A computational study on the characteristics of airflow in bilateral abductor vocal fold immobility.
OBJECTIVE
To evaluate airway sufficiency and airflow dynamics in a group of patients who underwent a posterior transverse laser cordotomy (PTLC) procedure.


METHODS
Mixed methods research, university hospital setting.


METHODS
Sixteen patients who underwent a PTLC procedure volunteered to be involved in this study. Dyspnea levels, voice, and glottic opening in indirect laryngoscopy were evaluated subjectively. The airway was evaluated objectively by pulmonary function tests, and glottic areas were measured from axial computed tomography (CT) images. The control group consisted of 63 subjects from the tomography archive. For computational fluid dynamics (CFD) analyses, two subjects from the study group were chosen on the basis of obstruction level, and a normal female subject was selected from the control group. Cartesian coordinates for airway boundaries were determined from axial CT images, and a three-dimensional computational model of the larynx was constructed. Flow simulations were performed with two different flow conditions during inspiration. Comparison of velocity, static pressure, turbulence intensity, and wall shear stress distribution values were made between selected cases and control.


RESULTS
Pulmonary data varied widely and did not correlate with the size of the glottic area or dyspnea level. CFD analyses revealed that in addition to obstruction at the glottic level, aerodynamic properties of the larynx are altered due to loss in muscular tonus. Also, the contour of the glottic opening was found to be very important in determining the character of airflow as laminar or turbulent.


CONCLUSIONS
Patients have considerable differences in their flow patterns and force distributions during respiration. Patient-specific models may help in evaluation and treatment planning.
Gökcan
M Kürşat
MK
Department of Otorhinolaryngology, Head and Neck Surgery, Ankara University Medical School, Ankara, Turkey. gokcan@medicine.ankara.edu.tr
Kurtuluş
D Funda
DF
Ustüner
Evren
E
Ozyürek
Elif
E
Kesici
G Gökçen
GG
Erdem
S Ceyhan
SC
Dursun
Gürsel
G
Yağci
Cemil
C
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003198:Computer Simulation; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007828:Laryngoscopy; D008875:Middle Aged; D016571:Neural Networks, Computer; D010366:Peak Expiratory Flow Rate / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology*; D049489:Stroboscopy; D036542:Tomography, Spiral Computed; D014741:Video Recording; D014797:Vital Capacity / Q000502:physiology; D014826:Vocal Cord Paralysis / Q000503:physiopathology* / Q000601:surgery; D014827:Vocal Cords / Q000503:physiopathology / Q000601:surgery