Minimally invasive swine spine surgery training: technical aspects, benefits, and anatomical limitations.

OBJECTIVE: To describe the technical specificities and feasibility of simulation of minimally invasive spine surgery in live pigs, as well as similarities and differences in comparison to surgery in humans. METHODS: A total of 22 Large White class swine models, weighing between 60 and 80kg, were submitted to surgical simulations, performed during theoretical-practical courses for training surgical techniques (microsurgical and endoscopic lumbar decompression; percutaneous pedicular instrumentation; lateral access to the thoracic spine, and anterior and retroperitoneal to the lumbar spine, and management of complications) by 86 spine surgeons. For each surgical technique, porcine anatomy (similarities and differences in relation to human anatomy), access route, and dimensions of the instruments and implants used were evaluated. Thus, the authors describe the feasibility of each operative simulation, as well as suggestions to optimize training. Study results are descriptive, with figures and drawings. RESULTS: Neural decompression surgeries (microsurgeries and endoscopic) and pedicular instrumentation presented higher similarities to surgery on humans. On the other hand, intradiscal procedures had limitations due to the narrow disc space in swines. We were able to simulate situations of surgical trauma in surgical complication scenarios, such as cerebrospinal fluid fistulas and excessive bleeding, with comparable realism to surgery on humans. CONCLUSION: A porcine model for simulation of minimally invasive spinal surgical techniques had similarities with surgery on humans, and is therefore feasible for surgeon training.

Minimally invasive swine spine surgery training: technical aspects, benefits, and anatomical limitations

ABSTRACT Objective To describe the technical specificities and feasibility of simulation of minimally invasive spine surgery in live pigs, as well as similarities and differences in comparison to surgery in humans. Methods A total of 22 Large White class swine models, weighing between 60 and 80kg, were submitted to surgical simulations, performed during theoretical-practical courses for training surgical techniques (microsurgical and endoscopic lumbar decompression; percutaneous pedicular instrumentation; lateral access to the thoracic spine, and anterior and retroperitoneal to the lumbar spine, and management of complications) by 86 spine surgeons. For each surgical technique, porcine anatomy (similarities and differences in relation to human anatomy), access route, and dimensions of the instruments and implants used were evaluated. Thus, the authors describe the feasibility of each operative simulation, as well as suggestions to optimize training. Study results are descriptive, with figures and drawings. Results Neural decompression surgeries (microsurgeries and endoscopic) and pedicular instrumentation presented higher similarities to surgery on humans. On the other hand, intradiscal procedures had limitations due to the narrow disc space in swines. We were able to simulate situations of surgical trauma in surgical complication scenarios, such as cerebrospinal fluid fistulas and excessive bleeding, with comparable realism to surgery on humans. Conclusion A porcine model for simulation of minimally invasive spinal surgical techniques had similarities with surgery on humans, and is therefore feasible for surgeon training.

Uso de esponja hemostática de gelatina para o desenvolvimento de infarto agudo do miocárdio em suínos / Use of the haemostatic gelatin sponge for development of the acute myocardium infarct in swine

O infarto agudo do miocárdio resulta da obstrução temporária de uma coronária com redução de sangue para parte do miocárdio, bastando alguns minutos de interrupção do fluxo sanguíneo para estabelecer a injúria. Foi cateterizado a porção distal da origem do 1° ramo diagonal da artéria coronária interventricular esquerda de dois suínos e infundida solução de esponja hemostática de gelatina. Pós um período de 21 dias os animais foram eutanasiados e o coração foi processado para microscopia de luz, revelando expressiva cicatriz na região apical do ventrículo esquerdo em um animal enquanto que no outro, a lesão estava localizada na parede ventricular esquerda, e com menor extensão. Foi possível observar também a presença de áreas não pertencentes à região infartada, com grande depósito de colágeno, sugerindo um processo bastante heterogêneo. Desta forma, podemos concluir que esta técnica não é interessante para o desenvolvimento de modelo experimental de infarto agudo do miocárdio.

The acute infarction of myocardium results of the temporary blockage of coronary with reduction of blood for part of the myocardium, some minutes of interruption of the sanguineous flow are sufficient for the establishment of injury. Was catheterized the distal portion of the origin of the first diagonal branch of coronary interventricular left artery from two swine and a solution of haemostatic gelatin sponge was infused. After a period of 21 days the animals had been euthanized and the heart was processed for light microscopy, show an expressive scar in the apical region of the left ventricle in an animal whereas in the other, the injury was located in the left ventricular wall, and with lesser extension. It was possible also to observe the presence of areas not pertaining to the infarction region, with great collagen deposit, suggesting a heterogeneous process. In such a way, we can conclude that this technique is not interesting for the development of acute experimental model of infarction of the myocardium.

Padrão de distribuição de células mononucleares de medula óssea em tecido cardíaco sadio por diferentes vias de infusão / Interaction between infusion route and bone marrow mononuclear cell distribution patterns in normal cardiac tissue

Introdução: A medicina regenerativa tem ganho grande importância nos últimos anos em decorrência da possibilidade de certas células se diferenciarem em linhagens celulares distintas e, assim, reconstruírem o tecido lesado. As células-tronco têm despontado como forma alternativa de tratamento para doenças pela sua capacidade de diferenciação nos mais de 100 tipos de tecido. A medula óssea contém células-tronco adultas, hematopoéticas e mesenquimais, que auxiliam na limitação do remodelamento cardíaco. Método: Foram utilizados 9 cães com peso entre 25 kg e 30 kg, divididos em três grupos: intracoronária, intramiocárdica-transendocárdica e retrógrada venosa. Células mononucleares da medula óssea foram coletadas por densidade Ficoll, marcadas com fluorocromo Hoechst e infundidas nas diferentes vias citadas anteriormente...

Background: Regenerative medicine has become increasingly important in recent years due to the possibility of certain cells to differentiate into different cell lines and thus recover the damaged tissue. The stem cell has emerged as an alternative treatment for diseases as a result of their ability to differentiate in more than 100 types of tissue. Bone marrow contains adult stem cells, hematopoietic and mesenchymal cells, which limit heart remodeling. Methods: Nine dogs weighing between 25 and 30 kg were divided into three groups: intracoronary group, intramyocardial-transendocardial group and retrograde venous group. Mononuclear cells were collected from bone marrow by Ficoll density, stained with Hoechst fluorocrom and infused through the different routes mentioned above...

Quantificação atrial de células mononucleares de medula óssea (CMMO) infundidas via intrapericárdica em suínos submetidos a infarto agudo do miocárdio / Atrial quantification of bone marrow mononuclear cells (BMMC) infusioned by intrapericardic route in swine submitted to myocardial infarction

Nas últimas décadas a medicina regenerativa tem se destacado em todo o mundo, graças ao surgimento da terapia com células-tronco, as quais tem grande capacidade de diferenciação em diversos tipos de linhagens celulares, reconstruindo tecidos lesados. A medula óssea, fonte das células utilizadas nesse estudo, contém células-tronco adultas, hematopoiéticas e mesenquimais, pertencentes ao grupo de células mononucleares, que dentre outras funções, são capazes de levar ao remodelamento cardíaco pós-processo isquêmico, e para tanto, podem ser introduzidas no coração sob algumas vias de infusão, sendo que a mais ser recentemente estudada foi a intrapericárdica, a qual foi eleita para o desenvolvimento deste estudo, sendo a qual utilizados 6 suínos, fêmeas, com média de peso de 25Kg, divididos em 2 grupos: 3 animais induzidos ao infarto agudo do mi do miocárdio e tratados com células mononucleares de medula óssea, e 3 animais que apenas receberam as mesmas células, porém não foram induzidos ao infarto (animais controle). As células mononucleares da medula porém óssea foram coletadas e separadas por densidade Ficoll, marcadas com fluorocromo HoechstⓇ e infundidas via intrapericárdica. Após analisarmos os átrios dos animais dos 2 grupos, percebemos que houve uma distribuição homogênea, independente da presença de fator quimiotático no grupo dos animais infartados e que s células foram capazes de sair do espaço pericárdico e transmuralmente ocupar toda a estratigrafia cardíaca. Não houve diferença significativa na quantidade de células encontradas, p>0,01, quando comparamos átrios de animais infartados versus átrios de animais não infartados.

In the last decades, the regenerative medicine have been applied and investigated worldwide due to the stem cell therapy, which has shown high capacity of differentiation into a diverse cell lineage, restoring damaged tissues. In this study we applied bone marrow, which contains adult stem cells, hematopoietic and mesenchimal lineages. Mesenchimal lineage belongs to the mononuclear cell group that among its function, have demonstrated capacity for cardiac remodeling after ischemic processes and, can be introduced into the heart by infusion techniques like intrapericardic technique which has been investigated lately. In this study we investigated the application of intrapericardic technique for mononuclear cell infusion in swine induced to myocardial infarction. We used 6 female swine, averaging 25 kg distributed into control group (3 animals) and experimental group (3 animals), which animal were induced to infarction and received mononuclear cell infusion by intrapericardic technique. Control group received only mononuclear cell infusion by the same technique in normal heart. Mononuclear cells were obtained by Ficoll density and were stained by Hoescht fluorocrome. Atria analysis in both groups revealed a homogeneous distribution of the infusioned cells in the atria with no significant difference, p>0.01 between control and experimental group.

Cultivo de cardiomiócitos suínos / Culture of swine cardiomyocites

A insuficiência cardíaca é uma das doenças mais deletérias no mundo ocidental. Muitas pesquisas foram desenvolvidas com o intuito de promover novos e mais eficientes abordagens terapêuticas para a doença. Estas novas propostas terapêuticas tem ênfase nas origens dos processos patológicos e no reestabelecimento da funcionalidade, tal como nos transplantes de células lisas ou estriadas musculares, de cardiomiócitos fetais e adultos no tecido cardíaco fibrosado. Neste estudo, protocolos desenvolvidos e testados em ratos e camundongos e previamente publicados foram adaptados para cardiomiócitos suínos, objetivando estabelecer um protocolo para cultivo de cardiomiocitos em suínos. Três protocolos foram testados (A- digestão enzimática em coração de adulto, B- digestão enzimática em coração fetal e C- explante de coração adulto e fetal) e apenas um produziu resultados confiáveis (protocolo B) sugerindo a formação de fibras cardíacas, no entanto, faz-se necessária avaliação imunocitoquímica e análises ultraestruturais para a confirmação da hipótese.

Cardiac insufficiency is one of the most harmful disease in the occidental world; A range of researches have been developed in order to provide new and more efficient therapeutics for the disease. New therapeutics purposes have been directed to the origin of the pathological process and aim to re-establish functional physiology, as in transplants of cells like smooth or striated muscular cells, fetal or adult cardiomyocytes into the fibroid myocardium. In this study, previous published protocols developed in rats and mice were adapted for swine cardiomyocytes. The main goal was to stablish a viable protocol for swine cardiomiocyte culture, and the establishment of an experimental model using swine. Three protocols were tested (A - enzimatic digestion in adult heart; B- enzimatic digestion in fetal heart; C - explant of samples of adult and fetal hearts. We observed that protocol B produced a reliable result suggesting cardiac fibre formation, although, further immunecitochemistry and ultrastructural will be investigated to confirm the hypothesis.

Avaliação da técnica de arteriografia cerebral guiada por fluoroscopia em suínos / Evaluation of the cerebral arteriography technique guided for fluoroscopy in swine

The cerebral arteriography is a radiologic exam for demonstration of arterial vascularization using an injection of positive contrast for visualization of blood supply. In this research six pigs were submitted to cerebral arteriography under general anesthesia and with the assistant of fluoroscopy the femoral artery was catheterized until the carotid common right artery using contrast under selective form. The aim of this work was to analyze this technique as a complementary method in cases of suspect of alterations of blood flow. This technique shows be effective to obtain nithid images and to determinate the cerebral irrigation. Keywords: Cerebral arteriography, swine, fluoroscopy.

A arteriografia cerebral é um exame radiológico demonstrativo da vascularização arterial por meio de injeção de solução de contraste radio-positivo possibilitando adequada visualização da vascularização sanguínea. Neste experimento seis suínos foram submetidos à arteriografia cerebral, sob anestesia geral e com auxílio de fluoroscópio, a artéria femoral foi cateterizada e um guia foi direcionado à artéria carótida comum direita de forma seletiva por meio de contraste. Este trabalho teve como objetivo avaliar esta técnica como método complementar ao exame radiográfico simples em casos de suspeita de alteração do fluxo sangüíneo. A técnica mostrou-se efetiva para a obtenção de imagens nítidas e determinação da área de irrigação cerebral. Palavras-Chave: Arteriografia cerebral, suínos, fluoroscopia.