Changes In Airway Volume Research Articles

Changes in Upper Airway Volume Following Orthognathic Surgery.

Reduced volume of the internal skeletal dimensions of the face is 1 of the main causes of obstructive sleep apnea, and attention to patients' airways is necessary when planning orthognathic treatment. This study aims to describe changes in upper airway volume following virtually planned orthognathic surgery.A retrospective pilot study was designed with 30 randomly selected patients (10 men and 20 women, aged 23.1 ± 6.8 years, molar-relations: 15 neutral, 8 distal, and 7 mesial). Cone-beam computed tomography scans were performed before surgery and 1 week following surgery. The authors did total upper airway volume measurements and obtained 1-mm slices at vertical levels in the velo-, oro-, and hypopharynx and at the smallest visible cross-section.Measurements before and after surgery were compared using Student t test.After orthognathic surgery, the minimum cross-sectional area at the vertical level increased from 83 mm ± 33 before surgery to 102 mm ± 36 after surgery (P = 0.019). In patients with neutral and distal occlusions, the minimum cross-sectional slice volume increased in 87% but in only 57% with mesial occlusion.The present findings suggest that orthognathic surgery increases upper airway volume parameters, but a few patients have continued impairment of the airways following orthognathic surgery. Further studies are needed to confirm an individual surgical planning approach that potentially could bring the minimum cross sectional area out of the risk zone.

Soft, hard-tissues and pharyngeal airway volume changes following maxillomandibular transverse osteodistraction: Computed tomography and three-dimensional laser scanner evaluation.

Maxillomandibular transverse osteodistraction (MMTOD) is an alternative approach to the traditional treatment for transverse maxillary and mandibular deficiencies and crowding. The aim was to report soft and hard-tissues changes and airway volume variation. In this study, skeletally mature, non-syndromic patients with transverse maxillary and mandibular hypoplasia, who underwent a MMTOD between 2010 and 2012, were included. Surgical changes were analysed using clinical evaluation, three-dimensional facial surface data and computed tomography analysis before (T0) and after the completion of post-op orthodontic treatment (T1). Nineteen patients (eight males and eleven females; average age: 26.3 years) were enrolled. MMTOD produces facial changes in the cheek, paranasal areas, nasal base and chin. Facial changes are mostly explained by the underlying skeletal movements, which are essentially represented by the transverse enlargement of both the maxilla and the mandible. Following MMTOD, the airway volume and the lateral dimension of the cross-sectional airway increased significantly. MMTOD is a technique that allows an increase in airway volume and in both maxillary and mandibular arch perimeters simultaneously by increasing skeletal width. Facial appearance is improved and a stable occlusion is obtained.

Volumetric upper airway changes after rapid maxillary expansion: a systematic review and meta-analysis.

Although Rapid Maxillary Expansion (RME) has been used for over a century, its effect on upper airways has not yet adequately been assessed in an evidence-based manner. To investigate the volumetric changes in the upper airway spaces following RME in growing subjects by means of acoustic rhinometry, three-dimensional radiography and digital photogrammetry. Literature search of electronic databases and additional manual searches up to February 2016. Randomized clinical trials, prospective or retrospective controlled clinical trials and cohort clinical studies of at least eight patients, where the RME appliance was left in place for retention, and a maximum follow-up of 8 months post-expansion. After duplicate data extraction and assessment of the risk of bias, the mean differences and 95 per cent confidence intervals (CIs) of upper airway volume changes were calculated with random-effects meta-analyses, followed by subgroup analyses, meta-regressions, and sensitivity analyses. Twenty studies were eligible for qualitative synthesis, of which 17 (3 controlled clinical studies and 14 cohort studies) were used in quantitative analysis. As far as total airway volume is concerned patients treated with RME showed a significant increase post-expansion (5 studies; increase from baseline: 1218.3mm3; 95 per cent CI: 702.0 to 1734.6mm3), which did not seem to considerably diminish after the retention period (11 studies; increase from baseline: 1143.9mm3; 95 per cent CI: 696.9 to 1590.9mm3). However, the overall quality of evidence was judged as very low, due to methodological limitations of the included studies, absence of untreated control groups, and inconsistency among studies. RME seems to be associated with an increase in the nasal cavity volume in the short and in the long term. However, additional well-conducted prospective controlled clinical studies are needed to confirm the present findings. None. Australian Society of Orthodontics Foundation for Research and Education Inc.

Supra-Epiglottic Upper Airway Volume in Elderly Patients with Obstructive Sleep Apnea Hypopnea Syndrome.

ObjectiveSmall upper airway measurements areas and high body mass index are recognized risk factors for obstructive sleep apnea syndrome (OSAS) in non-elderly populations; however, there is limited information regarding elderly patients. We evaluated whether upper airway volume is associated with OSAS and OSAS treated with continuous positive airway pressure (CPAP) treatment and whether BMI is correlated with upper airway volume and measurements in elderly subjects.MethodsIn 60 volunteers aged 75.58±0.9 years: 20 OSAS, 20 OSAS chronically treated with CPAP, and 20 controls, semi-automatic segmentation, retropalatal distance and transverse diameter of the supra-epiglottic upper airway were evaluated using 3DT1-weighted magnetic resonance imaging. Anteroposterior to transverse diameter ratio was defined as retropalatar diameter/transverse diameter.ResultsThere were no significant differences in supra-epiglottic upper airway volume between OSAS, CPAP treated patients, and controls. There were significant differences in retropalatal distance and anteroposterior to transverse diameter ratio between OSAS, CPAP treated patients, and controls (P = 0.008 and P<0.0001 respectively). There was a significant correlation between body mass index and retropalatal distance (P<0.05) but not with supra-epiglottic upper airway volume.ConclusionIn elderly subjects, OSAS and body mass index are not associated with changes in supra-epiglottic upper airway volume but are associated with modification of pharynx shape.

Computational fluid dynamics for the assessment of upper airway changes in skeletal Class III patients treated with mandibular setback surgery.

To analyze and compare pharyngeal airflow characteristics pre- and post-mandibular setback surgery in patients with Class III skeletal dysplasia using cone beam computed tomography (CBCT) and computational fluid dynamics (CFD). Records of 29 patients who had received orthodontic treatment along with mandibular setback surgery were obtained. CBCT scans were obtained at three time points: T1 (before surgery), T2 (average of 6 months after surgery), and T3 (average of 1 year after surgery). Digitized pharyngeal airway models were generated from these scans. CFD was used to simulate and characterize pharyngeal airflow. Mean airway volume was significantly reduced from 35,490.324 mm3 at T1 to 24,387.369 mm3 at T2 and 25,069.459 mm3 at T3. Significant increase in mean negative pressure was noted from 3.110 Pa at T1 to 6.116 Pa at T2 and 6.295 Pa at T3. There was a statistically significant negative correlation between the change in airway volume and the change in pressure drop at both the T2 and T3 time points. There was a statistically significant negative correlation between the amount of mandibular setback and change in pressure drop at the T2 time point. Following mandibular setback surgery, pharyngeal airway volume was decreased and relative mean negative pressure was increased, implying an increased effort required from a patient for maintaining constant pharyngeal airflow. Thus, high-risk patients undergoing a large amount of mandibular setback surgery should be evaluated for obstructive sleep apnea and the proposed treatment plan be revised based on the risk for potential airway compromise.

Dimensional changes of upper airway after rapid maxillary expansion evaluated with cone beam computed tomography

PurposeThe objective of this research study was to assess the effect of rapid maxillary expansion treatment on nasal cavity, upper airway, as well as facial height and convexity using cone beam computed tomography (CBCT). MethodsWe evaluated 15 patients with maxillary width deficiency treated with rapid maxillary expansion (RME). Patients were subjected to CBCT at the beginning of the RME treatment and again after the retention period of 4 months in order to measure the changes of retropalatal and retroglossal airways, nasal cavity and cephalometric parameters. The measurements of the before and after RME scans were compared using a paired t test. ResultsThe average increase of the retropalatal airway volume (2.31mm3) and the total upper airway volume (3.23mm3) was statistically significant (p=0.04 and p=0.05 respectively), while the change in retroglossal airway volume (0.92mm3) was not significant. Significant increase was observed in the transverse distances of the anterior, middle and posterior areas of the lower third of nasal cavity following the RME treatment (p=0.008, p=0.003 and p=0.002 respectively). No significant difference was observed in the cross-sectional areas passing epiglottis (EP), soft palate (SP) and posterior nasal spine (P) planes or other cephalometric parameters before and 4 months after the treatment. ConclusionsThe RME treatment resulted in significant increase in the transverse width of the nasal cavity, as well as upper and retropalatal airways. However, this effect was not observed for the cross-sectional areas of the upper airway, anterior and posterior facial heights and facial convexity following RME treatment.

Computational airflow analysis before and after maxillomandibular advancement surgery

BackgroundThe purpose of this study was to analyze pharyngeal airflow using computational fluid dynamics (CFD) in obstructive sleep apnea (OSA) patients before and after maxillomandibular advancement (MMA). MethodsDigitized pharyngeal airway models of 19 obstructive sleep apnea patients were generated from cone beam computed tomography scans presurgery and an average of 18.3 ± 17.3 days postsurgery. CFD was used to simulate and characterize pharyngeal airflow, which was assumed to be turbulent at an inspiration rate of 340 mL/s. Standard steady-state numerical formulation were used for airflow simulations. ResultsMean pressure drop during inspiration was significantly reduced from 34.82 ± 65.65 Pa presurgery to 3.06 ± 3.96 Pa postsurgery. Mean maximum airflow velocity along the airway was also significantly reduced from 11.14 ± 8.49 m/s presurgery to 4.09 ± 3.07 m/s postsurgery. There was a significant increase in mean airway volume of 66.8% postsurgery. There was a 75% mean reduction in airway resistance postsurgery. There was a decrease in the pressure gradient and total pressure drop postsurgery for all 19 patients. There was a statistically significant moderate, negative correlation between the change in airway resistance and the change in airway volume postsurgery. No correlation was found between skeletal advancement and airway volume or airway resistance. ConclusionsA decrease in relative pressure implies less effort required for maintaining constant pharyngeal airflow according to CFD analyses on airways of OSA patients after MMA surgery.

Volumetric changes in pharyngeal airway in Class II division 1 patients treated with Forsus-fixed functional appliance: A three-dimensional cone-beam computed tomography study.

Objective:Recent years have witnessed a renewed interest to determine a quantifiable relationship between mandibular advancement performed with an orthodontic appliance and the resulting airway volume. The study was conducted to evaluate the volumetric changes in pharyngeal airway space using cone-beam computed tomography (CBCT) in Class II division 1 patients with retrognathic mandible treated by Forsus-fixed functional appliance and to compare them with their pretreatment findings.Materials and Methods:Thirty patients with Class II division 1 malocclusion of age group 10–17 years were selected randomly and evaluated for changes in pharyngeal airway volume with and without Forsus-fixed functional appliance. Patients in each group underwent CBCT scan of head and neck region at pretreatment stage and 6 months after the initial scan. Institutional approval for the project was obtained from the Ethical Committee. Volumetric changes of upper (oropharynx) and lower (hypopharynx) pharyngeal airways were measured on scanogram using computer software and intragroup comparisons were done.Results:There was a statistically significant increase in the volume of both hypopharynx and oropharynx and also total airway volume in patients treated with Forsus-fixed functional appliance. Three-dimensional reconstruction of the airway also demonstrates a considerable increase in pharyngeal airway space.Conclusion:Forsus-fixed functional appliance can be a promising appliance for improving pharyngeal airway volume in Class II division 1 patients with retrognathic mandible thus preventing obstructive sleep apnea and other respiratory problems in future. However, the long-term implications of this treatment modality need further consideration and a longer period of follow-up.

Volumes of Velopharyngeal and Glossopharyngeal Airway Were Not Changed after Uvulopalatopharyngoplasty: Report of Three Cases.

Objective. The aim of this study was to investigate the changes in velopharyngeal and glossopharyngeal airway morphology and volume after uvulopalatopharyngoplasty in three adult obstructive sleep apnea syndrome patients who had bilateral large tonsils using three-dimensional computed tomography. Case Report. All three patients (one male and two females) who presented with a history of heavy snoring and excessive daytime sleepiness were examined with overnight nocturnal polysomnography, which indicated moderate-to-severe obstructive sleep apnea syndrome. Because all patients had large tonsils, uvulopalatopharyngoplasty was expected to enlarge the pharyngeal airway. Polysomnography and three-dimensional computed tomography scanning were performed and compared, both before and 3 months after uvulopalatopharyngoplasty. Results. Unexpectedly, although the morphology of the glossopharyngeal airway clearly changed after UPPP, the volume changes in the velopharyngeal and glossopharyngeal airways were negligible.

Correlation of Airway Volume With Orthognathic Surgical Movement Using Cone-Beam Computed Tomography

Orthognathic surgery can induce changes in airway volume. The aim of this study was to determine whether there is a correlation of surgical movement of the maxilla or mandible to airway volume changes. This was a prospective cohort study and the sample was composed of patients undergoing single-jaw orthognathic procedures from 2004 through 2007. Cone-beam computed tomograms were obtained before surgery (T0), immediately after surgery (T1), and at least 6months after surgery (T2). The airway was segmented from 3-dimensional images and identified as the whole airway, consisting of the naso-, oro-, and hypopharynx. The volumetric percentage of change of the airway between time points was compared and correlated to the surgical movements using paired t test and cubic regression analysis. The level of statistical significance was set at a P value less than or equal to .05. The sample was composed of 33 patients. Sixteen patients underwent maxillary advancement with mean advancement of 5.4mm (3 to 8mm), 13 underwent mandibular advancement with mean advancement of 8.0mm (5 to 15mm), and 4 underwent mandibular setback of 4.0mm. For maxillary advancement at T1, volume percentages of change for the whole airway and the naso-, oro-, and hypopharynx were 18.4 (P ≤ .05), 53.8 (P ≤ .05), 26.3, and 5.5%, respectively, and at T2, the changes were 10.0, 46.7(P ≤ .05), 6.8, and 1.0%, respectively. For mandibular advancement at T1, volume percentages of change were 34.6 (P ≤ .05), 26.1, 54.1 (P ≤ .05), and 17.4%, respectively, and at T2, the changes were 15.0 (P ≤ .05), -3.7, 23.5 (P ≤ .05), and 12.1%, respectively. There were no meaningful long-term airway changes with mandibular setback. The study results suggest that there might be an anatomic limit to pharyngeal airway expansion associated with single-jaw orthognathic surgery.

Changes in Upper Airway Volume in Edentulous Obstructive Sleep Apnea Patients Treated with Modified Mandibular Advancement Device.

This study was an attempt to verify the utility of complete dentures modified as a mandibular advancement device (MAD) in effecting expansion in pharyngeal volume to treat obstructive sleep apnea (OSA) in edentulous patients. The sample consisted of 17 patients (12 male, 5 female, average age 61 ± 4 years; BMI, 22 ± 5; apnea hypopnea index [AHI] 15 to 30). All patients had worn complete dentures for at least 1 year; all patients had the dentures modified to a MAD. Five variables were assessed preoperatively and 6 months after wearing the modified MADs. These variables were: sleep efficiency, AHI, oxygen desaturation events/hr., mean oxygen saturation, snoring index, and airway volume. This assessment was done by subjecting the patients to all-night polysomnography. Without any prosthesis or device in the edentulous patients, the mean velopharyngeal volume was 8.05 ± 0.58 cm(3) , oropharyngeal volume was 2.14 ± 0.38 cm(3) , and hypopharyngeal volume was 3.26 ± 0.78 cm(3) . With complete dentures (unaltered) in the edentulous patients, the mean velopharyngeal, oropharyngeal, and hypopharyngeal volumes were 10.73 ± 0.98 cm(3) , 2.60 ± 0.48 cm(3) , and 4.31 ± 0.89 cm(3) , respectively. There was a statistically significant change in the airway volume following insertion of the complete dentures modified as MADs with velopharyngeal, oropharyngeal, and hypopharyngeal volume recorded as 11.76 ± 1.07 cm(3) , 3.33 ± 0.51 cm(3) , and 4.94 ± 0.83 cm(3) , respectively. From the results obtained in this limited small sample study, it was inferred that the pharyngeal expansion induced by complete dentures modified as MADs effectively reduced symptoms of OSA. Increased volume was most pronounced in the velopharynx region followed by hypopharynx and oropharynx.

Effects of Le Fort I Osteotomy on the Nasopharyngeal Airway—6-Month Follow-Up

The literature discussing the impact of a single Le Fort I osteotomy on nasopharyngeal airways is limited. This study assessed the volumetric changes in the nasopharyngeal airway after a single Le Fort I osteotomy and explored the correlation between these changes and 3-dimensional surgical movements of the upper jaw. This retrospective study was conducted in 40 patients who had undergone a single Le Fort I (maxillary advancement with or without impaction) to correct Class III malocclusion with maxillary hypoplasia. Preoperative (T1) and 6-month postoperative (T2) cone-beam computed tomographic (CBCT) scans of these patients were used for analysis. Maxillary surgical movements and volumetric changes in the nasopharyngeal airway were measured. The reproducibility of the measurements was evaluated using paired t tests and intraclass correlation coefficients. The Wilcoxon test and Pearson correlation coefficient were applied to evaluate the volumetric changes in the nasopharyngeal airway space and assess the correlations of these changes to the maxillary surgical movements. Six patients were excluded from the study owing to major differences (>5°) in their head and neck posture between the T1 and T2 CBCT scans. The errors of the repeated measurements were insignificant (P > .05), with a high level of agreement (r = 0.99; P < .05) between the repeated digitization of the landmarks. There was a statistically significant impact of a Le Fort I osteotomy on the right maxillary sinus (decreased by 17.8%) and the lower retropalatal space (expanded by 17.3%; P < .05). The correlation between the change in airway volume and the magnitude of surgical maxillary movements was moderate (r = .4). Similarly, there was a moderate correlation between changes in the upper nasopharynx and those in the hypopharynx. The single Le Fort I osteotomy was found to increase the retroglossal airway volume. This could be important for the treatment of obstructive sleep apnea in patients with maxillary deficiency. A long-term follow-up assessment of a larger sample with a functional assessment of airway would be beneficial to confirm these findings.

Postsurgical volumetric airway changes in 2-jaw orthognathic surgery patients

Findings from early cephalometric studies on airway changes after 2-jaw orthognathic surgery have been challenged because the previous anteroposterior interpretation of airway changes can now be evaluated in 3 dimensions. The aims of this study were to use cone-beam computed tomography to quantify the nasopharynx, oropharynx, and total airway volume changes associated with skeletal movements of the maxilla and mandible in a sample of patients undergoing 2-jaw orthognathic surgery for correction of skeletal malocclusion. Skeletal movements and airway volumes of 71 postpubertal patients (31 male, 40 female; mean age, 18.8 years) were measured. They were divided into 2 groups based on ANB angle, overjet, and occlusion (Class II: ANB, >2°; overjet, >1 mm; total, 35 subjects; and Class III: ANB, <1°; overjet, <1 mm; total, 36 subjects). Presurgical and postsurgical measurements were collected for horizontal, vertical, and transverse movements of the maxilla and the mandible, along with changes in the nasopharynx, oropharynx, and total airways. Associations between the directional movements of skeletal structures and the regional changes in airway volume were quantified. Changes in the most constricted area were also noted. Horizontal movements of D-point were significantly associated with increases in both total airway (403.6 ± 138.6 mm(3); P <0.01) and oropharynx (383.9 ± 127.9 mm(3); P <0.01) volumes. Vertical movements of the posterior nasal spine were significantly associated with decreases in total airway volume (-459.2 ± 219.9 mm(3); P = 0.04) and oropharynx volume (-639.7 ± 195.3 mm(3); P <0.01), increases in nasopharynx (187.2 ± 47.1 mm(3); P <0.01) volume, and decreases in the most constricted area (-10.63 ± 3.69 mm(2); P <0.01). In the Class III patients only, the vertical movement of D-point was significantly associated with decreases in both total airway (-724.0 ± 284.4 mm(3); P = 0.02) and oropharynx (-648.2 ± 270.4 mm(3); P = 0.02) volumes. A similar negative association was observed for the most constricted area for the vertical movement of D-point (-15.45 ± 4.91 mm(2); P <0.01). Optimal control of airway volume is through management of the mandible in the horizontal direction and the vertical movement of the posterior maxilla for all patients. The surgeon and the orthodontist should optimally plan these movements to control gains or losses in airway volume as a result of orthognathic surgery.

Three-dimensional computed tomography analysis of airway volume changes between open and closed jaw positions

Airway dimensions are closely linked to the bone and soft-tissue craniofacial anatomy. Reduction of the airway is seen with airway disorders and can impair function. The purpose of this retrospective study was to determine whether changing from open to closed jaw position affects the volume of the nasal cavity, nasopharynx, and oropharynx; the soft palate; the soft-tissue thickness of the airway; and the most constricted area of the airway. Following reliability studies, in this retrospective study, we analyzed cone-beam computed tomography scans taken in both closed and open jaw positions of 60 subjects who were undergoing diagnosis and treatment of temporomandibular disorders. On each scan, condyle-fossa measurements, volumes of airway segments (nasal cavity, nasopharynx, oropharynx), soft palate areas, soft tissue thicknesses of the airway, and the most constricted area of the airway and its location were measured using Dolphin imaging software (version 11.5; Patterson Dental Supply, Chatsworth, Calif). Differences between the 2 jaw positions were analyzed with paired t tests, accepting P≤0.05 as significant. Significant changes in airway dimensions were found between the closed and open jaw positions. With jaw opening, the nasopharynx volume increased, whereas the oropharynx volume decreased. Significant decreases were also found for measurements of basion to posterior airway wall, cervical vertebrae to posterior airway wall, most constricted area, nasal cavity volume, and soft palate area when the jaw was open. Changing jaw position significantly affects airway dimensions.

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A 2-Year Follow-Up of Changes After Bimaxillary Surgery in Patients With Mandibular Prognathism: 3-Dimensional Analysis of Pharyngeal Airway Volume and Hyoid Bone Position

The aims of this study were to use 3-dimensional cone-beam computed tomography (CBCT) to evaluate how the upper airway and hyoid bone position changed after orthognathic surgery in patients with skeletal Class III malocclusions and to analyze the relations among upper airway changes, the change in the position of the hyoid bone, and postsurgical stability. CBCT scans were obtained from 15 patients with mandibular prognathism before surgery (T0), 6 months after surgery (T1), 1 year after surgery (T2), and 2 years after surgery (T3). Positional displacement of the hyoid bone was assessed using the coordinates at T0, T1, T2, and T3. In addition, the volume of each patient's pharyngeal airway was measured. Differences in CBCT scans at the established time points were determined by the Wilcoxon signed rank test. The Spearman correlation coefficient was used to determine the relations among changes in hyoid bone position, airway volume, and skeletal reference points. The hyoid bone moved backward at 6 months after surgery (T0 to T1), and the total volume of the pharyngeal airway was considerably decreased at the same time points. At 1 year after surgery (T1 to T2), although the hyoid moved more posteriorly and the total volume of the pharyngeal airway was decreased, the changes were not major. At 2 years after surgery, the hyoid bone moved anteriorly and the size of the upper pharyngeal airway was increased (T2 to T3). The hyoid bone moved posteriorly and the pharyngeal airway volume was decreased at 6 months after bimaxillary surgery. These measurements had a tendency to recover at 2 years postoperatively. The decrease in pharyngeal airway volume was not correlated with positional changes of the hyoid bone.

Predicting Success of Transoral Robotic Surgery for OSA Using Preoperative Sleep Endoscopy and MRI Analysis

Objectives: Determine the relationship between surgical success and both preoperative drug-induced sleep endoscopy (DISE) airway caliber changes and volumetric magnetic resonance imaging (MRI) in patients with obstructive sleep apnea (OSA) undergoing transoral robotic assisted posterior glossectomy and uvulopalatopharyngoplasty (OSA-TORS). Methods: From 2009 to present, as part of a nonrandomized prospective trial, patients with OSA undergoing OSA-TORS had preoperative DISE and pre- and postoperative volumetric MRI of the upper airway. Quantitative analysis of the endoscopy and MRI were compared with surgical success based upon pre- and postoperative polysomnogram, with success defined as postoperative apnea-hypopnea index (AHI) &lt;20 and AHI decrease ≥50%. Preoperative MRI volumes were also compared against DISE changes. Results: Thirty-five apneics undergoing OSA-TORS underwent DISE, 21 received MRIs. DISE data showed that patients with surgical success had a smaller percentage decrease in overall airway collapse in the retroepiglottic ( P = .045) and retroglottic regions ( P = .08) compared with nonsuccesses. Larger preoperative MRI retroglottic airway volumes correlated with increased retroglottic ( P = .05) and retroepiglottic ( P = .03) lateral airway collapse on DISE, however, differences in pre- and postoperative MRI airway volumes did not correlate with surgical success. Conclusions: Larger retroglottic airway volume on MRI correlated with greater lateral airway collapse during DISE, but not with surgical success. Successes after OSA-TORS had significantly smaller airway collapse in the retroepiglottic regions than nonsuccesses during DISE, possibly due to better baseline muscle tone, allowing for better ability to benefit from the relatively small change in airway volume that OSA-TORS provides. Preoperative quantitative DISE could be used to identify patients more likely to succeed after OSA-TORS.

Pharyngeal airway volume and its relationship to the facial morphology in nasal breathing and mouth breathing subjects (A comparative computerized tomography study)

The value of lateral cephalometric radiographs to evaluate the pharyngeal airway is limited because it provided 2-dimensional (2D) images of complex 3-dimensional (3D) anatomic structures. Three dimensional analyses of the airway volumes are required to understand oral and pharyngeal adaptations in mouth breathing and nasal breathing subjects. The aim of this study was to measure the pharyngeal airway volume and the size of the face, then compare between pharyngeal airway volume in mouth breathing and nasal breathing subjects and find the gender difference in each group, also to study the relation between pharyngeal airway volume and the size of the face. Material and Methods: Fifty patients including 28 males and 22 females with an age ranged between 18-35 years suffered from clinical symptoms of nasal obstruction and mouth breathing was detected by otolaryngolog ist and sent to be imaged by Brilliance™ 64, Philips multi-detector computed tomography. Twenty normal subjects (10 males and 10 females) were selected as control. Angular and linear variables were measured in addition to the size of the face and the pharyngeal airway volume. Results: A statistically significant relationship between the pharyngeal airway volume and the mode of respiration and between pharyngeal airway volume and genders were detected. The pharyngeal airway volume was larger in nasal breathers than in mouth breathers and it was larger in males than in females. The size of the face was larger in males than females. Conclusion: CT volumetric images provide more reliable and accurate information for measurement of the pharyngeal airway volume, so the changes in the pharyngeal airway volume can be studied before and after surgery and this will aid in selection of the best treatment option in addition to control the relapse after orthodontic treatment with mouth breathing patients. Keyword: Pharyngeal airway volume, size of the face, mouth breathing, computerized tomography. (J Bagh Coll

Does Upper Premolar Extraction Affect the Changes of Pharyngeal Airway Volume After Bimaxillary Surgery in Skeletal Class III Patients?

The purpose of this study was to assess the pharyngeal airway volume change after bimaxillary surgery in patients with skeletal Class III malocclusion and evaluate the difference in postoperative pharyngeal airway space between upper premolar extraction cases and nonextraction cases. Cone-beam computed tomographic scans were obtained for 23 patients (13 in extraction group and 10 in nonextraction group) who were diagnosed with mandibular prognathism before surgery (T0) and then 2 months (T2) and 6 months after surgery (T3). Using InVivoDental 3-dimensional imaging software, volumetric changes in the pharyngeal airway space were assessed at T0, T2, and T3. The Wilcoxon signed-rank test was used to determine whether there were significant changes in pharyngeal airway volume between time points. The Mann-Whitney U test was used to determine whether there were significant differences in volumetric changes between the extraction and nonextraction groups. Volumes in all subsections of the pharyngeal airway were decreased (P < .05) except for changes in the oropharyngeal airway volume in the nonextraction group from T0 to T2. There were significant differences between the extraction and nonextraction groups in the changes of oro- and total pharyngeal airway volumes from T0 to T3. The null hypothesis was rejected. The extraction of upper premolars rather than nonextraction decreased the pharyngeal airway space more in patients with mandibular prognathism who planned to have bimaxillary surgery.