Processo para fabricação de produto composto de substrato e revestimento para utilização em implantes cirúrgicos

Em 27/12/2016: Anuidade de pedido de patente de invenção no prazo extraordinário.DepositadaA presente invenção descreve a metodologia de processamento de pós para a fabricação de produto composto de substrato (1) de liga de titânio e revestimento poroso (6) de titânio puro, para aplicação em implantes cirúrgicos. O processamento envolve técnicas de metalurgia do pó, que visam garantir a obtenção de um substrato (1) com alta densidade e propriedades mecânicas compatíveis com as solicitações impostas a implantes cirúrgicos, e um revestimento (6) com porosidade controlada, de forma a possibilitar a penetração do tecido ósseo (11) dentro dos poros, proporcionando uma melhor fixação do implante

Porous titanium for biomedical applications : an experimental study on rabbits

Objective: The aim of this study was to carry out an in vivo assessment of bone ingrowth in two different types of porous titanium -the first being completely porous, and the second with a porous surface and dense nucleus, manufactured by powder metallurgy- and to evaluate their mechanical properties. Study design: Ten scaffolds from each group were submitted to metallographic analysis and compression tests. Next, two scaffolds of each type were inserted into 14 rabbits, which were sacrificed 8 weeks after surgery. The samples were submitted for histological examination. Results: Metallographic analysis revealed interconnected pores, and the average interconnected pore diameter was about 360 mm, with 36% total porosity. The totally porous titanium samples and the titanium samples with porous surface and dense nucleus showed an average compressive strength of 16.19 MPa and 69.27 MPa, respectively. After 8 weeks, the animals showed bone ingrowth, even into the most internal pores. Conclusions: The pore morphology was effective in permitting bone ingrowth in both groups. Titanium scaffolds with a porous surface and dense nucleus showed the best mechanical properties and most adequate interface

Análise histomorfométrica de implantes de titânio puro com superfície porosa versus superfície rugosa

The purpose of this study was to analyze the bone repair around commercially pure titanium implants with rough and porous surface, fabricated using powder metallurgy technique, after their insertion in tibiae of rabbits. Seven male rabbits were used. Each animal received 3 porous-surface implants in the left tibia and 3 rough-surface implants in the right tibia. The rabbits were sacrificed 4 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological and histomorphometric analyses to evaluate new bone formation at the implant-bone interface. Means (%) of bone neoformation obtained in the histomorphometric analysis were compared by Student's t-test for paired samples at 5% significance level.. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. The histomorphometric analysis revealed means of new bone formation at implant-bone interface of 79.69 ± 1.00% and 65.05 ± 1.23% for the porous- and rough-surface implants, respectively. Statistically significant difference was observed between the two types of implants with respect to the amount new bone formation (pO propósito deste estudo foi avaliar a reparação óssea ao redor de implantes de superfície porosa comparados com implantes de superfície rugosa, ambos confeccionados de titânio puro grau 2 por meio da técnica de metalurgia do pó. Os implantes foram inseridos em tíbias de coelhos. Foram utilizados neste estudo 7 coelhos machos, sendo que cada um recebeu 3 implantes de superfície porosa na tíbia esquerda e 3 implantes de superfície rugosa na tíbia direita. Os animais foram sacrificados 4 semanas após a cirurgia e os fragmentos das tíbias contendo os implantes foram submetidos à análise histológica e histomorfométrica, visando analisar a neoformação óssea na interface osso-implante. As médias (%) obtidas na análise histomorfométrica foram avaliadas por meio do teste estatístico t-student de amostras pareadas com nível de significância de 5%. Os resultados da análise histológica mostraram que a osseointegração foi obtida nos dois tipos de implantes com similar qualidade de tecido ósseo. Na análise histomorfométrica, verificaram-se médias de neoformação óssea na interface osso-implante de 79,69% ± 1,00 e 65,05 ± 1,23 para os implantes de superfície porosa e rugosa, respectivamente, e foi observada diferença estatisticamente significante entre os dois tipos de implantes com relação à quantidade de neoformação óssea. Concluiu-se que os implantes de superfície porosa contribuíram para a osseointegração devido à sua maior superfície de contato na interface osso-implante

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Obtention de composites SiCf/SiC à partir de composites Cf/C et caractérisation de leurs propriétés

Les composites SiCf/SiC formés par une matrice de carbure du silicium (SiC) renforcée avec des fibres de SiC, sont des matériaux intéressants dans le secteur aérospatial et pour les applications dans hautes températures, car ils présentent une excellente résistance au choc thermique, une fiable densité, une grande dureté spécifique, une bonne résistance à l'usure et à l'impact, et une relative inertie chimique, y compris dans des environnements oxydants. Dans ce travail, un composite SiCf/SiC a été obtenu par la méthode de réaction chimique avec une phase vapeur à partir d'un composite carbone/carbone (C/C). La conversion du composite C/C s'est produite par la réaction à haute température du carbone précurseur avec du SiO gazeux, produit par la réaction entre les composants de deux types de mélange : le premier, contenant 60%SiC + 10% AI2O3 et l'autre, contenant 50% SiO2 + 50% Si (% masse), portés à des températures entre 1400 et 1800 C. Dans ces conditions, autant la matrice que les fibres de carbone sont converties dans SiC. Les composites obtenus ont présenté les mêmes microstructure et morphologie que le composite C/C précurseur. Deux types de composite ont été étudiés : un "non dense" et l'autre "dense", avec une plus quantité de matrice. Le composite SiCf/SiC dense a présenté une porosité de 40 %, une résistance à la flexion approximativement de 45.7 MPa et une perte de masse de 3% lors d'un essai de torche à plasma à la température de 1450C pendant 100 secondes. La valeur de la diffusivité thermique dans la direction longitudinale est de 2 fois supérieur à celle de la direction transversale pour le composite non dense, à cause de la disposition des fibres dans la structure. Dans la direction transversale, l'augmentation de la valeur de diffusivité thermique est proportionnelle à l'augmentation de la quantité de matrice pour le composite dense. La valeur de la diffusivité thermique dans la direction longitudinale n'a pas varié significativement du composite non dense au dense, prouvant que le transfert de la chaleur se produit essentiellement par les fibres de SiC.BORDEAUX1-BU Sciences-Talence (335222101) / SudocSudocFranceF