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, GALACTIC‐HF: 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 (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤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 (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF 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 pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk 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 – 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 (Diskimplant®) 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 développement de techniques adaptées aux cas les plus complexes. La prise en charge de ces cas difficiles et leur stabilité dans le temps peuvent être améliorées par une meilleure connaissance des conséquences mécaniques de la mise en charge fonctionnelle.C'est dans ce but que nous avons voulu développer un modèle numérique de l'os mandibulaire, permettant l'étude de la répartition 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 première étape de ce travail est consacrée à la détermination du module d'Young de l'os cortical mandibulaire par une méthode originale: l'analyse inverse.Grâce à une méthodologie rigoureuse, nous avons déterminé ce module d'Young à une échelle représentative pour l'implantologie dentaire, rendant ainsi le développement du modèle numérique plus fiable.La seconde étape est dédiée au développement d'un modèle numérique de l'os mandibulaire, utilisable en implantologie, à l'aide du logiciel FORGE 2005®, Ce modèle est appliqué à l'étude de la répartition des contraintes après mise en place d'un implant à insertion latérale ( Diskimplant®), et validé par l'expérience

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 méthode des éléments finis est un outil de modélisation utilisé dans des domaines variés de la médecine et surtout de la chirurgie comme l'orthopédie, la traumatologie et la chirurgie cardiovasculaire. Mais cet outil présente également de nombreuses applications en chirurgie maxillofaciale. Nous présentons l'intérêt de cette méthode en exposant les principes ainsi que les différents champs d'application en chirurgie maxillofaciale. Le but est de permettre aux novices de comprendre les résultats d'études utilisant cette méthode = 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 d’implantation sous-sinusienne (1re partie)

Le sinus maxillaire constitue un obstacle à l’implantation au niveau de la partie postérieure du maxillaire. Pour passer outre cet obstacle, l’intervention la plus fréquemment proposée consiste en un soulevé de la muqueuse, l’espace compris entre ladite muqueuse et le plancher sinusien étant comblé par des greffons iliaques ou pariétaux. Il s’agit donc d’interventions majeures qui peuvent provoquer des complications importantes. De nouvelles techniques permettent actuellement d’exploiter une hauteur de plancher n’excédant pas 5 mm. Ces interventions non invasives sont représentées par les techniques dites de SUMMERS, les implants cylindriques stabilisés, le diskimplant et le zygomadisk. D’autres interventions ont été proposées : l’implant ptérygo- maxillaire, l’implant zygomatique. Ces techniques, si elles n’exigent pas le prélèvement de greffons, s’avèrent en réalité complexes et sont à la limite des techniques invasives

Techniques non invasives d’implantation sous-sinusienne (2e partie)

Le sinus maxillaire constitue un obstacle à l’implantation au niveau de la partie postérieure du maxillaire. Pour passer outre cet obstacle, l’intervention la plus fréquemment proposée consiste en un soulevé de la muqueuse, l’espace compris entre ladite muqueuse et le plancher sinusien étant comblé par des greffons iliaques ou pariétaux. Il s’agit donc d’interventions majeures qui peuvent provoquer des complications importantes. De nouvelles techniques permettent actuellement d’exploiter une hauteur de plancher n’excédant pas 5 mm. Ces interventions non invasives sont représentées par les techniques dites de SUMMERS, les implants cylindriques stabilisés, le diskimplant et le zygomadisk. D’autres interventions ont été proposées : l’implant ptérygo- maxillaire, l’implant zygomatique. Ces techniques, si elles n’exigent pas le prélèvement de greffons, s’avèrent 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