37 research outputs found
Determination of Young's modulus of mandibular bone using inverse analysis
International audienceDevelopment of a numerical model applicable to clinical practice, and in particular oral implantology, requires knowledge of the mechanical properties of mandibular bone. The wide range of mechanical parameters found in the literature prompted us to develop an inverse analysis method that takes into account the exact geometry of each specimen tested, regardless of its shape. The Young's modulus of 3000. MPa we determined for mandibular bone using this approach is lower than the values reported in the literature. This difference can be explained by numerous experimental factors, related in particular to the bone specimens used. However, the main reason is that, unlike most previously published papers on the subject, the heterogeneity of bone led us to select a specimen size at the upper end of the scale, close to clinical reality
The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2
Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701
Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTICâHF: baseline characteristics and comparison with contemporary clinical trials
Aims:
The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTICâHF) trial. Here we describe the baseline characteristics of participants in GALACTICâHF and how these compare with other contemporary trials.
Methods and Results:
Adults with established HFrEF, New York Heart Association functional class (NYHA)ââ„âII, EF â€35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokineticâguided dosing: 25, 37.5 or 50âmg bid). 8256 patients [male (79%), nonâwhite (22%), mean age 65âyears] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NTâproBNP 1971âpg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTICâHF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressureâ<â100âmmHg (n = 1127), estimated glomerular filtration rate <â30âmL/min/1.73 m2 (n = 528), and treated with sacubitrilâvalsartan at baseline (n = 1594).
Conclusions:
GALACTICâHF enrolled a wellâtreated, highârisk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation
Modélisation numérique de l'os mandibulaire appliquée à l'implantologie dentaire et maxillo-faciale
The increasing use of implant dentistry requires the development of innovative techniques adapted to complex maxillo-facial configurations. To manage theses difficult cases and to insure and improve the results stability over time , it is necessary now to get a better understanding of the mechanical implications of the fonctional implant loading.To reach this goal, a numerical model of the mandibular bone has been set up.The objective is to study the stress distribution within the bone and in the neighbourhood of implants.A first stage of this work has been devoted to the identification of the elastic properties of the cortical mandibular bone by the use of an advanced inverse analysis methodology.This coupled experimental â numerical approach has been validated and leads to a reliable numerical approach to study implant dentistry.The second stage of this work deals with the use of the numerical simulation to study the stress distribution around an implant inserted laterally (DiskimplantÂź) in a mandibular bone.Numerical simulation are validated experimentally and give promising results in the field of implant dentistry.L'implantologie dentaire est actuellement en plein essor, et justifie du dĂ©veloppement de techniques adaptĂ©es aux cas les plus complexes. La prise en charge de ces cas difficiles et leur stabilitĂ© dans le temps peuvent ĂȘtre amĂ©liorĂ©es par une meilleure connaissance des consĂ©quences mĂ©caniques de la mise en charge fonctionnelle.C'est dans ce but que nous avons voulu dĂ©velopper un modĂšle numĂ©rique de l'os mandibulaire, permettant l'Ă©tude de la rĂ©partition des contraintes au sein de l'os et au contact des implants, et ainsi d'en optimiser le nombre, la forme et la position.La premiĂšre Ă©tape de ce travail est consacrĂ©e Ă la dĂ©termination du module d'Young de l'os cortical mandibulaire par une mĂ©thode originale: l'analyse inverse.GrĂące Ă une mĂ©thodologie rigoureuse, nous avons dĂ©terminĂ© ce module d'Young Ă une Ă©chelle reprĂ©sentative pour l'implantologie dentaire, rendant ainsi le dĂ©veloppement du modĂšle numĂ©rique plus fiable.La seconde Ă©tape est dĂ©diĂ©e au dĂ©veloppement d'un modĂšle numĂ©rique de l'os mandibulaire, utilisable en implantologie, Ă l'aide du logiciel FORGE 2005Âź, Ce modĂšle est appliquĂ© Ă l'Ă©tude de la rĂ©partition des contraintes aprĂšs mise en place d'un implant Ă insertion latĂ©rale ( DiskimplantÂź), et validĂ© par l'expĂ©rience
Modélisation numérique de l'os mandibulaire appliquée à l'implantologie dentaire et maxillo - faciale
PARIS-MINES ParisTech (751062310) / SudocSudocFranceF
Apport de la méthode des éléments finis en chirurgie maxillofaciale = Contribution of the finite element method in maxillofacial surgery
International audienceLa mĂ©thode des Ă©lĂ©ments finis est un outil de modĂ©lisation utilisĂ© dans des domaines variĂ©s de la mĂ©decine et surtout de la chirurgie comme l'orthopĂ©die, la traumatologie et la chirurgie cardiovasculaire. Mais cet outil prĂ©sente Ă©galement de nombreuses applications en chirurgie maxillofaciale. Nous prĂ©sentons l'intĂ©rĂȘt de cette mĂ©thode en exposant les principes ainsi que les diffĂ©rents champs d'application en chirurgie maxillofaciale. Le but est de permettre aux novices de comprendre les rĂ©sultats d'Ă©tudes utilisant cette mĂ©thode = The finite element method is a numerical modeling tool used in various fields in medicine and surgery such as orthopedics, traumatology, and cardiovascular surgery. But this tool also has several applications in maxillofacial surgery. We present the advantages of this method by describing its principles as well as the various fields of application in maxillofacial surgery. This article was intended to help novices understand the results of various studies using this method
Techniques non invasives dâimplantation sous-sinusienne (1re partie)
Le sinus maxillaire constitue un obstacle Ă lâimplantation
au niveau de la partie postérieure du maxillaire. Pour passer
outre cet obstacle, lâintervention la plus frĂ©quemment
proposĂ©e consiste en un soulevĂ© de la muqueuse, lâespace
compris entre ladite muqueuse et le plancher sinusien Ă©tant
comblĂ© par des greffons iliaques ou pariĂ©taux. Il sâagit donc
dâinterventions majeures qui peuvent provoquer des complications
importantes.
De nouvelles techniques permettent actuellement dâexploiter
une hauteur de plancher nâexcĂ©dant pas 5 mm. Ces
interventions non invasives sont représentées par les techniques
dites de SUMMERS, les implants cylindriques stabilisés,
le diskimplant et le zygomadisk.
Dâautres interventions ont Ă©tĂ© proposĂ©es : lâimplant ptĂ©rygo-
maxillaire, lâimplant zygomatique. Ces techniques, si
elles nâexigent pas le prĂ©lĂšvement de greffons, sâavĂšrent en
réalité complexes et sont à la limite des techniques invasives
Techniques non invasives dâimplantation sous-sinusienne (2e partie)
Le sinus maxillaire constitue un obstacle Ă lâimplantation
au niveau de la partie postérieure du maxillaire. Pour passer
outre cet obstacle, lâintervention la plus frĂ©quemment
proposĂ©e consiste en un soulevĂ© de la muqueuse, lâespace
compris entre ladite muqueuse et le plancher sinusien Ă©tant
comblĂ© par des greffons iliaques ou pariĂ©taux. Il sâagit donc
dâinterventions majeures qui peuvent provoquer des complications
importantes.
De nouvelles techniques permettent actuellement dâexploiter
une hauteur de plancher nâexcĂ©dant pas 5 mm. Ces
interventions non invasives sont représentées par les techniques
dites de SUMMERS, les implants cylindriques stabilisés,
le diskimplant et le zygomadisk.
Dâautres interventions ont Ă©tĂ© proposĂ©es : lâimplant ptĂ©rygo-
maxillaire, lâimplant zygomatique. Ces techniques, si
elles nâexigent pas le prĂ©lĂšvement de greffons, sâavĂšrent en
réalité complexes et sont à la limite des techniques invasives
Primary clear cell meningioma of the orbit mimicking a metastatic carcinoma: usefulness of immunohistochemistry and cytogenetic analysis.
Clear cell meningiomas (CCM) are rare tumors of the nervous system that usually occur in young patients and display high recurrence rates and potentially aggressive behavior. In this report, we describe a primary CCM of the orbit in an 84-year-old man with a previous history of a clear cell carcinoma of the kidney. Histologically, the tumor demonstrated a sheet-like proliferation of clear polygonal cells. Differential diagnosis includes metastasis of clear cell carcinomas. Immunohistochemistry, by showing that tumor cells expressed vimentin, epithelial membrane antigen, and progesterone antigens, and cytogenetic analysis, by identifying a monosomy 22, confirmed the diagnosis of CCM