Computational fluid dynamics and trigeminal sensory examinations of empty nose syndrome patients

Abstract

Objective The precise pathogenesis of empty nose syndrome (ENS) remains unclear. Various factors such as nasal aerodynamics and sensorineural dysfunction have been suspected, yet, evidence is limited. This study reported the first examination of both nasal aerodynamics and trigeminal sensory factors in actual ENS patients. Study Design Prospective case control. Methods We enrolled 6 patients diagnosed with ENS. Three patients had pre- and post-inferior turbinate (IT) reduction computed tomography (CT) scans, which allowed comparison of their nasal aerodynamics changes through Computational Fluid Dynamic (CFD) simulation. Their symptoms were confirmed through SNOT-22, ENS6Q, acoustic rhinometry and rhinomanometry findings. Nasal trigeminal sensitivity that potentially mediates their perception of airflow, was assessed via menthol lateralization detection thresholds (LDT) and compared with 14 healthy controls. Results Post-surgical reductions in nasal resistance were observed and significantly lower than normal (p<0.05). CFD analysis showed that, paradoxically for all ENS patients, IT reduction did not draw more airflow to the airway surrounding the ITs, but rather resulted in nasal airflow forming into a narrow jet towards the middle meatus region, leaving the airway surrounding the inferior turbinate with significantly reduced airflow intensity and air-mucosal interactions (inferior region flow percentage reduced from 35.7%±15.9% to post-surgery 17.7%±15.7, p<0.05; inferior wall-shear-stress, reduced from 7.5±4.2×10−2 Pa to 3.4±3.1×10−2 Pa, p<0.01). ENS patients also had significantly impaired menthol LDT compared to healthy controls (p<0.005). Conclusion The results indicated that a combinatory of factors, including paradoxically distorted nasal aerodynamic, impaired sensorineural sensitivity, and potential pre-disposing conditions, may contribute to the development of ENS.

Computational modeling and validation of human nasal airflow under various breathing conditions

“…In recent years, CFD has been increasingly used to predict the airflow and related transport phenomena in human nasal cavities (Bates et al, 2015; Li et al, 2017; Otto et al, 2017; Zhao and Jiang, 2014; Zhao et al, 2014a; Zhao et al, 2014b). Compared to experimental measurements, CFD has the advantages of low cost, non-invasiveness, and ease in obtaining detailed results in both the spatial and temporal domains.…”

Effects of “trigeminal training” on trigeminal sensitivity and self-rated nasal patency

“…In fact, a subjectively congested nose may not exclusively have an anatomical origin but might also result from insensitivity of the nasal trigeminal nerve. In this context, it seems possible that the feeling of a decreased patency of the nasal cavity may stem from decreased trigeminal sensitivity [22, 23]. …”

Quantification of tissue‐engineered trachea performance with computational fluid dynamics

“…The numerical method applied in the current study has been used and validated to model human nasal airflow. [18][19][20][21]…”