Numerical modeling of a human stented trachea under different stent designs

Malvè, Mauro; Palomar, Amaya Pérez del; Mena, A.; Trabelsi, Olfa; López-Villalobos, José Luis; Ginel, A.; Panadero, Francisco Rodríguez; Doblaré, M.

doi:10.1016/j.icheatmasstransfer.2011.04.012

Cited by 31 publications

(41 citation statements)

References 37 publications

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“…24,28,33,34 While metallic stents are extensively described in literature for cardiovascular applications from a mechanics and fluid dynamics perspective, 1,5,34 these devices have not yet been analyzed in the respiratory system. Previous studies have also compared endoscopy images with patient specific trachea geometries and expanded stent models in order to gain qualitative informations about the role of mechanical stresses and fluid dynamic contributions 30,31,33 but the correlation between the geometry of the stent and the local effects of these stimuli acting on the wall was not carried out. In cases where this data is available, characterization of local stimuli arising from solid and fluid mechanics may help to improve knowledge of the relative importance of these stimuli.…”

Section: Introductionmentioning

confidence: 99%

On Studying the Interaction Between Different Stent Models and Rabbit Tracheal Tissue: Numerical, Endoscopic and Histological Comparison

et al. 2015

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Stenting technique is employed worldwide for treating atherosclerotic vessel and tracheal stenosis. Both diseases can be treated by means of metallic stents which present advantages but are affected by the main problem of restenosis of the stented area. In this study we have built a rabbit trachea numerical model and we have analyzed it before and after insertion and opening of two types of commercial stent: a Zilver R Flex T M Stent and a WallStent T M . In experimental parallel work, two types of stent were implanted in 30 New Zealand rabbits divided in two groups of 10 animals corresponding to each stent type and a third group made up of 10 animals without stent. The tracheal wall response was assessed by means of computerized tomography by endoscopy, macroscopic findings and histopathological study 90 days after stent deployment. Three idealized trachea models, one model for each group, were created in order to perform the computational study.The animal model was used to validate the numerical findings and to attempt to find qualitative correlations between numerical and experimental results. Experimental findings such as inflammation, granuloma and abnormal tissue growth, assessed from histomorphometric analyses were compared with derived numerical parameters such as wall shear stress (WSS) and maximum principal stress. The direct comparison of these parameters and the biological response supports the hypothesis that WSS and tensile stresses may lead to a greater tracheal epithelium response within the stented region, with the latter seeming to have the dominant role. This study may be helpful for improving stent design and demonstrates the feasibility offered by in-silico investigated tracheal structural and fluid dynamics.

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Section: Introductionmentioning

confidence: 99%

On Studying the Interaction Between Different Stent Models and Rabbit Tracheal Tissue: Numerical, Endoscopic and Histological Comparison

et al. 2015

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“…For more complex situations, CT-derived virtual drawings are superior [15] . In the case of severe malacia, it could be of benefit to measure real-time diameter under simulation of different ventilation pressures and/or frequencies which can be done easily by jet catheter ventilation and cone beam CT-derived data acquisition [16] . In real clinical situations, a tumor will be removed and a stenosis will be dilated first.…”

Section: Image and Data Acquisitionmentioning

confidence: 99%

“…The software interface must close the gaps between radiology data and practitioner expertise as well as between medical aims and practicability, which might be limited by material availability and engineering tools. Several groups are working on these types of modeling software for airway stenoses with a graphical user interface [16][17][18] .…”

Section: Cad Designingmentioning

confidence: 99%

Towards Individualized Tracheobronchial Stents: Technical, Practical and Legal Considerations

Freitag

Gördes²,

Zarogoulidis

et al. 2017

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Stent placement has been established as a standard procedure for treating airway obstructions. Other indications are localized malacias and fistulas. Though many different stents with various diameters and lengths are available, the shapes are hardly ever ideal because of the distorted anatomy in patients with diseased airways. There are technical and legal limitations for customizing purchased airway stents. Individually tailored stents would be preferable. New techniques of additive manufacturing such as 3D printing make it possible to produce optimized stents for a particular patient. Using CT data and bronchoscopic images, stents can be constructed that match a particular anatomical situation and apply the optimized expansion force. We give an overview of the currently available manufacturing techniques for polymeric stents and report about our own experience. Direct on-site printing of polyurethane stents in a hospital and printing individual extrusion molds for silicone stents in a certified cleanroom are both feasible. Furthermore, there are promising attempts of combining mechanically customized stents with surface modifications, drug-eluting features, biodegradability, and time-dependent adaptation (4D printing). Truly optimized airway stents with the potential of solving the well-known stent problems such as granulation tissue formation, remodeling, mucostasis, and infections are in reach. The technical hurdles are probably easier to overcome than the legal constraints. The legal situations are discussed from a physician's and a manufacturer's perspective.

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“…However, these do not take the airway deformation into account and are focused on providing detailed information of the flow features in each pulmonar branch. More recently, fluid solid interaction studies performed for tracheal geometries tube and single or multiple bifurcations can be found in literature [16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

“…Recently we also analyze the tracheal behavior under implantations of different stent type (Dumon© and Ultraflex© stent) [21] with the aim of studying the impact of different prostheses on the smooth muscle and evaluate the risk of stent migration. In this work we propose a possible improvement of the Dumon prosthesis with the aim of preventing mucous plugging episodes, which is, as aforementioned, one of the most common postoperatory problems for this stent.…”

Section: Introductionmentioning

confidence: 99%