Development of a Serum-Free Culture Method for Endothelial Cells of the Stria Vascularis and Their Pro-Inflammatory Secretome Changes Induced by Oxidative Stress.

OBJECTIVES: Reactive oxygen species in the stria vascularis (SV) of the cochlea may be involved in the pathogenesis of sensorineural hearing loss. However, the effects of oxidative stress on SV endothelial cells (SV-ECs) remain largely unknown, and no feasible in vitro cell culture model exists for the functional study of SV-ECs. METHODS: We isolated primary SV-ECs from the SV of neonatal mice. The apoptosis-reducing effects of fibronectin in SV-ECs cultured with serum-free medium were determined using ß-galactosidase staining and flow cytometry. SV-ECs incubated in serum-free medium were treated with various H2O2 concentrations to evaluate the effects of H2O2 on their viability. The secretome of SV-ECs treated with or without H2O2 (100 µM or 500 µM) was analyzed using high-resolution mass spectrometry. The function of the SV-EC secretome was evaluated by a macrophage assay. RESULTS: We successfully isolated and characterized the SV-ECs. Treatment with H2O2 at concentrations up to 500 µM for 2 hours and further incubation with serum-free medium in plates precoated with fibronectin showed no significant effect on apoptosis. Compared to the control SV-ECs, the amount of differential proteins in the secretome of SV-ECs stimulated with 500 µM H2O2 was much higher than in those treated with 100 µM H2O2. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses suggested that the proteins differentially expressed in SV-ECs treated with 500 µM H2O2 were involved in the regulation of multiple signaling pathways and cellular processes. The secretome of H2O2-stimulated SV-ECs exhibited significant pro-inflammatory effects on macrophages. CONCLUSION: We successfully established an in vitro serum-free culture method, identified the differential proteins released by oxidative stress-induced ECs and their functions, and revealed the pro-inflammatory effects of the secretome of H2O2-stimulated SV-ECs. Therefore, SV-ECs might elicit immunoregulatory effects on bystander cells in the microenvironment of oxidative stress-induced cochlea, especially cochlear macrophages.

Cochlear Implantation Outcomes in Children With CDH23 Mutations-Associated Hearing Loss.

OBJECTIVE: Mutations in the cadherin 23 gene (CDH23) have been reported to cause cochlear damage, but few studies have investigated the auditory and speech outcome of patients after cochlear implantation. Here, we describe the genetic, auditory, and postoperative outcomes of patients with CDH23 mutations who received cochlear implants. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. METHODS: Targeted deafness-related gene panels were sequenced in Chinese families with profound sensorineural hearing loss. The clinical features of subjects carrying potentially pathogenic CDH23 mutations were analyzed. RESULTS: Between 2017 and 2019, we identified 5 children with prelinguistically profound hearing loss at our center who harbored 6 variants of CDH23 that segregated with the disease. Of these, 4 variants were novel (c.2591G>T, c.4785G>C, c.5765A>G, and c.9280_9281insTT). All affected individuals had a loss of outer hair cell function, with an average residual hearing level of 3 to 10 dB SPL. Cochlear implantations were arranged for the patients at 11 to 36 months of age. All children made gains in their hearing, language, and speech performances 14 to 120 months after surgery. Their auditory outcomes improved during follow-up intervals. CONCLUSION: This study revealed that children with congenital cochlear defects caused by CDH23 variants can acquire an acceptable auditory and speech outcome after cochlear implantation. Early genetic detection and prenatal counseling for rare deafness genes such as CDH23 remain a priority for the future.

Quantification of endolymphatic hydrops and its correlation with Meniere's disease clinical features.

OBJECTIVE: We aimed to quantitatively evaluate the degree of endolymphatic hydrops and its correlation with the clinical features of Meniere's disease. METHODS: We retrospectively collected data from patients with Meniere's disease who underwent gadolinium-enhanced magnetic resonance imaging (MRI) at our department from January 2018 to December 2019. Mimics software was used to perform three-dimensional modelling of the labyrinth, and volume information was obtained to calculate the endolymphatic hydrops index (EHI). A correlation analysis was conducted with data from pure tone audiometry, electrocochleography (EchoG), vestibular myogenic-evoked potential (VEMP) testing, caloric testing and video head impulse testing (vHIT). A two-dimensional method was also employed to calculate the hydrops ratio (HR) of cochlea and vestibule. The test-retest reliability of EHI/HR from different operators was evaluated. RESULTS: A total of 23 affected ears were examined, and the EHI was significantly correlated with Meniere's disease stage, low-frequency hearing threshold, EchoG summating potential/action potential ratio (-SP/AP) and VEMP binaural asymmetry ratio, but no significant correlation was observed between EHI and the caloric test or vHIT. The Intraclass correlation coefficient (ICC) of EHI data calculated by two otologists was 0.946 (p < .001). And the ICC of cochlea and vestibule HR were 0.844 and 0.832 (p < .001). CONCLUSION: Mimics software can be used to quantitatively evaluate the degree of endolymphatic hydrops and have shown higher test-retest reliability than traditional two-dimensional evaluation method. Endolymphatic hydrops correlates with clinical data, such as Meniere's disease stage, low-frequency hearing threshold, EchoG and VEMP asymmetry ratio.

Notched Sound Alleviates Tinnitus by Reorganization Emotional Center.

BACKGROUND: Tinnitus is a common disease, and sound therapy is an effective method to alleviate it. Previous studies have shown that notched sound not only changes levels of cortical blood oxygen, but affects blood oxygen in specific cerebral cortical areas, such as Brodmann area 46 (BA46), which is associated with emotion. Extensive evidence has confirmed that tinnitus is closely related to emotion. Whether notched sound plays a role in regulating the emotional center is still unclear. METHODS: This study included 29 patients with newly diagnosed chronic tinnitus who were treated with notched sound. Functional near-infrared spectroscopy (fNIRS) was conducted before and after treatment to observe bilateral changes in cortical blood oxygen in the cerebral hemispheres. We compared the changes in connectivity between the two regions of interest (the superior temporal gyrus and BA46), as wells as other cortical regions before and after treatment. RESULTS: The results showed (1) That global connectivity between the bilateral auditory cortex of the superior temporal sulcus and the ipsilateral cortex did not change significantly between baseline and the completion of treatment, and (2) That the connectivity between channel 14 and the right superior temporal sulcus decreased after treatment. The overall connectivity between the right BA46 region and the right cortex decreased after treatment, and decreases in connectivity after treatment were specifically found for channels 10 and 14 in the right parietal lobe and channels 16, 20, 21, and 22 in the frontal lobe, while there was no significant change on the left side. There were no significant changes in the questionnaire measures of tinnitus, anxiety, or depression before and after treatment. CONCLUSION: The results of the study indicate that cerebral cortex reorganization occurs in tinnitus patients after submitted to treatment with notched sound for 1 month, and that notched sound decreases the connectivity between the auditory cortex and specific brain regions. SIGNIFICANCE: Notched sound not only regulates the auditory center through lateral inhibition, but also alleviates tinnitus by reorganizing the emotional control center.

Combined application of single-energy metal artifact reduction and reconstruction techniques in patients with Cochlear implants.

BACKGROUND: The purpose of this study was to develop an effective method of reducing metal artifacts in cochlear implant (CI) electrodes. METHODS: The temporal bones of 30 patients (34 ears) after CI were examined with 320-detector row computed tomography, which was evaluated by two senior radiologists using a double-blind method. Noise, artifact index, signal-to-noise ratio, and the subjective image quality score were compared before versus after using single-energy metal artifact reduction (SEMAR). The electrode position, single electrode visibility, and electrode count were evaluated using SEMAR combined with either multi-planar reconstruction (MPR) or maximum intensity projection. RESULTS: The two radiologists' measurements had good consistency. SEMAR significantly reduced the image noise and artifacts index and significantly improved the signal-to-noise ratio and subjective image quality score (P < 0.01). The combination of SEMAR with MPR was conducive to accurate assessment of electrode position and single-electrode visibility. The combination of SEMAR with MIP facilitated accurate and intuitive matching of the assessed electrode count with the number of electrodes implanted during the operation (P = 0.062). CONCLUSION: SEMAR significantly reduces metal artifacts generated by CI electrodes and improves the quality of computed tomography images. The combination of SEMAR with MPR and maximum intensity projection is beneficial for evaluating the position and number of CI electrodes.

Chinese validation and clinical application of the tinnitus functional index.

OBJECTIVE: The Tinnitus Functional Index (TFI) is a new diagnostic measure of the functional impact of tinnitus that is also a sensitive measure of treatment-related changes. However, the TFI has not been translated into Chinese and fully validated in China. The aim of the present study was to evaluate the validity of a Chinese version of the TFI as a diagnostic measure of tinnitus severity in a sample of Chinese patients and to verify the value of its clinical application in China. DESIGN: A sample of 206 patients whose primary complaint was tinnitus was used to analyze the reliability and validity of the TFI. In addition, patients were asked to fill out the Tinnitus Handicap Inventory (THI) and the Center for Epidemiologic Studies-Depression Scale (CES-D), the Beck Anxiety Inventory (BAI), and the Satisfaction With Life Scale (SWLS) to compare TFI with their association. The internal consistency of the TFI was assessed with Cronbach's alpha coefficient. The factor structure of the TFI was assessed by Exploratory Factor Analysis (EFA). The extracted factors were compared to those of the original TFI scale. RESULTS: The reliability of the Chinese version of the TFI (Cronbach' s α = .969) showed high internal consistency. The exploratory factor analysis (EFA) of the TFI showed that six factors with one main factor could be extracted instead of eight factors as described in the original version. Nevertheless, relations to the original eight subscales could be demonstrated. A high correlation between the TFI and the THI (r = .865, p < 0.01) and lower correlations between the TFI and the CES-D (r = .334, p < 0.01), BAI (r = .559, p < 0.01), and SWLS (r = - 0.324, p < 0.01) confirmed the satisfactory convergent and discriminant validity of the TFI. CONCLUSION: After translated and validated a Chinese version of the TFI and found that the TFI had high reliability and validity, which means both instruments are reliable instruments to assess the severity of tinnitus in clinical applications in China.

Cortical Activation Patterns of Different Masking Noises and Correlation With Their Masking Efficacy, Determined by Functional Near-Infrared Spectroscopy.

Acoustic therapy in tinnitus treatment is poorly characterized, and efficacy assessment depends on subjective descriptions. Narrow-band noise, notched sound, and white noise have positive therapeutic effects on monotonous tinnitus. Considering the tonotopic characteristics of the auditory system and the spectral characteristics of these three masking sounds, the activation pattern of the auditory cortex and the mechanism of inhibiting tinnitus may be different. This study aimed to compare the activation patterns of three spectrally different masking noises and study the correlation between the masking effects and variational amplitude of oxygenated hemoglobin (HbO) in the corresponding cortical regions. We also assessed near-infrared spectroscopy brain function imaging (NIRS) as an objective assessment tool in acoustic therapy. Patients with persistent non-pulsatile tinnitus and control volunteers without tinnitus were enrolled in this study. The subjects were seated in a sound-proof room, with two optode arrays covering the bilateral temporal lobe. Auditory stimuli were presented; stimulation sequences followed the block design: different noises appeared randomly and repeated in five cycles. Tinnitus match and residual inhibition were performed in the tinnitus group. The data analyses were conducted using the NIRS_SPM toolbox. The group analysis results showed that the narrow-band noise caused a marginally significant decrease in HbO signal in the Brodmann 21 region (BA21), while white noise caused a significant increase in HbO signal in BA21. Notched sound did not cause significant changes in the HbO signal in the temporal cortex. And none of the three masking noises caused significant changes in the HbR signal in the temporal cortex. The depth of residual inhibition induced by the narrow-band noise and white noise significantly correlated with ΔHbO in the region of interest (ROI). However, neither the depth nor duration of the residual inhibition induced by notched sound correlated with the ΔHbO. Thus, NIRS showed three cortical activation patterns induced by three different masking noises, and correlations between residual inhibition effects and change of HbO amplitude were found. NIRS could therefore be applied in objective assessment of acoustic therapy.

Yolk sac tumor of ear: a case report and literature review of the last 30 years.

Extra-gonadal pure yolk sac tumor of the ear is very rare. We report a case of a yolk sac tumor of the ear and review the English literature in PubMed. The initial complaint was a mass protruding out of the external auditory canal. Computed tomography (CT) showed a large irregularly enhancing isodense mass lesion measuring 42*16 mm in the right external auditory canal, the right mastoid process, and extending to the right back parapharyngeal space with unclear border. Laboratory studies revealed that serum alpha fetoprotein (AFP) was significantly elevated at 664.60 ng/ml (range, 0 to 25 ng/ml), and neuron-specific enolase (NSE) was 28.3 ng/ml (range, 0 to 16.3 ng/ml). After finishing 6 cycles of chemotherapy, the patient underwent a total resection of yolk sac tumor of the ear. In addition, we review the English literature of the yolk sac tumor of the ear.

Smartphone Application WeChat for Clinical Follow-up of Discharged Patients with Head and Neck Tumors: A Randomized Controlled Trial.

BACKGROUND: Nowadays, social media tools such as short message service, Twitter, video, and web-based systems are more and more used in clinical follow-up, making clinical follow-up much more time- and cost-effective than ever before. However, as the most popular social media in China, little is known about the utility of smartphone WeChat application in follow-up. In this study, we aimed to investigate the feasibility and superiority of WeChat application in clinical follow-up. METHODS: A total of 108 patients diagnosed with head and neck tumor were randomized to WeChat follow-up (WFU) group or telephone follow-up (TFU) group for 6-month follow-up. The follow-ups were delivered by WeChat or telephone at 2 weeks, 1, 2, 3, and 6 months to the patients after being discharged. The study measurements were time consumption for follow-up delivery, total economic cost, lost-to-follow-up rate, and overall satisfaction for the follow-up method. RESULTS: Time consumption in WFU group for each patient (23.36 ± 6.16 min) was significantly shorter than that in TFU group (42.89 ± 7.15 min) (P < 0.001); total economic cost in WFU group (RMB 90 Yuan) was much lower than that in TFU group (RMB 196 Yuan). Lost-to-follow-up rate in the WFU group was 7.02% (4/57) compared with TFU group, 9.80% (5/51), while no significance was observed (95% confidence interval [CI]: 0.176-2.740; P = 0.732). The overall satisfaction rate in WFU group was 94.34% (50/53) compared with 80.43% (37/46) in TFU group (95% CI: 0.057-0.067; P = 0.034). CONCLUSIONS: The smartphone WeChat application was found to be a viable option for follow-up in discharged patients with head and neck tumors. WFU was time-effective, cost-effective, and convenient in communication. This doctor-led follow-up model has the potential to establish a good physician-patient relationship by enhancing dynamic communications and providing individual health instructions. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR-IOR-15007498; http://www.chictr.org.cn/ showproj.aspx?proj=12613.

Interleukin-17A promotes MUC5AC expression and goblet cell hyperplasia in nasal polyps via the Act1-mediated pathway.

BACKGROUND: Recent studies demonstrated that nasal polyps (NP) patients in China and other Asian regions possessed distinct Th17-dominant inflammation and enhanced tissue remodeling. However, the mechanism underlying these observations is not fully understood. This study sought to evaluate the association of interleukin (IL)-17A with MUC5AC expression and goblet cell hyperplasia in Chinese NP patients and to characterize the signaling pathway underlying IL-17A-induced MUC5AC expression in vitro. METHOD: We enrolled 25 NP patients and 22 normal controls and examined the expression of IL-17A, MUC5AC and act1 in polyp tissues by immunohistochemical (IHC) staining, quantitative polymerase chain reaction (qPCR) and western blot. Moreover, by using an in vitro culture system of polyp epithelial cells (PECs), IL-17A-induced gene expression was screened in cultured PECs by DNA microarray. The expression of IL-17RA, IL-17RC, act1 and MUC5AC and the activation of the MAPK pathway (ERK, p38 and JNK), were further examined in cultured PECs and NCI-H292 cells by qPCR and western blotting, respectively. RESULTS: We found that increased IL-17A production was significantly correlated with MUC5AC and act1 expression and goblet cell hyperplasia in polyp tissues (p<0.05). IL-17A significantly stimulated the expression of IL-17RA, IL-17RC, act1 and MUC5AC, and the activation of the MAPK pathway in cultured PECs and NCI-H292 cells (p<0.05). In addition, IL-17RA, IL-17RC and act1 siRNA significantly blocked IL-17A-induced MUC5AC production in vitro (p<0.05). CONCLUSION: Our results suggest that IL-17A plays a crucial role in stimulating the production of MUC5AC and goblet cell hyperplasia through the act1-mediated signaling pathway and may suggest a promising strategy for the management of Th17-dominant NP patients.

Biological characteristics of CD133(+) cells in nasopharyngeal carcinoma.

Cancer stem cells are regarded as the cause of tumour formation and recurrence in nasopharyngeal carcinoma (NPC). However, ideal surface markers for stem cells in NPC remain unidentified. In the present study, we investigated the expression of CD133, Nanog and Sox2 in the nasopharyngeal carcinoma cell line CNE2 and primarily cultured NPC cells using immunofluorescence or flow cytometry. A cell population with a CD133(+) phenotype was enriched using magnetic-activated cell sorting technology. We demonstrated that CD133(+) cells exhibited a strong potential for self-renewal, proliferation and differentiation and a greater potential for in vivo tumour formation in nude mice compared to CD133(-) cells, although the percentage of CD133(+) cells was small. However, the specific marker antigens Nanog and Sox2 were simultaneously expressed in normal cancer stem cells. Our results showed that CD133 can serve as a specific surface marker for nasopharyngeal cancer stem cells.

The elevated expression of osteopontin and vascular endothelial growth factor in sinonasal inverted papilloma and its relationship with clinical severity.

BACKGROUND: Osteopontin (OPN) is involved in cell survival, immunity, and tumor progression. The overexpression of OPN has been proposed as a biomarker of progression and metastasis for several tumor types, but it is still unclear whether it is up-regulated in sinonasal inverted papilloma (SIP). METHODS: We enrolled 33 subjects with SIP and 15 normal controls to determine the importance of OPN and vascular endothelial growth factor (VEGF) in SIP. Using immunohistochemistry, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay, we examined the distribution, mRNA expression, and protein levels, respectively, of OPN and VEGF. We then correlated these values with clinical severity. RESULTS: The immunostaining levels for OPN and VEGF were significantly increased in SIP tissues compared with control tissues (p < 0.05), as were their mRNA expression and protein levels (p < 0.05). The correlation between OPN and VEGF expression and the clinical stage of SIP was significant (p < 0.05). CONCLUSION: Our findings indicate that OPN and VEGF were both overexpressed in the analyzed SIP tissues and were associated with clinical severity, suggesting that the OPN-VEGF axis might contribute to tumor progression by enhancing angiogenesis. Therefore, OPN may serve as a potential therapeutic target for preventing SIP progression and recurrence.

Removal of tracheobronchial foreign bodies via suspension laryngoscope and Hopkins telescope in infants.

OBJECTIVES: Tracheobronchial foreign body aspiration is a life-threatening accident in infants, and is still a formidable clinical emergency to both otorhinolaryngologists and anesthesiologists. In this study, we attempted to assess the safety and ease of tracheobronchial foreign body removal in infants via suspension laryngoscopy and Hopkins telescopy under general anesthesia with endotracheal intubation. METHODS: The retrospective clinical study from 2006 to 2010 included 50 infants with foreign body aspiration, of whom 35 underwent suspension laryngoscopy and Hopkins telescopy and the other 15 underwent rigid bronchoscopy. All of the procedures were under general anesthesia with endotracheal intubation. RESULTS: All of the patients underwent temporary extubation. The foreign body was successfully removed in 46 cases and was not found in the other 4 cases. The mean operation time in the rigid bronchoscopy group was 13.20+/-9.01 minutes, and that in the Hopkins telescopy group was 5.79+/-3.54 minutes. The oxygen saturation level was below 90% in 17 cases, of which 7 were in the rigid bronchoscopy group and 10 were in the Hopkins telescopy group. The vital signs, including the partial pressure of carbon dioxide in expiratory gas and the heart rate, were stable in all cases. CONCLUSIONS: Foreign body removal in infants via suspension laryngoscopy and Hopkins telescopy under general anesthesia with endotracheal intubation should be promoted, since it is relatively safe and easy for both anesthesiologists and otorhinolaryngologists to perform and has a remarkable success rate.

[Numerical simulation study on effects of ambient temperature on airflow in the nasal cavity].

OBJECTIVE: To study the aerodynamics of the normal human nasal cavity under different ambient temperatures. METHODS: Based on CT scanning, a model of a healthy adult's nasal cavity was established using computational fluid dynamics software from Fluent. Airflow in this model was simulated and calculated at ambient temperatures of 0 °C, 24 °C, and 37 °C during periodic breathing. RESULTS: Ambient temperature only had an impact on the temperature in the nasal cavity during the inspiratory phase, and the temperature distribution was not symmetrical in the inspiratory acceleration and deceleration phases. The ambient temperature significantly affected airflow speed in main nasal passages during the inspiratory process, but had little impact on flow status (proportion and streamline of airflow in different nasal passages). Temperature differences increased the irregular air movement within sinuses. The anterior nasal segment, including the area between the valve and the head of the middle turbinate, was the most effective part of the nasal airway in heating the ambient air. CONCLUSIONS: Our findings describe the effects of ambient temperature on airflow parameters in the nasal cavity within a single respiratory cycle. This data is more comprehensively and accurately to determine the relationship between nasal cavity aerodynamics and physiological functions.

[A comparative study on numerical simulation of the normal nasal airflow during periodic breathing and steady-state breathing].

OBJECTIVE: To compare the characteristics of normal nasal airflow during periodic breathing and steady-state breathing. METHODS: Fluent software was used to simulate the nasal cavity and paranasal sinus structures following CT scanning of a normal adult subject. Air flow velocity, pressure, distribution and streamlines were calculated and compared during periodic breathing and steady-state breathing. RESULTS: The same flux, the performance of nasal airflow on 15.600 s of periodic breathing and steady-state expiratory (entrance flow was 697.25 ml/s) were as follows: air flow in the common and middle meatus accounted for more than 50% and 30% of total nasal cavity flow during two respiratory status. Flow velocity and pressure of nasal cavity and each paranasal sinus were extremely similar. The flow trace during two respiratory status in the inferior and lower part of the common meatus were predominately straight in form.Flow were parabolic in the middle and superior meatus and the middle and upper parts of the common meatus. The flow trace of nasal airflow on 16.495 s of periodic breathing had wide areas vortex in nasopharynx and limen nasi, the average speed was 0.0706 m/s, while the entrance flow 7.62 ml/s stable state of the left nasal expiratory, the average speed was 0.0415 m/s, the flow trace was similar to 697.25 ml/s. CONCLUSION: The same flow, except in the junction of the respiratory cycle, the performance of normal nasal airflow during periodic breathing and steady-state breathing were similar.

Damage of nasal mucociliary movement after intensity-modulated radiation therapy of nasopharyngeal carcinoma.

BACKGROUND AND OBJECTIVE: Radiation usually results in paranasal sinusitis in patients with nasopharyngeal carcinoma (NPC), which influences patients' quality of life. This study aimed to determine the relationships between dose distribution in the nasal cavity and nasal mucous injury in patients with NPC treated by intensity-modulated radiation therapy (IMRT), and to find the tolerable radiation dose for the nasal mucous. METHODS: Sixty-six patients with NPC treated by IMRT between October 2006 and November 2008 were enrolled. The irradiation dose in the nasal cavity was determined by the computer with the IMRT work platform. Mucociliary transport rate (MTR) was detected by modified saccharine test before IMRT, at the end of IMRT, and at 3, 6, and 12 months after IMRT. RESULTS: The data were available for 129 nasal cavities. The cavities receiving a mean dose below or equal to 37 Gy showed substantial preservation of nasal mucous after IMRT. The MRT decreased to (62.82 ± 38.59)%, (56.78 ± 37.79)%, (64.05 ± 39.37)%, and (71.13 ± 39.55)% of pre-IMRT value at 4 time points after IMRT, with significant differences among the data (P < 0.05). In contrast, when the cavities received a mean dose higher than 37 Gy, no significant differences in MTR among the time points were observed. At 3 months after IMRT, the MTR was the lowest (38.27% of pre-RT value). CONCLUSIONS: A mean radiation dose of ≤ 37 Gy for the nasal cavity is an optimal dose to protect the nasal cavity function.

[Influence of uncinate process on aerodynamic characteristics of nasal cavity and maxillary sinus].

OBJECTIVE: This study aimed to investigate the influence of uncinate process on air flow velocity, trace, distribution, air pressure, as well as the air flow exchange of nasal cavity and paranasal sinuses. METHODS: Fluent software was used to simulate two nasal cavity and paranasal sinus structures following CT scanning, one had normal nasal cavity, the another had the nasal cavity with uncinate process removed. Air flow velocity, pressure, distribution and trace lines were calculated and compared by Navier-Stokes equation and numerically visualized between two models. RESULTS: Air flow of two models in the common and middle meatus accounted for more than 50% and 30% of total nasal cavity flow. Flow velocity of two models were maximal in the common meatus, followed by the middle meatus. The maximal velocity existed on the left nasal district between limen nasi and head of inferior turbinate. The flow traces of two models were similar. In the normal model, the air flow velocity of the district around uncinate process was almost the same in inhale and exhale. In the model with the uncinate process removed, the air flow velocity of the district around uncinate process was faster, the air flow velocity in expiratory phase was quicker. Compared with the normal nasal cavity, there was more exchange of maxillary sinus in the model with cut uncinate process. CONCLUSIONS: In the view of flow dynamics, the uncinate process effects the air flow velocity of the district around uncinate process and the exchange of maxillary sinus, the contribution of nasal flow is connected with the morphosis of the uncinate process.

[Effect of endoscopic sinus surgery on airflow of the nasal cavity and paranasal sinuses: a computational fluid dynamics study.].

OBJECTIVE: To study the airflow velocity, trace, distribution, pressure, as well as the airflow exchange between the nasal cavity and paranasal sinuses in a computer simulation of nasal cavity pre and post virtual endoscopic sinus surgery (ESS). METHODS: Computational fluid dynamics (CFD) technique was applied to construct an anatomically and proportionally accurate three-dimensional nasal model based on a healthy adult woman's nasal CT scans. A virtual ESS intervention was performed numerically on the normal nasal model using Fluent 6.1.22 software. Navier-Stokes and continuity equations were used to calculate and compare the airflow characteristics between pre and post ESS models. RESULTS: (1) After ESS flux in the common meatus decreased significantly. Flux in the middle meatus and the connected area of opened ethmoid sinus increased by 10% during stable inhalation and by 9% during exhalation. (2) Airflow velocity in the nasal sinus complex increased significantly after ESS. (3) After ESS airflow trace was significantly changed in the middle meatus. Wide-ranging vortices formed at the maxillary sinus, the connected area of ethmoid sinus and the sphenoid sinus. (4) Total nasal cavity resistance was decreased after ESS. (5) After ESS airflow exchange increased in the nasal sinuses, most markedly in the maxillary sinus. CONCLUSIONS: After ESS airflow velocity, flux and trace were altered. Airflow exchange increased in each nasal sinus, especially in the maxillary sinus.

Computational fluid dynamics simulation of airflow in the normal nasal cavity and paranasal sinuses.

BACKGROUND: This study aimed to investigate airflow velocity, trace, distribution, and air pressure, as well as the airflow exchange between the nasal cavity and paranasal sinus in a normal subject using computational fluid dynamics. METHODS: Fluent software is used to simulate nasal cavity and paranasal sinus structure after CT scanning of a normal adult subject. Airflow velocity, pressure, distribution, and trace lines were calculated by Navier-Stokes equation and numerically visualized. RESULTS: Airflow in the common and middle meatus accounted for >50 and 30% of total nasal cavity flow. Flow velocity was maximal in the common meatus, followed by the middle meatus. Flow velocity and flux in each paranasal sinus was extremely low. The flow trace in the inferior and lower part of the common meatus was predominately straight in form. Flow was parabolic in the middle and superior meatus and the middle and upper parts of the common meatus. Air pressure was high at the front end of the inferior and middle turbinate and the uncinate process. There was little pressure difference/flow exchange between inner and outer aspects of the paranasal sinus. CONCLUSION: The major airflow forms are straight (lower common and inferior meatus) and parabolic (middle and upper common meatus and middle superior). Flow force is strongest at the front end of the inferior and middle turbinate and uncinate process. There is very little exchange between the paranasal sinus and the nasal cavity during stable airflow.

Numerical flow simulation in the post-endoscopic sinus surgery nasal cavity.

In this study we utilized computational fluid dynamic (CFD) techniques to construct a numerical simulation of nasal cavity airflow pre and post virtual functional endoscopic surgery (FESS). A healthy subject was selected, and CFD techniques were then applied to construct an anatomically and proportionally accurate three-dimensional nasal model based on nasal CT scans. A virtual FESS intervention was performed numerically on the normal nasal model using Fluent software. Navier-Stokes and continuity equations were used to calculate and compare airflow, velocity, distribution and pressure in both the pre and post FESS models. In the post-FESS model, there was an increase in airflow distribution in the maxillary, ethmoid and sphenoid sinuses, and a 13% increase through the area connecting the middle meatus and the surgically opened ethmoid. There was a gradual decrease in nasal resistance in the posterior ethmoid sinus region following FESS. These findings highlight the potential of this technique as a powerful preoperative assessment tool to aid clinical decision-making.