Computational Analysis of Polymeric Biodegradable and Customizable Airway Stent Designs.

The placement of endotracheal prostheses is a procedure used to treat tracheal lesions when no other surgical options are available. Unfortunately, this technique remains controversial. Both silicon and metallic stents are used with unpredictable success rates, as they have advantages but also disadvantages. Typical side effects include restenosis due to epithelial hyperplasia, obstruction and granuloma formation. Repeat interventions are often required. Biodegradable stents are promising in the field of cardiovascular biomechanics but are not yet approved for use in the respiratory system. The aim of the present study is to summarize important information and to evaluate the role of different geometrical features for the fabrication of a new tracheo-bronchial prosthesis prototype, which should be biodegradable, adaptable to the patient's lesion and producible by 3D printing. A parametric design and subsequent computational analysis using the finite element method is carried out. Two different stent designs are parameterized and analyzed. The biodegradable material chosen for simulations is polylactic acid. Experimental tests are conducted for assessing its mechanical properties. The role of the key design parameters on the radial force of the biodegradable prosthesis is investigated. The computational results allow us to elucidate the role of the pitch angle, the wire thickness and the number of cells or units, among other parameters, on the radial force. This work may be useful for the design of ad hoc airway stents according to the patient and type of lesion.

Interpenetrating alginate network as drug delivery matrix: Effects on protein stability and release.

The study investigates the rheological properties and protein release capacity of a uniform hydrogel composed of sodium alginate (SA) and poloxamer (P407). The hydrogel is prepared through the sustained release of calcium ions, resulting in a reinforced and homogeneous interpenetrating networks (IPNs) of SA and P407 polymeric chains. By adjusting the amount of crosslink agent, the hydrogel exhibites an adjustable dissolution ratio and adaptable gelling time. Moreover, the composite showed a well-structured network and superior mechanical strength, enabling the sustained release of both calcium ions and Soybean Trypsin Inhibitor (STI) protein, a model of Bone Morphogenic Protein (BMP). Importantly, the protein release kinetic can be tuned based on the SA content in the polymeric blend, highlighting the versatile nature of this hydrogel for drug delivery purposes.

Design and Development of a Hemorrhagic Trauma Simulator for Lower Limbs: A Pilot Study.

One of the main preventable leading causes of death after a trauma injury is the hemorrhagic shock. Therefore, it is extremely important to learn how to control hemorrhages. In this paper, a hemorrhagic trauma simulator for lower limb has been developed and a pilot study has been accomplished to trail the simulator. Four different bleeding scenarios have been tested per participant, gathering information about the manual pressure exerted to control the bleeding. Data, altogether, from 54 hemorrhagic scenarios managed by final year medical students and doctors were gathered. Additionally, a post-simulation questionnaire, related to the usability of the simulator, was completed. All the participants managed to control the simulated bleeding scenarios, but the pressure exerted to control the four different scenarios is different depending if the trainee is a student or a doctor, especially in deep venous hemorrhages. This research has highlighted the different approach to bleeding control treatment between medical students and doctors. Moreover, this pilot study demonstrated the need to deliver a more effective trauma treatment teaching for hemorrhagic lesions and that hemorrhagic trauma simulators can be used to train and evaluate different scenarios.