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.

Comparación de recidiva posterior a hernioplastía diafragmática con cierre directo versus colocación de parche / Comparison of recurrence after diaphragmatic hernioplasties with direct closure versus patch placement

Resumen Objetivo: Investigar con cuál técnica quirúrgica, cierre directo o con parche de Goretex, las hernias diafragmáticas congénitas operadas tienen más recidiva. Metodología: Los datos de los pacientes sometidos a reparación por hernia diafragmática congénita en el Hospital Nacional de Niños, entre enero 2008 y el 31 diciembre de 2017, fueron revisados retrospectivamente. De los 94 pacientes, solo 59 cumplen con los criterios de inclusión. Para la comparación de las variables cuantitativas se empleó pruebas de T de Student e intervalos de confianza al 95 %; las variables cualitativas se analizaron por la prueba de Fisher con un nivel de significancia de 0,05. Resultados: La mayoría de las hernias diafragmáticas operadas fueron izquierdas (78 %) y posterolaterales (91 %). La técnica de reparación más frecuente utilizada fue el cierre directo (68%). Hubo más recidivas posteriores a cierre con parche de Goretex. Se presentaron entre 1 y 12 meses postoperatorio. No hubo diferencia estadísticamente significativa entre recidivas con técnica de cierre directo versus cierre con parche de Goretex. Conclusión: Realizar un cierre directo del diafragma es una buena opción quirúrgica para reparación de hernia diafragmática congénita. No hubo en este estudio diferencias estadísticamente significativas en cuanto a recidiva entre utilizar técnica con cierre directo o con parche.

Abstract Objective: To investigate with which surgical technique, direct closure or use of a Goretex patch, congenital diaphragmatic hernias recurre more. Methodology: The data of the patients who underwent repair of congenital diaphragmatic hernia at the National Children's Hospital from January 2008 to December 31, 2017, were reviewed retrospectively. Of the 94 patients, only 59 met the inclusion criteria. For the comparison of the quantitative variables, Student's t-test and 95% confidence intervals were used, the qualitative variables were analyzed by the Fisher's test with a significance level of 0.05. Results: Most of the operated diaphragmatic hernias were left 78% and posterolateral 91%. The most frequent repair technique used was direct closure, 68%. There were more recurrences after closing when a Goretex patch was used. They occurred between 1 and 12 months post-operatively. There was no statistically significant difference between recurrences with the direct closure technique versus closure with the Goretexpatch. Conclusion: Performing a direct closure of the diaphragm is a good surgical option for surgical repair of congenital diaphragmatic hernias. There were no statistically significant differences in relapse in this study between using the direct closure or patch technique.

Fifteen years of experience with frontalis suspension using polytetrafluoroethylene (Gore-Tex®) suture in blepharoptosis repair / 15 anos de experiência em suspensão frontal com fio de politetrafluoretileno (Gore-Tex®) na correção de ptose palpebral

ABSTRACT Purpose: To review the outcomes of frontalis suspension surgeries with the use of polytetrafluoroethylene in patients with blepharoptosis. Methods: A retrospective observational study analyzed the outcomes of frontalis suspension surgeries performed in a single institution from 2003 to 2018. All procedures were performed with closed incision and single pentagon techniques. Outcomes were classified as satisfactory or unsatisfactory, with satisfactory defined as a margin reflex distance of >3 mm and <1 mm between eyelids and unsatisfactory as hypocorrection, surgical complications, and asymmetry. Results: We included a total of 76 eyelids from 52 patients in our study. Within a mean postoperative follow-up of 16.8 ± 18.5 months (range, 3-95), 59 (77.6%) eyelids had a satisfactory outcome, and 17 (22.4%) were unsatisfactory (8 cases of asymmetry, 3 granulomas, 3 suture extrusions, 2 abscesses, and 1 case of cellulitis). Nine eyelids from the unsatisfactory group required reoperation. Among the patients with a follow-up of ³12 months (38 surgeries), lasting results were observed in most eyelids, except for 2 late-onset suture extrusions. Conclusion: The use of polytetrafluoroethylene in frontalis suspension surgery was shown to be predictable, safe, and lasting. Our findings support previous studies that have shown adequate functional results and low complication rates.

RESUMO Objetivo: Revisar os resultados de cirurgias de sus pensão ao músculo frontal com o uso de fio de politetrafluoretileno em pacientes com blefaroptose. Métodos: Em um estudo observacional retrospectivo, foram analisados os resultados das cirurgias de músculo frontal de uma instituição, realizadas entre 2003 e 2018. Todos os procedimentos foram realizados com incisão fechada e técnica de pentágono. Os desfechos foram classificados como satisfatórios ou insatisfatórios com definição satisfatória definida como distância margem-reflexo >3mm e <1mm entre as pálpebras e insatisfatória como hipocorreção, complicações cirúrgicas e assimetria. Resultados: Incluímos um total de 76 pálpebras de 52 pacientes em nosso estudo. Com um tempo médio de seguimento pós-operatório de 16,8 ± 18,5 meses (intervalo 3-95), 59 (77,6%) pálpebras apresentaram desfecho satisfatório e 17 (22,4%) insatisfatórios (8 casos de assimetria, 3 granulomas, 3 extrusões de sutura, 2 abscessos e 1 caso de celulite). Nove pálpebras do grupo insatisfatório necessitaram de reoperação. Entre os pacientes com seguimento ³12 meses (38 cirurgias), resultados duradouros foram observados na maioria dos casos, exceto por 2 extrusões de sutura de surgimento tardio. Conclusão: O uso de politetrafluoretileno na cirurgia de músculo frontal mostrou ser previsível, seguro e duradouro, Nossos achados corroboram com estudos prévios que mostraram resultados funcionais adequados e baixos índices de complicação.

Preservação do rebordo alveolar com perda óssea vestibular associada a biomaterial e membrana PTFE densa intencionalmente exposta ao meio bucal / Preservation of the alveolar ridge with buccal bone loss associated with biomaterial and d-PTFE membrane intentionally exposed to the buccal environment

O uso de membranas em casos de regeneração óssea guiada tornou-se comum e representa um recurso para ganho de tecido ósseo. As membranas de politetrafluoretileno denso (d-PTFE) são uma opção quando há necessidade de mantê-las expostas ao meio bucal. Neste estudo, relata-se a utilização de uma membrana d-PTFE para regeneração óssea em alvéolo pós-extração em região estética.

The use of membranes in cases of guided bone regeneration has become common and represents a resource for bone tissue gain. Dense polytetrafl uoroethylene (d-PTFE) membranes are an option when there is a need to keep them exposed in the oral cavity. In this study, we report the use of a d-PTFE membrane for bone regeneration in the post-extraction socket in the esthetic zone.

Immunolocalization of markers for bone formation during guided bone regeneration in osteopenic rats

Objective The aim of this paper was to evaluate the repair of onlay autogenous bone grafts covered or not covered by an expanded polytetrafluoroethylene (e-PTFE) membrane using immunohistochemistry in rats with induced estrogen deficiency. Material and Methods Eighty female rats were randomly divided into two groups: ovariectomized (OVX) and with a simulation of the surgical procedure (SHAM). Each of these groups was again divided into groups with either placement of an autogenous bone graft alone (BG) or an autogenous bone graft associated with an e-PTFE membrane (BGM). Animals were euthanized on days 0, 7, 21, 45, and 60. The specimens were subjected to immunohistochemistry for bone sialoprotein (BSP), osteonectin (ONC), and osteocalcin (OCC). Results All groups (OVX+BG, OVX+BMG, SHAM+BG, and SHAM+BMG) showed greater bone formation, observed between 7 and 21 days, when BSP and ONC staining were more intense. At the 45-day, the bone graft showed direct bonding to the recipient bed in all specimens. The ONC and OCC showed more expressed in granulation tissue, in the membrane groups, independently of estrogen deficiency. Conclusions The expression of bone forming markers was not negatively influenced by estrogen deficiency. However, the markers could be influenced by the presence of the e-PTFE membrane. .

Early postoperative changes in hematological, erythrocyte aggregation and blood coagulation parameters after unilateral implantation of polytetrafluoroethylene vascular graft in the femoral artery of beagle dogs

PURPOSE: The failure of small-caliber vascular grafts still means a serious problem. Concerning the early postoperative complications we aimed to investigate the hemostaseological and hemorheological aspects of this issue in a canine model. METHODS: In the Control group only anesthesia was induced. In the Grafted group under general anesthesia a 3.5-cm segment was resected unilaterally from the femoral artery and replaced with a PTFE graft (diameter: 3 mm). On the 1st-3rd-5th-7th and 14th postoperative days the skin temperature of both hind limbs was measured, and blood sampling occurred for hematological, hemostaseological and hemorheological tests. RESULTS: The skin temperature of the operated versus intact limbs did not differ. In the Grafted group leukocyte count was elevated by the 1st postoperative day, while platelet count increased over the entire follow-up period. Fibrinogen concentration rose on the 1st-5th days, activated partial thromboplastin time increased on the 3rd-7th days. Erythrocyte aggregation was enhanced significantly on the 1st-5th days. In specimens taken on the 14th day, histologically we found matured thrombus narrowing the graft lumen. CONCLUSIONS: Small-caliber PTFE graft implantation into the femoral artery caused significant changes in several hemostaseological and hemorheological parameters. However, better clarifying the factors leading to early thrombosis of these grafts needs further studies. .

The inflammatory stimulus of a natural latex biomembrane improves healing in mice

The aim of the present study was to compare healing obtained with biomembranes with the natural healing process (sham) using biochemical and immunohistological assays. C57BL/6 mice were divided into 4 groups of 15 mice each and received different subcutaneous implants: natural latex biomembrane (NLB), denatured latex (DL), expanded polytetrafluorethylene (ePTFE), or sham. On the 2nd, 7th, and 14th days post-treatment, 5 mice per group were sacrificed and biopsied for the following measurements: oxidative stress based on malondialdehyde (MDA), myeloperoxidase (MPO) and hydrogen peroxide by the method of ferrous oxidation-xylenol orange (FOX), as well as glutathione and total proteins; histological evaluation to enumerate inflammatory cells, fibroblasts, blood vessels, and collagen, and immunohistochemical staining for inducible nitric oxide synthase, interleukin-1β, vascular endothelial growth factor (VEGF), and transforming growth factor-β1 (TGF-β1). On day 2 post-treatment, NLB stimulated a dense inflammatory infiltrate mainly consisting of polymorphonuclear cells, as indicated by increased MPO (P < 0.05), but oxidative stress due to MDA was not observed until the 7th day (P < 0.05). The number of blood vessels was greater in NLB (P < 0.05) and DL (P < 0.05) mice compared to sham animals on day 14. NLB induced fibroplasia by day 14 (P < 0.05) with low expression of TGF-β1 and collagenesis. Thus, NLB significantly induced the inflammatory phase of healing mediated by oxidative stress, which appeared to influence the subsequent phases such as angiogenesis (with low expression of VEGF) and fibroplasia (independent of TGF-β1) without influencing collagenesis.

Filling the nasal dorsum with Gore-tex in rhinoplasties / Uso do Gore-tex para preenchimento do dorso nasal em rinoplastias

BACKGROUND: Many autogenous and exogenous materials have been frequently used for the production of grafts and implants in rhinoplasties. The ideal graft or implant should be biocompatible, biointegrated, non-absorbable, and easily moldable and should not cause an inflammatory response. Gore-tex, an expandable form of polytetrafluoroethylene (PTFE) has been used since the 1970s for vascular graft production. Although Gore-tex is extremely versatile and has extensive uses and low complication rates, the demonstration of Gore-tex use in aesthetic surgery is very limited in medical literature. METHODS: We performed a retrospective study of 7 patients who received Gore-tex implants in order to fill the nasal dorsum from January 2005 to December 2007. All patients were assessed for aesthetic and functional factors and for the presence or absence of complications. RESULTS: All patients had good postoperative evolution, with great satisfaction in terms of aesthetic and functional aspects and no complications. CONCLUSIONS: Gore-tex is a satisfactory synthetic material as it is inexpensive, easily moldable, has good biocompatibility, and has shown no incidence of extrusion or infection in implants used for nasal dorsum filling in previously reported cases.

INTRODUÇÃO: Muitos materiais autógenos e exógenos vêm sendo utilizados com frequência para confecção de enxertos e implantes nas rinoplastias. O enxerto ou implante ideal deve ser biocompatível, biointegrável, não-absorvível, facilmente moldável e não deve causar resposta inflamatória. O Gore-tex, uma forma expansível do politetrafluoretileno (PTFE), é usado desde a década de 1970 na confecção de próteses vasculares. Apesar de seu uso ser extremamente versátil e extenso, oferecendo baixas taxas de complicação, a demonstração na literatura médica de seus resultados, quando usado na cirurgia estética, é muito restrita. MÉTODO: Realizado estudo retrospectivo sobre a evolução de 7 pacientes submetidos a implantes de Gore-tex visando ao preenchimento do dorso nasal, no período de janeiro de 2005 a dezembro de 2007. Todos os pacientes foram avaliados quanto a fatores estéticos e funcionais, e quanto à presença ou não de complicações. RESULTADOS: Todos os pacientes tiveram boa evolução pós-operatória, com grande satisfação do ponto de vista estético e funcional, e sem complicações. CONCLUSÕES: O Gore-tex mostrou-se um material sintético satisfatório, de baixo custo, facilmente moldável, com boa biocompatibilidade e com incidência nula de extrusão ou infecção para implantes de preenchimento de dorso nasal nos casos apresentados.

Expanded polytetrafluoroethylene in canine bile duct injury: a critical analysis / Politetrafluoroetileno expandido na lesão do ducto biliar em cães: uma análise crítica

PURPOSE: Analyze the morphological and structural outcomes of a patch of expanded polytetrafluoroethylene in the treatment of an iatrogenic injury of the common bile duct. METHODS: In Group 1 (Sham), 7 dogs underwent 3 laparotomies with intervals of 30 days between them. In Group 2, 10 dogs underwent transient common bile duct obstruction. After 30 days, this biliary occlusion was undone and a patch of expanded polytetrafluoroethylene replaced a fragment removed from the duct's wall. Thirty days after this last surgery, cholangiographic assessment of prosthesis patency and macro and microscopic evaluation of the biliary tract were performed. Daily clinical inspection completed the study outcomes. The Wilcoxon non-parametric test was used for statistical analysis. RESULTS: In all dogs enlargement of the biliary tree diameter was observed 30 and 60 days after the first surgical procedure. Partial adhesion of the patch to the common bile duct as a free luminal foreign body was found in 6 dogs. The prosthesis was completely integrated to surrounding tissue in the remaining four. CONCLUSION: Although a feasible option for the treatment of biliary duct iatrogenic lesions, the expanded polytetrafluoroethylene prosthesis must be used with caution considering the potential risks for complications.

OBJETIVO: Analisar, evolutivamente, a morfologia e a estrutura de um fragmento de politetrafluoretileno expandido utilizado no tratamento de uma lesão iatrogênica do ducto biliar comum. MÉTODOS: No grupo 1 (Simulação), sete cães foram submetidos a três laparotomias com intervalos de 30 dias entre elas. No grupo 2, em dez cães realizou-se uma obstrução tansitória do ducto biliar comum. Após 30 dias, a oclusão biliar foi desfeita e um fragmento da parede ductal foi substituído por um retalho de politetrafluoretileno expandido. Trinta dias após esta última operação, foram efetuadas uma avaliação colangiográfica da perviedade da prótese e uma análise macro e microscópica do trato biliar. Inspeções clínicas diárias completaram o estudo evolutivo. O teste não paramétrico de Wilcoxon foi utilizado para análises estatísticas. RESULTADOS: Decorridos 30 e 60 dias do primeiro procedimento cirúrgico, observou-se, em todos os cães, aumento do diâmetro da árvore biliar. Em seis cães verificou-se a presença do fragmento da prótese parcialmente aderido à parede do ducto biliar comum e também solta no lúmen da via biliar. A prótese estava completamente integrada aos tecidos circunvizinho nos demais quarto animais. CONCLUSÃO: A prótese de politetrafluoretileno expandido apresenta-se como uma opção factível para o tratamento das lesões iatrogênicas do ducto biliar, entretanto, deve ser utilizada com cautela, considerando o risco potencial de complicações.

Partial Pericardial Defect Incidentally Discovered During Coronary Bypass Surgery

A 71-yr-old male patient with three vessel coronary artery disease underwent a coronary artery bypass graft. The patient was found to have a large pericardial defect at the apex of the heart that measured approximately 18 cm in circumference. The edge of the pericardial defect impinged on the epicardial coronary arteries. The left phrenic nerve descended via the dorsal boundary of the pericardial defect. Following coronary artery bypass grafting, the pericardial defect was repaired with a polytetrafluorethylene patch. The patient had an uncomplicated postoperative course.

Secure reconstruction technique after partial nephrectomy irrespective of tumor size and location

Introduction: Nephron-sparing surgery for large renal masses is not considered a safe procedure because of high complication rate. We present our experience using expanded polytetrafluoroethylene (Gore-Tex®) and Hem-O-Lok® (Weck® Clip) as hemostatic agents during open partial nephrectomy (OPN) to perform nephron-sparing surgery for large renal masses. Materials and Methods: Sixty patients underwent OPN for suspicious renal cell carcinomas. Thirty-four patients with tumors < 2.5 cm in size underwent OPN with Gore-Tex® alone (group 1). Clinical data from a computerized database were reviewed and compared to a contemporary group of 26 patients with tumors ≥ 2.5 cm in size who underwent OPN with Gore-Tex® and Hem-O-Lok® (group 2). Results: The mean patient age was 53 years (range, 35-85 years), and the mean duration of follow-up was 41.8 months (range, 6-56 months). The mean cold ischemic times were 24.0 minutes (range, 12-37 minutes) and 35.3 minutes (range, 18-65 minutes) respectively in group 1 and 2. The tumor sizes in groups 1 and 2 were 1.7 ± 0.4 cm and 4.74 ± 2.75 cm, respectively. No major complications, such as urine leakage or delayed bleeding, were noted in either group. Conclusions: Nephron-sparing surgery using Gore-Tex® alone or a Gore-Tex® and Hem-O-Lok® combination was safe without high-priced hemostatic agents because the tensile strength was sufficient to maintain firmness in the repaired parenchyma. In addition, the procedure is easy to perform and takes less time to complete. Furthermore, major complications, recurrence, and impaired renal function did not occur with this procedure.

Suspensão ao músculo frontal com politetrafluoretileno para o tratamento da blefaroptose / Frontalis suspension with polytetrafluorethylene for the treatment of blepharoptosis

OBJETIVO: Relatar a experiência com o uso do fio de politetrafluoretileno nas cirurgias de suspensão ao músculo frontal para correção de blefaroptose. MÉTODOS: Foram estudados todos os casos de blefaroptose grave submetidos à cirurgia pela técnica de suspensão ao músculo frontal como fio de politetrafluoretileno, no período de fevereiro de 2003 a abril de 2007. Foram realizadas 36 cirurgias em 23 pacientes, a média de seguimento foi de 15,8 meses (variando de 3 a 36 meses). A técnica cirúrgica utilizada foi a descrita por Fox. RESULTADOS: Entre as causas de blefaroptose foram encontradas: congênita em 20 (86,95 por cento) pacientes, blefarofimose em 2 (8,69 por cento) pacientes e traumática em 1 (4,35 por cento) paciente. Na primeira semana de pós-operatório, 6 (26,08 por cento) pacientes referiram assimetria palpebral, 4 (17,39 por cento) notaram edema local, 3 (13,04 por cento) pacientes apresentaram granuloma no local do fio e 1 (4,35 por cento) paciente apresentou celulite facial na região frontal unilateral. Após 3 meses de seguimento, 3 (13,04 por cento) pacientes referiram assimetria palpebral, e em 1 (4,35 por cento) paciente persistia o granuloma. CONCLUSÃO: O politetrafluoretileno - Modelo CV3, 6.0 (Gore-Tex®; W.L. Gore & Associates Inc, Flagstaff, AZ, EUA) é um material adequado com bons resultados funcionais (86,9 por cento), baixos índices de complicação (4,35 por cento) e insatisfação (13,4 por cento), podendo ser uma alternativa em relação à fáscia lata, na cirurgia de suspensão ao frontal para tratamento de ptose palpebral grave.

PURPOSE: To evaluate the functional results and complications of the use of expanded polytetrafluoroethylene in frontalis suspension surgery for the treatment of blepharoptosis. METHODS: Frontalis suspension procedure with polytetrafluoroethylene was performed between 2003 and 2007 on 23 patients (36 eyes) with blepharoptosis. An average follow-up time was 15.8 months (range, 3 to 36). Surgical technique used was described by Fox. RESULTS: The causes of blepharoptosis found were: congenital in 20 patients (86.95 percent), blepharophimosis in 2 (8.69 percent) and traumatic in 1 (4.35 percent). At the first week of postoperatory 6 (26.08 percent) patients related palpebral asymmetry, 4 (17.39 percent) noticed local edema, 3 (13.04 percent) presented granulomas and 1 (4.35 percent) presented facial cellulitis on the ipsilateral frontal region. After 3 months of follow-up 3 (13.04 percent) patients related palpebral asymmetry and 1 (4.35 percent) persisted the granuloma. CONCLUSION: Polytetrafluoroethylene - Model CV3, 6.0 (Gore-tex®, W.L. Gore & Associates Inc, Flagstaff, AZ, EUA) is an adequate material with good functional results (86.9 percent), relatively few complications (4.35 percent) and insatisfaction (13.4 percent) that could be an alternative for fascia lata in the surgery of frontalis suspension for the treatment of blepharoptosis.

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.

Optical density of bone repair after implantation of homogenous demineralized dentin matrix in diabetic rabbits

This research evaluated the bone repair process after implantation of homogenous demineralized dentin matrix (HDDM) in surgical defects in the parietal bone of rabbits with alloxan-induced diabetes, using a polytetrafluorethylene (PTFe) barrier for guided bone regeneration. Thirty-six rabbits were used and divided into four groups: control (C, n = 12), diabetic (D, n = 12, left parietal bone), diabetic with PTFe (D-PTFe, same 12 rabbits, right parietal bone), and diabetic with PTFe associated to HDDM (D-PTFe+HDDM, n = 12). Bone defects were created in the parietal bone of the rabbits and the experimental treatments were performed, where applicable. The rabbits were sacrificed after 15, 30, 60 and 90 days. The bone defects were examined radiographically and by optical density (ANOVA and Tukey test, p < .05). The radiographic findings showed that the D-PTFe+HDDM group presented greater radiopacity and better trabecular bone arrangement when compared to that of the C, D and D-PTFe groups. The statistical analysis showed significant differences in the optical density of the newly formed bone among the studied groups. It was possible to conclude that HDDM was biocompatible in diabetic rabbits.

Prótese vascular derivada do látex / Latex-derived vascular prosthesis

CONTEXTO: O desenvolvimento de prótese vascular tem sido vital para os avanços e realizações da cirurgia vascular reconstrutora durante as últimas 5 décadas. OBJETIVOS: Desenvolver um novo modelo de prótese vascular microperfurada, confeccionada em tecido recoberto com um composto derivado do látex natural da seringueira (Hevea brasiliensis) e avaliar sua perviedade, trombogenicidade, biocompatibilidade e o processo de cicatrização, além de algumas propriedades mecânicas (adaptabilidade, elasticidade, impermeabilidade e possibilidade de sutura), utilizando como controle a prótese de politetrafluoretileno expandido no mesmo animal. MÉTODOS: Quinze cães foram separados em três grupos de cinco animais. Implantou-se a prótese de tecido e látex microperfurada e, no membro pélvico contralateral, a prótese de politetrafluoretileno expandido em todos os cães. O seguimento pós-operatório foi de 4, 8 e 12 semanas. A apreciação dos resultados foi feita segundo as avaliações clínicas dos pulsos, complicações (coleção líquida, deiscência, granuloma e infecção), arteriografias, análise macroscópica e elétron-micrografias de varredura. RESULTADOS: Os testes estatísticos aplicados não evidenciaram diferenças significativas (p > 0,05) em relação às complicações pós-operatórias e perviedade dos enxertos. Ambas as próteses integraram-se adequadamente aos tecidos circunvizinhos, com um tecido de incorporação formado por fibras colágenas. Constatou-se a presença de neoíntima recoberta por endotélio em toda a extensão da superfície luminal da prótese de tecido e látex microperfurada. Ao contrário, na prótese de politetrafluoretileno expandido, o desenvolvimento endotelial sobre a superfície neointimal limitou-se às regiões próximas às anastomoses. CONCLUSÕES: A prótese de tecido e látex microperfurada demonstrou qualidades estruturais (adaptabilidade, elasticidade, impermeabilidade e possibilidade de sutura) satisfatórias como substituto vascular. Estimulou...

BACKGROUND: The development of vascular grafts has been crucial for advances and achievements in reconstructive vascular surgery over the past 5 decades. OBJECTIVES: To develop a new model of microperforated vascular graft using fabric covered with a natural latex-derived polymer taken from Hevea brasiliensis and assess its patency, thrombogenicity, biocompatibility and healing process, besides some mechanical properties (adaptability, elasticity, impermeability and possibility of suture), using expanded polytetrafluoroethylene graft as control. METHODS: Fifteen dogs were divided into three groups of five animals. The microperforated latex graft was implanted in all dogs and the expanded polytetrafluoroethylene graft was implanted in the contralateral pelvic limb. Postoperative follow-up was 4, 8 and 12 weeks. Analysis of results was performed according to clinical evaluation of pulses, complications (fluid collection, dehiscence, granuloma and infection), arteriography, macroscopic analysis and scanning electron micrography. RESULTS: Statistical tests revealed no significant differences (p > 0.05) concerning post-operative complications and graft patency. Both grafts were properly integrated to surrounding tissues, with connective tissue formed by collagen fibers. A neointimal layer covering all extension of the luminal surface was observed in the microperforated latex graft. Conversely, the endothelial development over the neointimal surface was limited to regions adjacent to the anastomoses in the expanded polytetrafluoroethylene graft. CONCLUSIONS: The microperforated latex graft showed satisfactory structural qualities (adaptability, elasticity, impermeability and possibility of suture) as a vascular substitute. It stimulated endothelial growth beyond contact regions with the artery in anastomoses and was biocompatible in the dog's arterial system, presenting adequate tissue integration.

Expanded polytetrafluoroethylene and polypropylene in the repairing of abdominal wall defects in Wistar rats: comparative study

PURPOSE: To compare the use of polypropylene and PTFE meshes in the treatment of incisional hernias made experimentally on Wistar rats. METHODS: The experiment used 24 Wistar rats divided into three cohorts: C-A (ressection of a segment of abdominal wall), E-A (ressection and placement of PTFEe mesh), E-B (resection and placement of polypropylene mesh). After 28 days, the mesh and the surrounding tissue were removed and submitted to macroscopic analysis (assessment of the abdominal wall for presence of abscess in the surgical wound and/or skin necrosis, and adhesions) as well as microscopic analysis (presence of fibrosis, necrosis and abscess, counting of macrophages, mononuclears and polymorphonuclears). RESULTS: Adhesions and abscesses in the surgical wound were observed more commonly associated to the group treated with PTFEe. The size of the fibrous tissue was greater in the group treated with polypropylene. Cohort E-A showed PTFEe mesh enveloped by organized fine connective tissue. No groups presented necrosis on the site of the insertion. The highest mononuclear inflammatory reaction occurred in association to PTFEe when compared to the control group, but the findings for the polypropylene mesh were also significant when compared to the control group. In the analysis of the results obtained for cohorts E-A and E-B, a minimal occurrence of polymorphonuclears was noticed in both groups, which indicates low tissue reactivity to both materials used in the present experiment. CONCLUSION: Even with epithelization and proliferation of connective tissue, anchorage between PTFEe and abdominal wall is insufficient, which can result in reherniations.

OBJETIVO: Comparar o uso de tela de PTFEe e polipropileno no tratamento de hérnias incisionais produzidas experimentalmente em ratos Wistar. MÉTODOS: 24 ratos Wistar foram distribuídos em três subgrupos: C-A (ressecção de segmento da parede abdominal), E-A (ressecção e colocação de tela de PTFEe), E-B (ressecção e colocação de tela de polipropileno). Após 28 dias, retirou-se a peça e procedeu-se à análise macroscópica (inspeção da parede abdominal, avaliando presença de abscesso na ferida operatória e/ou necrose de pele, e aderências) e microscópica (presença de fibrose, necrose e abscesso, e contagem de macrófagos, mononucleares e polimorfonucleares). RESULTADOS: Aderências e abscesso na ferida operatória foram observados mais intensamente no subgrupo tratado com PTFEe. O tamanho do tecido fibrótico foi mais acentuado no subgrupo tratado com polipropileno. Já o subgrupo E-A apresentou a tela de PTFEe envolvida por tecido conectivo fino organizado. Não houve necrose no local de inserção da prótese em todos os subgrupos. Maior reação inflamatória mononuclear ocorreu com o PTFEe quando comparado com o grupo controle, mas com o uso de polipropileno os achados foram significativos se comparados ao grupo controle. Na análise dos resultados obtidos com os grupos E-A e E-B verificou-se que houve ocorrência mínima de polimorfonucleares em ambos os grupos de animais analisados, indicando assim uma baixa reatividade tecidual de ambos materiais nestes animais experimentais. CONCLUSÃO: Mesmo ocorrendo epitelização e proliferação de tecido conjuntivo, a ancoragem entre o PTFEe e a parede abdominal é insuficiente, o que pode resultar numa maior recorrência de hérnias.

Vertebrobasilar dolichoectasia as a cause of trigeminal neuralgia: the role of microvascular decompression. Case report

O objetivo desse estudo é relatar um caso de neuralgia trigeminal causado por dolicoectasia vertebrobasilar tratado com descompressão microvascular. Um homem (63 anos) consultou por neuralgia trigeminal recorrente na hemiface esquerda (territórios V2 e V3). A angiotomografia cerebral revelou compressão mecânica do nervo trigêmio esquerdo devido à dolicoectasia vertebrobasilar. O paciente foi submetido à craniotomia suboccipital esquerda. Introduziu-se Teflon® na área de conflito neurovascular, obtendo-se uma descompressão satisfatória. O paciente apresentou remissão da dor imediatamente. A dolicoectasia vertebrobasilar é uma causa rara de neuralgia trigeminal e uma excelente evolução pode ser alcançada com a descompressão microvascular.

Principios fundamentales en regeneración ósea; su aplicación para implantes endoóseos: parte II / Fundamental principles in bone regeneration; its application for endoosseous implants: 2nd part

El presente y futuro de la ROG apuntan a la simplificación de la técnica utilizando membranas reabsorbibles y biomateriales que sustituyen el hueso autólogo, e intentando obtener los mismos resultados que con la técnica antes mencionada. Los límites de la implantología se están acabando con el advenimiento de este joven capítulo de ROG, cuyos objetivos reparador y restaurador del sistema incrementan en importancia debido al fracaso y la insuficiencia de los primeros niveles de prevención en nuestra odontología