A numerical simulation of a patient’s nasal airflow was developed via computational fluid dynamics.Accordingly,computerized tomography scans of a patient with septal deviation and allergic rhinitis were obtained.The ...A numerical simulation of a patient’s nasal airflow was developed via computational fluid dynamics.Accordingly,computerized tomography scans of a patient with septal deviation and allergic rhinitis were obtained.The three-dimensional(3D)nasal model was designed using InVesalius 3.0,which was then imported to(computer aided 3D interactive application)CATIA V5 for modification,and finally to analysis system(ANSYS)flow oriented logistics upgrade for enterprise networks(FLUENT)to obtain the numerical solution.The velocity contours of the cross-sectional area were analyzed on four main surfaces:the vestibule,nasal valve,middle turbinate,and nasopharynx.The pressure and velocity characteristics were assessed at both laminar and turbulent mass flow rates for both the standardized and the patient’s model nasal cavity.The developed model of the patient is approximately half the size of the standardized model;hence,its velocity was approximately two times more than that of the standardized model.展开更多
The objective of this study is to systematically assess the influences of the larynopharyneal anatomical details on airflow and particle behaviors during exhalation by means of image-based modeling. A physiologically ...The objective of this study is to systematically assess the influences of the larynopharyneal anatomical details on airflow and particle behaviors during exhalation by means of image-based modeling. A physiologically realistic nose-throat airway was developed with medical images. Individual airway anatomy such as uvula, pharynx, and larynx were then isolated for examination by progressively simplifying this image-based model geometry. Low Reynolds number (LRN) k-w model and Langrangian tracking model were used to simulate the dynamics of airflow and particle transport for a wide range of exhalation conditions (4-45 L/min) and particle sizes (1 nm-1 μm). Results showed that pharyngeal anatomical details exerted a significant impact on breathing resistance and particle profiles. Abrupt pressure drop resulting from the uvula-related airway obstruction was observed. Even though the total deposition rate in the nasal airway is largely unaffected by the upstream effect, the local deposition patterns vary notably. Results of this study also indicate that the pressure drop appears to be an appropriate parameter to characterize the geometric variations for diffusive depositions. Inclusion of pressure drop (D0.5Q-0.62dp0.07) gives an improved correlation than using the conventional diffusion factor (D0.5Q﹣0.28).展开更多
Background: Several large series have established endoscopic transnasal sellar surgery as the procedure of choice for removal of tumors in the sellar area. Although this procedure provides a less invasive approach to ...Background: Several large series have established endoscopic transnasal sellar surgery as the procedure of choice for removal of tumors in the sellar area. Although this procedure provides a less invasive approach to the sella, it entails complications such as nasal bleeding, impaired olfactory function, atrophic rhinitis, synechiae, etc. No studies have yet reported potential morbidities such as empty nose syndrome (ENS), although patients have a relatively empty nasal cavity after surgery. Therefore, we sought to verify the percentage of patients who truly met the diagnostic criteria for ENS after endoscopic transnasal sellar surgery, determine the variation between pre- and postoperative scores in each Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) item, and further evaluate the symptoms that may affect the patients the most after surgery. Methods: Between March 2015 and January 2019, eventually 11 patients who underwent extended endoscopic transnasal sellar surgery in Shin Kong Wu Ho-Su Memorial Hospital, a tertiary referral medical center in Taipei, Taiwan, were enrolled. The patients completed the recently validated ENS6Q after surgery. Results: One patient met the objective diagnostic criteria for ENS (score ≥ 11 in ENS6Q). Significant differences were observed in the pre- and postoperative total ENS6Q scores. The pre- and postoperative scores of “nose feeling too open” and nasal crusting showed statistically significant differences. Further, compared with the other items, the postoperative score of nasal crusting increased most obviously, and it may be the most apparent operation-related symptom. Conclusion: This study is the first to report the possibility of developing ENS after endoscopic transnasal sellar surgery. Although the transnasal endoscopic approach is a safe and minimally invasive procedure for the treatment of sellar lesions, possible complications such as ENS should be considered.展开更多
基金This research was funded by the Universiti Sains Malaysia,No.1001/PAERO/814276.
文摘A numerical simulation of a patient’s nasal airflow was developed via computational fluid dynamics.Accordingly,computerized tomography scans of a patient with septal deviation and allergic rhinitis were obtained.The three-dimensional(3D)nasal model was designed using InVesalius 3.0,which was then imported to(computer aided 3D interactive application)CATIA V5 for modification,and finally to analysis system(ANSYS)flow oriented logistics upgrade for enterprise networks(FLUENT)to obtain the numerical solution.The velocity contours of the cross-sectional area were analyzed on four main surfaces:the vestibule,nasal valve,middle turbinate,and nasopharynx.The pressure and velocity characteristics were assessed at both laminar and turbulent mass flow rates for both the standardized and the patient’s model nasal cavity.The developed model of the patient is approximately half the size of the standardized model;hence,its velocity was approximately two times more than that of the standardized model.
文摘The objective of this study is to systematically assess the influences of the larynopharyneal anatomical details on airflow and particle behaviors during exhalation by means of image-based modeling. A physiologically realistic nose-throat airway was developed with medical images. Individual airway anatomy such as uvula, pharynx, and larynx were then isolated for examination by progressively simplifying this image-based model geometry. Low Reynolds number (LRN) k-w model and Langrangian tracking model were used to simulate the dynamics of airflow and particle transport for a wide range of exhalation conditions (4-45 L/min) and particle sizes (1 nm-1 μm). Results showed that pharyngeal anatomical details exerted a significant impact on breathing resistance and particle profiles. Abrupt pressure drop resulting from the uvula-related airway obstruction was observed. Even though the total deposition rate in the nasal airway is largely unaffected by the upstream effect, the local deposition patterns vary notably. Results of this study also indicate that the pressure drop appears to be an appropriate parameter to characterize the geometric variations for diffusive depositions. Inclusion of pressure drop (D0.5Q-0.62dp0.07) gives an improved correlation than using the conventional diffusion factor (D0.5Q﹣0.28).
文摘Background: Several large series have established endoscopic transnasal sellar surgery as the procedure of choice for removal of tumors in the sellar area. Although this procedure provides a less invasive approach to the sella, it entails complications such as nasal bleeding, impaired olfactory function, atrophic rhinitis, synechiae, etc. No studies have yet reported potential morbidities such as empty nose syndrome (ENS), although patients have a relatively empty nasal cavity after surgery. Therefore, we sought to verify the percentage of patients who truly met the diagnostic criteria for ENS after endoscopic transnasal sellar surgery, determine the variation between pre- and postoperative scores in each Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) item, and further evaluate the symptoms that may affect the patients the most after surgery. Methods: Between March 2015 and January 2019, eventually 11 patients who underwent extended endoscopic transnasal sellar surgery in Shin Kong Wu Ho-Su Memorial Hospital, a tertiary referral medical center in Taipei, Taiwan, were enrolled. The patients completed the recently validated ENS6Q after surgery. Results: One patient met the objective diagnostic criteria for ENS (score ≥ 11 in ENS6Q). Significant differences were observed in the pre- and postoperative total ENS6Q scores. The pre- and postoperative scores of “nose feeling too open” and nasal crusting showed statistically significant differences. Further, compared with the other items, the postoperative score of nasal crusting increased most obviously, and it may be the most apparent operation-related symptom. Conclusion: This study is the first to report the possibility of developing ENS after endoscopic transnasal sellar surgery. Although the transnasal endoscopic approach is a safe and minimally invasive procedure for the treatment of sellar lesions, possible complications such as ENS should be considered.
