Biomechanical evaluation of an intramedullary nailing device by multibody analysis

The present study investigates the suitability of the multibody method as alternative approach to the finite element method in order to evaluate biomechanical performances of a Marchetti-Vicenzi self-locking nail under dynamic loading. Torsional, compressive and bending dynamic loads were simulated. Results in terms of bone-device contact forces and device stiffness were obtained confirming and supporting issues observed in clinical reports

Engineering and manufacturing of a dynamizable fracture fixation device system

The present work illustrates the dynamization of an orthopaedic plate for internal fracture fixation which is thought to shorten healing times and enhance the quality of the new formed bone. The dynamization is performed wirelessly thanks to a magnetic coupling. The paper shows the peculiarities of the design and manufacturing of this system: it involves two components, sliding with respect to each other with an uncertain coefficient of friction, and with a specific compounded geometry; there are stringent limits on component size, and on the required activation energy. Finally, the device belongs to medical devices and, as such, it must comply with the respective regulation (EU 2017/745, ASTM F382). The design of the dynamizable fracture fixation plate has required verifying the dynamic of the unlocking mechanism through the development of a parametric multibody model which has allowed us to fix the main design variables. As a second step, the fatigue strength of the device and the static strength of the whole bone-plate system was evaluated by finite element analysis. Both analyses have contributed to defining the final optimized geometry and the constitutive materials of the plate; finally, the respective working process was set up and its performance was tested experimentally on a reference fractured femur. As a result of these tests, the flexural stiffness of the bone-plate system resulted equal to 370 N/mm, while a maximum bending moment equal to 75.3 kNmm can be withstood without plate failure. On the whole, the performance of this dynamic plate was proved to be equal or superior to those measured for static plates already on the market, with excellent clinical results. At the same time, pre-clinical tests will be an interesting step of the future research, for which more prototypes are now being produced

Personalised 3D Assessment of Trochanteric Soft Tissues Improves HIP Fracture Classification Accuracy

Passive soft tissues surrounding the trochanteric region attenuate fall impact forces and thereby control hip fracture risk. The degree of attenuation is related to Soft Tissue Thickness (STT). STT at the neutral hip impact orientation, estimated using a regression relation in body mass index (BMI), was previously shown to influence the current absolute risk of hip fracture (ARF0) and its fracture classification accuracy. The present study investigates whether fracture classification using ARF0 improves when STT is determined from the subject’s Computed-Tomography (CT) scans (i.e. personalised) in an orientation-specific (i.e. 3D) manner. STT is calculated as the shortest distance along any impact orientation between a semi-automatically segmented femur surface and an automatically segmented soft tissue/air boundary. For any subject, STT along any of the 33 impact orientations analysed always exceeds the value estimated using BMI. Accuracy of fracture classification using ARF0 improves when using personalised 3D STT estimates (AUC = 0.87) instead of the BMI-based STT estimate (AUC = 0.85). The improvement is smaller (AUC = 0.86) when orientation-specificity of CT-based STT is suppressed and is nil when personalisation is suppressed instead. Thus, fracture classification using ARF0 improves when CT is used to personalise STT estimates and improves further when, in addition, the estimates are orientation specific

Design and characterization of a minimally invasive bipolar electrode for electroporation

Objective: To test a new bipolar electrode for electroporation consisting of a single minimally invasive needle. Methods: A theoretical study was performed by using Comsol Multiphysics® software. The prototypes of electrode have been tested on potatoes and pigs, adopting an irreversible electroporation protocol. Different applied voltages and different geometries of bipolar electrode prototype have been evaluated. Results: Simulations and pre-clinical tests have shown that the volume of ablated area is mainly influenced by applied voltage, while the diameter of the electrode had a lesser impact, making the goal of minimal-invasiveness possible. The conductive pole’s length determined an increase of electroporated volume, while the insulated pole length inversely affects the electroporated volume size and shape; when the insulated pole length decreases, a more regular shape of the electric field is obtained. Moreover, the geometry of the electrode determined a different shape of the electroporated volume. A parenchymal damage in the liver of pigs due to irreversible electroporation protocol was observed. Conclusion: The minimally invasive bipolar electrode is able to treat an electroporated volume of about 10 mm in diameter by using a single-needle electrode. Moreover, the geometry and the electric characteristics can be selected to produce ellipsoidal ablation volumes

Personalised 3D assessment of trochanteric soft tissues improves HIP fracture classification accuracy

Passive soft tissues surrounding the trochanteric region attenuate fall impact forces and thereby control hip fracture risk. The degree of attenuation is related to Soft Tissue Thickness (STT). STT at the neutral hip impact orientation, estimated using a regression relation in body mass index (BMI), was previously shown to influence the current absolute risk of hip fracture (ARF0) and its fracture classification accuracy. The present study investigates whether fracture classification using ARF0 improves when STT is determined from the subject’s Computed-Tomography (CT) scans (i.e. personalised) in an orientation-specific (i.e. 3D) manner. STT is calculated as the shortest distance along any impact orientation between a semi-automatically segmented femur surface and an automatically segmented soft tissue/air boundary. For any subject, STT along any of the 33 impact orientations analysed always exceeds the value estimated using BMI. Accuracy of fracture classification using ARF0 improves when using personalised 3D STT estimates (AUC = 0.87) instead of the BMI-based STT estimate (AUC = 0.85). The improvement is smaller (AUC = 0.86) when orientation-specificity of CT-based STT is suppressed and is nil when personalisation is suppressed instead. Thus, fracture classification using ARF0 improves when CT is used to personalise STT estimates and improves further when, in addition, the estimates are orientation specific

Le braccia del Mezzogiorno e la Milano del miracolo

Nel saggio vengono analizzate l'attenzione prestata dal nuovo quotidiano "il Giorno" ai problemi delle migrazioni interne nell'Italia degli anni Sessanta e le sue posizioni nel dibattito su emigrazione e industrializzazione nel Mezzogiorno

L'esilio di un maestro di libert\ue0

L'esperienza di esule sperimentata da Salvemini viene analizzata in relazione alle precariet\ue0 esistenziali degli emigranti, al suo rapporto con il mondo dell'antifascismo, con quello degli intellettuali anglosassoni e nella traformazione del suo pensiero sulla democrazia

Le custodi della montagna : donne e migrazioni stagionali in una comunità alpina

Il saggio analizza le forme di femminilizzazione della societ\ue0 alpina provocate dalle consuetudini di emigrazione stagionale degli uomini, attraverso un case study di una comunit\ue0 nelle Alpi piemontesi

Democratici e socialisti nel Piemonte dell'Ottocento

Quali forme associazionistiche, quali comportamenti, quali ideali caratterizzarono, nel Piemonte di fine Ottocento, l'iniziale radicamento di organizzazioni di ispirazione democratica e socialista? Attraverso quali percorsi alcune parti della societ\ue0 di questa regione hanno indissolubilmente intrecciato la loro partecipazione alla politica con l'adesione alla parte "rossa"? A questi interrogativi il libro risponde concentrando l'attenzione verso gli anni che precedettero l'organizzazione in partito dei gruppi di ispirazione democratica e socialista e privilegiando programmaticamente la dimensione regionale