Abstract
Objectives: 1. To begin to determine if the results of nasal surgery can be modelled pre-operatively in a computational model of nasal airflow. 2. To commence an investigation of the correlation between nasal airflow and the sensations of nasal patency and olfaction.
Method: Geometrical computational models of the nasal cavities are constructed from multislice CT scans. A hemi-spherical airflow inlet in front of the face is created and the model meshed using ICEM CFD. Airflow analysis is performed with Fluent version 6.1. Prior to nasal surgery the possible results of several surgical procedures are modelled by altering the geometrical model and repeating the airflow analysis, although the final procedure is chosen by the operating surgeon on the basis of clinical experience as virtual surgery is still at the validation stage. After surgery, when healing is complete, the CT scan is repeated and the airflow analysis is compared to the result predicted by the simulation of that procedure. The patient's symptoms are quantified before and after surgery by means of validated questionnaires and olfactory ability is objectively measured. Changes in these variables are correlated with airflow in the olfactory slit and patterns of shear stress distribution in the nasal cavities.
Results: The virtual nasal surgery procedure has been completed for one volunteer patient. Predicted airflow patterns from virtual surgery compared favourably to those obtained following the real operation. Nasopharyngeal pressure was within 10% of that predicted. A reduced sensation of nasal blockage accompanied a posterior shift of median wall shear stress. Olfactory thresholds decreased in both nasal cavities, although olfactory slit airflow improved on one side.
Conclusion: This first report of the use of virtual nasal surgery in a real clinical case demonstrates that it may be a valid means of planning rhinological surgery. Levels of wall shear stress in the posterior aspect of the nasal cavity may be important for the sensation of nasal patency. High olfactory slit airflow appears to decrease olfactory ability just as poor olfactory ventilation is also associated with decreased olfactory ability.
Method: Geometrical computational models of the nasal cavities are constructed from multislice CT scans. A hemi-spherical airflow inlet in front of the face is created and the model meshed using ICEM CFD. Airflow analysis is performed with Fluent version 6.1. Prior to nasal surgery the possible results of several surgical procedures are modelled by altering the geometrical model and repeating the airflow analysis, although the final procedure is chosen by the operating surgeon on the basis of clinical experience as virtual surgery is still at the validation stage. After surgery, when healing is complete, the CT scan is repeated and the airflow analysis is compared to the result predicted by the simulation of that procedure. The patient's symptoms are quantified before and after surgery by means of validated questionnaires and olfactory ability is objectively measured. Changes in these variables are correlated with airflow in the olfactory slit and patterns of shear stress distribution in the nasal cavities.
Results: The virtual nasal surgery procedure has been completed for one volunteer patient. Predicted airflow patterns from virtual surgery compared favourably to those obtained following the real operation. Nasopharyngeal pressure was within 10% of that predicted. A reduced sensation of nasal blockage accompanied a posterior shift of median wall shear stress. Olfactory thresholds decreased in both nasal cavities, although olfactory slit airflow improved on one side.
Conclusion: This first report of the use of virtual nasal surgery in a real clinical case demonstrates that it may be a valid means of planning rhinological surgery. Levels of wall shear stress in the posterior aspect of the nasal cavity may be important for the sensation of nasal patency. High olfactory slit airflow appears to decrease olfactory ability just as poor olfactory ventilation is also associated with decreased olfactory ability.
| Original language | English |
|---|---|
| Title of host publication | 35th AIAA Fluid Dynamics Conference and Exhibit |
| Number of pages | 1 |
| DOIs | |
| Publication status | Published (in print/issue) - 19 Jun 2012 |
