Computational fluid dynamics (CFD) models have become very effective tools for predicting the flow field within the carotid bifurcation, and for understanding the relationship between local hemodynamics, and the initiation and progression of vascular wall pathologies. As prescribing proper boundary conditions can affect the solutions of the equations governing blood flow, in this study, we investigated the influence to assumptions regarding the outflow boundary conditions in an image-based CFD model of human carotid bifurcation. Four simulations were conducted with identical geometry, inlet flow rate, and fluid parameters. In the first case, a physiological time-varying flow rate partition at branches along the cardiac cycle was obtained by coupling the 3D model of the carotid bifurcation at outlets with a lumped-parameter model of the downstream vascular network. Results from the coupled model were compared with those obtained by imposing three fixed flow rate divisions (50/50, 60/40, and 70/30) between the two branches of the isolated 3D model of the carotid bifurcation. Three hemodynamic wall parameters were considered as indicators of vascular wall dysfunction. Our findings underscore that the overall effect of the assumptions done in order to simulate blood flow within the carotid bifurcation is mainly in the hot-spot modulation of the hemodynamic descriptors of atherosusceptible areas, rather than in their distribution. In particular, the more physiological, time-varying flow rate division deriving from the coupled simulation has the effect of damping wall shear stress (WSS) oscillations (differences among the coupled and the three fixed flow partition models are up to 37.3% for the oscillating shear index). In conclusion, we recommend to adopt more realistic constraints, for example, by coupling models at different scales, as in this study, when the objective is the outcome prediction of alternate therapeutic interventions for individual patients, or to test hypotheses related to the role of local fluid dynamics and other biomechanical factors in vascular diseases.

Medical devices are designed, tested, and placed on the market in a highly regulated environment. Wearable sensors are crucial components of various medical devices: design and validation of wearable sensors, if managed according to international standards, can foster innovation while respecting regulatory requirements. The purpose of this paper is to review the upcoming European Union (EU) Medical Device Regulations 2017/745 and 2017/746, the current and future International Electrotechnical Commission (IEC) and International Organization for Standardization (ISO) standards that set methods for design and validation of medical devices, with a focus on wearable sensors. Risk classification according to the regulation is described. The international standards IEC 62304, IEC 60601, ISO 14971, and ISO 13485 are reviewed to define regulatory restrictions during design, pre-clinical validation and clinical validation of devices that include wearable sensors as crucial components. This paper is not about any specific innovation but it is a toolbox for interpreting current and future regulatory restrictions; an integrated method for design planning, validation and clinical testing is proposed. Application of this method to design wearable sensors should be evaluated in the future in order to assess its potentially positive impact to fostering innovation and to ensure timely development.

The optimization of loading protocols following dental implant insertion requires setting up patient-specific protocols, customized according to the actual implant osseointegration, measured through quantitative, objective methods. Various devices for the assessment of implant stability as an indirect measure of implant osseointegration have been developed. They are analyzed here, introducing the respective physical models, outlining major advantages and critical aspects, and reporting their clinical performance. A careful discussion of underlying hypotheses is finally reported, as is a suggestion for further development of instrumentation and signal analysis.

We propose a culture-free approach to osteochondral repair with minced autologous cartilage fragments loaded onto a scaffold composed of a hyaluronic acid (HA)-derived membrane, platelet-rich fibrin matrix (PRFM) and fibrin glue. The aim of the study was to demonstrate in vitro the outgrowth of chondrocytes from cartilage fragments onto this scaffold and, in vivo, the formation of functional repair tissue in goat osteochondral defects. Two sections were considered: 1) in vitro: minced articular cartilage from goat stifle joints was loaded onto scaffolds, cultured for 1 or 2 months, and then evaluated histologically and immunohistochemically; 2) in vivo: 2 unilateral critically-sized trochlear osteochondral defects were created in 15 adult goats; defects were treated with cartilage fragments embedded in the scaffold (Group 1), with the scaffold alone (Group 2), or untreated (Group 3). Repair processes were evaluated morphologically, histologically, immunohistochemically and biomechanically at 1, 3, 6 and 12 months. We found that in vitro, chondrocytes from cartilage fragments migrated to the scaffold and, at 2 months, matrix positive for collagen type II was observed in the constructs. In vivo, morphological and histological assessment demonstrated that cartilage fragment-loaded scaffolds led to the formation of functional hyaline-like repair tissue. Repair in Group 1 was superior to that of control groups, both histologically and mechanically. Autologous cartilage fragments loaded onto an HA/PRFM/fibrin glue scaffold provided a viable cell source and allowed for an improvement of the repair process of osteochondral defects in a goat model, representing an effective alternative for one-stage repair of osteochondral lesions.