom 8. bis zum 10. Interkostalraum. Nach interkostaler Schnittinzision wurde eine Zitzenkanüle bis in den Pleuraspalt vorgeschoben. Der spontane Einstrom von Raumluft in das Cavum pleurae führte zum Teilkollaps des ipsilateralen Lungenflügels. Die Kanüle wurde durch eine Trokar-Hülsen-Einheit ersetzt und die Hülse stellte nach Entfernung des Trokars den Zugang für die Optik. Je Hemithorax wurde die Untersuchungszeit auf 20 Minuten festgelegt. Sie begann im kranialen Pleuraspalt, wurde über (dorso)-kranial, (dorso)-medial, (dorso)-kaudal, ventrokaudal und ventral fortgeführt und endete mit ventrokranial ausgerichteter Optik. Ergebnisse: Die meisten im Cavum pleurae gelegenen Organe konnten ohne die Insufflation von CO2 ausreichend adspiziert werden. Während der links- und rechtsseitigen Thorakoskopien gelang die Adspektion großer Bereiche der Pleura costalis mit den Mm. intercostales interni sowie den Aa. et Vv. intercostales dorsales, Anteile der Lungenflügel und des Ligamentum pulmonale, der Aorta thoracica, des thorakalen Ösophagus, des M. longus colli, von Lymphknoten des Lc. thoracicum dorsale sowie der Lnn. mediastinales caudales, der Pars thoracica des Truncus sympathicus und des Truncus vagalis dorsalis des N. vagus. Des Weiteren konnten der M. psoas major, Anteile des Diaphragmas und der V. phrenica cranialis, der Hiatus aorticus, der Arcus lumbocostalis sowie unregelmäßig die A. et V. bronchoesophagea adspiziert werden. Die Untersuchung des rechten kranialen Pleuraspaltes war mit Einschränkungen behaftet und spiegelte sich in einer reduzierten Darstellung der sympathische Nervenfasern aus dem Ggl. cervicothoracicum, des Truncus costocervicalis dextra sowie der V. costocervicalis dextra wider. Linksseitig war die Betrachtung dieser Organe bzw. der korrespondierenden linksseitig angelegten Organe regelmäßig möglich. Weiterhin gelang während der linksseitigen Untersuchung die Adspektion des Ln. tracheobronchalis sinister, des Truncus brachiocephalicus sowie der V. azygos sinistra. Rechtsseitig konnte die V. azygos dextra stets adspiziert werden. Die Darstellung des Ductus thoracicus erfolgte nur bei einem der untersuchten Rinder infolge einer pathologischen Kompression. Während der Untersuchungen unter passivem Lungenkollaps war das Perikard nur bei einer rechtsseitigen Thorakoskopie zu sehen. Die Zweituntersuchungen des ipsilateralen Pleuraspaltes fanden während der Insufflation von CO2 bis zu einem Überdruck von 5 mm Hg statt. Dies sollte einen stärkeren Lungenkollaps bewirken und damit die Sicht auf intrapleural gelegene Organe verbessern. Während der Insufflation waren beidseits größere Anteile der Rippen und des Zwerchfells sowie das Perikard linksseitig bei drei Rindern und rechtsseitig bei einem Rind darstellbar. Postoperative Röntgenaufnahmen dienten dem Ausschluss des Vorhandenseins eines ipsi- oder kontralateralen Pneumothorax. Schlussfolgerung: Die Studie zeigt, dass Thorakoskopien an stehenden, gesunden Rindern sicher und komplikationsarm durchzuführen sind. Die beschriebene, minimal-invasive Technik stellt eine wertvolle, zusätzliche Methode zur tierschonenden Abklärung intrathorakaler Erkrankungen beim Rind dar. Der diagnostische, palliative oder therapeutische Nutzen muss in weiterführenden Untersuchungen ermittelt werden. / Objective: A study on 15 healthy cows was conducted to prove the thoracoscopic technique with the aim to establish a basis for further application of this procedure on cattle. Focus was on developing an adequate examination technique, displaying and describing of physical as well as pathological findings on intrathoracic organs examined endoscopically. Furthermore perioperative complications and indications of this minimally invasive method on cattle should be presented. Methods: The animals underwent a left and right side thoracoscopy under passive lung collapse and under insufflation of CO2. Therefore four thoracoscopies at each cow and a total of 60 thoracoscopies were performed with a waiting time of 24 hours between each examination. The cows were restrained in a stock and locally anesthetized. The endoscopic portal was lined up horizontally with the level of the ventral margin of the coxal tuber, at the point where the local anaesthetic had been injected and varied between the eighth and the tenth intercostal space. After a vertical stab incision through the skin and subcutaneous tissues a blunt stainless teat cannula was introduced into the pleural space. At this point air streamed spontaneously into the pleural space following by an ipsilateral lung collapse. The teat cannula was then removed and replaced by a sharp guarded trocar. After that the trocar was removed and the endoscope was passed through the remaining cannula. The time assessment for examination of each thorax was 20 minutes, started in the cranial pleural space, was continued in the (dorso)-cranial, (dorso)-medial, (dorso)-caudal, ventrocaudal und ventral direction and ended with ventrocranially aligned optic. Results: Most of the intrathoracic organs were seen without additional CO2 insufflation. During left and right side thoracoscopies large parts of the costal pleura, the internal intercostal muscles, the dorsal intercostal veins and arteries, parts of the lungs and the pulmonary ligament, the thoracic aorta, the thoracic part of the esophagus and the longus colli muscle, caudal mediastinal lymph nodes and lymph nodes associated with the dorsal thoracic lymph center, the thoracic part of the sympathic trunk and the dorsal vagus nerve were seen. Furthermore the psoas major muscle, parts of the diaphragm and the cranial phrenic vein, the aortic hiatus, the lumbocostal arch and intermittently the broncho-esophageal artery and vein could be identified. There were some constraints during right side thoracoscopy of the cranial pleural space which caused a limited view at the sympathic nerve fibres associated with the cervicothoracic ganglion, the right costocervical trunk and the right costocervical vein. At the left side these organs, the corresponding left side organs respectively, were constantly seen. Moreover during the exam at the left pleural space the left tracheobronchial lymph node, the brachiocephalic trunk and the left azygos could be well identified. During right side thoracoscopy the right azygos vein was always visible. In one case the presentation of the thoracic duct succeeded as a result of its pathological compression. During examination under passive lung collapse the pericard was visualized in one cow during right side thoracoscopy. The second thoracoscopies of the ipsilateral pleural space were conducted during insufflation of CO2 with a pressure of 5 mm Hg. A stronger lung collapse should result during insufflation with an enhanced view of the organs located intrapleurally. During insufflation at both sides larger parts of the ribs and diaphragm as well as the pericard on the left side at three cattle and on the right side at one cattle could be seen. Postoperative radiographies ensured the absence of an ipsi- or contralateral pneumothorax. Conclusion: This study shows that thoracoscopies on standing healthy cattle could be safely performed without major perioperative complications or side effects. The described minimally invasive procedure is a valuable, gentle and additional method to diagnose intrathoracic diseases in cattle. The use of thoracoscopy as diagnostic tool, for curative and palliative therapy should be identified in further studies.

Pasaulyje operacijos minimaliai invazine metodika tampa vis labiau populiaresnės. Literatūroje galima rasti argumentų ,,už” ir ,,prieš” šia metodiką.. Minimalios invazijos šalininkai teigia, kad pagrindinis metodikos privalumas — greitesnė pacientų reabilitacija. Oponentų teigimu minimalios invazijos totalinis kelio sąnario endoprotezavimas nėra pranašesnis už įprastinį, netgi mano, jog tai padidina komponentų padėties klaidų tikimybę, bei komplikacijų riziką. 70 kelio sąnario artroze sergančių pacientų buvo įtraukta į atsitiktinių imčių tyrimą. 35 pacientai operuoti minimaliai invazine metodika, 35 įprastine. Mes tyrėme operacijos laiką, kelio sąnario judesius. Po 6 ir 12 savaičių kelio sąnario funkcija buvo vertinta pagal Kelio Sąnario draugijos skalę. Rentgenologiniam ištyrimui priekinę, šoninę kelio bei priekinę visos kojos rentgenogramas. Ligonių pasiskirstymas pagal, lytį amžių, kūno masės indeksą bei kelio sąnario pakitimus statistiškai reikšmingai tarp grupių nesiskyrė. Tyrimo metu nustatėme minimaliai invazinė metodika operuotų pacientų greitesnį kelio judesių atsistatymą, geresnius funkcinius rezultatus po 6 sav., bei ilgesnę operacijos trukmę. Po 12 savaičių skirtumo tarp grupių nenustatėme. Taip pat nenustatėme protezo komponentų padėties skirtumų tarp grupių. / Minimally invasive surgery is getting more interest in literature recently. However the reports regarding the effectiveness of this particular technique are controversial. There are reports in the literature that minimally invasive technique is associated with increased number of technical mistakes. Advantages of this technique are faster rehabilitation. In randomized controlled trial we analyzed 70 knee osteoarthritis patients admitted for elective total knee replacement. All patients were randomized to do surgery using minimally invasive or conventional technique. We analyzed operation time, range of motions 1-6 days after surgery. After 6 and 12 week we evaluated total knee replacement patiens according KSS score. For radiographic examination we performed anterior, lateral and long standing x-rays after the surgery. Preoperative data such as severity of osteoarthirtis, sex, age, and functional score did not differ within the groups. Minimally invasive group was associated with longer operation time, faster recovery of range of motions, better knee function 6 weeks after surgery. 12 week after total knee replacement we did not find any differences between the groups. Component position and leg axis deviation did not differ between the groups.

Minimally invasive surgeries (MIS) are fundamentally constrained by image quality,access to the operative field, and the visualization environment on which thesurgeon relies for real-time information. Although invasive access benefits the patient,it also leads to more challenging procedures, which require better skills andtraining. Endoscopic surgeries rely heavily on 2D interfaces, introducing additionalchallenges due to the loss of depth perception, the lack of 3-Dimensional imaging,and the reduction of degrees of freedom.By using state-of-the-art technology within a distributed computational architecture,it is possible to incorporate multiple sensors, hybrid display devices, and3D visualization algorithms within a exible surgical environment. Such environmentscan assist the surgeon with valuable information that goes far beyond what iscurrently available. In this thesis, we will discuss how 3D visualization and reconstruction,stereo displays, high-resolution display devices, and tracking techniques arekey elements in the next-generation of surgical environments.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 4 uppsatser.

Background. Barlow’s mitral valve (MV) disease re- mains a surgical challenge. We compared short- and medium-term outcomes of neochordal (“loop”) versus edge-to-edge (“Alfieri”) minimally invasive MV repair in patients with Barlow’s disease. Methods. From January 2009 to April 2014, 123 consecutive patients with Barlow’s disease (defined as bileaflet billowing or prolapse [or both], excessive leaflet tissue, and annular dilatation with or without calcifica- tion) underwent minimally invasive MV operations for severe mitral regurgitation (MR) at our institution. Three patients (2.4%) underwent MV replacement during the study period and were excluded from subsequent anal- ysis. The loop MV repair technique was used in 68 pa- tients (55.3%) and an edge-to-edge repair was performed in 44 patients (35.8%). Patients who underwent a combi- nation of these 2 techniques (n [ 8 [6.5%]) were excluded. The median age was 48 years, and 62.5% of patients were men. Concomitant procedures included closure of a patent foramen ovale or atrial septal defect (n [ 19), tricuspid valve repair (n [ 5), and atrial fibril- lation ablation (n [ 15). Follow-up was performed 24.7 ± 17 months postoperatively and was 98% complete. Results. No deaths occurred perioperatively or during follow-up. Aortic cross-clamp time (64.1 ± 17.6 minutes versus 95.9 ± 29.5 minutes) and cardiopulmonary bypass (CPB) time (110.0 ± 24.2 minutes versus 146.4 ± 39.1 mi- nutes) were significantly shorter (p < 0.001) in patients who received edge-to-edge repair. Although patients who underwent edge-to-edge repair received a larger annulo- plasty ring (38.6 ± 1.5 mm versus 35.8 ± 2.7 mm; p < 0.001), the early postoperative resting mean gradients were higher(3.3±1.2mmHgversus2.6±1.2mmHg;p[ 0.007) and the mitral orifice area tended to be smaller in this group (2.8 ± 0.7 cm2 versus 3.0 ± 0.7 cm2; p [ 0.06). The amount of residual MR was similar between groups (0.3 ± 0.6 versus 0.6 ± 1.0 for edge-to-edge versus loop procedures, respectively; p [ 0.08). More than mild MR requiring early MV reoperation was present in 3 patients who underwent loop procedures (4.4%) and in no patients who had edge-to-edge procedures (p [ 0.51). During follow-up, 2 patients (1 in each group) required MV replacement for severe MR. The 4-year freedom from MV reoperation was 92.8% ± 5.0% in the Alfieri group compared with 90.9% ± 4.6% in the loop group (p [ 0.94). Conclusions. Minimally invasive MV repair can be accomplished with excellent early and medium-term outcomes in patients with Barlow’s disease. The edge- to-edge (Alfieri) repair can be performed with reduced operative times when compared with the loop technique, but it results in mildly increased transvalvular gradients and mildly decreased valve opening areas without any difference in residual MR.

A técnica de videolaparoscopia exploratória da cavidade abdominal utilizada atualmente em equinos implica em uma série de dificuldades. Há necessidade do acesso cirúrgico bilateral da cavidade abdominal ou anestesia geral para acesso ventral com a finalidade de obter uma avaliação adequada das vísceras e, consequentemente, um diagnóstico mais preciso. Esse procedimento prolonga o tempo e aumenta os riscos de complicações transoperatórias e pós-cirúrgicas. Apesar de ser uma técnica bem estabelecida com situações em que as vantagens de sua utilização são evidentes, alguns fatores ainda limitam sua difusão, entre eles podemos destacar: o custo do equipamento que limita a utilização fora de Universidades, Centros de Pesquisas ou clínicas particulares especializadas em cirurgias veterinárias. Com o objetivo de minimizar os aspectos negativos dessa técnica e viabilizar seu uso na rotina clínica e cirúrgica de equinos, surgiu a ideia de buscar uma nova via de acesso à cavidade abdominal e utilizando o videocolonoscópio, equipamento de menor custo. No presente estudo, foi analisado o uso do endoscópio flexível na exploração abdominal de equinos machos castrados e fêmeas pelo acesso perianal. A técnica foi avaliada quanto à viabilidade de permitir ou não o acesso à cavidade e identificação das vísceras abdominais em equinos. Além disso, buscou-se verificar se o endoscópio flexível permite a obtenção de amostras de tecido hepático para avaliação histológica. Os animais foram, alimentados, desverminados e avaliados diariamente por meio de exame clínico geral durante o período do experimento. Colheitas de amostras de sangue para hemograma e dosagem de fibrinogênio foram realizadas antes e após o procedimento cirurgico para posterior analise. Todos os cuidados de rotina em relação à antissepsia cirúrgica foram devidamente tomados e os animais submetidos a protocolo de sedação e analgesia. Os procedimentos de pós-operatório como terapia analgésica, anti-inflamatória, inspeção e higienização diária do local de incisão foram prestados. O procedimento cirúrgico teve início com incisão na região perianal laterodorsal direita entre o ânus e o musculo semimembranoso utilizando bisturi e tesoura, seguida de divulsão romba com o dedo ao longo da parede retal até alcançar uma profundidade aproximada de 10 cm, momento no qual foi introduzida cânula metálica com 56 cm de comprimento e 16 mm de diâmetro (Ø). Por meio desta cânula foi introduzido o endoscópio flexível (videocolonoscópio), sendo o restante da introdução da cânula acompanhada por visualização indireta em monitor. A cânula foi forçada lentamente até atingir a cavidade peritoneal, momento a partir do qual foi realizada exploração da cavidade abdominal. As vísceras observadas foram anotadas em ficha especialmente desenvolvida para esta finalidade. Como parte da avaliação hepática foi realizada biópsia e o material obtido analisado no setor de patologia da Faculdade de Veterinária da UFRGS. Após dez dias de pós-operatório, quando em plenas condições de saúde, os equinos receberam alta. Os resultados permitem inferir que, o uso do endoscópio flexível na identificação das vísceras abdominais por meio de laparoscopia perianal é viável na rotina clínica e cirúrgica de equinos e possibilita obter amostras teciduais para avaliação histológica. No entanto, o emprego da técnica exige o treinamento da equipe cirúrgica, principalmente do cirurgião, bom planejamento e um diagnóstico pré-operatório incompleto que necessite complementação diagnóstica. / The technique of exploratory laparoscopy abdominal cavity used currently in horses involves a series of difficulties. There is need for bilateral abdominal cavity surgical access or general anesthesia for ventral access for the purpose of obtaining an adequate assessment of the viscera and, consequently, a more accurate diagnosis. This procedure extends and increases the risks of post-surgical complications and transoperatórias. Despite being a well-established technique in situations where the advantages of its use are evident, some factors still limit its spread, some of them are: the cost of equipment that limits the use out of universities, research centers or private clinics specialized in veterinary surgeries. In order to minimize the negative aspects of this technique and enable its use in routine clinical and surgical equine, the idea of seeking a new route to the abdominal cavity and using videocolonoscópio, lower equipment cost. In the present study, we analyzed the use of the flexible endoscope in the abdominal exploration equine barrows and gilts for access perianal. The technique was evaluated on the feasibility of allowing or not the access cavity and identification of the abdominal viscera in horses. In addition, sought to verify that the flexible endoscope allows obtaining liver tissue samples for histological evaluation. The animals were fed, wormed and evaluated daily by a general clinical examination during the period of the experiment. Sampling of blood for blood count and fibrinogen were measured before and after the surgical procedure for subsequent analysis. All routine care in relation to surgical antisepsis were duly taken and animals undergoing sedation and analgesia protocol. Procedures as postoperative analgesic therapy, anti-inflammatory, inspection and cleaning daily incision site were provided. The procedure began with surgical incision in the right laterodorsal perianal region between the anus and the semimembranosus muscle using a scalpel and scissors, then blunt dilatation of the finger along the rectal wall until it reaches an approximate depth of 10 cm, at which the metal cannula with 56 cm length and 16 mm in diameter (Ø) was introduced. Through this cannula was inserted flexible endoscope (videocolonoscópio), the remainder of the introduction of the cannula followed by indirect viewing monitor. The cannula was forced slowly to the peritoneal cavity, the time from which it was held exploration of the abdominal cavity. The cannula was forced slowly to the peritoneal cavity, the time from which it was held exploration of the abdominal cavity. The viscera were observed in annotated form specially developed for this purpose. As part of the evaluation of the liver, biopsy was performed and the obtained material analyzed at the pathology of the Veterinary School of UFRGS. After ten days postoperatively, when in full health, horses were discharged. The results allow us to conclude that the use of the flexible endoscope in the identification of abdominal viscera through perianal laparoscopy is feasible in routine clinical and surgical equine and enables to obtain tissue samples for histologic evaluation. However, the use of the technique requires training of the surgical team, especially the surgeon, good planning and a preoperative diagnosis requiring incomplete diagnostic workup.

Estão disponíveis para treinamento videocirúrgico métodos in vitro e treino em animais, antes de se estar apto para chegar ao paciente propriamente dito. O treino em animais vivos tem sua importância no fato de mimetizar situações reais, permitindo o treinamento, não só da técnica, mas também de conduta e trabalho em equipe. Em contrapartida, o uso de animais vivos utilizados em treinamento cirúrgico (vivissecção) e pesquisa têm encontrado oposição em questões éticas e de bem estar animal. A utilização de cadáveres para o treinamento e desenvolvimento de novas técnicas cirúrgicas em Medicina tem se tornado uma alternativa interessante para a videocirurgia. No presente estudo foram testados como modelos experimentais cadáveres de cães conservados com a solução de Larssen modificada, que mantém as características teciduais do cadáver semelhantes às de um cão vivo. Foram utilizados 10 cães oriundos da rotina do Hospital de Clínicas Veterinárias da Universidade Federal do Rio Grande do Sul ou do Centro de Controle de Zoonoses de Porto Alegre, com indicação de eutanásia por patologias graves e sem tratamento. Após a eutanásia, foram preparados com solução de Larssen modificada, a fim de manterem características teciduais semelhantes as de um cão vivo, sendo armazenados em freezer após o preparo. Estes cadáveres, depois de descongelados, foram testados quanto a viabilidade do modelo para treinamento de nefrectomia total laparoscópica e tireoidectomia videoendoscópica. Foram avaliadas no transoperatório, características teciduais como: coloração, textura e odor dos cadáveres e também, a pressão de dióxido de carbono utilizada para a insuflação. O modelo experimental em cadáveres de cães conservados com solução de Larssen modificada foi viável e efetivo para treinamento em videocirurgia nas técnicas propostas; embora alguns cães, durante a nefrectomia laparoscópica evidenciassem os rins friáveis. No que se refere às características teciduais avaliadas, foram semelhantes às de um animal vivo, e a pressão média de dióxido de carbono utilizada durante a nefrectomia total laparoscópica foi de 15,58 mmHg e para a tireoidectomia videoendoscópica foi de 15,75 mmHg. / In consideration of the fact that training with live animals simulates real situations, it has still its importance. It allows not only technical training but also conduct and teamwork. In contrast, the use of live animals in surgical training (vivisection) and research has found opposition due to ethical and animal welfare concerns. The use of cadavers for training and development of new surgical techniques in medicine has become an interesting alternative for videosurgery. In the present study cadavers of dogs, conserved with a modified Larssen solution were used as experimental models. This modified Larssen solution preserves the tissue of the body with similar characteristics to the tissue of alive dogs. Ten dogs from the routine of the Veterinary Hospital of the Federal University of Rio Grande do Sul and the Porto Alegre's Zoonosis Control Center with indication of euthanasia for serious diseases were used for this study. After euthanasia the dogs were prepared with the modified Larssen solution and were stored in freezers. Before beginning procedures the cadaveres were defrosted, the bodies of the dogs were tested to evaluate the training feasibility for laparoscopic total nefrectomy and videoendoscopic thyroidectomy. In the next step characteristics like coloration, tissue structure, odor and pressure of carbon dioxide for inflation has been evaluated. The experimental model to prepare dog cadavers with modified Larssen solution proved to be practicable and effective for training in videosurgery within the proposed procedures. Even though, some dogs showed friable kidneys during laparoscopic nephrectomy. In relation to the evaluated tissue characteristics, the experimental model showed similar characteristics of a living animal. The middle pressure of carbon dioxide was 15,58 mmHg during laparoscopic total nefrectomy and 15,75 mmHg during videoendoscopic thyroidectomy.

Simulação computacional de ambientes cirúrgicos têm sido amplamente utilizados, normalmente para treinamentos, ajudando no desenvolvimento de habilidades essenciais e minimizando erros em procedimentos cirúrgicos. Para estes ambientes, é essencial a obtenção de um comportamento mais realista, sendo importante o uso de técnicas com alta precisão, além de uma simulação em tempo real. A fim de melhor controlar este trade-off entre eficiência e eficácia, apresentamos um ambiente híbrido e adaptativo que combina um conjunto de métodos para alcançar uma boa precisão e desempenho na simulação. Nosso sistema mescla métodos físicos de deformação (Método de Elementos Finitos e Mass-Mola) com um método não-físico que aproxima o comportamento dos primeiros (Green Coordinates), sendo capaz de utilizar o método apropriado dependendo da situação. Para melhor simular um ambiente cirúrgico completo, foram implementadas ferramentas adicionais para interação, permitindo pegar e manipular, queimar, e sentir os objetos do cenário. Nosso sistema proporciona grande imersão ao usuário, consumindo menos recursos computacionais e aumentando as taxas de atualização da simulação. / Computational simulation of surgical environments have been widely used usually for trainings, improving essential skills and minimizing errors in surgical procedures. As these environments are always looking for a more realistic behavior, it is important to use high-precision techniques while ensuring a real-time simulation. In order to better manage this trade-off between efficiency and effectiveness, we present a hybrid and adaptive environment that combines a set of methods to achieve good accuracy and performance for a simulation. Our system merges physically deformation methods (Finite Elements Method and Mass Spring Damper) with a non-physical method that approximates the formers behavior (Green Coordinates), being able to use the appropriate method depending on the situation. To simulate an approximation of a complete surgical environment, we also implement interaction tools, such as picking, burning, and haptic feedback. Our system provides great immersion for the user, consuming less computational resources and increasing update rates.

Minimally invasive surgery (MIS) is becoming increasing popular and widely adopted on account of relative post-operative advantages (shorter hospital stays, less scarification, trauma and post-operative pain) it offers patients when compared to open surgery. Nonetheless, the surge in demand for MIS procedures are not met with commensurate availability of experts in the field, thus leading to excessive stress attributable to increased case load, and an increase in the number of surgery interns requiring training with far less MIS experts to provide it. Also, musculoskeletal discomforts experienced by MIS surgeons have been attributed to ergonomic factors among other causes, and a required verification of the viability of fundamentals of laparoscopic surgery (FLS) as a valid ergonomic discriminator between traditional MIS and robot-assisted MIS was tested and validated. Real-time, subject-centered, and objective quantification of surgical skills has long been a challenge. A proposed solution is presented here involving the application of complexity theory (time delay and Hurst exponent principles) to the analysis of phase space reconstructions of time series data, generated by periodic changes in Euler coordinates of surgical graspers while being used by MIS novices and experts. A comparison of Hurst exponent and time delay values over multiple iterations of the same task provides quantitative insight on MIS skills improvement and experience.

Due to its inherent complexity such as limited work volume and degree of freedom, minimally invasive surgery (MIS) is ergonomically challenging to surgeons than traditional open surgery. Specifically, MIS can expose performing surgeons to excessive ergonomic risks including muscle fatigue that may lead to critical errors in surgical procedures. Therefore, detecting the vulnerable muscles and time-to-fatigue during MIS is of great importance in order to prevent these errors. In this research, different surgical skill and ergonomic assessment methods are reviewed and their advantages and disadvantages are studied. According to the literature review, which is included in chapter 1, some of these methods are subjective and those that are objective provide inconsistent results. Muscle fatigue analysis has shown promising results for skill and ergonomic assessments. However, due to the data analysis issues, this analysis has only been successful in intense working conditions. The goal of this research is to apply an appropriate data analysis method to minimally invasive surgical setting which is considered as a low-force muscle activity. Therefore, surface electromyography is used to record muscle activations of subjects while they performed various real laparoscopic operations and dry lab surgical tasks. The muscle activation data is then reconstructed using Recurrence Quantification Analysis (RQA), which has been proven to be a reliable analysis, to detect possible signs of muscle fatigue on different muscle groups. The results of this data analysis method is validated using subjective fatigue assessment method. In order to study the effect of muscle fatigue on subject’s performance, standard Fundamental of Laparoscopic Surgery (FLS) tasks performance analysis is used.