Impact of Middle versus Inferior Total Turbinectomy on Nasal Aerodynamics

Abstract

Objectives: This computational study aims to (1) use virtual surgery to theoretically investigate the maximum possible change in nasal aerodynamics after turbinate surgery, (2) quantify the relative contributions of the middle and inferior turbinates to nasal resistance and air conditioning, and (3) quantify to what extent total turbinectomy impairs the nasal air-conditioning capacity.

Study design: Virtual surgery and computational fluid dynamics.

Setting: Academic tertiary medical center.

Subjects and methods: Ten patients with inferior turbinate hypertrophy were studied. Three-dimensional models of their nasal anatomies were built according to presurgery computed tomography scans. Virtual surgery was applied to create models representing either total inferior turbinectomy (TIT) or total middle turbinectomy (TMT). Airflow, heat transfer, and humidity transport were simulated at a steady-state inhalation rate of 15 L/min. The surface area stimulated by mucosal cooling was defined as the area where heat fluxes exceed 50 W/m(2).

Results: In both virtual total turbinectomy models, nasal resistance decreased and airflow increased. However, the surface area where heat fluxes exceed 50 W/m(2) either decreased (TIT) or did not change significantly (TMT), suggesting that total turbinectomy may reduce the stimulation of cold receptors by inspired air. Nasal heating and humidification efficiencies decreased significantly after both TIT and TMT. All changes were greater in the TIT models than in the TMT models.

Conclusion: TIT yields greater increases in nasal airflow but also impairs the nasal air-conditioning capacity to a greater extent than TMT. Radical resection of the turbinates may decrease the surface area stimulated by mucosal cooling.

Keywords: computational fluid dynamics simulations; empty nose syndrome; inferior turbinate reduction; middle turbinate resection; mucosal cooling; nasal airflow sensation; nasal airway obstruction; secondary atrophic rhinitis.

© American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

Figures

Figure 1

(A) Lateral view of the 3-dimensional pre-surgery model. (B) Outline of the pre-surgery (PRE), total inferior turbinectomy (TIT), and total middle turbinectomy (TMT) models overlaid on the pre-surgery CT scan.

Figure 2

Average airspace cross-sectional areas as a function of distance from the nostrils in the pre-surgery (PRE), total middle turbinectomy (TMT), and total inferior turbinectomy (TIT) models.

Figure 3

(A) Unilateral nasal resistance and (B) unilateral airflow in the virtually operated nasal cavity in the pre-surgery, TMT, and TIT models. Symbols denote statistically significant differences (* pre-surgery vs. total turbinectomy, § TMT vs. TIT).

Figure 4

(A) 3D pre-surgery model. (B) Air velocity at coronal section D=0.65. (C) Airflow distribution among inferior, middle, and superior regions at D=0.65. Symbols denote statistical significance (* pre-surgery vs. total turbinectomy, § TMT vs. TIT).

Figure 5

(A) Nasal heating efficiency and (B) nasal humidification efficiency in the pre-surgery, TMT, and TIT models. Symbols denote statistically significant differences (* pre-surgery vs. total turbinectomy, § TMT vs. TIT).

Figure 6

Average surface area stimulated by mucosal cooling in the pre-surgery, total middle turbinectomy (TMT), and total inferior turbinectomy (TIT) models. Symbol denotes statistically significant differences (* pre-surgery vs. TIT).