THE USE OF SURGICAL ADHESIVE AND SUTURE FIXING MESHES TO THE ABDOMINAL WALL: AN EXPERIMENTAL STUDY IN RATS.

AIM: Proper fixation of the surgical mesh determines the success of a herniorrhaphy. Understanding the inflammatory response and the mechanical properties of the mesh helps to define whether a fixation method is superior. This study aimed to evaluate the healing of defects in the abdominal wall of rats, comparing the repair of macroporous polypropylene meshes fixed with surgical glue and polypropylene thread. METHODS: In 20 Wistar rats, a defect was produced in the abdominal wall, with the integrity of the parietal peritoneum. For correction, the meshes were fixed with surgical glue (2-octyl cyanoacrylate) (subgroup C1), or polypropylene suture (subgroup C2). The two subgroups of 10 animals were euthanized on the 90th postoperative day, and the fragments of the abdominal wall were submitted to macroscopic, histological, and tensiometric analysis. RESULTS: Macroscopic analysis did not show any abnormalities. Tensiometry on the 90th postoperative day in subgroup C1 showed mean rupture tension of 28.47N and in subgroup C2 32.06N (p=0.773). The inflammatory process score revealed that both groups are in the subacute phase (p=0.380). CONCLUSION: The fixation of a polypropylene macroporous mesh to repair an abdominal wall defect can be performed with surgical glue (2-octyl cyanoacrylate) or polypropylene suture, both methods being equally effective.

COMPARATIVE ANALYSIS OF TISSULAR RESPONSE AFTER ABDOMINAL WALL REPAIR USING POLYPROPYLENE MESH AND BOVINE PERICARDIUM MESH.

BACKGROUND: The use of polypropylene meshes for surgical repair of the abdominal wall contributes to a reduction of the of recurrence rates of hernias or defects. However, its intra-abdominal use comes along with the formation of adhesions and several complications. The study and the search for alternative materials, including bovine pericardium, have been regarded as an option for the correction and treatment of resulting hernias with better adaptations and effectiveness. AIM: Evaluating the inflammatory process of the bovine pericardium in comparison with the inflammatory process of synthetic polypropylene mesh. METHOD: Bovine pericardium mesh and polypropylene mesh were placed, both on the same animal. The first group had the mesh removed for analysis on day 20, and the second group on day 40. The variables congestion, granulation, giant cells, necrosis, acute inflammation, chronic inflammation and collagen were analyzed. RESULTS: All variables were found in greater numbers as a response to the polypropylene mesh, except for the collagen, which, on day 40, was greater in response to the bovine pericardium mesh. CONCLUSION: The data in this study suggest that there is less inflammatory reaction in response to bovine pericardium mesh when compared to polypropylene mesh.

BETWEEN PROLENE®, ULTRAPRO® AND BARD SOFT® MESHES WHICH PRESENTS THE BEST PERFORMANCE IN THE REPAIR OF THE ABDOMINAL WALL?

BACKGROUND: In the definition of the mesh to be used to correct hernias, porosity, amount of absorbable material and polypropylene should be considered in the different stages of healing process. AIM: To evaluate the inflammatory reaction in the use of macro and microporous meshes of high and low weight in the repair of defects in the abdominal wall of rats. METHODS: Ninety Wistar rats (Rattus norvegicus albinus) were used. The animals were submitted to similar surgical procedures, with lesion of the ventral abdominal wall, maintaining the integrity of the parietal peritoneum and correction using the studied meshes (Prolene®, Ultrapro® and Bard Soft®). Euthanasia was performed at 30, 60 and 120 days after surgery. The abdominal wall segments were submitted to histological analysis using H&E, Masson's trichrome, immunohistochemistry, picrosirius red and tensiometric evaluation. RESULTS: On the 120th day, the tensiometric analysis was superior with Ultrapro® macroporous mesh. The inflammatory process score showed a significant prevalence of subacute process at the beginning and at the end of the study. Microporous meshes showed block encapsulation and in macroporous predominance of filamentous encapsulation. CONCLUSION: The Ultrapro® mesh showed better performance than the others in healing process of the abdominal wall.

VEGETABLE CELLULOSE NANOFIBER DRESSING AIDS IN THE HEALING PROCESS OF THIRD-DEGREE BURNS? STUDY ON RATS.

BACKGROUND: The treatment of 3rd degree burns represents a major medical challenge. Pinus vegetable cellulose is a biomaterial with characteristic similar to bacterial cellulose. AIM: To evaluate the safety of cellulose membrane (Pinus sp) in the treatment of 3rd burns in rats and to compare its effectiveness with the bacterial membrane already on the market. METHOD: Thirty-three Wistar rats were beaten with a 3rd degree burn on back skin by applying water at 98º C for 30 s. Then, they were divided into three groups (n=11): group 1 - simple dressing with gauze; group 2 - dressing with bacterial cellulose membrane; and group 3 - dressing with vegetable cellulose membrane. The animals were maintained for 15 days to check the general clinical status, macroscopic aspect, contraction of the wounds and microscopic analysis for the degree of healing and collagenization. RESULTS: They were clinically well during the experiment. During the removal of the dressing, there was bleeding in the wound of the control group, unlike the groups treated with cellulose membranes, which protected the bed from injury. The macroscopic evaluation showed a greater contraction of the wounds treated with the membranes in relation to the control. A microscopic analysis revealed that most of the wounds were in advanced healing degree with predominance of mature collagen in all groups. CONCLUSION: Pinus sp cellulose membrane showed efficacy similar to that of the bacterial membrane in the treatment of 3rd degree burns.

Histological evaluation of capsules formed by texturized silicone implants with and without polyester mesh coverage (Parietex®). A study on female rats.

PURPOSE: To evaluate capsules formed by microtextured silicone implants with and without Parietex® mesh coverage histologically. METHODS: Sixty Wistar rats were divided in two groups (meshed and unmeshed). Each group was, then, divided into two subgroups for evaluation at 30 and 90 days. Capsules were analyzed based on hematoxylin and eosin (HE) and picrosirius staining. RESULTS: The number of fibroblasts, neutrophils and macrophages was similar among all subgroups. There was a higher lymphocyte reaction in the 30-day meshed group (p = 0.003). Giant cell reaction, granulation tissue and neoangiogenesis were similar among the subgroups. Synovial metaplasia was milder at 90-day in the unmeshed (p = 0.002) and meshed group (p < 0.001). Capsular thickness was significantly greater in the meshed samples (30-day p < 0.001 and 90-day p < 0.001). There was a similar amount of collagen types I and III in both groups. CONCLUSIONS: The mesh-covered implants produced capsules similar to the microtextured ones when analyzing inflammatory variables. Synovial metaplasia was milder at 90 than at 30 days, and the capsular thickness was significantly greater in the meshed group. A similar amount of collagen types I and III was observed. Due to these characteristics, the mesh coverage did not seem to significantly affect the local inflammatory activity.

Spontaneous Condyle-Like Development after Total Resection of Mandible Giant Osteochondroma: Case Report and a Follow-Up for Five Years.

Osteochondroma manifests as a benign tumor that occurs as an abnormal bony development. This tumor is commonly asymptomatic and presents an exophytic outgrowth on bone surfaces, near synovial joints, a condition that invariably induces evident facial deformities. Treatment for this type of tumor usually involves a surgical approach promoting a total or partial resection of the affected anatomical area associated to prosthetic reconstruction of the bone area extracted. We present a case report about a giant mandibular condyle osteochondroma in a 37-year-old female patient. Her treatment involved a total condylectomy without immediate condylar reconstruction, which would be performed in a posterior surgical approach. During the patient's follow-up (every 6 months of post operation), a spontaneous and rudimentary condyle-like formation was observed. Because the stomatognathic function and facial harmony were satisfactory, we observed the condyle-like development for 5 years of follow-up. Also, because both the aesthetic aspect and functional evolution of the maxillary bone were considered satisfactory, no complementary reconstruction surgical treatment was required for the giant osteochondroma of the mandibular condyle.

PINE NANOCELLULOSE AND BACTERIAL NANOCELLULOSE DRESSINGS ARE SIMILAR IN THE TREATMENT OF SECOND-DEGREE BURN? EXPERIMENTAL STUDY IN RATS.

BACKGROUND: Crusts in 7th follow-up day: G1 yes; G2 no; G3 no (left to right). Bespite all the advances in medicine and the wide variety of dressings available, the treatment of burn wounds still represents an important medical challenge. The pinus cellulose membrane dressing is a biomaterial with characteristics similar to those of bacterial cellulose, but with lower cost. AIM: To evaluate the efficacy of pinus nanocellulose membrane on healing of deep second degree burns in rats and compare with Membracel®. METHOD: Thirty male Wistar rats were submitted to deep second degree burn in dorse, with boiling water at 97o C for 20 s, generating a 314 mm² area wound. The animals were distributed in three dressing groups (n=10): group 1 - simple gauze; group 2 - bacterial cellulose membrane (Membracel®); and group 3 - pinus cellulose membrane. They were evaluated for 20 days to verify clinical condition, macro and microscopic appearance and wound contraction. RESULTS: All of them remained clinically well with no differences in weight. Crusts were observed in group 1, and none in groups 2 and 3. Regarding to scar contraction, groups 2 and 3 were similar, better than group 1. Microscopic analysis showed predominance of advanced healing degree in groups 1 and 3, and initial in group 2. Mature collagen was predominant in all groups. CONCLUSION: The pinus nanocellulose membrane is effective in the treatment of experimental second degree burn in rats and its effectiveness is similar to that of the bacterial nanocellular membrane.

TENSIOMETRIC ANALYSIS OF MESHES USED IN ABDOMINAL VENTRAL WALL DEFECTS IN RATS.

BACKGROUND: Among the various strategies to avoid exaggerated foreign body reaction in the treatment of hernias is the limitation of the amount of polypropylene or the use of absorbable material. AIM: To evaluate the healing of defects in the abdominal wall of rats, comparing microporous polypropylene, macroporous polypropylene and polypropylene/polyglecaprone at the 30º, 60º and 120º postoperative day. METHODS: Wistar rats were submitted to defect production in the ventral abdominal wall, with integrity of the parietal peritoneum. Prolene®, Ultrapro® and Bard Soft® meshes were used in the correction of the defect. Nine subgroups of 10 animals were submitted to euthanasia at 30th, 60th and 120th postoperative day. Fragments of the abdominal wall of the animals were submitted to tensiometric analysis. RESULTS: The tensiometry at the 30th postoperative day showed greater resistance of the tissues with Bard Soft® (macroporous mesh) in relation to the tissues with Prolene® (microporous mesh). On the 60th postoperative day Bard Soft® maintained the superior resistance to the tissues comparing to Prolene Mesh®. On the 120th postoperative day the tissues repaired with Ultrapro® (macroporous mesh) proved to be more resistant than the ones by Prolene® (microporous mesh) and Bard Soft® (macroporous mesh). CONCLUSION: The tissues repaired with macroporous meshes showed greater resistance than with microporous meshes at all stages, and at 120 days postoperative Ultrapro® performed better than the others.

Vegetable cellulose nanofiber dressing aids in the healing process of third-degree burns? study on rats / Curativo de nanofibras de celulose vegetal auxilia na cicatrização de queimaduras de terceiro grau? estudo em ratos

ABSTRACT Background: The treatment of 3rd degree burns represents a major medical challenge. Pinus vegetable cellulose is a biomaterial with characteristic similar to bacterial cellulose. Aim: To evaluate the safety of cellulose membrane (Pinus sp) in the treatment of 3rd burns in rats and to compare its effectiveness with the bacterial membrane already on the market. Method: Thirty-three Wistar rats were beaten with a 3rd degree burn on back skin by applying water at 98º C for 30 s. Then, they were divided into three groups (n=11): group 1 - simple dressing with gauze; group 2 - dressing with bacterial cellulose membrane; and group 3 - dressing with vegetable cellulose membrane. The animals were maintained for 15 days to check the general clinical status, macroscopic aspect, contraction of the wounds and microscopic analysis for the degree of healing and collagenization. Results: They were clinically well during the experiment. During the removal of the dressing, there was bleeding in the wound of the control group, unlike the groups treated with cellulose membranes, which protected the bed from injury. The macroscopic evaluation showed a greater contraction of the wounds treated with the membranes in relation to the control. A microscopic analysis revealed that most of the wounds were in advanced healing degree with predominance of mature collagen in all groups. Conclusion: Pinus sp cellulose membrane showed efficacy similar to that of the bacterial membrane in the treatment of 3rd degree burns.

RESUMO Racional: O tratamento das queimaduras de 3˚ grau representa grande desafio na área médica. A celulose vegetal de pinus é biomaterial com características semelhantes às da celulose bacteriana. Objetivo: Avaliar a segurança da membrana de celulose vegetal (Pinus sp) no tratamento de queimaduras de terceiro grau em ratos e comparar sua eficácia com a da membrana bacteriana já comercializada. Método: Trinta e três ratos Wistar foram submetidos à queimadura de 3º grau na pele do dorso mediante aplicação de água a 98º C durante 30 s. Em seguida, foram distribuídos em três grupos (n=11): grupo 1 - curativo simples com gaze; grupo 2 - curativo com membrana de celulose bacteriana; e grupo 3 - curativo com membrana de celulose vegetal . Os animais foram avaliados durante 15 dias para verificar o estado clínico geral, aspecto macroscópico, contração das feridas e análise microscópica pelo grau de cicatrização e colagenizacao. Resultados: Permaneceram clinicamente bem durante o experimento. Durante a retirada do curativo houve sangramento na ferida do grupo controle, diferentemente dos grupos tratados com as membranas de celulose, que protegeram o leito da lesão. A análise microscópica mostrou que a maioria das feridas apresentava-se em grau avançado de cicatrização, com predomínio de colágeno maduro em todos os grupos. Houve maior contração das feridas tratadas com as membranas em relação ao grupo controle. Conclus ão: A membrana de celulose de Pinus sp apresentou eficácia semelhante à da membrana bacteriana no tratamento de queimaduras de 3˚ grau.

Between prolene®, ultrapro® and bard soft® meshes which presents the best performance in the repair of the abdominal wall? / Dentre as telas prolene®, ultrapro® ebard soft® qual apresenta melhor desempenho no reparo da parede abdominal?

ABSTRACT Background: In the definition of the mesh to be used to correct hernias, porosity, amount of absorbable material and polypropylene should be considered in the different stages of healing process. Aim: To evaluate the inflammatory reaction in the use of macro and microporous meshes of high and low weight in the repair of defects in the abdominal wall of rats. Methods: Ninety Wistar rats (Rattus norvegicus albinus) were used. The animals were submitted to similar surgical procedures, with lesion of the ventral abdominal wall, maintaining the integrity of the parietal peritoneum and correction using the studied meshes (Prolene®, Ultrapro® and Bard Soft®). Euthanasia was performed at 30, 60 and 120 days after surgery. The abdominal wall segments were submitted to histological analysis using H&E, Masson's trichrome, immunohistochemistry, picrosirius red and tensiometric evaluation. Results: On the 120th day, the tensiometric analysis was superior with Ultrapro® macroporous mesh. The inflammatory process score showed a significant prevalence of subacute process at the beginning and at the end of the study. Microporous meshes showed block encapsulation and in macroporous predominance of filamentous encapsulation. Conclusion: The Ultrapro® mesh showed better performance than the others in healing process of the abdominal wall.

RESUMO Racional: Na definição da tela a ser utilizada na correção das hérnias deve-se considerar a porosidade, quantidade de material absorvível e polipropileno ou inabsorvível nas diversas fases da cicatrização. Objetivo: Avaliar a reação inflamatória das telas macro e microporosas de alta e baixa gramatura no reparo de defeito da parede abdominal de ratos. Método: Foram utilizados 90 ratos da raça Wistar (Rattus norvegicus albinus). Os animais foram submetidos a procedimentos cirúrgicos semelhantes, com lesão da parede abdominal ventral, mantendo a integridade do peritônio parietal e correção utilizando as telas Prolene®, Ultrapro® e Bard Soft®. Realizou-se a eutanásia aos 30, 60 e 120 dias de pós-operatório. Os segmentos da parede abdominal foram submetidos à análise histológica com H&E, tricômio de Masson, imunoistoquímica, picrosirius red e análise tensiométrica. Resultado: No 120º dia a análise tensiométrica mostrou superioridade da tela macroporosa Ultrapro®. O escore do processo inflamatório demonstrou prevalência significativa de processo subagudo no início e no final do estudo. As telas microporosas mostraram encapsulamento em bloco e as macroporosas encapsulamento predominantemente filamentar. Conclusão: A tela Ultrapro® mostrou melhor desempenho em relação às demais na cicatrização da parede abdominal.

Comparative analysis of tissular response after abdominal wall repair using polypropylene mesh and bovine pericardium mesh / Análise comparativa da resposta tecidual após reparo da parede abdominal utilizando tela de polipropileno e de pericárdio bovino

ABSTRACT Background: The use of polypropylene meshes for surgical repair of the abdominal wall contributes to a reduction of the of recurrence rates of hernias or defects. However, its intra-abdominal use comes along with the formation of adhesions and several complications. The study and the search for alternative materials, including bovine pericardium, have been regarded as an option for the correction and treatment of resulting hernias with better adaptations and effectiveness. Aim: Evaluating the inflammatory process of the bovine pericardium in comparison with the inflammatory process of synthetic polypropylene mesh. Method: Bovine pericardium mesh and polypropylene mesh were placed, both on the same animal. The first group had the mesh removed for analysis on day 20, and the second group on day 40. The variables congestion, granulation, giant cells, necrosis, acute inflammation, chronic inflammation and collagen were analyzed. Results: All variables were found in greater numbers as a response to the polypropylene mesh, except for the collagen, which, on day 40, was greater in response to the bovine pericardium mesh. Conclusion: The data in this study suggest that there is less inflammatory reaction in response to bovine pericardium mesh when compared to polypropylene mesh.

RESUMO Racional: O uso de telas de polipropileno para a correção cirúrgica da parede abdominal contribui para redução dos índices de recidiva das hérnias ou defeitos. No entanto, o seu uso intra-abdominal cursa com a formação de aderências e diversas complicações. O estudo e a busca por materiais alternativos, como pericárdio bovino, têm se mostrado uma opção na correção e tratamento de hérnias que resultem com melhores adaptações e efetividades. Objetivo: Avaliar o processo inflamatório do pericárdio bovino em comparação ao processo inflamatório da tela sintética de polipropileno. Método: Foi realizada a colocação de tela de pericárdio bovino e polipropileno, ambas no mesmo animal. O primeiro grupo as teve retiradas para análise no dia 20, e o segundo grupo no dia 40. Foram analisadas as variáveis congestão, granulação, células gigantes, necrose, inflamação aguda, inflamação crônica e colágeno. Resultados: Todas as variáveis foram encontradas em maior número como resposta a tela de polipropileno, exceto a variável colágeno, que no dia 40 apresentou-se em maior quantidade em resposta à tela de pericárdio bovino. Conclusão: Há menor reação inflamatória em resposta a tela de pericárdio bovino, quando comparada com a de polipropileno.

Histological evaluation of capsules formed by texturized silicone implants with and without polyester mesh coverage (Parietex®). A study on female rats

ABSTRACT Purpose To evaluate capsules formed by microtextured silicone implants with and without Parietex® mesh coverage histologically. Methods Sixty Wistar rats were divided in two groups (meshed and unmeshed). Each group was, then, divided into two subgroups for evaluation at 30 and 90 days. Capsules were analyzed based on hematoxylin and eosin (HE) and picrosirius staining. Results The number of fibroblasts, neutrophils and macrophages was similar among all subgroups. There was a higher lymphocyte reaction in the 30-day meshed group (p = 0.003). Giant cell reaction, granulation tissue and neoangiogenesis were similar among the subgroups. Synovial metaplasia was milder at 90-day in the unmeshed (p = 0.002) and meshed group (p < 0.001). Capsular thickness was significantly greater in the meshed samples (30-day p < 0.001 and 90-day p < 0.001). There was a similar amount of collagen types I and III in both groups. Conclusions The mesh-covered implants produced capsules similar to the microtextured ones when analyzing inflammatory variables. Synovial metaplasia was milder at 90 than at 30 days, and the capsular thickness was significantly greater in the meshed group. A similar amount of collagen types I and III was observed. Due to these characteristics, the mesh coverage did not seem to significantly affect the local inflammatory activity.

Pine nanocellulose and bacterial nanocellulose dressings are similar in the treatment of second-degree burn? experimental study in rats / Os curativos de nanocelulose de pinus e nanocelulose bacteriana são semelhantes no tratamento da queimadura de segundo grau? estudo experimental em ratos

ABSTRACT Background: Despite all the advances in medicine and the wide variety of dressings available, the treatment of burn wounds still represents an important medical challenge. The pinus cellulose membrane dressing is a biomaterial with characteristics similar to those of bacterial cellulose, but with lower cost. Aim: To evaluate the efficacy of pinus nanocellulose membrane on healing of deep second degree burns in rats and compare with Membracel®. Method: Thirty male Wistar rats were submitted to deep second degree burn in dorse, with boiling water at 97o C for 20 s, generating a 314 mm² area wound. The animals were distributed in three dressing groups (n=10): group 1 - simple gauze; group 2 - bacterial cellulose membrane (Membracel®); and group 3 - pinus cellulose membrane. They were evaluated for 20 days to verify clinical condition, macro and microscopic appearance and wound contraction. Results: All of them remained clinically well with no differences in weight. Crusts were observed in group 1, and none in groups 2 and 3. Regarding to scar contraction, groups 2 and 3 were similar, better than group 1. Microscopic analysis showed predominance of advanced healing degree in groups 1 and 3, and initial in group 2. Mature collagen was predominant in all groups. Conclusion: The pinus nanocellulose membrane is effective in the treatment of experimental second degree burn in rats and its effectiveness is similar to that of the bacterial nanocellular membrane.

RESUMO Racional: Apesar de todos os avanços da medicina e da grande variedade de curativos disponíveis, o tratamento das queimaduras ainda representa importante desafio médico. O curativo de membrana de celulose de pinus é biomaterial com características semelhantes à de celulose bacteriana, mas de menor custo. Objetivo: Avaliar a eficácia da membrana de nanocelulose de pinus na cicatrização de queimaduras profundas de segundo grau em ratos e comparar com a Membracel®. Método: Trinta ratos Wistar machos foram submetidos à queimadura profunda de segundo grau em dorso, com água fervente a 97o C por 20 s, gerando lesão de 314 mm². Os animais foram distribuídos em três grupos de curativos (n = 10): grupo 1 - gaze simples; grupo 2 - membrana de celulose bacteriana (Membracel®); e grupo 3 - membrana de celulose de pinus. Eles foram avaliados por 20 dias para verificar o quadro clínico, aspecto macro e microscópico e a contração da ferida. Resultados: Todos permaneceram clinicamente bem, sem diferenças de peso. Crostas foram observadas no grupo 1 e nenhuma nos grupos 2 e 3. Em relação à contração da cicatriz, os grupos 2 e 3 foram semelhantes, melhores que o grupo 1. A análise microscópica mostrou predomínio de grau de cicatrização avançado nos grupos 1 e 3, e inicial no grupo 2. O colágeno maduro foi predominante em todos os grupos. Conclusão: A membrana de nanocelulose de pinus é eficaz no tratamento de queimaduras experimentais de segundo grau em ratos e sua eficácia é semelhante à da membrana nanocelular bacteriana.

Comparative study between polypropylene and polypropylene/poliglecaprone meshes used in the correction of abdominal wall defect in rats.

PURPOSE: To evaluate the healing process of a defect in the ventral abdominal wall of rats, comparing the polypropylene and polypropylene/poliglecaprone meshes on the 30(th) and 60(th) postoperative day. METHODS: Thirty two Wistar rats were submitted to a ventral abdominal wall defect, with integrity of the parietal peritoneum. In the repair, were used polypropylene (group A) and polypropylene/poliglecaprone (group B) meshes. The groups were subdivided into four subgroups of eight animals euthanized on the 30(th) (A30 and B30) and 60(th) postoperative day (A60 and B60). Fragments of the abdominal wall of the animals were submitted to macroscopic, tensiometric and histological evaluations. RESULTS: The tensiometry on subgroup A30 showed a mean average break point of 0.78 MPa and in A60, 0.66 Mpa. In subgroup B30 it was 0.84 MPa and in B60, 1.27 Mpa. The score of the inflammatory process showed subacute phase on A30 and B30 sub-groups and chronic inflammatory process in subgroups A30 and 60B. CONCLUSIONS: The tensile strength was higher on the wall repaired by polypropylene/poliglecaprone mesh in the 60(th) post-operative day. Histology showed higher concentration of fibrosis on the surface of the polypropylene mesh with a tendency to encapsulation. In polypropylene/poliglecaprone subgroups the histology showed higher concentration of fibrosis on the surface of mesh filaments.

Tensiometric analysis of meshes used in abdominal ventral wall defects in rats / Estudo tensiométrico de telas utilizadas na correção de defeito na parede abdominal ventral de ratos

ABSTRACT Background: Among the various strategies to avoid exaggerated foreign body reaction in the treatment of hernias is the limitation of the amount of polypropylene or the use of absorbable material. Aim: To evaluate the healing of defects in the abdominal wall of rats, comparing microporous polypropylene, macroporous polypropylene and polypropylene/polyglecaprone at the 30º, 60º and 120º postoperative day. Methods: Wistar rats were submitted to defect production in the ventral abdominal wall, with integrity of the parietal peritoneum. Prolene®, Ultrapro® and Bard Soft® meshes were used in the correction of the defect. Nine subgroups of 10 animals were submitted to euthanasia at 30th, 60th and 120th postoperative day. Fragments of the abdominal wall of the animals were submitted to tensiometric analysis. Results: The tensiometry at the 30th postoperative day showed greater resistance of the tissues with Bard Soft® (macroporous mesh) in relation to the tissues with Prolene® (microporous mesh). On the 60th postoperative day Bard Soft® maintained the superior resistance to the tissues comparing to Prolene Mesh®. On the 120th postoperative day the tissues repaired with Ultrapro® (macroporous mesh) proved to be more resistant than the ones by Prolene® (microporous mesh) and Bard Soft® (macroporous mesh). Conclusion: The tissues repaired with macroporous meshes showed greater resistance than with microporous meshes at all stages, and at 120 days postoperative Ultrapro® performed better than the others.

RESUMO Racional: Dentre as várias estratégias para evitar exagerada reação de corpo estranho no tratamento das hérnias está a limitação da quantidade de polipropileno na tela ou utilização de material absorvível. Objetivo: Avaliar a cicatrização de defeito em parede abdominal de ratos, comparando-se as telas de polipropileno microporosa, polipropileno macroporosa e polipropileno/poliglecaprone. Métodos: Em 90 ratos Wistar foi produzido defeito na parede abdominal ventral, com integridade do peritônio parietal. Na correção foram utilizadas as telas Prolene®, Ultrapro® e Bard Soft®. Nove subgrupos de 10 animais foram submetidos à eutanásia no 30º, 60º e 120º dia do pós-operatório. Fragmentos da parede abdominal dos animais foram submetidos à análise tensiométrica. Resultados: A tensiometria aos 30dias mostrou maior resistência do tecido com tela Bard Soft® em relação à de Prolene®; no 60º dia a Bard Soft® manteve a resistência superior ao Prolene®; no 120º dia a reparação com tela macroporosa Ultrapro® mostrou-se mais resistentes que a de Prolene® e Bard Soft®. Conclusão: Os tecidos reparados com telas macroporosas demonstraram maior resistência do que as microporosas em todas as fases, sendo que aos 120 dias de pós-operatório a Ultrapro® teve melhor desempenho que as demais.

Cecorraphy in single layer using polypropylene and poliglecaprone 25 threads: comparative study in rats.

PURPOSE: To compare sutures with polypropylene and poliglecaprone 25 after partial cecotomy in rats. METHODS: Thirty six rats divided into two groups, A and B, of 18 animals; each group was also divided into three subgroups of six animals sacrificed at 4(th), 7(th) and 14(th) days after surgery. Were studied the mortality, morbidity, complications attributable to sutures, macroscopy, optical microscopy and measurement of hydroxyproline at the level of the suture. RESULTS: There were no deaths or wound complications such as hematoma, seroma, abscess, evisceration or eventration. On microscopic evaluation reepithelization, coaptation and inflammation in both groups did not differ significantly. The average rate of tissue hydroxyproline found in the samples on the 4(th) day after surgery, was 21.38 mg/g tissue for group A and 16.68 mg/g for group B; on day 7 after surgery, the average was 15.64 mg/g tissue for group A and 26.53 mg/g for group B; on day 14, the average was 8.09 mg/g tissue for group A and 25.07 mg/g for group B. CONCLUSION: There were no differences on clinical evolution, macroscopic aspect, microscopic data and hydroxyproline concentration on both sutures.

[The influence of the number of bars on the axial compressive strength of uniplanar external fixators in polyurethane tibia models]. / A influência do número de barras na resistência à compressão axial dos fixadores externos monoplanares em modelos de tíbias de poliuretano.

OBJECTIVE: This is an experimental study with the objective of analyses the increase of rigidity in synthetic tibia bones with external fixators, with single and double connecting rods and with stable and unstable fracture patterns. METHODS: The external fixators were used in the monoplanar, half pin configuration submitted to an axial compression load using the connecting bar in different patterns. Forty-eight similar models to the human tibia had been used. In all the models were left an interval of 0,5 cm between the fragments and were made cuts of 15 masculine and 45 masculine to simulate stable and unstable fracture patterns, respectively. The models had been divided in four groups in accordance with the cut (15 masculine and 45 masculine) and the number of metallic bars in assembly (1 and 2 bars). The study used the Instron testing machine which the models were submitted to the axial load until the fragments that were separated by a gap made full contact. RESULTS: The instability forces in the assembly with a double bar had been sufficiently superior to the forces with only one bar. It was still observed that the group with unstable fracture pattern and with only one connecting rod had a lesser variability compared with the other groups and presented more homogeneous results, with a minor average. CONCLUSION: The assembly with a double longitudinal connecting rod in the studied models is more stable than the others to stand compression load.

[Biomechanic analysis of the sewed tendons for the reconstruction of the anterior cruciate ligament]. / Análise biomecânica da solidarização de tendões para reconstrução do ligamento cruzado anterior.

OBJECTIVE: To evaluate the difference of the mechanical behavior of bended tied (sewed) and not tied hamstring tendons in order to evaluate if it has any effective function. METHODS: Twenty-four fresh bovine digital tendons had been used. Alginate to determine the area of the tendon transversal section was used. Ten bovine tendons had been bended and tied following the manufacturer orientation, ten others pairs had not been tied. Claws had been developed for the grafts fixation to the universal machine, for the setting simulation. The superior one was characterized to be bipartite and to have controlled passage for the pins and the inferior claw is characterized to have alternating teeth. RESULTS: The maximum load of the not tied samples of the test was 849,4 N +/- 386,8 the area was 30,4 mm(2) +/- 7,7, and 29 +/- 17 Mpa of tension. The tied ones had gotten maximum load of 871,8 N +/- 484,9, area of 35 mm(2) +/- 5,8, and 24 +/- 10 Mpa of tension. It did not have statistical difference between the two groups (p>0,05). CONCLUSION: The probability distribution showed that with 400 N the not tied tendons represents 83,8% of trustworthiness and the tied ones represents 78,5%.

Healing reaction to mammary prostheses covered by textured silicone and silicone foam in rats.

PURPOSE: To compare the capsular reaction to two different coverings of silicone prosthesis through the biophysical characteristic of adherence and microscopical aspects of the inflammatory reaction and collagen formation. METHODS: Thirty two Wistar rats were used. In the dorsum of each animal a silicone elastomer with a smooth superficies and another coated with texturized silicone (Mentor) was implanted. Another one, with the same smooth superficies and other coated with silicone foam (Lifesil), making up in each side, of the dorsum, the texturized and silicone foam group respectively. The animals were split into four groups to be evaluated at 7, 14, 30 and 60 days. On the evaluation dates the implant adherence was verified witch a tensiometer and the values in kgf were obtained. The material was sent to histological analysis with hematoxilin-eosin and picrosirius colorations, to evaluate the inflammatory reaction and collagen synthesis, respectively. The obtained data were submitted to statistical treatment. RESULTS: There was more adherence of the tissue to the silicone foam (P<0,001). The inflammatory reaction was more intense in the same group, but without statistical significance. The number of giant cells and granulomas were more frequent in the silicone foam group. There was statistical significance at the 60 days for granulomas (P<0,028) and for all subgroups about number of giant cells (P< 0,012 to P<0,036). The thickness of the capsule in the silicone foam group was bigger, with statistical significance at seven days (P<0,028) and 60 days (P<0,012). The collagen deposition showed no difference in statistical analysis. CONCLUSION: The capsular reaction to the silicone foam showed stronger adherence, bigger thickness and had more number of granulomas and giant cells. No difference was observed in the intensity of inflammatory reaction in relation to type I and III collagen, when compared to the texturized cover.

Intraperitoneal meshes in the repair of abdominal wall defects: comparison of polyester with collagen versus polypropylene with polyglycolic acid.

OBJECTIVE: To compare the clinical and histological outcomes of the repair of induced abdominal wall defects with Parietex and Optilene Mesh Elastic + Safil in direct contact with abdominal viscera (intraperitoneal position, IPOM). METHODS: Sixteen rabbits were allocated into two groups with 8 animals each, corresponding to evaluation on the 30th and 60th postoperative days. All animals were submitted to two standardized symmetric abdominal wall defects, comprising all muscular layers and the peritoneum, followed by repair through the intraperitoneal placement of two different meshes. The experimental design allowed each animal to be its own control. Macroscopic aspects evaluated were: surgical site infection, mesh erosion, suture insufficiency, fistulae, intra-abdominal infection and adhesion formation. Microscopic parameters analyzed consisted of collagen deposition and the immunohistochemical healing process. RESULTS: The formation of intraperitoneal adhesions and the other macroscopic outcome measures evaluated did not present significant statistical differences between the two meshes, neither did type I and III collagen deposition and MMP-1 and MMP-8 antibody expression. MMP-13 antibody exhibited significantly higher expression on the 30th postoperative day with Optilene+Safil and on the 60th day with Parietex. CONCLUSION: Due to the similar results obtained, both macroscopically and microscopically, the meshes can be considered equivalent with respect to the healing of surgical wounds in abdominal wall defects in rabbits.