In the evidence-based diagnosis of nasal breathing disorders and the planning of corrective surgical procedures, it is not sufficient to examine only the general characteristics of airflow - averaged values of aerodynamic parameters such as airflow rate, pressure drop, and aerodynamic nasal resistance. It is necessary to investigate the effect of airflow on the mucosa at the micro level, which, when pathological conditions develop, leads to excessive drying of the nasal cavity surface. To do this, it is necessary to compare the width of the laminar boundary layer – the parietal region, where the maximum change in airflow velocity is observed, and the height of the nasal mucosa irregularity. The calculated values of the laminar airflow boundary layer were obtained from model representations of the complex spatial configuration of the nasal cavity using a circular channel of equivalent diameter.
KEYWORDS: 3D modeling, Data modeling, Visual process modeling, Instrument modeling, Aerodynamics, 3D printing, Prototyping, Mathematical modeling, Computed tomography, Visualization
The essence of the development is to obtain data from imaging tools, as a rule, spiral computed tomography, which allows visualizing bone-cartilaginous and soft tissue structures of the nasal cavity with high spatial resolution and contrast, preparing a 3D model for prototyping using specialized programs - slicers dividing the reproduced object into sections, taking into account the hardware features of the prototyping device, the 3D printing stage for obtaining a mode and implementation of this model is given manipulation - training with the help of selected surgical instruments. After a virtual change in the spatial configuration of the nasal cavity and re-manufacturing of a real model, it is possible to conduct comparative tests of both full-scale models on an aerodynamic bench to determine and analyse indicators of nasal resistance – pressure drop and corresponding air flow.
The article is devoted to the problem of studying microcirculation, because one of the reasons for the development of microcirculation disorders is hypoxia, which is associated with a violation of the normal anatomy of the capillary wall, changes in the properties of blood rheologies, acceleration or deceleration of microflow. Capillaries are the first to react to long-term disturbance of nasal breathing by changing the functional state and morphological restructuring of micro vessels in the bloodstream. Based on the results of the research work, software was developed that was tested on patients with pathology of intranasal structures and impaired respiratory function. The advanced method of optical capillaroscopy allows not only to perform a visual assessment of the condition of microvessels, but also to determine such an important parameter as blood flow velocity and actually replace the laser Doppler study.
The possibilities of optical capillaroscopy to determine microcirculatory disorders are considered. Methods for evaluating microcirculation by measuring the size of a pillar and its departments, as well as the speed of capillary blood flow, which may indicate a state of microcirculation in general are proposed. The physical model of the capillary is considered, as well as the classification of the stages of microcirculation disturbance, which is used to form a medical conclusion about the severity of hemodynamic disorders. Also, for the system of computer capillaroscopy, methods for calibrating and segmenting images of microvessels are proposed.
The article is devoted to the study of the negative influence of air flow on the mucous membrane of the nasal cavity. in the section the basic provisions of the aerodynamics of the nasal cavity are considered, the main characteristics of the laminar boundary layer in the nasal cavity are determined. it is determined that the thickness of the boundary layer strongly depends on the mode of respiration, with forced breathing, the difference in the thickness of the boundary layer between the norm and in the narrowing of the nasal passage significantly decreases. with a quiet breath, the thickness of the boundary layer will essentially depend on the equivalent diameter of the nasal canal. thus, with the growth of the equivalent diameter of the nasal passages, the thickness of the boundary layer increases significantly, which is especially noticeable when forced respiration. therefore, the negative effect of air flow will be manifested, above all, with increased costs and narrowing of the nasal cavity and depend on the heterogeneity of the mucous membrane of the nasal cavity, which with forced breathing is more likely to go beyond the laminar boundary layer. in calculating the parameters of the boundary layer, it is necessary to specify the parameters of air flow, obtained as a result of computer olfactometry or physiological data for the corresponding breathing regimes. with the increase of respiration and the corresponding reduction of the thickness of the boundary layer of the air stream, the risk of negative influence of turbulent air flow on the mucous membrane of the nasal cavity increases. the use of this method makes it possible at the stages of diagnosis and surgical planning to quantify the effect of the negative influence of air flow on the mucous membrane of the nasal cavity, which is associated with turbulent drying and determine the areas that are subject to surgical correction by the proposed criterion.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.