A model of airflow in the nasal cavities: Implications for nasal air conditioning and epistaxis

Does Total Turbinectomy Always Lead to Empty Nose Syndrome? A Computational Virtual Surgery Study

INTRODUCTION

Computational fluid dynamic (CFD) modeling has previously indicated that distorted nasal airflow patterns may contribute to empty nose syndrome (ENS); however, no data show that aggressive turbinate surgery always leads to ENS. We aim to use virtual surgery planning (VSP) to investigate how a total inferior turbinectomy affects airflow parameters compared with ENS patients.

METHODS

We retrospectively recruited six nasal obstruction patients who underwent turbinate reduction surgery. We virtually performed total inferior turbinectomy on these patients to compare CFD modeling results to patients' actual surgical outcomes and to that of a previously collected ENS patient cohort (n = 27).

RESULTS

Patients' actual surgery outcomes were excellent, with Nasal-Obstruction Symptom Evaluation (NOSE) score (pre: 72.5 ± 13.2 vs post-surgery: 10.8 ± 9.8, p < 0.001) and unilateral visual analog scale (VAS) scores of nasal obstruction (pre: 6 ± 2.56 vs post-surgery: 1.2 ± 1, p < 0.001) improved and was statistically significant. The virtual turbinectomy does not create the same distorted nasal airflow patterns as seen in ENS patients, with no statistically significant difference in nasal resistance as compared with post-actual surgery (virtual turbinectomy: 0.10 ± 0.03 Pa/mL*s; actual surgery: 0.12 ± 0.04 Pa/mL*s; ENS: 0.11 ± 0.04, p > 0.05) nor in regional wall shear force distribution, an important indicator of air/mucosa stimulation (inferior turbinate WSF%: virtual 47.3% ± 11.3% vs actual 51.5% ± 15.1%, p > 0.05); however, both are statistically significant higher than that of ENS patients (WSF: 32.2% ± 12.5%, p < 0.001), despite ENS cohort having wider inferior airway cross-sectional area (CSA) than actual surgeries.

CONCLUSION

Empty nose syndrome is likely a multifactorial disease process that cannot be solely attributed to aggressive turbinate reduction surgery.

LEVEL OF EVIDENCE

3 Laryngoscope, 135:562-569, 2025.

Computational analysis of nasal airflow and its alteration by a nasal dilator

Nasal airflow obstruction correlates with several ailments, such as higher patency, increased friction at the mucosal wall or the so-called Little's area, improper air conditioning, and snoring. Nasal dilators are frequently employed, mainly due to their ease of access and use, combined with their non-permanent and non-surgical nature. Their overall efficacy, however, has not been clearly demonstrated so far, with some studies reporting conflicting outcomes, mainly because being based on subjective evaluations. This study employs Computational Fluid Dynamics simulations to analyze the flow inside a real nose, performs an objective assessment of a nasal dilator's effect in terms of airflow and air conditioning, reporting flow paths, friction levels, heat and water fluxes and detailed temperature and humidity distributions. Coincidentally, the studied nose presents a septal deviation, with one nostril being wider than the other. The tubes of the dilator used in both nostrils are identical, as with any standard commercial dilator. Consequently, the dilator widens one nostril, as intended, but results in an obstruction in the other. This allows simultaneously addressing two situations, the nominal function of the dilator, as well as an off-design case. Results indicate a 24 % increase in nasal patency in the design situation. The effect, however, is limited, as quantified by appropriate measures, such as the flow-generated friction at the nose surfaces and the temperature fluxes. Hence, the effect of such a dilator in nominal conditions is perhaps not as large as might be hoped. In the off-design situation, nasal resistance increases by 62 %, an undesirable effect, illustrating the consequences of using an inappropriate dilator.

Comparison of microparticle transport and deposition in nasal cavity of three different age groups

Objective: The nasal cavity effectively captures the particles present in inhaled air, thereby preventing harmful and toxic pollutants from reaching the lungs. This filtering ability of the nasal cavity can be effectively utilized for targeted nasal drug delivery applications. This study aims to understand the particle deposition patterns in three age groups: neonate, infant, and adult.Materials and methods: The CT scans are built using MIMICS 21.0, followed by CATIA V6 to generate a patient-specific airway model. Fluid flow is simulated using ANSYS FLUENT 2021 R2. Spherical monodisperse microparticles ranging from 2 to 60 µm and a density of 1100 kg/m3 are simulated at steady-state and sedentary inspiration conditions.Results: The highest nasal valve depositions for the neonate are 25% for 20 µm, for infants, 10% for 50 µm, 15% for adults, and 15% for 15 µm. At mid nasal region, deposition of 15% for 20 µm is observed for infant and 8% for neonate and adult nasal cavities at a particle size of 10 and 20 µm, respectively. The highest particle deposition at the olfactory region is about 2.7% for the adult nasal cavity for 20 µm, and it is <1% for neonate and infant nasal cavities.Discussion and conclusions: The study of preferred nasal depositions during natural sedentary breathing conditions is utilized to determine the size that allows medication particles to be targeted to specific nose regions.

Human nasal cartilage: Functional properties and structure-function relationships for the development of tissue engineering design criteria

Nose reconstruction often requires scarce cartilage grafts. Nasal cartilage properties must be determined to serve as design criteria for engineering grafts. Thus, mechanical and biochemical properties were obtained in multiple locations of human nasal septum, upper lateral cartilage (ULC), and lower lateral cartilage (LLC). Within each region, no statistical differences among locations were detected, but anisotropy at some septum locations was noted. In the LLC, the tensile modulus and ultimate tensile strength (UTS) in the inferior-superior direction were statistically greater than in the anterior-posterior direction. Cartilage from all regions exhibited hyperelasticity in tension, but regions varied in degree of hyalinicity (i.e., Col II:Col I ratio). The septum contained the most collagen II and least collagen I and III, making it more hyaline than the ULC and LLC. The septum had a greater aggregate modulus, UTS, and lower total collagen/wet weight (Col/WW) than the ULC and LLC. The ULC had greater tensile modulus, DNA/WW, and lower glycosaminoglycan/WW than the septum and LLC. The ULC had a greater pyridinoline/Col than the septum. Histological staining suggested the presence of chondrons in all regions. In the ULC and LLC, tensile modulus correlated with total collagen content, while aggregate modulus correlated with pyridinoline content and weakly with pentosidine content. However, future studies should be performed to validate these proposed structure-function relationships. This study of human nasal cartilage provides 1) crucial design criteria for nasal cartilage tissue engineering efforts, 2) quantification of major and minor collagen subtypes and crosslinks, and 3) structure-function relationships. Surprisingly, the large mechanical properties found, particularly in the septum, suggests that nasal cartilage may experience higher-than-expected mechanical loads. STATEMENT OF SIGNIFICANCE: While tissue engineering holds promise to generate much-needed cartilage grafts for nasal reconstruction, little is known about nasal cartilage from an engineering perspective. In this study, the mechanical and biochemical properties of the septum, upper lateral cartilage (ULC), and lower lateral cartilage (LLC) were evaluated using cartilage-specific methods. For the first time in this tissue, all major and minor collagens and collagen crosslinks were measured, demonstrating that the septum was more hyaline than the ULC and LLC. Additionally, new structure-function relationships in the ULC and LLC were identified. This study greatly expands upon the quantitative understanding of human nasal cartilage and provides crucial engineering design criteria for much-needed nasal cartilage tissue engineering efforts.

Characterizing the respiratory-induced mechanical stimulation at the maxillary sinus floor following sinus augmentation by computational fluid dynamics

Background: The relationship between maxillary sinus pneumatization and respiratory-induced fluid mechanics remains unclear. The purpose of this study was to simulate and measure the respiratory-induced mechanical stimulation at the sinus floor under different respiratory conditions and to investigate its potential effect on the elevated sinus following sinus-lifting procedures.

Methods: The nasal airway together with the bilateral maxillary sinuses of the selected patient was segmented and digitally modeled from a computed tomographic image. The sinus floors of the models were elevated by simulated sinus augmentations using computer-aided design. The numerical simulations of sinus fluid motion under different respiratory conditions were performed using a computational fluid dynamics (CFD) algorithm. Sinus wall shear stress and static pressure on the pre-surgical and altered sinus floors were examined and quantitatively compared.

Results: Streamlines with minimum airflow velocity were visualized in the sinus. The sinus floor pressure and the wall shear stress increased with the elevated inlet flow rate, but the magnitude of these mechanical stimulations remained at a negligible level. The surgical technique and elevated height had no significant influence on the wall pressure and the fluid mechanics.

Conclusion: This study shows that respiratory-induced mechanical stimulation in the sinus floor is negligible before and after sinus augmentation.

Septal deviation in the nose of the longest faced crocodylian: A description of nasal anatomy and airflow in the Indian gharial (Gavialis gangeticus) with comments on acoustics

The remarkably thin rostrum in the Indian gharial (Gavialis gangeticus) imparts challenges to nasal physiology. Competition for space in the slim jaws necessitates a thin nasal septum, leaving this taxon susceptible to nasal passage abnormalities such as septal deviation. Here we describe the nasal anatomy of gharials based on multiple individuals including one that showcases an extreme instance of nasal septum deviation. We found that gharials have both confluent nostrils and choanae, which may be important for their unique nasal acoustics. The deviated nasal septum in the female showed distinct waviness that affected the nasal passages by alternately compressing them. We performed a computational fluid dynamic analysis on the nasal passages to visualize the effects of septal deviation on airflow. Our analysis found the deviated septum increased nasal resistance and wall shear stress during respiration, resulting in unequal distribution of the air field between both sides of the nasal passage. Our findings indicate that gharials-and potentially other longirostrine crocodylians-may be particularly susceptible to septal deviations. Lastly, we observed pterygoid bullae to be present in both sexes, though their morphology differed. Airflow in the male pterygoid bullae produced a Bernoulli effect which may be responsible for the unique "pop" sounds recorded in this species.

Common evolutionary patterns in the human nasal region across a worldwide sample

OBJECTIVES

Variation in the external nasal region among human populations has long been proposed in the literature to reflect adaptations to facilitate thermoregulation, air conditioning, and moisture retention in local climates and environments. More specifically, adaptations in populations living in colder climates have often been assumed due to correlational relationships found between variation in the nasal region and climatic variables. Here, we test this hypothesis by applying a quantitative genetics approach based on the Lande model to assess whether variation in the nasal region can be explained by random neutral processes (e.g., genetic drift) or if non-random forces (i.e., adaptation) have contributed significantly to its diversity.

MATERIALS AND METHODS

A mixed-sex sample representing 28 population groups from Howells' craniometric dataset were analyzed (n = 2504). Twenty standard measurements were chosen to reflect the external skeletal morphology of the nasal region. We apply statistical tests developed from evolutionary quantitative genetics theory to analyze patterns of within- and between-population divergence under a null hypothesis of genetic drift.

RESULTS

This study finds a rejection of genetic drift in all analyses, across tests that involve all 28 populations, exclusively cold-climate populations, and with cold-climate populations excluded, indicating that non-random evolutionary forces have contributed significantly to variation in the nasal region overall.

DISCUSSION

These results show that nasal region adaptation is not exclusive to cold-climate populations, which have often been implicated in the literature to drive nasal variation, instead suggesting that the propensity for adaptation in the nasal region is shared among all human populations.

Computational investigation of dust mite allergens in a realistic human nasal cavity

Aim: Inhaled allergens from house dust mite (HDM) are a major source of allergic disease such as allergic rhinitis and asthma. It has been a challenge to properly evaluate health risks caused by HDM related allergens including mite bodies, eggs and fecal pellets. This paper presents a numerical study on particle deposition of dust mite allergens in a human nasal cavity. Materials and methods: A realistic nasal cavity model was reconstructed from CT scans and a Computational Fluid Dynamics analysis of steady airflow was simulated. The discrete phase model was used to trace particle trajectories of three dust mite related particles. Results: The flow and particle model were validated by comparing with nasal resistance measurement and previous literature respectively. Aerodynamic characteristics and deposition of dust mite allergens in the nasal cavity were analyzed under different breathing conditions including rest and exercising conditions. Conclusions: The numerical results revealed the roles of different nasal cavity regions in filtering various types of dust mite allergens with consideration of breathing conditions.

Comparison of topical treatment methods used in recurrent anterior epistaxis: a randomized clinical trial

Introduction

Recurrent epistaxis is a common medical problem faced by ENT specialists, emergency physicians, and pediatricians. The facts that many treatment modalities are being searched and no single treatment method is universally accepted yet support this information.

Objective

We aimed to compare the clinical efficacy of topical antiseptic ointment, topical decongestant ointment and chemical cauterization treatments, which are frequently used in recurrent anterior epistaxis, both singly and in combination.

Material-methods

Between August 2017 and February 2018, 137 patients who were diagnosed with recurrent anterior epistaxis were randomly divided into 5 groups. group I received topical antiseptic ointment, group II received topical decongestant ointment, group III received chemical cauterization, group IV received topical antiseptic ointment + chemical cauterization and group V received topical decongestant ointment + chemical cauterization treatment. All patients were phoned 2 weeks and 1 month after the treatment and questioned about the presence (failure) or absence (success) of at least 1 episode of epistaxis. Patients with comorbid diseases were excluded. Treatment success was statistically analysed.

Results

There was no significant difference (p > 0.05) between the groups in the success rate at 15th day after treatment. Group IV and group V had higher success rates at 30th day after treatment compared with group I and group II (p < 0.05). In group III 30th day treatment success was not different from the other 4 groups (p > 0.05).

Conclusion

Although the number of patients who improved with chemical cauterization (group III) was higher in our study, no significant difference was observed in single treatment modalities (group I‒III) at 14th day and 30th day after treatment. Although no statistically significant difference was observed between combined treatments (group IV—V) and single treatments (group I‒III) in the 2nd week after treatment, combined treatments were significantly more effective in the 1st month.

Climatic adaptation in human inferior nasal turbinate morphology: Evidence from Arctic and equatorial populations

OBJECTIVES

The nasal turbinates directly influence the overall size, shape, and surface area of the nasal passages, and thus contribute to intranasal heat and moisture exchange. However, unlike the encapsulating walls of the nasal cavity, ecogeographic variation in nasal turbinate morphology among humans has not yet been established. Here we investigate variation in inferior nasal turbinate morphology in two populations from climatically extreme environments.

MATERIALS AND METHODS

Twenty-three linear measurements of the inferior turbinate, nasal cavity walls, and airway passages were collected from CT scans of indigenous modern human crania from Equatorial Africa (n = 35) and the Arctic Circle (n = 35). MANOVA and ANCOVA were employed to test for predicted regional and sex differences in morphology between the samples.

RESULTS

Significant morphological differences were identified between the two regional samples, with no evidence of significant sexual dimorphism or region-sex interaction effect. Individuals from the Arctic Circle possessed superoinferiorly and mediolaterally larger inferior turbinates compared to Equatorial Africans. In conjunction with the surrounding nasal cavity walls, these differences in turbinate morphology produced airway dimensions that were both consistent with functional expectations and more regionally distinct than either skeletal component independently.

CONCLUSION

This study documents the existence of ecogeographic variation in human nasal turbinate morphology reflecting climate-mediated evolutionary demands on intranasal heat and moisture exchange. Humans adapted to cold-dry environments exhibit turbinate morphologies that enhance contact between respired air and nasal mucosa to facilitate respiratory air conditioning. Conversely, humans adapted to hot-humid environments exhibit turbinate morphologies that minimize air-to-mucosa contact, likely to minimize airflow resistance and/or facilitate expiratory heat-shedding.

Characterizing airflow profile in the postoperative maxillary sinus by using computational fluid dynamics modeling: A pilot study

BACKGROUND

Maxillary antrostomy is commonly performed during endoscopic sinus surgery. Little is known about the association surrounding recalcitrant maxillary sinusitis, antrostomy size, and intranasal airflow changes. Furthermore, the interaction between sinus mucosa and airflow is poorly understood. This study used computational fluid dynamics (CFD) modeling to investigate postoperative airflow characteristics between diseased and nondiseased maxillary sinuses in subjects with recurrent disease.

METHODS

A retrospective review of patients from a tertiary-level academic rhinology practice was performed. Seven subjects with endoscopic evidence of postoperative maxillary sinus disease that presented as chronic unilateral crusting at least 1 year after bilateral maxillary antrostomies were selected. A three-dimensional model of each subject's sinonasal cavity was created from postoperative computed tomographies and used for CFD analysis.

RESULTS

Although the variables investigated between diseased and nondiseased sides were not statistically significant, the diseased side in six subjects had a smaller antrostomy, and five of these subjects had both reduced nasal unilateral airflow and increased unilateral nasal resistance on the diseased side. The ratio of posterior wall shear stress (WSS) of the maxillary sinus to the total WSS was higher on the diseased side in six subjects. Results also showed strong correlations between antrostomy and CFD variables on the diseased side than on the nondiseased side.

CONCLUSION

This pilot study showed that the majority of the simulated sinonasal models exhibited common characteristics on the side with persistent disease, such as smaller antrostomy, reduced nasal airflow, increased nasal resistance, and increased posterior WSS. Although statistical significance was not established, this study provided preliminary insight into variables to consider in a larger cohort study.

A comparative study of propranolol versus silver nitrate cautery in the treatment of recurrent primary epistaxis in children

Background

Epistaxis is a common medical problem in pediatric population. Although in most cases it is mild and self-limiting, a proportion of childhood epistaxis is massive, recurrent, or resistant to conventional management.

Objective

To compare effectiveness of propranolol as a treatment option for childhood epistaxis versus conventional silver nitrate cautery.

Study design and methodology

This is a prospective interventional comparative study that was carried out during a period of 1 year (January 1, 2013 to December 31, 2013) at Qena University Hospital and Assiut University Children’s Hospital. One hundred children aged 6–12 years who presented with epistaxis to Qena University Hospital and Assiut University Children’s Hospital during the study period and fulfilling the inclusion criteria were included in the study. They were randomly assigned into one of two interventional groups, where 50 children were treated with oral propranolol (propranolol treatment group) and another 50 children were treated with conventional silver nitrate cautery (cauterization treatment group) for their epistaxis. Propranolol was given at a dose of 1.5–2 mg/kg/day (divided into three doses). Patients were followed for 6 months after their discharge for recurrence of epistaxis.

Results

Both groups of patients showed minimal recurrent epistaxis with rates of 14% for propranolol treated group and 12% for cauterization group, with no statistically significant difference between both groups. Local pain was found to be more in patients treated with silver nitrate cauterization.

Conclusion

Treatment of primary epistaxis with propranolol or silver nitrate cautery showed equal rates of recurrence, and local nasal pain was slightly more among silver nitrate cauterization treated group. Propranolol could be a favorable treatment option for patients with primary epistaxis. Further studies that include multiple centers and larger number of patients are recommended for more clarification of the effectiveness of such treatment option.

The Treatment of Spontaneous Epistaxis: Conservative vs Cautery

AIM

To find the best treatment for spontaneous epistaxis by a conservative approach or by an intervention with silver nitrate cautery.

STUDY DESIGN

A prospective study with two groups which were randomly selected for the conservative management or cautery.

MATERIALS AND METHODS

94 patients are studied in two groups of 42 patients who were treated conservatively and 52 patients who were treated with silver nitrate cautery. The patients were followed up for 1 week and the results were tabulated with regards to the recurrence of the bleeding.

RESULTS

Both the groups of patients who were treated conser-vatively or with cautery showed minimal recurrent bleeding with rates of 30% and 26% respectively. Statistically, there was no significant difference in the outcome. The pain was more in the cases which were treated with cautery.

CONCLUSION

Both the groups of patients who were treated conservatively or with cautery showed equal rates of the outcome, with the pain being slightly more in the group which was treated with cautery.

Aerodynamic characteristics inside the rhino-sinonasal cavity after functional endoscopic sinus surgery

BACKGROUND

The aim of this study was to evaluate effects of functional endoscopic sinus surgery (FESS) on transient nasal aerodynamic flow patterns using computational fluid dynamics (CFD) simulations.

METHODS

A three-dimensional model of the nasal cavity was constructed from CT scans of a patient with FESS interventions on the right side of the nasal cavity. CFD simulations were then performed for unsteady aerodynamic flow modeling inside the nasal cavity as well as the sinuses.

RESULTS

Comparisons of the local velocity magnitude and streamline distributions inside the left and right nasal cavity and maxillary sinus regions were presented. Because of the FESS procedures in the right nasal cavity, existences and distributions of local circulations (vortexes) were found to be significantly different for the same nasal airflow rate but at different acceleration, deceleration, or quiet phases in the maxillary sinus region on the FESS side. Because of inertia effects, local internal airflow with circulation existences was continuous throughout the whole respiration cycle. With a larger peak inspiration flow rate, the airflow intensity inside the enlarged maxillary sinus increased significantly. Possible outcomes on functional performances of the nose were also examined and discussed.

CONCLUSION

Surgical enlargements of natural ostium of the maxillary sinus will change the aerodynamic patterns inside the main nasal cavity and maxillary sinus regions, which may affect normal nasal physiological functions. Local inertia effects play more important roles for the internal nasal airflow pattern changes and thus such conventional FESS procedures should be carefully planned.

Assessments of nasal bone fracture effects on nasal airflow: A computational fluid dynamics study

BACKGROUND

The aim of this study was to evaluate effects of nasal bone fractures on nasal aerodynamic flow patterns using computational fluid dynamics (CFD) simulations.

METHODS

A three-dimensional model of nasal cavity with a nasal bone fracture was constructed from computerized tomography (CT) scans of a patient with use of software Mimics 13.0 (The Materilize Group, Leuven, Belgium). CFD simulations were performed using Fluent 6.3 (ANSYS, Inc., Canonsburg, PA) with a turbulent flow model. Numerical results were presented with velocity, streamline, and pressure contour distributions in left and right nasal cavities and were compared with those of a healthy one. Possible outcomes on functional performances or patencies of the nose were also examined and discussed.

RESULTS

For the nose with a nasal bone fracture, distributions of velocity contours showed there was more airflow in the right nasal cavity than in the left one, especially for inspiration status. In the left cavity, the airflow was redirected irregularly and there were also more circulations with larger sizes, higher pressure jumps, and greater wall shear stresses. Flow partitioning in the right and left cavities was noticeable with a larger nasal resistance compared with the healthy one. When the inspirational flow rate was increased, pressure jump from the nostril to the nasopharynx increased faster.

CONCLUSION

The aerodynamic flow was redistributed greatly for the nose with a nasal bone fracture compared with the healthy one, which might affect local normal nasal functions. Such physical assessments of nasal airflow based on a model from the patients' CT scans may help clinicians determine the best treatment in advance.

Investigation on the structure of nasal cavity and its airflow field in Crouzon syndrome

OBJECTIVE

Setup computational fluid dynamics (CFD) model of the nasal cavity in patients with Crouzon syndrome analyze inspiratory airflow hydrokinetics of its nasal cavity. After changing the morphosis structure of the nasal cavity by operation, compare the preoperative and postoperative alteration of the airflow field of the nasal cavity and evaluate the effect of operation on the physiological function of nasal ventilation.

METHODS

Eleven patients with Crouzon syndrome were underwent spiral computed tomographic laminar scanning to obtain DICOM data and establish the CFD model. The field features of the nasal cavity with inspiratory static state phase were simulated and analyzed by the Fluent software. The changed data on preoperative and postoperative flow field in the nasal cavity in 5 of 11 patients were compared and analyzed.

RESULTS

The nasal cavity of a patient with Crouzon syndrome reflected the structural features of relatively short and high-vaulted anteroposterior diameter. The nasal valve was the narrowest region in the nasal cavity and was the key region of producing obvious pressure drop. The inspiratory static state phase reflected comparatively high local airflow rate (approximately 2.469 m/s) and sheer force of the nasal wall. With the distance increasing from the anterior naris, the pressure inside the nasal cavity was decreased gradually. The pressure drop in the nasal cavity before the front end of the concha nasalis inferior (approximately 2 cm from anterior naris) accounted for most of the pressure of the whole nasal cavity (69%-88% of the overall pressure in nasal cavity and 79.24% on average). Osteotomy advancement and distraction osteogenesis increased the anteroposterior diameter of the nasal cavity and the changed nasal resistance.

CONCLUSIONS

By analyzing the structure of the nasal cavity of patients with Crouzon syndrome and the CFD numerical simulation of patients after the procedure, airflow distribution in patients' nasal cavity and the effect of the surgery on the structure of the nasal cavity and airflow field were realized. Nasal valve played a pivotal role in the airflow field distribution of the nasal cavity. Operation changed the nasal resistance, improved the ventilation of nasal cavity, but did not affect the airflow field distribution of nasal cavity.

Numerical simulation of the effects of inferior turbinate surgery on nasal airway heating capacity

BACKGROUND

The aim of this study was to evaluate the effects of inferior turbinate surgery on nasal airway heating capacity using computational fluid dynamics (CFD) simulations.

METHODS

Heat transfer simulations were performed for a normal nasal cavity and others with severely enlarged inferior turbinates, before and after three simulated surgical procedures: (1) resection of the lower third free edge of the inferior turbinate, (2) excision of the head of the inferior turbinate, and (3) radical inferior turbinate resection. The models were run with three different environmental temperatures.

RESULTS

The changes of airflow pattern with the reduction of inferior turbinate affected heat transfer greatly. However, the distribution of wall heat flux showed that the main location for heat exchange was still the anterior region. Under the cold environment, the nasal cavities with the head of inferior turbinate reduction were capable of heating the inspired air to 98.40% of that of the healthy one; however, for the case with lower third of inferior turbinate excised, the temperature was 11.65% lower and for the case with radical inferior turbinate resection, 18.27% lower temperature compared with the healthy nasal cavity.

CONCLUSION

The healthy nasal cavity is able to warm up or cool down the inspiratory airflow under different environmental temperature conditions; for the nasal cavities with turbinate surgeries, partial inferior turbinate reduction can still sustain such heating capacity. However, too much or total turbinate resection may impair the normal function of temperature adjustment by nasal mucosa.

Objective measures in aesthetic and functional nasal surgery: perspectives on nasal form and function

The outcomes of aesthetic and functional nasal surgery are difficult to assess objectively because of the intricate balance between nasal form and function. Despite historical emphasis on patient-reported subjective measures, objective measures are gaining importance in both research and the current outcomes-driven health care environment. Objective measures currently available have several shortcomings that limit their routine clinical use. In particular, the low correlation between objective and subjective measures poses a major challenge. However, advances in computer, imaging, and bioengineering technology are now setting the stage for the development of innovative objective assessment tools for nasal surgery that can potentially address some of the current limitations. Assessment of nasal form after aesthetic surgery is evolving from two-dimensional analysis to more sophisticated three-dimensional analysis. Similarly, assessment of nasal function is evolving with the introduction of computational fluid dynamics techniques, which allow for a detailed description of the biophysics of nasal airflow. In this article, we present an overview of objective measures in both aesthetic and functional nasal surgery and discuss future trends and applications that have the potential to change the way we assess nasal form and function.