Experimental evaluation of the use of starch and carboxymethylcellulose in the prevention of intraperitoneal adhesions in hernia surgery with coated meshes

ABSTRACT Purpose: Laparoscopic hernia repair involves a risk of adhesion between coated mesh and viscera. Plant polysaccharides such as starch and carboxymethylcellulose (SC) make up a product that acts as a barrier and prevents intraperitoneal adhesions. This study aimed to evaluate whether topical SC can also reduce adhesions between mesh and intra-abdominal organs. Methods: Forty rats each received placement of two intraperitoneal mesh fragments, one on each side of the abdominal wall. Randomly, 20 animals received SC on the right and other 20 on the left, leaving the contralateral side as a control. Fourteen days after the surgery, the animals underwent an additional laparotomy in which macroscopic analysis was performed. Results: As for the percentage of the mesh area affected by adhesion, one (2.6%) animal had > 75% adhesion on the experimental side, and 11 animals (28.9%) on the control side. The adhesion intensity score showed firm adhesions in three (7.9%) animals on the experimental side and nine (23.7%) on the control side. Conclusions: The use of SC decreased the intensity of adhesions and the surface area of the mesh affected by adhesions. There was no negative interference of the product in the incorporation of the mesh into the abdominal wall.

Experimental comparative study of arterial implants made of silicone reinforced with polyester fabric and expanded polytetrafluoroethylene (PTFE) in rabbits aorta / Estudo experimental comparativo de implantes arteriais em silicone com reforço de poliéster e politetrafluoretileno expandido (PTFE) em aorta de coelhos

ABSTRACT Objectives: the aim of this study was to compare the outcomes of a new silicone vascular prostheses with PTFE vascular prostheses, on a rabbit experimental model. Methods: forty rabbits underwent infra-renal aorta replacement with 4 mm diameter prostheses, twenty animals with PDMS and twenty animals with PTFE (control group). Retrograde aortic angiography was performed to assess patency. Histological graft samples were examined by electron microscopy to evaluate prostheses endothelialization. Results: patency rates were 100% for both grafts after 30 days; after 60 days, patency rate for PDMS was 92.3% (±7.4), and 73,8% (±13.1) at 90 days. PTFE grafts had patency rates of 87.5% (±11.7) at 60 and 90 days. No statistically significant difference was found in between groups for patency rates (p=0.62). Postoperative complications (death, paraplegia) rates (p=0.526) and aortic clamping times (p=0.299) were comparable in both groups. No statistically significant difference for stenosis was found on angiographical analysis between groups (p=0.650). Electron microscopy revealed limited anastomotic endothelial ingrowth in both prostheses. Conclusion: in this experimental model, PDMS and PTFE vascular prostheses had comparable outcomes and PDMS prosthesis could be used as a vascular graft.

RESUMO Objetivo: analisar novo tubo de silicone como material para prótese vascular e compará-lo a prótese de PTFE, em modelo experimental com coelhos. Métodos: quarenta coelhos foram submetidos a interposição, na aorta infrarrenal, de próteses de 4mm de diâmetro, sendo 20 animais com PDMS e 20 com PTFE (grupo controle). Foi realizada arteriografia retrógrada da aorta para avaliar a patência das próteses. Para avaliar a endotelização das próteses foi realizada microscopia eletrônica de maneira amostral pareada. Resultados: a patência em 30 dias foi de 100% para as duas próteses. Aos 60 dias, a taxa de patência do PDMS foi de 92,3% (± 7,4), e de 73,8% (±13,1) em 90 dias; as próteses de PTFE tiveram taxas de patência de 87,5% (± 11,7) aos 60 e 90 dias. Não foi observada diferença significativa entre as taxas de patência dos grupos (p=0,62). Não foi observada diferença entre os grupos quanto à evolução com complicações pós-operatórias (p=0,526) e quanto ao tempo de clampeamento da aorta (p=0,299). Não houve diferença significativa entre os grupos quanto ao grau de estenose das próteses (p=0,650) à avaliação angiográfica. A microscopia eletrônica mostrou crescimento endotelial limitado às regiões próximas às anastomoses nos dois tipos de próteses. Conclusões: o PDMS mostrou-se passível de utilização como prótese vascular, com resultados comparáveis aos do PTFE no modelo utilizado.

Splenic implant preservation after conservation in lactated Ringer´s solution / Preservação de implante esplênico autógeno após conservação em solução de Ringer-lactato

ABSTRACT Objective: to evaluate the morphology and function of autogenous splenic tissue implanted in the greater omentum, 24 hours after storage in Ringer-lactate solution. Methods: we divided 35 male rats into seven groups (n=5): Group 1: no splenectomy; Group 2: total splenectomy without implant; Group 3: total splenectomy and immediate autogenous implant; Group 4: total splenectomy, preservation of the spleen in Ringer-lactate at room temperature, then sliced ​​and implanted; Group 5: total splenectomy, ​​spleen sliced and preserved in Ringer-lactate at room temperature before implantation; Group 6: total splenectomy with preservation of the spleen in Ringer-lactate at 4°C and then sliced ​​and implanted; Group 7: total splenectomy and the spleen sliced for preservation in Ringer-lactate at 4°C before implantation. After 90 days, we performed scintigraphic studies with Tc99m-colloidal tin (liver, lung, spleen or implant and clot), haematological exams (erythrogram, leucometry, platelets), biochemical dosages (protein electrophoresis) and anatomopathological studies. Results: regeneration of autogenous splenic implants occurred in the animals of the groups with preservation of the spleen at 4ºC. The uptake of colloidal tin was higher in groups 1, 3, 6 and 7 compared with the others. There was no difference in hematimetric values ​​in the seven groups. Protein electrophoresis showed a decrease in the gamma fraction in the group of splenectomized animals in relation to the operated groups. Conclusion: the splenic tissue preserved in Ringer-lactate solution at 4ºC maintains its morphological structure and allows functional recovery after being implanted on the greater omentum.

RESUMO Objetivo: avaliar morfologia e função de tecido esplênico autógeno, implantado no omento maior, 24 horas após conservação em solução de Ringer-lactato. Métodos: foram estudados 35 ratos machos, distribuídos em sete grupos (n=5): Grupo 1: sem esplenectomia; Grupo 2: esplenectomia total sem implante; Grupo 3: esplenectomia total e implante autógeno imediato; Grupo 4: esplenectomia total, preservação do baço em Ringer-lactato à temperatura ambiente, em seguida, fatiado e implantado; Grupo 5: esplenectomia total, baço fatiado e preservado em Ringer-lactato à temperatura ambiente antes de ser implantado; Grupo 6: esplenectomia total com preservação do baço em Ringer-lactato a 4°C e, em seguida, fatiado e implantado; Grupo 7: esplenectomia total e baço fatiado, para preservação em Ringer-lactato a 4°C antes de ser implantado. Após 90 dias, realizaram-se estudos cintilográficos com estanho coloidal-Tc99m (fígado, pulmão, baço ou implante e coágulo), hematológicos (eritrograma, leucometria, plaquetas), bioquímicos (eletroforese de proteínas) e anatomopatológicos. Resultados: ocorreu regeneração dos implantes esplênicos autógenos nos animais dos grupos com preservação do baço a 4ºC. A captação de estanho coloidal foi superior nos grupos 1, 3, 6 e 7 em relação aos demais. Não houve diferença nos valores hematimétricos nos sete grupos. A eletroforese de proteínas mostrou diminuição da fração gama no grupo de animais esplenectomizados em relação aos grupos operados. Conclusão: o tecido esplênico conservado em solução de Ringer-lactato à temperatura de 4ºC mantém sua estrutura morfológica e permite a recuperação funcional após ser implantado sobre o omento maior.

Biocompatibility of Ricinus communis polymer with addition of calcium carbonate compared to titanium. Experimental study in guinea pigs / Biocompatibilidade do polímero de óleo de mamona com acréscimo de carbonato de cálcio comparado ao titânio. Estudo experimental em cobaias.

Objective: The aim of the present investigation was to determine whether the difference in inflammatory tissue reaction between the Riccinus communis (castor) polymer with calcium carbonate and the titanium implant is statistically significant. Methods: Thirty-two Cavia porcellus were allocated into four groups of eight animals each. We implanted the two types of materials in the retroperitoneal space of all the animals. They were euthanized at 7, 20, 30 and 40 days after surgery, and an histological study of the samples was conducted. Results: All implants showed characteristics of chronic inflammation regardless of the material and timepoint of evaluation. There was no statistically significant difference between Pm+CaCO3 and Ti with regard to the presence of granulation tissue, tissue congestion, histiocytes, lymphocytes, neutrophils, giant cells, and fibrosis (P> 0.05). Conclusion: The castor oil polymer plus calcium carbonate implant was not statistically different from the titanium implant regarding inflammatory tissue reaction. .

Objetivo: Determinar se a reação tecidual do implante retroperitoneal do polímero de óleo de mamona com acréscimo de carbonato de cálcio (Pm+CaCO3) é significativa, por meio de análise histopatológica, tendo como controle o implante de titânio não tratado (Ti). Métodos: Estudo experimental, intervencionista e randomizado com 32 cobaias. Os animais foram separados em quatro grupos iguais e eutanasiados com 7, 20, 30 e 40 dias após o ato cirúrgico. Foram confeccionadas lâminas em hematoxilina-eosina e em tricrômio de Masson. Em relação a variáveis qualitativas dicotômicas, para análise da diferença entre o Pm+CaCO3 e o Ti em cada momento de avaliação foi usado o teste binomial. Considerando os materiais separadamente, a comparação dos quatro grupos foi feita utilizandose o teste exato de Fisher. Valores de P<0,05 indicaram significância estatística. Resultados: Todos os implantes apresentaram características de inflamação crônica, independente do material e do momento de avaliação. Não houve diferença estatisticamente significativa entre o Pm+CaCO3 e o Ti considerando a presença de tecido de granulação, congestão tecidual, histiócitos, linfócitos, neutrófilos, células gigantes e fibrose (P>0,05). Conclusão: Não foi encontrada diferença significativa entre a reação tecidual do Pm+CaCO3 e a do Ti. .

Análise da biocompatibilidade de cones de biovidro e biovitrocerâmico (Biosilicato®) em cavidade eviscerada de coelho / Biocompatibility analisys of Bioglass® 45S5 and Biosilicate® cone in rabbit eviscerated cavity

OBJETIVO: Avaliar experimentalmente a biocompatibilidade de cones de biovidro e biovitrocerâmico em cavidades evisceradas de coelhos. MÉTODOS: Foram utilizados 45 coelhos albinos submetidos à cirurgia de evisceração do olho direito, seguida da inclusão de cones de biovidro e dois tipos de biovitrocerâmicos (chamados de FI e FII) na cavidade escleral. Os animais foram sacrificados em três momentos (7, 90 e 180 dias). Os parâmetros avaliados foram: peso, exame clínico diário, exames bioquímicos, avaliação histológica, exame morfométrico. RESULTADOS: Os animais mantiveram-se saudáveis durante o experimento, não tendo ocorrido extrusão do implante em nenhum animal. O exame morfológico mostrou que houve a formação de pseudocápsula ao redor dos cones, com superioridade dos cones de biovidro e biovitrocerâmico FI, os quais apresentaram menor reação inflamatória e menor formação da pseudocápsula ao redor dos cones que os demais. A reação inflamatória foi mais intensa após 7 dias da colocação dos cones, diminuindo em direção aos 180 dias, sendo menos intensa nos coelhos que receberam cones de biovidro. CONCLUSÃO: Os cones de biovidro e biovitrocerâmico FI e FII podem ser úteis para a reparação da cavidade anoftálmica, com melhor resposta quando se usa cones de biovidro e de biovitrocerâmico FI.

OBJECTIVE: To evaluate bioglass, bioglassceramic biocompatibility in rabbit's eviscerated cavities. METHODS: Forty- five rabbits were submitted to right eye evisceration, followed by the inclusion of bioglass and bioglassceramic I e II prosthesis in the escleral cavity. The animals were sacrificed at seven, 90 and 180 days after surgery. The animals had daily clinical exam; biochemical exam, histological analysis and morphometric evaluation. RESULTS: The animals stayed healthy during the expriment, with good cone integration to the host tissue. None cone extrusion were observed. Histologically, it was observed pseudocapsule formation around the cones and the inflammatory reaction was higher at M1, getting progressively lower while getting at M3, being the lowest in rabbits which received bioglass cones (GA) than at any other groups. CONCLUSION: Bioglass and bioglassceramic I e II cones can be useful to repair anophthalmic cavity.

Biocompatibilidade do polímero da mamona comparada ao implante de titânio para corações artificiais: estudo experimental em cobaias / Biocompatibility of Ricinus comunnis polymer compared to titanium implant used in artificial hearts: experimental study in guinea pigs

OBJETIVO: Determinar se a reação tecidual do implante retroperitoneal do polímero de óleo de mamona (Pm) é significativa ou não por meio de análise histopatológica, tendo como controle o implante de titânio (Ti). MÉTODOS: Estudo experimental, intervencionista e randomizado com 32 cobaias. Os animais foram divididos em quatro grupos iguais e eutanasiados com 7, 20, 30 e 40 dias após o ato cirúrgico. Foram confeccionadas lâminas em hematoxilina-eosina e em tricrômio de Masson. Na comparação dos tipos de material em relação a variáveis quantitativas, foi considerado o teste não-paramétrico de Wilcoxon. Em relação a essas variáveis, os grupos definidos pelo dia do sacrifício foram comparados usando-se o teste não-paramétrico de Kruskal-Wallis. Os resultados obtidos no estudo da fibrose foram expressos por frequências e percentuais. Para a comparação entre os grupos definidos pelo dia do sacrifício, em relação a variáveis qualitativas dicotômicas da fibrose, foi considerado o teste exato de Fisher. Para avaliar a diferença entre os materiais titânio e polímero em cada grupo, ainda em se tratando da fibrose, foi considerado o teste binomial. Valores de P<0,05 indicaram significância estatística. RESULTADOS: A análise das variáveis quantitativas não demonstrou diferença nas reações teciduais entre os materiais (P>0,05). A análise da variável qualitativa também não demonstrou diferença entre as reações teciduais dos materiais (P>0,05). CONCLUSÃO: Não foi encontrada significância estatística entre a reação tecidual do Pm e do Ti.

OBJECTIVE: The aim of the present investigation is to determine if the tissue reaction to the Riccinus communis (mamona) polymer has significant statistical difference compared to the tissue reaction provoked by the titanium implant. METHODS: Thirty two Cavia porcellus were divided into four groups containing eight animals each one. We implanted the two types of materials in the retroperitoneal space of all the animals. They were sacrificed at 7, 20, 30 and 40 days after surgery and the samples were submitted to histological study. RESULTS: The quantitative analysis did not show difference between the tissue reaction of the two materials (P>0.05). The analysis of the qualitative variable also did not show difference between the tissue reaction of the materials (P>0.05). CONCLUSION: Macroscopic and microscopic results showed that the castor oil polymer implant has no significant statistical difference compared to the titanium implant tissue reaction.

Modelo experimental de estenose traqueal mediante ressecção cirúrgica submucosa de anéis traqueais combinada com instilações de hidróxido de sódio / Experimental model of tracheal stenosis with submucosal resection of cartilaginous rings combined with sodium hydroxide instillations

OBJETIVO: Desenvolver, experimentalmente, malácia e estenose traqueal para testar novos modelos de órteses traqueais. MÉTODOS: Ressecamos três anéis cartilaginosos da traqueia cervical de cães no grupo A (n=5) e seis anéis no grupo B (n=4) para produzir malácia. Logo após, a mucosa da região com malácia recebeu aplicações de uma solução de hidróxido de sódio (NaOH) a 23 por cento, e os animais eram acompanhados com exames broncoscópicos para observar o desenvolvimento de estreitamento da luz da via aérea. Quando a estenose era de mais de 50 por cento da luz, ou havia sinais mínimos de insuficiência ventilatória, os animais eram sacrificados. O segmento de via aérea estreitada foi então coletado para análise histológica e era calculada a área de luz residual do segmento traqueal com estenose e malácia. RESULTADOS: Na análise histológica, foi constatada fibrose na submucosa e adventícia, associada a granulomas na mucosa. A luz residual média dos segmentos com estenose foi de 9 por cento e 12 por cento nos grupos A e B, respectivamente, (p>0,05). CONCLUSÃO: A combinação da ressecção de anéis cartilaginosos e da aplicação de NaOH 23 por cento na mucosa respiratória promoveu uma estenose traqueal intensa, porém esteve associada à perda de animais. Novos estudos são necessários para verificar se o emprego isolado de uma das técnicas seria mais seguro e eficaz para desenvolver estenose traqueal.

OBJECTIVE: To experimentally develop tracheal stenosis and malacia to test new models of tracheal stents. METHODS: We resected three cartilaginous rings from the cervical trachea of dogs in group A (n = 5) and six rings in group B (n = 4) to produce malacia. The mucosa of the region with malacia then received applications of a solution of sodium hydroxide (NaOH) at 23 percent, and the animals were accompanied with bronchoscopic examinations to observe the development of luminal narrowing of the airway. When the stenosis was of more than 50 percent or there were minimal signs of ventilatory failure, the animals were sacrificed. The segment of narrowed airway was then collected for histological analysis and calculation of the area of residual lumen in the tracheal segment with stenosis and malacia. RESULTS: In histological analysis, fibrosis was found in the submucosa and adventitia, associated with granulomas in the mucosa. The average residual lumen of the segments with stenosis was 9 percent and 12 percent in groups A and B, respectively (p> 0.05). CONCLUSION: The combination of resection of the cartilaginous rings and the application of 23 percent NaOH in the respiratory mucosa promoted severe tracheal stenosis, but was associated with loss of animals. Further studies are needed to verify that the isolated use of one of the techniques would be safer and more effective to develop tracheal stenosis.

Hemicelulose em reconstrução da parede abdominal em ratos / Reconstruction of the abdominal wall in rats with hemicellulose

INTRODUÇÃO: As perdas de substância da parede abdominal (PSPA) revestem-se de importância clínica e cirúrgica em função da alta frequência com que ocorrem, do sofrimento que produzem e do alto custo dos tratamentos atualmente ministrados. Nos últimos anos, tem-se observado o desenvolvimento de novas técnicas para a resolução das perdas de substância da PSPA, entre as quais se incluem a realização de retalhos e o uso de materiais biocompatíveis e sintéticos. MÉTODO: Esse estudo experimental aleatório e não controlado avaliou o uso da hemicelulose para a reparação das PSPA em 40 ratos Wistar EPM III, femêos. Os animais foram divididos em quatro grupos experimentais de estudo: I (n=10), II (n=10), III = (n=10) e IV (n=10). Todos os animais foram submetidos a anestesia geral utilizando-se o tiopental sódico, via intraperitonial. Foi provocada uma lesão de 2,0 x 3,0cm no tecido músculo-aponeurótico e peritônio da região anterior do abdome. A aposição da película de hemicelulose sobre a lesão foi realizada superpondo-se 15 películas de 2,0 x 3,0cm, umedecidas em soro fisiológico a 0,9 por cento. A película foi fixada à parede muscular adjacente e, em seguida, foi realizada a síntese da pele e panículo carnoso por meio de sutura contínua com fio de náilon de número cinco zeros. A eutanásia dos animais dos grupos I (n=10), II (n=10), III (n=10) e IV (n=10) foi realizada após 3, 28, 35 e 240 dias, respectivamente. CONCLUSÃO: Esse estudo concluiu que a hemicelulose foi eficiente em reparar as grandes perdas da parede abdominal em ratos.

INTRODUCTION: Substance losses of abdominal wall (SLAW) has a vital clinical and surgical importance due to the high frequency which they occur, the suffering they cause, the challenge of treatment and the high cost of treatment administered today. In the last years, has been observed the development of new techniques to resolve SLAW, some which include the making of flaps and the use of biocompatible and synthetic materials. METHODS: This random experimental and uncontrolled study evaluated the use of hemicellulose as a repair of SLAW in 40 EPM III Wistar female rats. The animals were divided in four experimental study groups: I (n=10), II (n=10), III (n=10), IV (n=10). All the animals were submitted to general anesthesia using sodium thiopental, via intraperitoneal. A lesion of aponeurotic muscle tissue and peritoneal from the region anterior abdominal was made. The placing of hemicellulose pellicle over the lesion was performed overlapping fifteen pellicles (2.0 x 3.0 cm each), bathed in 0.9 percent saline solution. The pellicle was fixed to adjacent muscle wall, the subcutaneous and skin was sutured by continuous suturing with 5-0 nylon suture. The provoked death (euthanasia) of the animals in each group - I (n=10), II (n=10), III (n=10), IV (n=10) - was done after 3, 28, 35, and 240 days, respectively. CONCLUSION: The conclusion of this study expressed that hemicellulose pellicle was efficient in the repair of SLAW in rats.

Biomechanical evaluation of microbial cellulose (Zoogloea sp.) and expanded polytetrafluoroethylene membranes as implants in repair of produced abdominal wall defects in rats

PURPOSE: To evaluate the Load of Rupture of implants of membranes of microbial cellulose (Zoogloea sp.) and extended polytetrafuoroethylene in sharp defects of abdominal wall of rats. METHODS: Sixty Wistar male rats, with a mean weight of 437,7g ± 40,9, anesthetized by a mixture of ketamine (5mg/100g) and xylazine (2mg/100g), were submitted to a rectangular (2x3cm) excision of the abdominal wall, including fascia, muscle and peritoneum, and treated with membranes of microbial cellulose (MC) (MC Group- 30 animals) or extended polytetrafluoroethylene (ePTFE) (ePTFE Group- 30 animals). Each group was subdivided in 14th POD, 28th POD and 60th POD Subgroups. Under anesthesia, animals were submitted to euthanasia at 14th POD, 28th POD and 60th POD for evaluation of Load of Rupture. RESULTS: Load of Rupture levels were significantly elevated (p<0, 05) among 14th, 28th and 60th postoperative days from each Group. When compared between groups, values of Load of Rupture were significantly larger (p<0, 05) in ePTFE Group than in MC Group. CONCLUSION: Resistance to strength at implant/host interface was more pronounced in PTFEe Group than in MC Group.

OBJETIVO: Avaliar a Carga de Ruptura de implantes de membranas de celulose microbiana (Zoogloea sp.) e de politetrafluoretileno expandido em defeitos agudos produzidos na parede abdominal de ratos. MÉTODOS: Sessenta ratos machos Wistar, com média de peso de 437,7g ± 40,9, anestesiados com uma mistura de cetamina (5mg/100g) e xilazina (2mg/100g), foram submetidos à excisão retangular (2x3cm) na parede ventral do abdômen, incluindo fáscia, músculo e peritônio. Subseqüentemente, foram tratados com implante de membranas de celulose microbiana (CM) (Grupo CM - 30 animais) ou de politetrafluoretileno expandido (PTFEe) (Grupo PTFEe - 30 animais). Cada grupo foi ainda subdividido nos Subgrupos 14º DPO, 28º DPO e 60º DPO. Os animais foram submetidos à eutanásia com doses letais de tiopental no 14º DPO, 28º DPO e 60º DPO, para avaliação da Carga de Ruptura na área do implante. RESULTADOS: Os níveis da Carga de Ruptura foram significativamente elevados (p<0,05) entre os Subgrupos 14º DPO, 28º DPO e 60º DPO de cada grupo estudado. Quando comparados entre Grupos, os valores da Carga de Ruptura foram significativamente maiores (p<0,05) no Grupo PTFEe do que no Grupo CM. CONCLUSÃO: A interface implante/hospedeiro apresentou maior resistência a tração no Grupo PTFEe do que no Grupo CM.

Desenvolvimento de uma órtese de Dumon modificada para aplicações traqueais: um estudo experimental em cães / Development of a modified Dumon stent for tracheal applications: an experimental study in dogs

OBJETIVO: Descrever o desenvolvimento de uma órtese de silicone e os testes in vivo de compatibilidade e aplicabilidade na traquéia canina normal. MÉTODOS: Quatro densidades de silicone foram testadas para a obtenção de protótipos. Para cada densidade, foi calculada a pressão exigida para causar a compressão, considerando-se uma área de contato de 1 cm² e uma redução de 30 por cento no diâmetro. A densidade selecionada foi 70-75 Shore A hardness. Adicionou-se sulfato de bário em pó ao silicone para tornar a órtese desenvolvida radiopaca e facilmente identificável ao exame radiológico. A órtese desenvolvida apresenta superfície externa corrugada com arcos salientes e descontínuos, semelhantes aos anéis traqueobrônquicos, para intercalação e fixação nas vias aéreas inferiores, superfície interna polida e extremidades lisas que evitam o dano por fricção. O protótipo considerado como sendo o mais adequado em termos de rigidez e flexibilidade foi implantado broncoscopicamente em traquéias caninas normais. Os animais foram sacrificados após oito semanas, e a traquéia foi removida para análise anatomopatológica. RESULTADOS: Não houve complicações após a implantação das órteses. Nenhuma precisou ser removida, e todas estavam bem posicionadas ao final de oito semanas. O estudo histopatológico mostrou que a membrana basal epitelial foi preservada. Foram observados pontos focais de desnudamento epitelial, leve infiltrado inflamatório sob a mucosa e, mais raramente, tecido de granulação com neoformação vascular e ausência de microorganismos. CONCLUSÕES: A órtese desenvolvida mostrou resistência aos esforços mecânicos e biocompatibilidade, não provocando reação tecidual adversa na traquéia canina, além de permanecer íntegra ao final do experimento.

OBJECTIVE: To describe the development of a silicone stent and perform in vivo testing for biocompatibility/applicability in the normal canine trachea. METHODS: Four different densities were tested in order to obtain the silicone prototypes. The pressure required for compression considering a contact area of 1 cm2, and a 30 percent reduction in diameter was calculated for each density. The best density was 70-75 Shore A hardness. Powdered barium sulfate was added to the silicone to make the stent radiopaque and easily identifiable in radiological imaging. This novel stent presents a corrugated external surface with discontinuous and protruding arcs resembling the tracheobronchial rings (for intercalation and fixation in the lumen of the lower airways), a highly polished inner surface and smooth extremities (to prevent friction-related damage). The prototype considered most appropriate in terms of rigidity and flexibility was bronchoscopically implanted in normal canine tracheas. After eight weeks, the animals were euthanized, and the tracheas were removed for anatomopathological analysis. RESULTS: There were no postimplantation complications, and none had to be removed. After eight weeks, the devices were found to be well-positioned. Histopathology revealed a well-preserved epithelial basal membrane, foci of denuded epithelium, mild submucosal inflammatory infiltrate with scattered granulation tissue, vascular neoformation, and no microorganisms. CONCLUSIONS: The stent developed proved resistant to mechanical stress, biocompatible in the canine trachea and well-preserved at the study endpoint.

Repair of large area of tracheal wall defects with silastic framework:an experimental study / 中华创伤杂志

Objective To explore the feasibility of artificial silastic framework(SF)in repair of large area of tracheal wall defects.Methods Twenty healthy adult dogs with tracheal defects for 2.5 cm?6.0 cm-3.0 cm?6.0cm were randomly and equally divided into experimental group(repaired with SF combined with sternohyoid fasciae)and control group(repaired with T-silastie tubule combined with sternohyoid fascial flap).After the operation,the animals were sacrificed at the 4th,8th,16th,24th, and 48th weeks respectively for harvesting the tracheae that were used for tracbeoscopically observing in- flammatory reaction of the repaired defect area and light microscopically observing epithelium healing on the repaired defect area.Results In the experiment group,the repaired trachea was smooth,without proliferation of granulation;and at the 8th week,the repaired defect area was covered with epithelial cells,with good functional recovery of respiration,phonation and deglutition.In the control group,there was obvious proliferation of granulation on the tracheal surface near anterior and posterior ends of T-silas tic tubule.The animals were under asphyxia to die with extraction of T-silastic tubule.Conclusions SF has excellent tracheal skeletal function.In the meantime,SF combined with sternohyoid fasciae is a simple but effective method for repair of large area of tracheal wall defects.

Evaluation of the short-term biocompatibility of a new kind of hydrogel prosthetic nucleus / 中国组织工程研究

Aim To evaluate the short-term biocompatibility of a newkind of prosthetic nucleus-Evergel, which is made from the modifiedpolyvinyl alcohol hydrogel. Methods According to China national standardGB/T16886 documents, the toxicity of Evergel prosthetic nucleus materialwas investigated by the cytotoxicity test, sensitization test, haemolysis test,Ames test, mice marrow micronucleus test and chromosome aberration test ofmammalian cell in vitro. Results This material had no cytoxicity, no sen-sitivity, no obvious haemolysis, and no mutagencity in Ames test, micemarrow micronucleus test and chromosome aberration test of mammalian cellin vitro. Conclusion The Evergel prosthetic nucleus has a good biocom-patibility and can be used clinically.

An experimental study of percutaneous vertebroplasty using instruments and drugs made in China / 中华放射学杂志

Objective To evaluate the efficacy of percutaneous vertebroplasty(PVP) using instruments and drugs made in China, and to provide the data for the clinical application Methods Polymethylmethacrylate(PMMA) without adding contrast was classified into 3 groups according to the ratio of powder/liquid as 2∶1,3∶2,1∶1,PMMA with contrast was also classified into 3 groups according to the ratio of powder/liquid/contrast as 2∶1∶1,3∶2∶1,1∶1∶1 There were 6 groups totally The periods and temperature of polymerizing process were measured The PMMA specimens of different group were made,with the diameter of 1 0 cm, height of 3 0 cm The density was determined in X ray pictures and mechanical testing with universal testing machine was performed PVPwas performed in the spines of 3 human cadavers with transpedicular route under fluoroscopic control The PMMA was injected into vertebra at an interval of one vertebra from T4-L4, 7 vertebra were injected on each cadaver The injected volume was recorded The spines were dissected into 42 single vertebrae, with all soft tissues removed Overall,21 pairs of adjacent vertebrae were subjected to axial compression in an universal testing machine The cranial vertebra of each pair was injected with PMMA, the caudal one served as a control Results Lower temperature was observed in the PMMA groups with adding contrast than those without adding contrast during the polymerizing process, the average temperature in the PMMA group with the ratio of powder/liquid/contrast as 3∶2∶1 was 67 4℃ There was significant X ray density difference between the groups with contrast and corresponding groups without contrast ( t = 20 00, t = 20 00, t = 22 86, P 0 05) The group with ratio of power/liquid/contrast 3∶2∶1 was (127? 4 70) s in the period of the paste, and the ultimate compressive strength (mPa) was 47 23 The punctures were successfully reached in all vertebra The injected PMMA average volume was 5 ml in the thoracic vertebra and 7 5 ml in the lumbar vertebra PMMA leaking into adjacent paravertebral tissue was demonstrated in 3 of 21 vertebrae The ultimate compressive strength of the vertebrae without PMMA injection in the 3 groups was 3 28,3 63,and 3 69, respectively The ultimate compressive strength of the injected PMMA vertebrae in the 3 groups was 4 52,4 73,and 4 81, respectively The ultimate compressive strength was significantly higher in the injected PMMA vertebrae than that in the vertebrae without PMMA injection( t =3 17,3 55,3 99, P

The preparation of biodegradable intravascular stent and the studies of its properties / 中华放射学杂志

Objective To investigate the preparation of a biodegradable intravascular stent (BIS) with poly-l-lactic acid (PLLA), and to evaluate its physical and mechanical properties, as well as its biocompatibility. Methods The study of this BIS was first prepared by PLLA with molecular weight of 100 000 unit as the strut, and then the micro-porous structure was fabricated and the film was coated at the struts. Following the solidified shaping of BIS, the primary physical and mechanical properties of the BIS were tested, and 22 zigzag type BISs were implanted into the aorta and iliac arteries of 11 canines, then they were euthanized according to a fixed timetable for histopathological assessment. Results Two types of BIS (spiral and zigzag) were prepared, and the strut diameter of the BIS was 0.1-0.6 mm, stent diameter of BIS was 6-15 mm, and stent length was 30-80 mm. Of this BIS, the radial strength was 1.6-2.0 kPa (1 kPa=7.5 mm Hg), the dilatable rate was 6.0-6.5, the shortening rate was smaller than 8%-10%, and the proportion of stent surface area to open surface area was 0.16-0.18 (