Tong Wang

Numerical simulation of normal nasal cavity airflow in Chinese adult: a computational flow dynamics model

Our purpose is to simulate the airflow inside the healthy Chinese nose with normal nasal structure and function by computational fluid dynamics (CFD) method and to analyze the relationship between the airflow and physiological function. In this study, we used the software MIMICS 13.0 to construct 20 3-dimensional (3-D) models based on the computer tomography scans of Chinese adults’ nose with normal nasal structure and function. Thereafter, numerical simulations were carried out using the software FLUENT 6.3. Then the characteristics of airflow inside the airway and sinuses were demonstrated qualitatively and quantitatively in steady state. We found that during the inhalation phase, the vortices and turbulences were located at anterior part and bottom of the nasal cavity. But there is no vortex in the whole nasal cavity during the expiratory phase. The distributions of pressure and wall shear stress are different in two phases. The maximum airflow velocity occurs around the plane of palatine velum during both inspiratory and expiratory phases. After the airflow passed the nasal valve, the peak velocity of inhaled airflow decreases and it increases again at the postnaris. Vice versa, the exhaled airflow decelerates after it passed the postnaris and it accelerates again at nasal valve. The data collected in this presentation validates the effectiveness of CFD simulation in the study of airflow in the nasal cavity. Nasal airflow is closely related to the structure and physiological functions of the nasal cavity. CFD may thus also be used to study nasal airflow changes resulting from abnormal nasal structure and nasal diseases.

Effects of septal deviation on the airflow characteristics: Using computational fluid dynamics models

Abstract Conclusions: Computational fluid dynamics (CFD) methods can provide detailed information on airflow characteristics in models of septal deviation. Different locations of septal deviation lead to variation of nasal airflow. Both the location of the septal deviation and the inferior turbinate hypertrophy in the concave side may play an important role in airflow patterns and airflow velocity. Objective: To investigate the airflow patterns and air velocity in different septal deviation models during inspiration, using CFD methods. Methods: Commercial software was used to construct three-dimensional (3D) models of nasal cavities with paranasal sinuses from the computed tomography (CT) scans of 15 patients with septal deviation and 4 controls. Considering the location of the most prominent point of the nasal septum, patients were classified into caudal, anterior, and media deviation groups. Results: Unlike airflow in the controls, airflow in the septal deviation models showed asymmetry in bilateral nasal cavities. The airflow patterns varied in the convex and concave sides in different septal deviation models. Caudal septal deviation models had the maximal peak velocity, while the the minimal peak velocity was found in the media deviation models. The peak velocity was not always located in the convex side, but was sometimes in the concave side.

A modified septoplasty with three high tension lines resection

Conclusion: The modified septoplasty with three tension lines resection is an effective and well-tolerated procedure, which can improve the objective and subjective outcomes, and provide a good approach that is applicable for various septal deviations, especially caudal deviation. Objectives: According to the biomechanics of the septal deviation, a modified septoplasty with three high tension lines resection was redefined. The purpose of this study was to review the surgical technique and objective and subjective outcomes. Methods: A retrospective review was conducted to identify patients undergoing septoplasty between 2005 and 2006 at Beijing Tongren Hospital. The records were reviewed for demographic data, intraoperative technique, surgical indications, objective and subjective outcomes, and postoperative complications. Results: A total of 54 patients were identified. The follow-up period ranged from 6 to 12 months. Indications for septoplasty included nasal obstruction (40.7%) and access (59.3%). The data showed that both the objective and subjective outcomes improved after septoplasty. Complications included transient dental pain/hypesthesia (5.6%), synechiae formation (7.4%), epistaxis (1.9%), septal hematoma (3.7%), asymptomatic septal perforation (0%), and nasal deformity (0%).

Eosinophilic Angiocentric Fibrosis of the Nasal Septum

Background. Eosinophilic angiocentric fibrosis (EAF) is a rare benign condition of unknown aetiology that causes stenosis of the upper respiratory tract. It is most commonly found at the nasal septum and sinus mucosa causing mucosal thickening and nasal obstructive symptoms. The diagnosis is mainly based on characteristic histologic findings. Case Report. A 27-year-old young woman presented with a slow growing mass at her anterior nasal septum for over eight years. She complained of persistent nasal obstruction, epistaxis, sometimes diffused facial pain, and chronic headache. 3 years ago, the tumor was partially resected for ventilation and a nasal septum perforation was left. Imaging findings indicated soft-tissue thickening of the anterior part of septum and adjacent lateral nasal walls. Pathological examination showed numerous inflammatory cells infiltrates containing eosinophils, fibroinflammatory lesion with a whorled appearance fibrosis which typically surrounded vessels. A diagnosis of eosinophilic angiocentric fibrosis was made. All laboratory tests were unremarkable. Skin prick test was positive. The tumor-like lesion was totally resected. Conclusions. EAF is a rare benign and progressive disorder causing destruction. Combined with radiological imaging of EAF historical findings contribute to the diagnosis. It is important to prevent tumor from recurrence by total resection of the lesion.

Aerodynamic investigation of the correlation between nasal septal deviation and Chronic rhinosinusitis

To compare the aerodynamic differences around ostiomeatal complex between the convex side and concave side in patients with concurrent nasal septal deviation and chronic rhinosinusitis, and to explore the potential correlation between nasal septal deviation and chronic rhinosinusitis occurrence from the perspective aerodynamics.

Combined endoscope-assisted translabyrinthine subtemporal keyhole approach for vestibular Schwannoma and auditory midbrain implantation: Cadaveric study

Abstract Conclusions: The combined endoscope-assisted translabyrinthine subtemporal keyhole approach can expose the internal auditory canal, cerebellopontine, and inferior colliculus satisfactorily in the same surgical setting. As a minimally invasive approach, this can be considered an effective method for removal of vestibular schwannoma and auditory midbrain implantation in the same surgical setting, while avoiding retraction of the cerebellum and serious adverse events and complications. Objectives: Patients with neurofibromatosis type II are the initial candidates for auditory midbrain implantation; the appropriate surgical approach should allow for tumor removal and electrode implantation in the same surgical setting. Here, we demonstrate the possibility of the combined endoscope-assisted translabyrinthine subtemporal keyhole approach to achieve this aim. Methods: Five formalin-fixed cadaver heads were used to simulate surgical procedures in 10 sides, by means of microscopy and endoscopy. The relationship between concerned structures was identified. Results: With the help of an endoscope, we exposed the internal auditory canal and cerebellopontine through a translabyrinthine approach and the inferior colliculus through a subtemporal keyhole approach. This double approach can be combined to expose the internal auditory canal and cerebellopontine and inferior colliculus satisfactorily in the same surgical setting. This combined approach can avoid retraction of the cerebellum and reduce serious adverse events and complications.

Apnea–hypopnea index decreased significantly after nasal surgery for obstructive sleep apnea: A meta-analysis

Background: Nasal surgeries have been applied to obstructive sleep apnea (OSA) patients with nasal obstruction for decades. However, the efficiency of nasal surgery in improving OSA remains controversial. The aim of this study was to identify whether isolated nasal surgery can improve apnea–hypopnea index (AHI). Methods: Computerized searches were performed in MEDLINE, Web of Science, Cochrane Library, and Scopus from January 1, 2000 to April 30, 2016. A total of 18 articles and 587 participants were included. There were 1 randomized controlled trials, 2 nonrandomized trials, 11 prospective studies, and 4 retrospective studies. Data regarding study design (prospective/retrospective clinical trial, randomized, and controlled), population size, participant characteristics (age, gender, and body mass index), surgical intervention, and outcomes (AHI, Epworth sleep scale [ESS]) was collected. Results: Statistically significant improvement in AHI (subgroup 1: weighted mean difference [WMD] [95%confidence interval (CI)], −4.17 [−7.62, −0.73]; subgroup 2: WMD [95%CI], −4.19 [−7.51, −0.88]; overall: WMD [95%CI], −4.15 [−6.48, −1.82]) and ESS (subgroup 1: WMD [95%CI], −2.14 [−3.08, −1.19]; subgroup 2: WMD [95%CI], −4.70 [−5.95, −3.44]; overall: WMD [95%CI], −4.08 [−5.27, −2.88]) was revealed. Conclusion: Both AHI and ESS improved significantly after isolated nasal surgery, but the improvement of AHI is slightly significant. Future randomized controlled trials are needed to confirm the long-term benefits of nasal surgery on OSA.

Polysomnographic effect of nasal surgery on positional and non-positional obstructive sleep apnea/hypopnea patients

Abstract Conclusion: The polysomnographic (PSG) effects of nasal surgery on positional obstructive sleep apnea/hypopnea syndrome (OSAHS) patients (PPs) and non-positional OSAHS patients (NPPs) were different. Objective: We aimed to determine the PSG data changes after nasal surgery and evaluate the PSG effect of nasal surgery on PPs and NPPs, respectively. Methods: A total of 79 OSAHS patients with nasal obstruction were recruited. Preoperative rhinomanometry and overnight polysomnography were recorded. Patients were distributed into three groups based on the severity level of the apnea and hypopnea indexes (AHI) (mild, moderate, and severe OSAHS). Three groups were each subdivided into two subgroups (PPs and NPPs). Postoperative data were obtained at least 6 months later. Results: After surgery, although nasal resistance decreased significantly in all patients, the total rate of success and response in treating OSAHS was only 22.7%. Grouped on the basis of the severity level of AHI, the lowest SpO2 increased and AHI, supine AHI, and arousal indexes decreased significantly only in mild OSAHS (p < 0.05). Subdivided according to the presence or absence of positional dependency, the lowest SpO2 increased and supine AHI decreased significantly in both PPs and NPPs with mild OSAHS and in PPs with moderate OSAHS (p < 0.05). AHI significantly increased in PPs with severe OSAHS (p < 0.05). Supine sleep time was relatively prolonged significantly in PPs with moderate and severe OSAHS (p < 0.05).

Olfactory event-related potential in patients with rhinosinusitis-induced olfactory dysfunction.

Background Olfactory disorders are a common syndrome in the rhinology clinic. Olfactory event–related potential (OERP) has been considered as an important alternative method to evaluate olfactory function. The aim of this study was to find the consistency of OERP and the psychophysics olfactory test (T&T olfactometry assessment) in rhinosinusitis patients with or without nasal polyposis. Methods Both the psychophysics olfactory test and the OERP were performed in all patients before functional endoscopic sinus surgery (FESS). Detailed information including demographic, comorbidity, subjective symptoms, CT, and endoscopic examination were recorded. Six months later, the T&T test and OERP were reexamined in patients with preoperative identified OERP. Results Preoperative OERP was identified in 26 patients of the nonpolyp group and 12 patients of the polyp group. Good correlation existed between T&T scores and amplitude and latency of N1 and P2 in 26 nonpolyp patients (p < 0.05). No meaningful correlation was apparent in 12 polyp patients (p > 0.05). Significant correlation existed in 7 polyp patients with a free olfactory cleft (OC) according to CT (p < 0.05). The other 5 patients with partial OC obstruction were anosmic according to the psychophysics olfactory test; however, OERP was present. Six months later, T&T scores decreased significantly only in these five patients (p < 0.05). Significant correlation was obtained between postoperative T&T scores and OERP in both polyp and nonpolyp groups (p < 0.05). Conclusion OERP can be used to investigate olfactory function of rhinosinusitis patients. Nasal polyp obstruction in specific parts of the OC might influence the consistency between the psychophysics olfactory test and OERP.

Airflow and temperature distribution inside the maxillary sinus: A computational fluid dynamics simulation

Abstract Conclusion: The airflow velocity and flux in maxillary sinuses were much lower than those in the nasal cavity, and the temperature in maxillary sinuses was much higher than the temperature in the middle meatus. With the increase of maximum diameter of the ostium, the above indices changed little. Objectives: The purpose of the paper was to investigate, first, the flow and temperature distribution inside normal maxillary sinus in inspiration, and second, flow and temperature alteration with the increase of maximum ostium diameter. Methods: Three-dimensional models with nasal cavities and bilateral maxillary sinuses were constructed for computational fluid dynamics analysis. Virtual surgeries were implemented for the maxillary ostium, the maximum diameters of which were 8, 10, 12, and 15 mm, respectively. The finite volume method was used for numerical simulation. The indices of velocity, pressure, vector, and temperature were processed and compared between models. Results: The airflow velocity in maxillary sinuses (average velocity 0.062 m/s) was much lower than that in the middle meatus (average velocity 3.26 m/s). With the increase of ostium diameter, airflow characteristics distributed in the maxillary sinuses changed little. The normal temperature in the maxillary sinus remained almost constant at 34°C and changed little with the increase of ostium diameter.