Numerical simulation of soft palate movement and airflow in human upper airway by fluid-structure interaction method

In this paper, the authors present airflow field characteristics of human upper airway and soft palate movement attitude during breathing. On the basis of the data taken from the spiral computerized tomography images of a healthy person and a patient with Obstructive Sleep Apnea-Hypopnea Syndrome （OSAHS）, three-dimensional models of upper airway cavity and soft palate are reconstructed by the method of surface rendering. Numerical simulation is performed for airflow in the upper airway and displacement of soft palate by fluid-structure interaction analysis. The reconstructed threedimensional models precisely preserve the original configuration of upper airways and soft palate. The results of the pressure and velocity distributions in the airflow field are quantitatively determined, and the displacement of soft palate is presented. Pressure gradients of airway are lower for the healthy person and the airflow distribution is quite uniform in the case of free breathing. However, the OSAHS patient remarkably escalates both the pressure and velocity in the upper airway, and causes higher displacement of the soft palate. The present study is useful in revealing pathogenesis and quantitative mutual relationship between configuration and function of the upper airway as well as in diagnosingdiseases related to anatomical structure and function of the upper airway.

Evaluation of Airway Obstruction at Soft Palate Level in Male Patients with Obstructive Sleep Apnea/Hypopnea Syndrome:Dynamic 3-Dimensional CT Imaging of Upper Airway

This study examined the dynamic characteristics of upper airway collapse at soft palate level in patients with obstructive sleep apnea/hypopnea syndrome（OSAHS） by using dynamic 3-Dimensional（3-D） CT imaging.A total of 41 male patients who presented with 2 of the following symptoms,i.e.,daytime sleepiness and fatigue,frequent snoring,and apnea with witness,were diagnosed as having OSAHS.They underwent full-night polysomnography and then dynamic 3-D CT imaging of the upper airway during quiet breathing and in Muller＇s maneuver.The soft palate length（SPL）,the minimal cross-sectional area of the retropalatal region（mXSA-RP）,and the vertical distance from the hard palate to the upper posterior part of the hyoid（hhL） were compared between the two breathing states.These parameters,together with hard palate length（HPL）,were also compared between mild/moderate and severe OSAHS groups.Association of these parameters with the severity of OSAHS [as reflected by apnea hypopnea index（AHI） and the lowest saturation of blood oxygen（LSaO2）] was examined.The results showed that 31 patients had severe OSAHS,and 10 mild/moderate OSAHS.All the patients had airway obstruction at soft palate level.mXSA-RP was significantly decreased and SPL remarkably increased during Muller＇s maneuver as compared with the quiet breathing state.There were no significant differences in these airway parameters（except the position of the hyoid bone） between severe and mild/moderate OSAHS groups.And no significant correlation between these airway parameters and the severity of OSAHS was found.The position of hyoid was lower in the severe OSAHS group than in the mild/moderate OSAHS group.The patients in group with body mass index（BMI）≥26 had higher collapse ratio of mXSA-RP,greater neck circumference and smaller mXSA-RP in the Muller＇s maneuver than those in group with BMI26（P0.05 for all）.It was concluded that dynamic 3-D CT imaging could dynamically show the upper airway changes at soft palate level in OSAHS patients.All the OSAHS patients had airway obstruction of various degrees at soft palate level.But no correlation was observed between the airway change at soft palate level and the severity of OSAHS.The patients in group with BMI≥26 were more likely to develop airway obstruction at soft palate level than those with BMI26.

Numerical analysis of respiratory flow patterns within human upper airway

A computational fluid dynamics （CFD） approach is used to study the respiratory airflow dynamics within a human upper airway. The airway model which consists of the airway from nasal cavity, pharynx, larynx and trachea to triple bifurcation is built based on the CT images of a healthy volunteer and the Weibel model. The flow character- istics of the whole upper airway are quantitatively described at any time level of respiratory cycle. Simulation results of respiratory flow show good agreement with the clinical mea- sures, experimental and computational results in the litera- ture. The air mainly passes through the floor of the nasal cavity in the common, middle and inferior nasal meatus. The higher airway resistance and wall shear stresses are distrib- uted on the posterior nasal valve. Although the airways of pharynx, larynx and bronchi experience low shear stresses, it is notable that relatively high shear stresses are distrib- uted on the wall of epiglottis and bronchial bifurcations. Besides, two-dimensional fluid-structure interaction models of normal and abnormal airways are built to discuss the flow-induced deformation in various anatomy models. The result shows that the wall deformation in normal airway is relatively small.

Computational Fluid Dynamics Simulation of the Upper Airway of Obstructive Sleep Apnea Syndrome by Muller Maneuver

This study aimed to use computer simulation to describe the fluid dynamic characteristics in patients with obstructive sleep apnea syndrome（OSAS） and to evaluate the difference between during quiet respiration and the Muller maneuver（MM）. Seven patients with OSAS were involved to perform computed tomographic（CT） scanning during quiet respiration and the MM. CT data in DICOM format were transformed into an anatomically three-dimensional computational fluid dynamics（CFD） model of the upper airway. The velocity magnitude, relative pressure, and flow distribution were obtained. Numerical simulation of airflow was performed to discuss how the MM affected airflow in the upper airway. To measure the discrepancy, the SPSS19.0 software package was utilized for statistic analysis. The results showed that the shape of the upper airway became narrower, and the pressure decreased during the MM. The minimal cross-sectional area（MCSA） of velopharynx was significantly decreased（P〈0.05） and the airflow velocity in MCSAs of velopharynx and glossopharynx significantly accelerated（P〈0.05） during the MM. This study demonstrated the possibility of CFD model combined with the MM for understanding pharyngeal aerodynamics in the pathophysiology of OSAS.

Computational Analysis of Airflow in Upper Airway under Light and Heavy Breathing Conditions for a Realistic Patient Having Obstructive Sleep Apnea

Background:Obstructive sleep apnea is a sleeping disorder that has troubled a sizeable population.There is an active area of research on obstructive sleep apnea that intends to better understand airflow behaviors and therefore treat patients more effectively.This paper aims to investigate the airflow characteristics of the upper airway in an obstructive sleep apnea(OSA)patient under light and heavy breathing conditions by using Turbulent Kinetic Energy(TKE),an accurate method in expressing the flow concentration mechanisms of sleeping disorders.It is important to visualize the concentration of flow in the upper airway in order to identify the severity level of the obstruction during sleep.Methods:Computational fluid dynamic(CFD)analysis was used as a solution tool to evaluate the airflow during light and heavy breathing conditions.A medical imaging technique was used to extract the 3D model from the CT scan images.Additionally,mesh generation and simulation were carried out via CFD software to evaluate the light and heavy breathing characteristics related to obstructive sleep apnea.Steady state Reynold’s averaged Navier-Stoke(RANS)with the k-ωshear stress transport(SST)turbulence model was utilized.The airflow characteristics were quantified using parameters such as pressure distribution,skin friction coefficient,velocity profile,Reynolds number,turbulent Reynolds number and turbulence kinetic energy.Results:Contour plots at different planes were used to visualize the airflow distribution as it passed through different cross-sectional areas of the airway.The results revealed that the presence of a smaller cross-sectional area of the airway caused an increase in airflow parameters,especially during heavy breathing.Furthermore,turbulent airflow conditions along the airway were noticed during heavy breathing.The severity of OSA could be measured by the turbulent kinetic energy which is able to show the behavior and concentration of mean flow.This study is expected to provide crucial and important results by visualizing the concentration of airflow mechanisms and characteristics of a patient’s airway during light and heavy breathing. These findings enable TKE to be used as a new tool for characterizing theseverity of obstructive sleep apnea in the upper airways of patients.

Upper Airway Changes after Maxillary Distraction Osteogenesis in Cleft Lip and Palate Patients

Purpose: To measure the upper airway changes associated with maxillary distraction osteogenesis in cleft lip and palate patients in the immediate post operative period and 12 months later. Materials and Methods: Seven patients with repaired cleft lip and palate (CLP) presented with severe maxillary hypoplasia. They were examined initially at T1 predistraction phase. Records taken included radiographs (orthopantograms OPG, lateral cephalometric, posteroanterior). Cephalometric analysis was done to evaluate the upper airway. Mean age is 17 years and the reverse overjet > 6 mm. They underwent maxillary Le Fort I distraction using external rigid distracters (RED). Cephalometric analysis to evaluate the upper airway was repeated at the end of the consolidation phase T2 and twelve months after distractor removal T3. Results: The range of maxillary advancement was between 8 - 15 mm (mean 9 mm). The anteroposterior distance of the superior velopharynx (PPS) and middle velopharynx (SPPS) increased at T2. A small amount of reduction in these values was recorded at T3. The inferior velopharynx (MPS) and the oropharynx (IPS, EPS) showed minimum increase in anteroposterior distance in only two patients at T2 and no change at T3. Conclusion: All seven patients showed clinical improvement in the upper airway and an increase in the upper airway values on lateral cephalometric radiographs.

Strategies for Segmenting the Upper Airway in Cone-Beam Computed Tomography (CBCT) Data

The wide availability, low radiation dose and short acquisition time of Cone-Beam CT (CBCT) scans make them an attractive source of data for compiling databases of anatomical structures. However CBCT has higher noise and lower contrast than helical slice CT, which makes segmentation more challenging and the optimal methods are not yet known. This paper evaluates several methods of segmenting airway geometries (nares, nasal cavities and pharynx) from typical dental quality head and neck CBCT data. The nasal cavity has narrow and intricate passages and is separated from the paranasal sinuses by thin walls, making it is susceptible to either over- or under-segmentation. The upper airway was split into two: the nasal cavity and the pharyngeal region (nasopharynx to larynx). Each part was segmented using global thresholding, multi-step level-set, and region competition methods (the latter using thresholding, clustering and classification initialisation and edge attraction techniques). The segmented 3D surfaces were evaluated against a reference manual segmentation using distance-, overlap- and volume-based metrics. Global thresholding, multi-step level-set, and region competition all gave satisfactory results for the lower part of the airway (nasopharynx to larynx). Edge attraction failed completely. A semi-automatic region-growing segmentation with multi-thresholding (or classification) initialization offered the best quality segmentation. With some minimal manual editing, it resulted in an accurate upper airway model, as judged by the similarity and volumetric indices, while being the least time consuming of the semi-automatic methods, and relying the least on the operator’s expertise.

Large isolated fibrous tumors in the upper esophagus: A case report

BACKGROUND Solitary fibrous tumors(SFT)are rare spindle cell tumors that are usually benign.A total of 10 cases of SFTs in the upper esophagus have ever been reported.Here,we report the anesthetic management of a patient with a large isolated fibrous tumor of the upper esophagus compressing the tracheal membrane.We also provide a literature review of the current research.CASE SUMMARY We report the case of a 49 year old male with“cough aggravation and wheezing after exercise”,who underwent esophagectomy for a large isolated fibrous tumor compressing the tracheal membrane in the upper esophagus.We advise the use of a single-lumen tube with a blocker in patients with difficult airways to reduce the incidence of airway injury and fibrinoscopy at all stages of the perioperative period to guide airway management.This case study is the first report of the anesthetic management of a large,isolated fibrous tumor compressing the tracheal membrane in the upper esophagus.CONCLUSION This rare case emphasizes the importance of perioperative management of anesthesia in patients with large isolated fibrous tumors of the upper esophagus that compress the tracheal membrane.The use of blocker reduce the incidence of airway injury and fibrinoscopy at the perioperative period to guide airway mana-gement.

Exploration on the Treatment of Upper Airway Cough Syndrome Based on the Pathogenesis of Hidden Pathogen(Evil)

Upper airway cough syndrome refers to a clinical syndrome with chronic cough as the main manifestation caused by the reverse flow of secretions from various upper airway diseases such as allergic rhinitis,rhino-sinusitis,adenoid hypertrophy and other parts of the nose and pharynx.Professor Yin Dan believes that the main disease of upper airway cough syndrome is due to cold fluid retained in lung,blood stasis endogenous,compound feeling of wind evil.The pathogenesis is external wind evil and the hidden pathogen together to cause the disease.In the treatment,the warm cold fluid retention is the core,accompanied by the activation of blood and wind,so that the wind evil can go away,the cold evil can be warmed,the phlegm can be removed,and the blood stasis can be dispersed,so as to achieve the purpose of treating the upper airway cough syndrome of the children’s cold fluid retention in lung.

Drinking a Structured Water Product on Markers of Hydration,Airway Health and Heart Rate Variability in Thoroughbred Racehorses:a Small-scale,Clinical Field Trial

Racehorses in training are in situations of repeated stress that may have effects on hydration and health.It was hypothesized that daily consumption of a structured water(SW)product for 4 weeks will result in improved hydration,improved upper airway health and increased heart rate variability.Two groups of Thoroughbred racehorses matched for physiological,training and racing attributes were studied for 4 weeks.One group(n=17)received 10 L(about 15%)of their daily water as SW(followed by ad libitum filtered deep well water)and the control group(n=15)only filtered deep well water.Blood samples and bioelectrical impedance analysis(BIA)measures were obtained at baseline,2 and 4 weeks.Hydration was assessed using BIA.The upper airway was assessed by nasopharyngeal endoscopy at baseline and weekly within 60 minutes of breezing.On weekly breeze days heart rate was recorded at rest,during exercise and recovery and data were analysed for heart rate variability.Compared to controls,horses drinking SW showed increased hydration improved upper airway health post-breezing and increased heart rate variability.It is concluded that drinking 10 L daily of SW increased hydration and may have conferred some wellness benefits.

Upper respiratory tract disease and bronchial asthma

930119 Lung sound analysis of upper airwayobstruction.SHI Yi(施毅),et al.Dept RespirMed,General Hosp,Nanjing Command,210002.Chin J Tuberc & Respir Dis 1992;15(4):228-230.The frequency spectrum of stridor was stud-ied by the computer program in the patientswith upper airway obstruction.The resultsshowed that the peak frequency of respiratorysound increased significantly,the frequencyspectrum got wider and moved to the high fre-quency area above 200Hz and the E ratio wassmaller than 1.These changes were more ap-

11.3.Upper respiratory tract disease and bronchial asthma

920096 A clinical trial of treating asthma ofmoderate severity with beclomethason dip-ropionate aerosol.SHEN Xun (沈勋),et al.DeptPulmon Med,Zhongshan Hosp,Shanghai MedUniv,200032.Chin J Intern Med 1991; 30 (9):536-538.In order to investigate the efficacy of steroidinhalation in treating asthma of moderate sever-

Twin-block在骨性Ⅱ类错[牙合]下颌后缩患儿中的应用

目的:探讨Twin-block在骨性Ⅱ类错[牙合]下颌后缩患儿中的应用效果。方法:选取2019年1月-2021年1月笔者医院接收的84例骨性Ⅱ类错[牙合]下颌后缩患儿设置为研究对象,按随机抽签法分为对照组、研究组,各42例,对照组采用直丝弓矫治器,研究组采用Twin-block矫治器。比较两组治疗前后咀嚼功能、牙齿咬合力、下颌骨变化、软组织面型变化、上气道矢状径,并统计家属治疗满意度。结果:治疗后,研究组咀嚼功能、牙齿咬合力、下颌骨变化指标、软组织面型变化指标均优于对照组(P<0.05);治疗后,研究组上气道矢状径高于对照组(P<0.05);研究组家属治疗满意度(95.24%)明显高于对照组(73.81%)(P<0.05)。结论:Twin-block应用于骨性Ⅱ类错[牙合]下颌后缩患儿治疗中,能改善咀嚼功能,增强牙齿咬合力,促进下颌骨生长,提高面型美观度,扩大上气道矢状径,利于改善呼吸功能,获得家属对治疗效果的高度评价。

上气道CT矢状数据在阻塞性睡眠呼吸暂停综合征诊疗中价值及应用

目的:探讨通过上气道CT来了解阻塞性睡眠呼吸暂停综合征(OSAHS)患者呼吸阻塞平面及病情严重程度的方法。方法:51例患者作多导睡眠监测图监测及上气道CT扫描,并行三维重建,测量上气道矢状位中颏下舌骨距离、软腭长度、舌骨平面C4前角距离及最小生命间隙,同时进行各测量值与体重指数、最低血氧饱和度(LSaO_(2))及呼吸暂停低通气指数(AHI)的相关性分析。结果:颏下舌骨距离与AHI及LSaO_(2)无相关(P>0.05),最小生命间隙(LC)与AHI呈负相关(P<0.05),与LSaO_(2)无相关(P>0.05);软腭长度与AHI呈正相关(P<0.01),与LSaO_(2)负相关(P<0.01);气道最小面积及舌骨平面C4前角距离与AHI均呈负相关(P<0.01),与LSaO_(2)均呈正相关(P<0.01),结论:上气道矢状位CT中的软腭长度、最小生命间隙、气道最小面积及舌骨平面C4前角距离对OSAHS病情的轻重判别有意义,能快速初步判定其阻塞平面。

无托槽隐形矫治器在儿童前牙美学治疗中的应用效果及对舒适满意度和咀嚼功能的影响

目的:研究无托槽隐形矫治器在儿童前牙美学治疗中的效果,并观察是否影响患儿的舒适满意度及咀嚼功能。方法:本文采用前瞻性研究,选择笔者医院2018年1月-2022年1月行前牙正畸治疗的86例患者为研究对象,随机将患者分为观察组和对照组,每组43例。观察组患儿采取无托槽隐形矫治器矫治,对照组患儿采取传统固定矫治器矫治。比较两组患儿的治疗美学效果、咀嚼指标、上气道形态、颞下颌关节、矫治测量指标以及并发症之间的差异。结果:观察组患儿的前牙美学分类为Ⅰ类的比例显著高于对照组(P<0.05);治疗后,两组患儿的美观度、舒适度、固定力、语言功能满意度以及咀嚼效率评分均显著提升,且观察组患儿评分均显著高于对照组(P<0.05);L1MP、SNA、LPW、UPW方面,两组患儿均改善明显,且观察组较对照组更优(P<0.05);两组患儿的关节窝深度、关节结节倾斜角、髁突长轴、矢状面倾斜角、髁突上部高、髁突相对位置显著改善,且观察组的相关指标均优于对照组(P<0.05);两组患儿的U1-NA、L1-NB、U1-APg、U6-PtPNS均显著降低,且观察组显著低于对照组(均P<0.05);两组患儿的牙龈感染、周围组织炎症反应、口腔不适发生概率比较,差异无统计学意义(P>0.05)。结论:无托槽隐形矫治器应用于儿童前牙美学治疗中,能显著提升患儿舒适满意度和咀嚼功能,治疗效果显著。

从痰论治小儿上气道咳嗽综合征中医研究概况及思考

上气道咳嗽综合征(upper airway cough syndrome, UACS)是引起儿童慢性咳嗽的主要原因之一,西医治疗该病方式较单一且复发率较高。中医结合小儿体质、喂养特点、发病及临床表现,发现患儿发病与“痰邪”密切相关。临床诊疗中,“从痰”论治该病具有较好的疗效且具备复发率低、不良反应少的优势。

拔牙矫治对成年骨性Ⅱ类高角错[牙合]患者上气道及周围组织的影响

目的:通过对比骨性Ⅱ类高角错[牙合]成年患者拔牙和不拔牙矫治前后上气道形态、舌骨位置和颅颌面结构的变化,分析拔牙矫治对该类患者上气道形态结构的影响,为其临床治疗方案的选择提供理论依据。方法:收集就诊于吉林大学口腔医院正畸科已完成正畸治疗的骨性Ⅱ类高角错[牙合]成年患者60例,根据是否进行减数矫治分为拔牙组和非拔牙组,每组30例,对2组患者的临床资料进行回顾性分析。获取患者治疗前后的头颅定位侧位片,应用Dolphin软件对患者上气道形态、舌骨位置和颅颌面组织结构进行定点描绘和测量,采用SPSS 23.0统计软件对相关测量数据进行统计学分析。结果:与矫治前比较,矫治后拔牙组患者悬雍垂尖与中咽壁点的距离(U-MPW)、会厌谷点与下咽壁点的距离(V-LPW)、上中切牙长轴与前颅底平面的下内交角(U1-SN)和下中切牙长轴与下颌平面的上内交角(L1-MP)明显减小(P<0.05),[牙合]平面与前颅底平面的夹角(OP-SN)和上下中切牙长轴之间的夹角(U1-L1)明显增大,(P<0.05),其余测量指标差异无统计学意义(P>0.05);与矫治前比较,矫治后非拔牙组患者矫治后上牙槽座点-鼻根点-下牙槽座点角(ANB)明显减小(P<0.05),OP-SN和L1-MP明显增大(P<0.05),其余测量指标差异无统计学意义(P>0.05)。结论:成年骨性Ⅱ类高角错[牙合]患者在拔牙矫治后上气道矢状径变窄,主要发生在上气道口咽段和喉咽段,而舌骨位置未发生明显改变。

双颌手术后骨性Ⅲ类患者上气道、自然头位和舌骨位置变化的三维评估

目的本研究旨在评估双颌手术后骨性Ⅲ类患者上气道、自然头位和舌骨位置的短期和长期变化。方法在这项回顾性研究中,对骨性Ⅲ类患者分别在手术前(T0)、手术后3个月(T1)和手术后2年(T2)拍摄锥形束CT(cone⁃beam computed tomography,CBCT)。创建三维图像以评估术后变化,并分析上气道、自然头位和舌骨之间的相关性。结果对30例接受双颌手术的骨性Ⅲ类患者(男13例和女17例)进行了评估,他们的平均年龄为21岁(17~30岁)。T1和T2后,腭咽段、舌咽段和总上气道的体积明显缩小。下颌骨位置的变化与上气道体积的变化之间存在明显的相关性(P<0.05)。NSL/OPT和NSL/CVT在T1和T2后增大。NSL/CVT的变化与腭咽段和舌咽段体积的变化呈正相关(P<0.05)。结论双颌手术可能导致上气道体积减小、颅颈角增大、舌骨向下和向后移动。颅颈角的变化可能会引起上气道的改变。

陈团营基于“风咳”理论治疗小儿上气道咳嗽综合征(风痰恋肺证)经验

文章主要总结陈团营副主任医师运用中医“风咳”理论治疗小儿上气道咳嗽综合征(风痰恋肺证)的临床经验。上气道咳嗽综合征是以咳嗽为主要或唯一临床表现的一组临床综合征,伴鼻塞、流涕、咽痒、咽干有异物感、脓性分泌物等症状,常由各种鼻炎、腺样体肥大及慢性咽炎等一系列上气道疾病引起,是引起小儿慢性咳嗽的第二大原因,需要引起临床关注。临床上,上气道咳嗽综合征常合并其他疾病共同引起慢性咳嗽,所以其诊断及治疗较为困难。西医治疗上气道咳嗽综合征常采用口服抗组胺药物或白三烯受体拮抗剂、鼻用糖皮质激素对症处理以及手术等治疗,但上述疗法均具有一定的局限性,未能根除病因,疗效不尽如人意。陈师具有多年中医临床经验,认为小儿上气道咳嗽综合征(风痰恋肺证)的病因为风邪侵犯人体,导致肺脾功能失调,痰邪内生,或素体肺脾不足,痰湿内生,复感风邪所致。病位以肺为主,涉及脾及鼻咽二窍,病机关键为风痰恋肺,肺失宣肃。方用祛风消痰方以祛风宣肺,消痰止咳,对于虚证者,兼以补虚;对于实证者,则增强祛邪之力,临床获得显著疗效。

气流作用下气道组织变形的流固耦合研究

悬雍垂腭咽成形术(UPPP)是一种治疗阻塞性睡眠呼吸暂停(OSA)的常规外科手术,然而由于手术作用机制仍不清楚,手术成功率较低.现有的研究大多忽略了患者上气道的具体形态以及呼吸作用下气道软组织的弹性变形,不足以有效指导手术治疗.文章基于OSA患者在术前、术后的CT扫描图像,构建了精确的三维上气道模型,通过双向流固耦合(FSI)计算,模拟研究了呼吸作用下上气道软组织的弹性变形和气道内气流流动情况.比较手术成功案例和失败案例中OSA患者上气道的流速、压力分布及气道弹性变形情况,从气道流体流动状态和气道软组织变形的角度解释了OSA的发生原因与手术作用机制.结果表明,最小横截面积尺寸并不是UPPP手术成功与否的决定性因素,成功的手术应当是减轻气道壁负压力程度、降低气道进出口之间的压降.此外,使用双向FSI方法,文章进一步构建了简化的人体二维软腭模型,探究了软腭弹性模量对吸气过程的影响,发现当软腭的弹性模量在0.5~1.5 MPa的范围内时,刚度更小的软腭会改善流场的流动情况,但也更易发生变形塌陷.文章所发展的流固模型为个性化预测手术效果提供了研究工具.