Minimum Cross-sectional Area Research Articles

ОЦЕНКА ВЕРХНИХ ДЫХАТЕЛЬНЫХ ПУТЕЙ И ОКРУЖАЮЩИХ МЯГКИХ ТКАНЕЙ У ПАЦИЕНТОВ С АНОМАЛИЯМИ ОККЛЮЗИИ В САГИТТАЛЬНОЙ ПЛОСКОСТИ ПО ДАННЫМ КОНУСНО-ЛУЧЕВОЙ КОМПЬЮТЕРНОЙ ТОМОГРАФИИ

The relationship between facial morphology and upper airway (UA) dimensions is well established in scientific literature. Due to that, upper airway assessment is an important step of orthodontic treatment planning and diagnosis. Three-dimensional cone-beam computer tomography analysis (CBCT) of upper airway is simple and readily available method of measuring linear and angular parameters, cross-sectional area, and volume of the UA. 
 The aim of the study is to measure the UA and surrounding tissue dimensions in patients with different types of sagittal malocclusion. 63 CBCT scans of adult patients without history of trauma, orthodontic treatment and congenital syndromes, diagnosed with distal, mesial, and normal occlusion have been studied using Materialise Mimics 21.0. Three-dimensional models of UA were created, and measurements of volume and cross-sectional area were taken using centerline and conventional cephalometric analysis. Non-parametric statistical correlational analysis was conducted.
 There were statistically significant differences between patients with mesial and distal occlusion. Moderate statistically significant correlations between facial morphology and UA dimensions have been found. In patients with distal occlusion, extended head position, posterior position of the hyoid bone, transverse maxillary and mandibular deficiency UA tend to have smaller size. The most predictive factor for minimal cross-sectional area of UA is the craniocervical angle and the distance between mandibular condyles.

Effects of mandibular advancement devices on upper airway dimensions in obstructive sleep apnea: responders versus non-responders

Study objectivesTo compare the effects of mandibular advancement device (MAD) therapy on upper airway dimensions between responders and non-responders with mild to moderate obstructive sleep apnea (OSA).MethodsThirty-one participants (21 men and 10 women) with a mean ± SD apnea-hypopnea index (AHI) of 16.6 ± 6.7 events/h, and aged 48.5 ± 13.9 years, were included in this study. Polysomnographic recordings and cone beam computed tomography (CBCT) scans in supine position were performed for every participant at baseline and at 3-month follow-up with their MAD in situ. Responders were defined as having ≥ 50% reduction in baseline AHI with a residual AHI < 10 events/h. The primary outcome variable was the minimal cross-sectional area of the upper airway (CSAmin).ResultsNo significant differences were found between responders (n = 15) and non-responders (n = 16) in age, gender distribution, body mass index, and neck circumference (P = 0.06–0.93), nor in AHI and CSAmin (P = 0.40 and 0.65, respectively) at baseline. The changes of the CSAmin with MAD in situ in the responder group were not significantly different compared to those in the non-responder group (P = 0.06).ConclusionWithin the limitations of this study, we conclude that the changes of the upper airway dimensions induced by MADs are not significantly different between responders and non-responders with mild to moderate OSA.Trial registrationClinicalTrials.gov Identifier: NCT02724865. https://clinicaltrials.gov/ct2/show/NCT02724865

Association between nasal airway minimal cross-sectional areas and obstructive sleep apnoea.

Patients with obstructive sleep apnoea (OSA) frequently present with some form of upper airway anatomical impairment. Considerable research has been conducted on the role of the structures of the jaw and pharynx in the pathogenesis of OSA; however, the significance of the nose is somewhat unclear. Computed tomography is a widely used imaging modality for assessing the nasal cavity and paranasal sinuses, but only a small amount of the acquired data is used. Our aim was to ascertain whether the size of the cross-sectional areas of the nasal airway, measured from cone beam computed tomography (CBCT) images, is associated with OSA severity. A total of 58 patients with OSA, without any major paranasal sinus inflammatory pathology, were included in this register-based study. Patients had previously undergone ambulatory polysomnography and CBCT. The cross-sectional areas of the nasal cavity were measured in CBCT coronal sections. Statistical analyses were performed to determine any correlation between the cross-sectional area measurements and apnoea-hypopnoea index (AHI) or any significant difference in cross-sectional areas between AHI severity groups. No correlation was found between AHI and the smallest, total, or sum of the anterior cross-sectional areas of the nasal airway. Furthermore, there was no statistically significant difference in the cross-sectional areas between patients with the highest and lowest AHI. The small cross-sectional area of the anterior nasal cavity in patients without any major nasal pathology does not appear to be associated with OSA severity.

Predictive value of reduced pulmonary arterial elasticity in acute pulmonary embolism for right ventricular dysfunction.

Computed tomography pulmonary angiography (CTPA) yields indices, such as the right ventricular/left ventricular (RV/LV) ratio > 1.0, which are commonly used for risk stratification of patients with acute pulmonary embolism (APE). Although pulmonary artery elasticity (PAE) has been previously described, its relationship with right ventricular dysfunction (RVD) has not been explored. Here, we investigated whether PAE, measured using CTPA, is associated with RVD. Patients who underwent retrospective electrocardiogram-gated CTPA and had a definitive diagnosis of APE were included in the study. The subjects were classified into RVD and non-RVD groups according to the RVD on echocardiography. PAE, involving aortic distensibility (AD), aortic compliance (AC), and aortic stiffness (ASI), and right heart function indices were compared between the two groups, and their correlations were examined. Receiver operating characteristic (ROC) curves were generated to evaluate the specificity and sensitivity of the RVD prediction. Thirty-five patients with APE were enrolled in the study (RVD: 18, non-RVD: 17). The groups showed no significant differences in age, sex, number of patients receiving thrombolysis, and number of high-risk conditions (P > 0.05). Regarding PAE parameters, AD was significantly reduced in the RVD group compared to that in the non-RVD group (P < 0.05), whereas AC and ASI were not statistically different (P > 0.05). The ratio of the maximum cross-sectional area of PA and AA (PA/AAmax),the ratio of the minimum cross-sectional area of PA and AA(PA/AAmin), diameter of the coronary sinus, RV/LV diameter, RV/Lvarea, the ratio of the end-diastolic volume of right ventricular and left ventricular (RV/LVDV), the ratio of the end-systolic volume of right ventricular and left ventricular (RV/LVSV) were significantly greater in the RVD group than in the non-RVD group (P < 0.05). Correlation analysis of AD and right heart function parameters showed that AD was negatively correlated with PA/AAmax, PA/AAmin, RV/LV diameter, RV/LVDV, and PAE measured by ultrasound, with correlation coefficients ranging from - 0.336 to - 0.580 (P < 0.05). The ROC curves of AD and RV/LVdiameter to predict RVD had areas under the curve of 0.748 and 0.712, sensitivities of 82.35% and 70.59%, specificities of 66.67% and 72.22%, and cutoff values of 4.9433 and 1.1105, respectively. AD obtained by retrospective ECG-gated CTPA may be helpful in assessing RVD in patients with APE while accurately diagnosing APE. It contributes to timely diagnosis and treatment and improves the prognosis of patients with APE.

Deep Learning Models for Automatic Upper Airway Segmentation and Minimum Cross-Sectional Area Localisation in Two-Dimensional Images.

To develop and validate convolutional neural network algorithms for automatic upper airway segmentation and minimum cross-sectional area (CSAmin) localisation in two-dimensional (2D) radiographic airway images. Two hundred and one 2D airway images acquired using cone-beam computed tomography (CBCT) scanning were randomly assigned to a test group (n = 161) to train artificial intelligence (AI) models and a validation group (n = 40) to evaluate the accuracy of AI processing. Four AI models, UNet18, UNet36, DeepLab50 and DeepLab101, were trained to automatically segment the upper airway 2D images in the test group. Precision, recall, Intersection over Union, the dice similarity coefficient and size difference were used to evaluate the performance of the AI-driven segmentation models. The CSAmin height in each image was manually determined using three-dimensional CBCT data. The nonlinear mathematical morphology technique was used to calculate the CSAmin level. Height errors were assessed to evaluate the CSAmin localisation accuracy in the validation group. The time consumed for airway segmentation and CSAmin localisation was compared between manual and AI processing methods. The precision of all four segmentation models exceeded 90.0%. No significant differences were found in the accuracy of any AI models. The consistency of CSAmin localisation in specific segments between manual and AI processing was 0.944. AI processing was much more efficient than manual processing in terms of airway segmentation and CSAmin localisation. We successfully developed and validated a fully automatic AI-driven system for upper airway segmentation and CSAmin localisation using 2D radiographic airway images.

Modeling of inhaled corticosteroids delivery for topical croup treatment in pediatric upper airways

Croup is the most frequent cause of pediatric upper airway obstruction characterized by spindle-shaped stenosis in the subglottis mucosa. Inhaled corticosteroids (ICSs) serve as the first-line therapy for croup. Traditional ICS particles (1–4 μm in diameter) are primarily designed for trachea and lung diseases and show extremely low larynx deposition. Moreover, the specific correlation between airway minimal cross-sectional area (CSA) and airway resistance has not been fully understood. In this study, three healthy pediatric upper airway models with commercial nebulizer masks attached to their faces were reconstructed from computed tomography (CT) scans. Virtual mild, moderate, and severe croup were incorporated into these healthy models. To enhance the performance of conventional nebulizing drug delivery, the aerodynamic properties of croup with different degrees of stenosis were quantitatively analyzed, and the respiratory transit and deposition of ICS particles sized between 1 to 20 μm in our target area (glottis + subglottis) were modeled utilizing the Computational Fluid Particle Dynamics (CFPD) method. Results showed that in all models, maximum deposition fractions (DF) can be reached when the ICS particle sizes are 7–8 μm, and for particles sized at 8 and 9 μm, all models can achieve effective target area delivery (≥75% of the maximum DF), whereas the majority of traditional nebulizers produce smaller particles than what we recommended. Pediatric upper airway resistance is negatively correlated with the minimum airspace CSA (R ∝ CSA−1), which is in good agreement with the Bernoulli Obstruction Theory. Furthermore, when the constriction of the subglottis reaches a specific level (≥70% obstruction), the upper airway pressure drop abruptly surged and the dyspneic respiration symptoms of patients develop instantly.

Upper airway morphology in adults with positional obstructive sleep apnea

PurposeTo compare the anatomical balance and shape of the upper airway in the supine position between adults with positional obstructive sleep apnea (POSA) and adults with non-positional OSA (NPOSA).MethodsAdults diagnosed with OSA (apnea-hypopnea index (AHI) > 10 events/h) were assessed for eligibility. POSA was defined as the supine AHI more than twice the AHI in non-supine positions; otherwise, patients were classified as NPOSA. Cone beam computed tomography (CBCT) imaging was performed for every participant while awake in the supine position. The anatomical balance was calculated as the ratio of the tongue size to the maxillomandibular enclosure size. The upper airway shape was calculated as the ratio of the anteroposterior dimension to the lateral dimension at the location of the minimal cross-sectional area of the upper airway (CSAmin-shape).ResultsOf 47 participants (28 males, median age [interquartile range] 56 [46 to 63] years, median AHI 27.8 [15.0 to 33.8]), 34 participants were classified as having POSA (72%). The POSA group tended to have a higher proportion of males and a lower AHI than the NPOSA group (P = 0.07 and 0.07, respectively). After controlling for both sex and AHI, the anatomical balance and CSAmin-shape were not significantly different between both groups (P = 0.18 and 0.73, respectively).ConclusionAdults with POSA and adults with NPOSA have similar anatomical balance and shape of their upper airway in the supine position.Trial registrationThis study was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR Trial ACTRN12611000409976).

Railway gravity retaining wall design using the flower pollination algorithm

An optimized cross-sectional area of a retaining wall assists in reducing material costs. Nevertheless, the design solution obtained from the traditional methods is not always the optimal one. Therefore, this study uses the flower pollination algorithm (FPA) to optimize the configuration of a gravity retaining wall, attempting to find the smallest cross-sectional area that meets design requirements. A key novelty is the use of a metaheuristic for gravity retaining wall design considering railway loading. First, the FPA is described in detail along with the general design methods for retaining walls and the definition of the optimisation problem. Next, a gravity retaining wall case study is performed and the FPA method is compared against alternative approaches, such as genetic algorithm (GA) and particle swarm optimization (PSO). Lastly, a parametric analysis is performed to assess the impact of the design parameters on the optimization outcomes. Results indicate the efficacy of FPA as an optimization method for the design of gravity retaining walls. Moreover, the reliability and speed of the algorithm’s convergence are attractive compared to alternative algorithms. The data further suggests that the integration of a landward-leaning wall back with a tilt angle of 14° can expedite the realization of the optimal minimum cross-sectional area. The wall height emerges as the primary influence over the minimum cross-sectional area, which displays marginal sensitivity to ground bearing capacities above 300 kPa. The algorithm can adeptly detect the thresholds in design requirements where retaining walls are impractical (e.g. when ground bearing capacity is a mere 100 kPa and the wall height exceeds 7 m), thereby indicating the need for alternative design exploration.

Comparing Airway Analysis in Two-Time Points after Rapid Palatal Expansion: A CBCT Study.

The aim of this study is to investigate the upper airway analysis at two-time points after the rapid maxillary expansion was performed, using cone-beam computed tomography. Subjects from the Orthodontic Department at the Aristotle University of Thessaloniki with unilateral or bilateral posterior crossbite were screened according to the selection criteria. A sample size calculation was performed, and a total of 14 subjects were recruited. All subjects received a rapid maxillary expansion with a Hyrax-type device as part of their comprehensive treatment. A CBCT was taken before the treatment (T1), immediately after the expansion was completed (T2), and 6 months after (T3). Their upper airway was measured using the CBCT images. Airway volume (V) and minimal cross-sectional area (MCS) were extracted and compared using SPSS to analyze the means. A statistically significant difference was found between all time points regarding both V and MCS (p < 0.001, p = 0.001). There was a statistically significant increase in both V and MCS measurements immediately after RPE expansion (T1-T2) and six months after expansion (T1-T3). Between the end of expansion and 6 months after (T2-T3), there was a decrease in V and no statistical difference in MCS. RPE can significantly increase the volume and minimal cross-sectional area of the nasal passage airway.

Effect of mouth breathing on upper airway structure in patients with obstructive sleep apnea

Objective:To compare the changes of morphology of pharynx in patients with obstructive sleep apnea hypopnea syndrome （OSAHS） and healthy individuals during oral or nasal breathing, and explore the relevant influencing factors. Methods:Twenty-nine adult patients with OSAHS and 20 non-snoring controls underwent MRI to obtain upper airway structural measurements while the subjects were awake and during mouth breathing with a nasal clip.The following were analyzed. ①The changes of upper airway structure of oral and nasal respiration in non-snoring control/OSAHS patients were observed; ②The differences and influencing factors of upper airway structure changes between OSAHS patients and controls were compared during breathing. Results:The control group consisted of 15 males and 5 females, with an apnea-hypopnea index （AHI）<5 events/h, while the OSAHS group comprised 26 males and 3 females with an AHI of 40.4±23.1 events/h and the mean lowest arterial oxygen saturation （LSaO2） was 79.5% ±10.0%. In the both groups, the vertical distance between the mandible and the posterior pharyngeal wall decreased （P<0.05）; The long axis of tongue body decreased （P<0.05）, and the contact area between tongue and palate decreased. There was no significant change in the total volume of the retropalatine（RP） and retroglossal（RG） airway in the control group （P>0.05）. However, the minimum cross-sectional area and volume of the RP airway in OSAHS decreased （P<0.001）. The lateral diameters of uvula plane in OSAHS decreased during mouth breathing, which was contrary to the trend in the control group （P=0.017）. The AHI of patients was positively correlated with the reduction of the volume of the RP airway during oral breathing （P=0.001）; The reduction of the distance between the mandible and the posterior pharyngeal wall was positively correlated with the length of the airway （P<0.001）. Conclusion:Mouth breathing leads to the shortening of the long axis of the tongue, the reduction of the contact area between the soft palate and the tongue, vertical distance between the mandible and the posterior pharyngeal wall, and the cross-sectional area of the epiglottis plane. These changes vary between OSAHS patients and controls. During mouth breathing, the diameters, areas and volumes of the RP area decreased, and were more significant in severe cases.

Airway changes in patients with unilateral cleft lip/palate (UCL/P) after maxillary advancement.

To assess the effect on the retropalatal airway (RPA), retroglossal airway (RGA), and total airway (TA) volumes and cephalometrics (SNA, SNB, ANB, PP-SN, Occl-SN, N-A, A-TVL, B-TVL) after maxillary advancement orthognathic surgery in patients with unilateral cleft lip/palate (UCL/P) using cone-beam computed tomography (CBCT). The CBCT scans of 30 patients (13 males and 17 females, 17-20 years old) with UCL/P were evaluated at two time points: preoperative (T1) and postoperative (T2). The interval between T1 and T2 ranged from 9-14 weeks, except for two patients in whom the interval was 24 weeks. Intraexaminer reliability was measured with an intraclass correlation coefficient test. A paired t-test was used to compare the airway and cephalometric measurements between T1 and T2, with a P value of .05 being considered significant. From T1 to T2, significant increases were found in the volumes of RPA (from 9574 ± 4573 to 10,472 ± 4767, P = .019), RGA (from 9736 ± 5314 to 11,358 ± 6588, P = .019), and TA (from 19,121 ± 8480 to 21,750 ± 10,078, P = .002). In addition, the RGA (from 385 ± 134 to 427 ± 165, P = .020) and TA (from 730 ± 213 to 772 ± 238, P = .016) sagittal area increased significantly. For minimal cross-sectional area (MCA), only the RPA increased significantly (from 173 ± 115 to 272 ± 129, P = .002). All cephalometric changes were statistically significant between T1 and T2 except for SNB. Maxillary advancement in patients with UCL/P produces statistically significant increases in the retropalatal (volumetric and MCA), retroglossal (volumetric and sagittal), and total (volumetric and sagittal) airways based on data from CBCT imaging.

Three-Dimensional Comparative Changes in the Pharyngeal Airway of Patients with Cleft after Two-Jaw Orthognathic Surgery.

The present study evaluated the three-dimensional changes of the pharyngeal airway after orthognathic surgery (OGS) in patients with unilateral and bilateral clefts, and in unilateral cleft patients with and without pharyngeal flap (PF). Forty-five patients with unilateral or bilateral clefts undergoing OGS were enrolled. Cone-beam computed tomographic images were obtained before and after OGS. We measured the pharyngeal airway volumes, minimal cross-sectional area, and the horizontal displacement of facial landmarks. The patients with bilateral cleft exhibited smaller initial velopharyngeal volume (unilateral, 8623 mm 3 ; bilateral, 7781 mm 3 ; P = 0.211), whereas the velopharyngeal volume increased significantly with a median of 744 mm 3 after OGS ( P = 0.031). The median horizontal displacement of A point was 2.9 and 2.6 mm among the patients with unilateral and bilateral clefts, respectively ( P = 0.276), and the median horizontal displacement of B point was -2.9 and -3.3 mm among patients with unilateral and bilateral clefts, respectively ( P = 0.618). The unilateral cleft patients with PF exhibited lower initial velopharyngeal volume (patients with a history of PF surgery, 7582 mm 3 ; patients without a history of PF surgery, 8756 mm 3 ; P = 0.129) and a lower increase in velopharyngeal volume (patients with a history of PF surgery, 437 mm 3 ; patients without a history of PF surgery, 627 mm 3 ; P = 0.739) after OGS. Midface hypoplasia and the decrease in the velopharyngeal volume were more prominent among the bilateral cleft patients and the unilateral cleft patients with PF. After OGS, the velopharyngeal volume increased considerably among the bilateral cleft patients, but no considerable differences were noted among the unilateral cleft patients with PF. Risk, II.

Nasal Patency in Sitting, Supine, and Prone Positions in Individuals with and without Allergic Rhinitis.

(1) Background: Physiological changes in nasal patency in response to posture contribute to sleep-related problems. Previously, we reported that the supine and prone positions cause a significant decrease in nasal patency in subjective and objective assessments of healthy individuals. Therefore, we conducted a study to evaluate the effect of posture on nasal patency in patients with allergic rhinitis (AR); (2) Methods: The present study comprised 30 patients diagnosed with AR and 30 healthy subjects without nasal disease (non-AR). Changes in nasal patency were evaluated in the sitting, supine, and prone positions. We used the visual analog scale to evaluate subjective nasal blockage. Acoustic rhinometry and endoscopy were used to objectively measure changes in nasal patency; (3) Results: In the non-AR group, the prone position had a significant effect on subjective nasal blockage compared with the sitting position, with significant decreases in the minimal cross-sectional area (mCSA) measured by acoustic rhinometry. Furthermore, endoscopy demonstrated a significantly increased inferior turbinate hypertrophy in the non-AR group. In the AR group, there was no statistical difference in subjective nasal blockage symptoms between the different positions. However, in objective examinations (acoustic rhinometry and endoscopy), the prone position showed significantly decreased nasal patency; (4) Conclusions: In patients with AR, subjective nasal blockage did not significantly increase in the supine or prone position. Endoscopy demonstrated increased inferior turbinate hypertrophy in supine and prone positions resulting in a significant reduction in nasal cavity mCSA, indicating an objective reduction in nasal patency.

Utilizing a Functional Lumen Imaging Probe for Evaluation of the Pediatric Airway, A Pilot Study.

Accurate and reproducible measurements of the pediatric airway are critical for diagnostic evaluation and management of subglottic and tracheal stenosis. The endoluminal functional lumen imaging probe (EndoFLIP) is a catheter-based imaging probe which utilizes impedance planimetry to calculate luminal parameters, including cross-sectional area and compliance. Herein, we demonstrate the feasibility of this system for multidimensional evaluation of the pediatric airway. 3D-printed pediatric laryngotracheal models were created based on computed tomography scans, then artificially deformed to simulate both circumferential and posterior subglottic stenosis. Two observers made six measurements of the minimum cross-sectional area (MCSA) and length of stenosis of each model with EndoFLIP. Agreement between observer measurements and model dimensions was evaluated using Lin's concordance correlation coefficient; inter-observer reliability was assessed using intraclass correlation. Four models were created: two without pathology (MCSA: 132.4, 44.3 mm2 ) and two with subglottic stenosis (MCSA: 28.7, 59.7 mm2 , stenotic length 27.8, 24.4 mm). Observer measurements of MCSA and length of stenosis demonstrated high concordance with the models (r = 0.99, 0.95, p < 0.001) with a mean error of 4.5% and 18.2% respectively. There was a low coefficient of variation (0.6%-2.8%) for measurements, indicating high precision. Interrater reliability was high for both MCSA and stenotic length (ICC: 0.99, 0.98). The EndoFLIP system allows for accurate and reproducible measurements of cross-sectional area and stenotic length in pediatric airway models. This method may provide further advantages in the evaluation of airway distensibility, as well as measurements of asymmetric airway pathology. NA Laryngoscope, 134:108-112, 2024.

Long-term evaluation of the upper airway following mandibular setback surgery in the patients with mandibular prognathism.

The aim of this study was to evaluate the changes in the upper airway following mandibular setback surgery. The patients underwent mandibular setback surgery and cone-beam computed tomography scan data obtained at four time points: before surgery, immediately after surgery, short- and long-term follow-up. Upper airway geometries were segmented and extracted at each time point. Time-averaged airflow through the upper airway was evaluated at each time point. The measurements of airway volume and minimum cross-sectional areas were obtained at four time points. The airway volume and cross-sectional areas of airway significantly decreased immediately after surgery (p = 0.013 for airway volume and 0.016 for cross-sectional area). At short-term follow-up, the decreased airway volume and cross-sectional areas still showed statistically significant difference to original dimension (p = 0.017 for airway volume and 0.006 for cross-sectional area). At long-term follow-up, although there were no statistical significances (p = 0.859 for airway volume and 0.721 for cross-sectional area), the airway volume and cross-sectional areas had increased slightly compared to those at short-term follow-up. Although the airflow and dimensional parameters of the upper airway worsened following mandibular setback surgery, there was a tendency to gradually recover during long-term follow-up.

Real-time measurement of minimum cross-sectional area and radius of curvature of miniature plate specimens using a high-speed laser profiler for calculating true stress-true strain curves

True stress-true strain curves are fundamental for designing and analyzing structures such as fusion reactors. These curves are typically obtained by conducting tensile tests on round bar specimens. However, due to material dimension limitations, plate specimens are sometimes used instead of round bar specimens. Obtaining true stress-true strain curves experimentally from plate specimens can be challenging. To address this challenge, this study aims to obtain true stress-true strain curves of miniature plate specimens using both analytical and experimental methods. The analytical method involved inverse finite element method (FEM), while the experimental method utilized real-time measurement of the minimum cross-sectional area and radius of curvature of a miniature plate specimen with a high-speed laser profiler. Comparing the true stresses obtained from the analytical and experimental methods, we found that the difference was typically within 5%. These findings suggest that inverse FEM and laser profilometry are effective methods for determining the true stress-true strain of miniature plate specimens.

Predictors of uvulopalatopharyngoplasty outcomes in patients with supine predominant positional obstructive sleep apnea: a prospective observational study

Background It is uncertain which factors substantially influence outcomes after uvulopalatopharyngoplasty (UPPP) in patients with supine predominant obstructive sleep apnea (POSA) Objective To explore the predictors of UPPP outcomes in POSA patients. Methods A total of 108 patient(52 positional patients (POSA) and 56 nonpositional patients(NPP)), who underwent the revised uvulopalatopharyngoplasty (H-UPPP), were retrospectively studied. The pre-operative information of these patients, including polysomnography (PSG), and upper airway CT, were collected for analysis. Results No difference was found in surgical success rates between POSA and NPP undergoing H-UPPP. In POSA patients, there were statistically significant differences between responders and nonresponders in body mass index (BMI), preoperative supine AHI, time of SaO2 < 90% (TS90) (all p < .05), minimal anteroposterior airway (mAP) (p = .016), minimal lateral airway (mLAT) (p = .002), minimal cross-sectional airway area (mCSA) (p < .001) at the velopharynx. mLAT (p = .014) and mCSA (p = .002) at the glossopharynx. The independent associated factors for surgical success were lower BMI (p < .001), narrowerm LAT (p = .002) and mAP (p < .001) at velopharynx, and wider mCSA (p < .001) at glossopharynx in POSA. Conclusion POSA patients with lower BMI, narrower mLAT and mAP at velopharynx, wider mCSA at glossopharynx were more likely to achieve a positive outcome with H-UPPP.

Assessment of factors influencing the olfactory bulb volume in patients with post-viral olfactory dysfunction.

To investigate the factors influencing the volume of the olfactory bulb (OB) in patients with post-viral olfactory dysfunction (PVOD). We collected 92 olfactory bulb volumes from patients with PVOD who underwent a sinus computed tomographic and magnetic resonance imaging (MRI) scan of the head and collected clinical information including gender, age, disease course, minimal cross-sectional area, nasal airway resistance, and olfactory function. OB volume was measured in MRI and the scans were evaluated according to the Lund-Mackay (LM) scoring system. Male patients with PVOD had a larger OB volume (β = 0.284, P < 0.05). OB volume was smaller in patients with a longer course of olfactory dysfunction (β = -0.254, P < 0.05). According to the LM scoring system, patients with a higher anterior ethmoidal sinus score had smaller OB volume (β = -0.476, P < 0.05). The study revealed that gender, disease course, and the score of anterior ethmoidal sinusitis can affect the OB volume in patients with PVOD.

Residual Mechanical Properties of Corroded Steel Bars after High-Temperature Exposure

Accidental fires in aged concrete structures can lead to combined damage from corrosion and fire. In this study, we aimed to explore the effects of corrosion and high temperature on the residual mechanical properties of hot-rolled plain and ribbed bars. The results indicated that the corroded steel bars still exhibited ductile failure after high-temperature exposure. Moreover, the combined action of high temperature and corrosion has little effect on the elastic modulus. The residual bearing capacity of the hot-rolled steel bar became smaller under the condition of temperatures above 600°C. When the temperatures experienced by the plain and ribbed steel bars were less than 600°C and 500°C, respectively, the high temperature accelerated the decrease in the nominal yield and ultimate strength. However, the yield and ultimate strengths based on the minimum cross-sectional area remained unchanged with an increase in the cross-sectional loss ratio. Similar to that at room temperature, the ultimate strain of steel bars subjected to high-temperature exposure decreased exponentially with an increase in the cross-sectional loss ratio. The new findings of this study can provide a theoretical basis for the safety assessment of aged reinforced concrete structures after exposure to fire.

Clinical efficacy analysis of functional rhinoplasty assisted by nasal endoscopy

Objective: To analyse the clinical effect of endoscopy-assisted functional rhinoplasty. Methods: Twenty-one patients with congenital or traumatic deviated nose with nasal obstruction admitted to Qilu Hospital (Qingdao) from January 2018 to December 2021, including 8 males and 13 females, aged 22 to 46 years, were retrospectively analysed. Endoscopy-assisted functional rhinoplasty was performed in all patients. Deviated nasal septum was corrected, nasal septum cartilage graft was prepared through open approach assisted by endoscopy, the nasal frame structure was adjusted with the endoscopy-assisted rhinoplasty combined with middle and inferior turbinoplasty, and the patient's nasal ventilation function and external nose cosmetology were restored. Visual Analogue Scale (VAS), Nasal Obstruction Symptom Evaluation (NOSE), nasal acoustic reflex and nasal resistance were examined preoperatively and 6 months postoperatively. The minimum cross-sectional area of the first two nasal cavities (MCA) MCA1 and MCA2 and their distance between nostrils to the minimum cross-sectional area (MD) MD1 and MD2 were recorded, and the ratio of both sides (expressed in a/b) was calculated. The nasal volume of 5 cm depth from nostril (NV5) and nasal resistance total (RT) were recorded to evaluate the nasal ventilation function to analyse the clinical effect of functional rhinoplasty assisted by nasal endoscope. SPSS 25.0 software was used for statistical analysis. Results: At 6 months after the operation, for nasal ventilation evaluation, the VAS and NOSE scores of nasal obstruction decreased significantly than those before the operation ((1.81±0.81) points vs (6.71±1.38) points, (4.19±2.06) points vs (12.05±2.67) points, all P<0.05). In the objective indexes, MCA1, MCA2 and NV5 were significantly increased whereas RT, MCA1a/MCA1b, MCA2a/MCA2b, MD1a/MD1b and MD2a/MD2b were significantly decreased compared with those before the operation (all P<0.05). The MD1 and MD2 levels before and after operation had no significant differences (all P>0.05). In the evaluation of external nose morphology, postoperative ROE was significantly increased, and the deviation value of nasal appearance was significantly decreased ((16.19±2.56) points vs (10.24±3.24) points, (1.55±1.16) mm vs (5.63±2.41) mm, all P<0.05). In terms of postoperative patient satisfaction, 19 cases (90.5%) were very satisfied with nasal ventilation function, 2 cases (9.5%) were satisfied with nasal ventilation function; 15 cases (71.4%) were very satisfied with nasal appearance, and 6 cases (28.6%) were satisfied with nasal appearance. Conclusions: Nasal endoscopy-assisted functional rhinoplasty can improve the nasal ventilation function and external nasal morphology at the same time, with good clinical effect and high patient satisfaction.