Soft palate length and upper airway relationship in OSA and non-OSA subjects

Clinical Prediction Models for Upper Airway Volume Based on Soft Palate and Airway Lumen Dimensions in Adults With Varying Vertical Skeletal Patterns

OBJECTIVES

To determine the intricate associations between soft palate dimensions, pharyngeal airway lumen area, the minimal constricted area of the airway (MinAx), and pharyngeal airway volume in subjects with diverse vertical skeletal patterns, and to develop prediction models that could help clinicians predict upper airway volume using soft palate dimensions, airway lumen dimensions, and MinAx.

MATERIALS AND METHODS

Pre-treatment lateral cephalometric radiographs and magnetic resonance imaging (MRI) scans of 80 women were classified into three vertical skeletal groups based on Frankfort-mandibular plane angle (FMA angle): hypodivergent (FMA < 26.9°, n = 26), normodivergent (26.9°≤ FMA ≤ 34.1°, n = 29), and hyperdivergent (FMA > 34.1°, n = 25). Soft palate dimensions, pharyngeal airway lumen data, MinAx, retropalatal airway volume (RPV), and retroglossal airway volume (RGV) data were measured using MRI. Forward multiple linear regression was used to predict pharyngeal airway volumes.

RESULTS

Among the eight predictive models developed, six exhibited strong performance, explaining 50%-77% of the variability in airway volumes. MinAx, RPV, and total pharyngeal airway volume (TPV) were considerably higher in hypodivergent subjects than in hyperdivergent subjects. Hyperdivergent subjects had a longer soft palate length (SPL) than normodivergent and hypodivergent subjects.

CONCLUSIONS

The present study highlights the necessity of considering soft palate dimensions and airway characteristics in orthodontic treatment planning, especially for patients with varying vertical skeletal patterns. Understanding these relationships can help in predicting potential airway issues and customising treatment plans accordingly.

Association Between Soft Tissue Measures From Computed Tomography and Upper Airway Collapsibility on Drug-Induced Sleep Endoscopy

OBJECTIVE

Positive airway pressure (PAP) titration during drug-induced sleep endoscopy (DISE) provides objective measures of upper airway collapsibility. While skeletal measurements relate to collapsibility measures on DISE, the influence of soft tissue dimensions on upper airway collapsibility is not known. We analyzed the relationship of measures of upper airway soft tissue volumes, specifically soft palate, pharyngeal lateral walls, and tongue, with metrics of collapsibility.

STUDY DESIGN

Cross-sectional analysis from a prospective cohort.

SETTING

Academic medical center.

METHODS

Patients seeking PAP alternative therapies for obstructive sleep apnea (OSA) underwent standardized supine computed tomography (CT) acquisition and DISE protocols. The CT analysis primarily focused on soft tissue volumes and, secondarily, on airway and skeletal volumetric measures. DISE with PAP administration (DISE-PAP) enabled the determination of the pressure at which inspiratory airflow first commenced (pharyngeal critical pressure, PcritA) and the pressure at which inspiratory flow limitation was abolished (pharyngeal opening pressure, PhOP). Both unadjusted and adjusted correlation analyses were performed to understand the relationship between upper airway anatomy and either PcritA or PhOP.

RESULTS

One hundred thirty-nine subjects completed both CT and DISE-PAP. On average, patients were male (70.5%), white (84.2%), middle-aged (56.6 ± 13.5 years), and overweight (29.6 ± 4.7 kg/m2), with moderate-severe apnea-hypopnea index (29.7 ± 21.3 events/h). Adjusted for age, sex, body mass index, and skeletal volumes, soft palate, and lateral pharyngeal wall volumes were not associated with PhOP or PcritA, but a larger tongue was associated with more positive PhOP (⍴ = 0.20, P = .02), and more positive PcritA (⍴ = 0.16, P = .07). Exploratory analyses revealed smaller minimum cross-sectional retropalatal area and intramandibular volume were also associated with increased collapsibility measures.

CONCLUSION

After controlling for clinical factors and skeletal volume, greater tongue volume was associated with more severe collapsibility during DISE. These results, in concert with previous work, suggest that greater tongue volume in a smaller skeletal dimensions contribute to the severity of airway collapsibility, a key driver of OSA pathogenesis.

Assessing the Accuracy of Lateral Cephalogram in Quantifying Three-Dimensional Pharyngeal Airway Morphology Compared to Cone-Beam Computed Tomography

BACKGROUND

When it comes to orthodontic diagnosis and treatment planning, the structures of the upper and lower airway space are crucial because of the role they play in craniofacial development.

AIM

The major objective of this study was to evaluate the accuracy of lateral cephalogram in the evaluation of upper and lower pharyngeal space by comparing it to clinical usage of cone-beam computed tomography (CBCT) in quantifying the 3D morphology of the pharyngeal airway.

METHODS AND MATERIALS

In total, 70 patients were included in the study. They had both a CBCT scan and a lateral cephalogram performed within a week of each other. Different cephalometric landmarks have been utilized to estimate linear and area dimensions for use in lateral cephalogram airway investigations. By superimposing the lateral cephalogram measurement of the vertical height of the pharyngeal airway over axial CBCT slices of 0.8 to 1 mm in thickness, airway volumes were calculated. For this study, we measured the pharyngeal airway space in each patient in two dimensions (2D) using the airway area from the lateral cephalogram and in three dimensions (3D) using the airway volume from the CBCT scan over the same region of interest, using a uniform scale and magnification throughout all split 3D volumes.

RESULTS

 The mean value of the area of pharyngeal space calculated by lateral cephalograph analysis (LCA) was 336.35 ± 86.49 mm2. The maximum value was 551.234 mm2. The minimum value was 206.32 mm2. The mean value of the volume of the same area calculated using CBCT was 3409.11 ± 1237.96 mm3. The maximum value was 5887.23 mm3. When the area calculated using LCA was compared with the volume calculated using CBCT, the correlation between them was significant statistically (r=0.831, p-value =0.000). The mean values of volume evaluated in 3D CBCT in males were 4198±1008 mm3 while for females it was 2980±1134.5 mm3. During the statistical analysis, these observations were found to have a positive correlation with increased volume of pharyngeal space in males as compared to that of females (p=0.006). The values of the area of pharyngeal space calculated using LCA in males was 370.1±60.9 mm2. while it was 301.9±88 mm2  in females.

CONCLUSION

The area estimated for the pharyngeal airway on LCA correlates strongly with the volume determined by a CBCT scan. Since we have considered pharyngeal space analysis using CBCT to be a reliable and standard methodology, therefore a positive correlation of area calculated using LCA with volume calculated using CBCT shows that the analysis made by LCA can be reliable.

Facial Contour Features Measured on CT Reflects Upper Airway Morphology in Patients With OSA

OBJECTIVE

To determine facial contour features, measured on computed tomography (CT), related to upper airway morphology in patients with obstructive sleep apnea (OSA); certain phenotype of facial abnormalities implying restriction of craniofacial skeleton and adipose tissue nimiety has predicted the value of the severity of OSA.

MATERIALS AND METHOD

Sixty-four male patients with OSA [apnea-hypopnea index (AHI) ≥10/h] who had upper airway CT were randomly selected to quantitatively measure indicators of facial contour and upper airway structures. Pearson correlation analyses were performed. Partial correlation procedure was used to examine correlations while controlling body mass index (BMI).

RESULTS

Upper airway anatomy can nearly all be reflected in the face, except retroglossal airway. Upper face width can be measured to assess the overall skeletal structures of the airway. Lower face width can be used to represent how much adipose tissue deposited. Hard palate, retropalatal, and hypopharyngeal airways have corresponding face indicators respectively. Midface width is a better predictor of AHI severity and minimum blood oxygen even than neck circumference because it contains the most anatomical information about the airway, including RP airway condition, soft palate length, tongue volume, etc. These correlations persisted even after correction for BMI.

CONCLUSIONS

All anatomical features of the upper airway except retroglossal airway can be reflected in the face, and midface width is the best predictor of AHI severity and minimum blood oxygen, even better than neck circumference and BMI.

Effect of premolar extraction and anchorage type for orthodontic space closure on upper airway dimensions and position of hyoid bone in adults: a retrospective cephalometric assessment

Background

This study aimed to assess the effect of premolar extraction and anchorage type for orthodontic space closure on upper airway dimensions and position of hyoid bone in adults by cephalometric assessment.

Methods

This retrospective study was conducted on 142 cephalograms of patients who underwent orthodontic treatment with premolar extraction in four groups of (I) 40 class I patients with bimaxillary protrusion and maximum anchorage, (II) 40 class I patients with moderate crowding and anchorage, (III) 40 class II patients with maximum anchorage, and (IV) 22 skeletal class III patients with maximum anchorage. The dimensions of the nasopharynx, velopharynx, oropharynx, and hypopharynx, and hyoid bone position were assessed on pre- and postoperative lateral cephalograms using AudaxCeph v6.1.4.3951 software. Data were analyzed by the Chi-square test, paired t-test, and Pearson's correlation test (alpha = 0.05).

Results

A significant reduction in oropharyngeal, velopharyngeal, and hypopharyngeal airway dimensions was noted in groups I, III, and IV (P < 0.001), which was correlated with the magnitude of retraction of upper and lower incisors (r = 0.6 - 0.8). In group II, a significant increase was observed in oropharyngeal and velopharyngeal dimensions (P < 0.001). A significant increase in nasopharyngeal dimensions occurred in all groups (P < 0.001). Also, in groups I and III, the position of hyoid bone changed downwards and backwards, which was correlated with reduction in airway dimensions (r = 0.4 - 0.6).

Conclusion

According to the present results, extraction orthodontic treatment affects upper airway dimensions and hyoid bone position. Maximum anchorage decreases airway dimensions while moderate anchorage increases airway dimensions.

Craniofacial Phenotype in Obstructive Sleep Apnea and Its Impact on Positive Airway Pressure (PAP) Adherence

Positive airway pressure (PAP) is an important treatment tool for patients with moderate and severe obstructive sleep apnea (OSA), and adherence to PAP significantly affects treatment outcomes. Disease severity, adverse effects, and psychosocial factors are known to predict medication adherence. Cephalometric parameters have been reported to positively correlate with upper airway collapse. However, research on the correlation between these cephalometric parameters and PAP adherence remains insufficient. This study aimed to identify this relationship. This study included 185 patients with OSA who were prescribed PAP. Polysomnography (PSG) was performed to diagnose OSA, and paranasal sinus computed tomography (PNS CT) was performed to check for comorbidities of the upper airway. In addition, cephalometric parameters such as the hyoid-posterior nasal spine (H-PNS), posterior nasal spine-mandibular plane (PNS-MP), and hyoid-mandibular plane (H-MP) were measured in the midsagittal and axial CT views. Adherence was evaluated 3-12 months after the PAP prescription. A total of 136 patients were PAP-adherent, and 49 were nonadherent. There were more males in the adherent group and a higher average height in the adherent group. The PSG results showed that the apnea-hypopnea index (AHI), respiratory disturbance index (RDI), oxygen desaturation index (ODI), arousal index (AI), rapid eye movement (REM) AHI, and supine AHI were significantly higher, and the lowest oxygen saturation was lower in the adherent group. In the analysis of covariance (ANCOVA) model adjusted for sex and height, among the cephalometric parameters, H-MP was significantly longer in the adherent group (p = 0.027), and H-PNS showed a longer tendency (p = 0.074). In the logistic regression analysis model, the odds ratio (OR) and 95% confidence intervals (95% CI) of adherence and severe OSA in the third tertile compared to the first tertile of H-MP were 2.93 (1.25-6.86) and 4.00 (1.87-8.56). In the case of H-PNS, they were 2.58 (1.14-5.81) and 4.86 (2.24-10.54), respectively. This study concluded that an inferiorly placed hyoid bone in adult patients is associated with PAP adherence and disease severity.

A computed tomographic evaluation of effect of mandibular advancement device at two different horizontal jaw positions in patients with obstructive sleep apnea

Statement of problem

Studies pertaining to the objective assessments of the efficacy of mandibular advancement device in patients with obstructive sleep apnea are scarce.

Purpose

The purpose of this clinical study was to evaluate the effect of MAD at two different horizontal positions of mandible on upper airway dimensions through computed tomography.

Material and methods

Twenty-nine consenting participants satisfying predetermined inclusion and exclusion criteria were enrolled and an adjustable two-piece MAD was fabricated at 50% maximum mandibular protrusion and after 4 weeks was adjusted to 70% protrusion. CT scans were obtained at baseline, 4 weeks after delivering MAD with 50% mandibular protrusion, and then after 4 weeks with 70% mandibular protrusion. Cross sectional area with diameters (lateral and anteroposterior) of upper airway was measured at three specific anatomic levels (retropalatal-RP, retroglossal-RG, and epiglottal-EG). Data were analyzed using the Student t-test for parametric analysis.

Results

Intragroup comparison revealed a statistically significant increase in lateral & anteroposterior dimensions as well as cross sectional area at all three anatomical levels at 4 weeks after MAD with 50% mandibular protrusion compared with baseline and 4 weeks after MAD with 70% mandibular protrusion compared with baseline. However, the difference between lateral and anteroposterior dimensions with MAD at 70% protrusion compared with MAD at 50% protrusion was not statistically significant. The difference between cross-sectional area was found to be statistically significant.

Conclusion

Mandibular advancement device at 70% mandibular protrusion is more effective compared with the device at 50% protrusion in relieving oropharyngeal obstruction seen in OSA.

Correlations between Morphology, the Functional Properties of Upper Airways, and the Severity of Sleep Apnea

Obstructive sleep apnea (OSA) is considered the silent killer pathology of the new millennium. This is due to increased risk factors such as obesity. Healthcare systems face an increasing burden from severe cases of OSA. We performed a study on a group of 152 Romanian patients with OSA recording data obtained through polysomnography and cephalometric variables, recorded in lateral plain X-rays. The results confirmed some of the data available from previous studies worldwide, but some of the variables presented a positive statistical correlation specific to our study group. For example, the apnea-hypopnea index (AHI) correlated with the uvula length but surprisingly did not correlate with body mass index (BMI) because obesity tends to become endemic in Romania. To our knowledge, this is one of the first studies focusing on cephalometric data in Romanian OSA patients. The results obtained through this study will be further analyzed in research on larger groups of Romanian OSA patients.

Postoperative Changes in Tongue Area and Pharyngeal Airway Space following Mandibular Setback Surgery through Intraoral Vertical Ramus Osteotomy

Purpose

The aim of this study was to determine changes in the tongue area and pharyngeal airway space (PAS) after intraoral vertical ramus osteotomy (IVRO).

Materials and Methods

Serial lateral cephalograms of 40 patients with mandibular prognathism who underwent IVRO were evaluated before (T1), immediately after (T2), and more than 1 year after (T3) surgery. Paired t-tests and Pearson's correlation analysis were used to evaluate the postoperative changes in the mandible, nasopharyngeal airway (NOP), retropalatal pharyngeal airway (RPP), retroglossal pharyngeal airway (RGP), hypopharyngeal airway (HOP), PAS, and tongue area (TA). The null hypothesis states that there are no significant correlations among the extent of mandibular setback and the changes in the TA and PAS after IVRO.

Results

Immediately after the operation (T12), the mandible was set back by 12.6 mm. The NOP, HOP, and PAS were significantly reduced by 35.7 mm², 116 mm², and 185 mm², respectively. The TA was increased by 69.6 mm². The changes in PAS and TA revealed no significant difference between female and male patients at T12, T23, and T13. Moreover, no significant correlations were found among the extent of mandibular setback, TA changes, and PAS changes after IVRO. Thus, the null hypothesis was accepted.

Conclusions

At the final follow-up (T13), no significant change was found in the PAS (including NOP, RPP, RGP, and HOP) and TA. The changes in PAS and TA revealed no significant difference between female and male patients at T12, T23, and T13.

Airway volume analysis: is there a correlation between two and three-dimensions?

Objectives

No consensus exists on the assessment of airway in CBCT scans. Two-dimensional measures remain the standard in the cephalometric analysis. This research aimed to evaluate linear and area measurements in two-dimensional views from specific airway regions of interest and compare these to the correspondent volume in CBCT exams.

Materials and Methods

250-selected CBCT scans were retrospectively analyzed. A trained and calibrated examiner performed the linear, area and volume measurements in specific sites for nasal cavity, nasopharynx and oropharynx compartments. Dolphin Software was used for the analysis. The correlations were performed using Pearson coefficient.

Results

The highest positive correlations were observed in the nasopharynx and oropharynx sagittal areas and the most constricted area in the oropharynx. Nasopharynx linear measures and nasopharynx coronal area did not present correlation with whole volume. Two-dimensional measurements in the soft palate (width and sagittal area) showed very low positive correlations. Although nasal cavity presented highest volume means, changes in oropharynx contributed more to variations in total volume, compared with the other two sections.

Conclusion

Airway sagittal areas, as well as the most constricted axial area in oropharynx remains a useful guide to correlate with airway volume in two-dimensional images.

Obstructive sleep apnea syndrome and olfactory perception: An OERP study

Obstructive Sleep Apnea Syndrome (OSA) is characterized by snoring associated with repeated apnea and/or obstructive hypopnea. The nasal airways of OSA patients, measured via acoustic rhinometry, could be significantly narrower than healthy subjects and this reduced nasal structure can impair olfactory function. The relationship between nasal structure and olfactory function, assessed via behavioral test results, indicates that there is a high prevalence of nasal airflow problems. Based on these assumptions, the purpose of this study was to carry out an assessment of olfactory perception in OSA patients through the Chemosensory Event-Related Potentials (CSERP), investigating the N1 component and the Late Positive Component (LPC). Twelve OSA patients, non-smokers, were recruited in the Pulmonary Rehabilitation Unit, scored with the Epworth Sleepiness Scales, after Polygraphic Recording, Apnea Hypopnea Index and Body Mass Index evaluation. The control group consisted of twelve healthy controls, non-smokers, recruited as volunteers. Subjects, during an EEG recording, performed an oddball olfactory recognition task based on two scents: rose and eucalyptus. Main results highlighted differences in N1 and LPC between OSA and controls. OSA patients presented faster N1 latencies and greater amplitude. The same trend was found in LPC, where OSA showed decreased latency and increased amplitude during rose stimulation, in the right inferior frontal cortex. and faster latencies in left centroparietal cortex OERP results can suggest an impairment in endogenous components. This result could be the consequence of the exogenous perceptual difficulty highlighted in N1 component. The increased arousal could also be related to the respiratory activity involved during the olfactory task.

Endotracheal tube placement during computed tomography of brachycephalic dogs alters upper airway dimensional measurements

Computed tomography (CT) is used to document upper airway lesions in dogs with brachycephalic obstructive airway syndrome. The presence of an endotracheal tube during CT scanning is often required for general anesthesia. We hypothesized that the endotracheal tube placement would change the soft tissue dimensions of the upper airway. The aims of this prospective, method comparison study were to evaluate the reliability of the previously reported upper airway CT measurements with endotracheal tube placement, and to propose measurements that are minimally affected by the endotracheal tube. Twenty brachycephalic dogs were included in this study. Each dog underwent head/neck CT with an endotracheal tube, followed by a second scan without the endotracheal tube. Ten measurements of the soft palate, nasopharynx, and trachea were performed. Tracheal dimension was significantly larger with the endotracheal tube compared to without, whereas the soft palate cross-sectional area was significantly smaller with the endotracheal tube than without the endotracheal tube. The influence of the endotracheal tube on the caudal nasopharynx cross-sectional (transverse-sectional) area varied with a mean proportional absolute difference of 35%. Rostral soft palate thickness, tracheal perimeter, and cross-sectional area of the rostral nasopharynx were the measurements least affected by the endotracheal tube (intraclass correlation coefficient = 0.964, 0.967, and 0.951, respectively). Therefore, we proposed that these three measurements may be most useful for future brachycephalic obstructive airway syndrome studies that require CT scanning of intubated animals. However, with endotracheal tube placement, measurements of soft palate length, caudal nasopharyngeal cross-sectional area, and trachea height and width may not be reliable.

Obesity as a Disease

Obesity is a complex disease with many causal factors, associated with multiple comorbidities that contribute to significant morbidity and mortality. It is a highly prevalent disease that poses an enormous health and economic burden to society. This article reviews the mechanisms of obesity and its related comorbidities.

Ankyloglossia as a risk factor for maxillary hypoplasia and soft palate elongation: A functional - morphological study

OBJECTIVES

To characterize associations between restricted tongue mobility and maxillofacial development.

SETTING AND SAMPLE POPULATION

Cross-sectional cohort study of 302 consecutive subjects from an orthodontic practice.

MATERIAL AND METHODS

Tongue mobility (measured with tongue range of motion ratio [TRMR] and Kotlow free tongue measurement) was correlated with measurements of the maxillofacial skeleton obtained from dental casts and cephalometric radiographs.

RESULTS

Tongue range of motion ratio and Kotlow measures of restricted tongue mobility were associated with (i) ratio of maxillary intercanine width to canine arch length, (ii) ratio of maxillary intermolar width to canine arch length and (iii) soft palate length. Restricted tongue mobility was not associated with hyoid bone position or Angle's skeletal classification.

CONCLUSIONS

Restricted tongue mobility was associated with narrowing of the maxillary arch and elongation of the soft palate in this study. These findings suggest that variations in tongue mobility may affect maxillofacial development.

Cephalometrics of Pharyngeal Airway Space in Lebanese Adults

Purpose. The upper airway space is significant in orthodontic diagnosis and treatment planning. The objectives of this study are to assess the dimensions of soft tissue elements of the upper pharyngeal space and evaluate potential correlations with modifying variables such as gender, skeletal class, and anthropometric parameters. Materials and Methods. Lateral cephalograms were obtained from 117 healthy young adult Lebanese subjects. Nineteen cephalometric linear/angular measurements of the nasopharynx, oropharynx, and hypopharynx were recorded. Anthropometric parameters including body mass index and neck circumference were measured. Results. Significant differences were demonstrated for 12 out of the 19 parameters considered between genders. Uvula and tongue dimensions and the distances between epiglottis-posterior pharyngeal wall and epiglottis-posterior nasal spine were significantly larger in males. The anteroposterior inclination of the uvula and the distances between the uvula and posterior pharyngeal wall were significantly greater in females. No significant differences were found between skeletal classes relative to most of the variables. Body mass index and neck circumference were positively correlated with the dimensions of tongue and uvula. Conclusions. Sexual dimorphism relative to some cephalometric variables and anthropometric parameters may account partly for larger oronasopharyngeal spaces in females. Anthropometric data need to be accounted for in population-related comparisons.

Three-dimensional analyses of palatal morphology and its relation to upper airway area in obstructive sleep apnea

OBJECTIVE

To evaluate the relationship between palatal morphology and pharyngeal airway morphology in patients who have obstructive sleep apnea (OSA) and compare with a nonsnoring and nonapneic control group.

MATERIALS AND METHODS

Three-dimensional maxillary dental cast measurements from 25 OSA patients (6 women, 19 men) with a mean age of 41.5 (4.8) years, and 25 control group participants (14 women, 11 men) without any symptom of OSA with a mean age of 38.3 (3.7) were correlated with an analysis of pharyngeal area evaluated with lateral cephalograms. Intermolar and intercanine widths and palatal volumes were calculated on the dental casts, and the upper airway area measurements were performed on lateral cephalograms.

RESULTS

OSA patients had smaller oropharyngeal volume and upper airway when compared with controls (P < .001). Palatal area measurements were significantly smaller in OSA (P < .001). OSA patients had significantly narrower maxilla with smaller intermolar and intercanine widths (P < .001). A positive correlation was found between the palatal morphology and pharyngeal dimensions.

CONCLUSIONS

A significant correlation exists between palatal morphology and pharyngeal airway.

Three-dimensional imaging of the upper airway anatomy in obstructive sleep apnea: a systematic review

INTRODUCTION

The pathogenesis of upper airway collapse in people with obstructive sleep apnea (OSA) is not fully understood. The aim of this study was to systematically review the literature in order to assess the most relevant anatomical characteristics of the upper airway related to the pathogenesis of OSA by analyzing the three-dimensional upper airway anatomy.

METHOD

A PICO (population/patient, intervention, comparison, outcome) search strategy, focusing on the upper airway anatomy of people with OSA, was conducted using the following databases: MEDLINE (PubMed), Excerpta Medica database (EMBASE), Web of Science, and Cochrane Library. The studies in which three-dimensional images were made from the participants who were awake and in the supine position during quiet breathing were selected in this systematic review.

RESULTS

Of the 758 unique retrieved studies, eight fulfilled the criteria for this systematic review. The minimum cross-sectional area of the upper airways of people with OSA, which is influenced by many factors such as hard and soft tissues surrounding the upper airway, was significantly smaller than that of those without OSA.

CONCLUSION

Within the limitation of the selected studies, this systematic review suggested that a small minimum cross-sectional area is the most relevant anatomical characteristic of the upper airway related to the pathogenesis of OSA.

The effect of teeth extraction for orthodontic treatment on the upper airway: a systematic review

PURPOSE

The purpose of this study was to evaluate the effect of teeth extraction for orthodontic treatment on the upper airway.

METHODS

Relevant trials assessing the effect of orthodontic extractions on the upper airway were retrieved electronically through PubMed, Embase, Medline, Web of Knowledge, and the Cochrane Library. The processes of literature search, selection, quality assessment, and data extraction were performed by two authors independently.

RESULTS

Seven articles were included in this systematic review. They were categorized into three groups according to their indications for extractions, namely anteroposterior discrepancy (group 1), crowding (group 2), and unspecified indications (group 3). In group 1, enrolled patients were diagnosed with class I bimaxillary protrusion and had four first premolars extracted, with a significant decrease in upper airway dimension. In group 2, increase in the upper airway dimension was reported in patients who were diagnosed with class I crowding and four first premolars extracted. In group 3, all patients were adolescents and no significant change in the upper airway dimension was observed.

CONCLUSIONS

Currently, it is difficult to draw evidence-based conclusions because of the exceeding heterogeneity among included studies, and more qualified trials are required to provide reliable evidence. Extractions followed by large retraction of the anterior teeth in adult bimaxillary protrusion cases could possibly lead to narrowing of the upper airway. Mesial movement of the molars appeared to increase the posterior space for the tongue and enlarge the upper airway dimensions. Although the effect of teeth extraction on upper airway dimension seems to be related to indications for extraction, accepted scientific evidence is still insufficient owing to the limited number of included studies. The relationship between the upper airway size and the respiratory function has not been demonstrated. While there may be a decrease in the upper airway volume, there is no evidence that this would turn an airway more collapsible. None of the studies assessed in this review had actual functional assessment of breathing. Additional qualified trials are necessary to verify reliability.

Efficacy of radiofrequency treatment of the soft palate for patients with mild to moderate obstructive sleep apnea hypopnea syndrome: treatment protocol with nine lesions to the soft palate

PURPOSE

The study aimed at assessing the efficacy and safety of a radiofrequency treatment (RFT) protocol with nine lesions to the soft palate in the treatment of mild to moderate obstructive sleep apnea hypopnea syndrome (OSAHS).

METHODS

Twenty-eight mild to moderate OSAHS patients underwent two sessions of RFT (CelonLab ENT system) at the palatal level within the interval from 6 to 8 weeks. Nine lesions (power setting of 10 W) were made per session. The baseline and posttreatment polysomnography and clinical tests battery consisting of visual analogue scales (VAS), Sleep Apnea Quality of Life Index (SAQLI), Beck Depression Inventory--second edition (BDI-II), and Epworth sleepiness scale (ESS) were applied to assess the RFT outcomes.

RESULTS

Mild to moderate OSAHS patients demonstrated statistically significantly reduced posttreatment mean VAS values for most of the OSAHS-related complaints. A significant improvement in sleepiness (ESS score 6.7 ± 3.7 vs 8.5 ± 4.1, p < 0.01), depressivity (BDI-II score 7.5 ± 6.5 vs 13.1 ± 11.7, p < 0.01), and health-related quality of life (SAQLI score 5.3 ± 0.8 vs 4.7 ± 0.9, p < 0.01) was observed after the RFT. The mean AHI decreased from 13.7 ± 5.9 to 8.3 ± 4.9 points (p < 0.01) in the entire group of patients. According to Sher's criteria of success, 17 out of 28 (60.7 %) patients improved after RFT. No major complications were noted with RFT.

CONCLUSIONS

RFT protocol with nine lesions to the soft palate seems to be an effective and safe treatment modality associated with low morbidity in selected mild to moderate OSAHS patients.

The impact of pharyngeal fat tissue on the pathogenesis of obstructive sleep apnea

PURPOSE

Obesity is the most important risk factor for obstructive sleep apnea (OSA); however, the exact underlying mechanisms are still not fully understood. The aim of this study was to examine the morphology of upper airways in overweight habitual snorers and in mild OSA patients. Furthermore, the associations between weight loss, parapharyngeal fat pad area and OSA were assessed in a 1-year randomised, controlled follow-up study originally conducted to determine the effects of lifestyle changes with weight reduction as a treatment of OSA.

METHODS

Thirty-six overweight adult patients with mild OSA [apnea-hypopnea index (AHI) 5-15 events/h] and 24 weight-matched habitual snorers (AHI < 5 events/h) were included in the study. All patients underwent nocturnal cardiorespiratory recordings and multislice computed tomography (CT) of parapharyngeal fat pad area, the smallest diameter and area in naso-, oro- and hypopharynx, the smallest diameter and area of the whole pharyngeal airway, the distance from the hyoid bone to the mandibular plane and to cervical tangent as well as the distance between mandibular symphysis and cervical spine. In addition, OSA patients were further randomised to receive either an active 1-year lifestyle intervention with an early weight loss programme or routine lifestyle counselling. After 1 year, the cardiorespiratory recordings and CT scans were repeated.

RESULTS

The pharyngeal fat pad area was significantly larger, and the distance from the hyoid bone to cervical spine was longer in patients with OSA than in habitual snorers (p = 0.002 and p = 0.018, respectively). The multiple regression analysis showed that besides a large pharyngeal fat pad area and a long distance from the cervical spine to hyoid bone, also a short distance from the mandibular symphysis to cervical tangent increased a risk to OSA. During the 1-year follow-up in OSA patients, the pharyngeal fat pad area and AHI decreased significantly in the intervention group (p = 0.003 and p < 0.001, respectively).

CONCLUSIONS

In the early stages of OSA, the pharyngeal fat pad seems to play an important role in the development of disease in overweight patients. Furthermore, weight reduction by lifestyle intervention-based programme reduces both central obesity and pharyngeal fat pads, resulting in an improvement of OSA.

Comparison of cone-beam computed tomography incidental findings between patients with moderate/severe obstructive sleep apnea and mild obstructive sleep apnea/healthy patients

OBJECTIVE

The objective of this study was to compare the incidental radiographic findings in the maxillofacial structures and the pharyngeal airway between subjects with moderate/severe obstructive sleep apnea (OSA) and mild OSA/healthy subjects using cone-beam computed tomography (CBCT) scans.

STUDY DESIGN

A total of 53 subjects with moderate/severe OSA (with a Respiratory Disturbance Index [RDI] ≥ 15 events/h) and 33 mild OSA/healthy subjects (RDI < 15), based on ambulatory somnographic assessment, were recruited. Supine CBCTs were taken and sent for radiological report. The incidental findings were compared between the 2 groups.

RESULTS

Moderate/severe subjects had larger prevalence of conchae bullosa, hypertrophic turbinates, hypertrophic tonsils, elongated or posteriorly placed soft palate, narrower airway, enlarged tongue, and focal calcifications, although no significant differences were found.

CONCLUSIONS

CBCT is useful in identifying maxillofacial and airway anomalies that could interfere with normal breathing; however, no significant difference was found in prevalence of incidental findings between subjects with moderate/severe OSA and mild OSA/healthy subjects. Further studies are necessary to generalize our results.

Magnetic resonance imaging in the evaluation of anatomical risk factors for pediatric obstructive sleep apnoea-hypopnoea: a pilot study

OBJECTIVE

Aim of our study was to identify anatomical risk factors involved in the development of pediatric OSAHS through a MRI-based case-control pilot study.

METHODS

MRI exams of the head and neck of 40 children affected by OSAHS were retrospectively evaluated. 25 indices referring to the air lumen, soft tissues and craniofacial skeleton were measured. Subsequently, the same process of measurement of indices was performed on MRI exams of 40 controls. For each index, then, we calculated in both groups mean, standard deviation, standard error and t value. Comparing the two series we finally calculated the degree of significance of each difference between children with OSAHS and controls through the Student's t-test.

RESULTS

Besides the expected and previously described differences of minimum retropharyngeal cross-sectional area (CSA), nasopharyngeal airway, combined upper airway volume, tonsillar and adenoid cross-sectional and volumetric indices, we found a higher midsagittal CSA of the soft palate and lower position of the hyoid bone, SNB angle and mandibular volume.

CONCLUSIONS

Results from our study population, certainly limited in terms of number of patients and considered age range, showed that not only adeno-tonsillar hypertrophy is important in determining the clinical syndrome: soft palate enlargement and certain skeletal pattern can even assume greater importance in the genesis and in the progression of the obstruction. MRI proved to be an accurate technique in the evaluation of the prevalent risk factor in children affected by OSAHS, leading to the most appropriate surgical approach.

Characteristics of sleep-disordered breathing in Japanese patients with acromegaly

Sleep-disordered breathing (SDB), especially sleep apnea-hypopnea syndrome (SAS), is often observed in patients with active acromegaly. This complication is a risk factor for cardiovascular disease and associated with increased morbidity and mortality in acromegaly. However there is little information on SDB in Japanese patients with acromegaly. We investigated the prevalence of SDB and association between the severity of SDB and various features and biomarkers in Japanese patients with acromegaly. Twenty-four Japanese patients with active acromegaly underwent overnight cardiorespiratory monitoring, hormonal assays and cephalometric measurements on X-ray. A high prevalence of SDB was detected in acromegaly (87.5%). Log apnea-hypopnea index (AHI) correlated positively with soft palate length / body height (X-ray) (r=0.44, p=0.043), but not with log growth hormone levels and insulin-like growth factor type-1 standard deviation scores, size of pituitary adenoma, disease duration, body mass index, waist circumference, estimated visceral fat area, heel pad thickness / height, tongue thickness/ height, or oropharyngeal dimension/ height. In conclusion, our study demonstrated a high prevalence of SDB in Japanese patients with acromegaly, and its severity correlated with soft palate length. Based on the high incidence of SDB identified in the present study, we recommend that all patients with acromegaly are routinely screened for SDB for early diagnosis and treatment.

Subcutaneous fat tissue thickness of the anterior neck and umbilicus in patients with obstructive sleep apnea

OBJECTIVE

To investigate the differences in thickness of subcutaneous fat tissue of the anterior neck and umbilicus of patients with and without obstructive sleep apnea (OSA), the relationship between thickness of subcutaneous fat tissue of the anterior neck and umbilicus and polysomnographic findings, and the influence of body mass index (BMI), anthropometric findings, and gender.

STUDY DESIGN

Cross-sectional study.

SETTING

Tertiary care university hospital.

SUBJECT AND METHODS

Seventy-three patients with OSA and 24 non-OSA patients were evaluated with polysomnography for 1 night. Anthropometric parameters and BMI were also investigated. Subcutaneous fat tissue thickness of anterior neck and umbilicus was assessed using ultrasound. The thickness of subcutaneous fat tissue adjacent to the submandibular gland, isthmus, hyoid, suprasternal notch, and umbilicus was measured with ultrasound. Data analysis was performed using SPSS.

RESULTS

Apnea-hypopnea index (AHI) was significantly and positively correlated with age (P = .016, r (2) = 0.244), BMI (P < .001, r (2) = 0.416), and anthropometric findings (waist circumference P < .001, r (2) = 0.337; hip circumference P = .008, r (2) = 0.269; neck circumference P = .002, r (2) = 0.309). Minimum oxygen saturation was significantly, negatively correlated with age (P = .002, r (2) = -0.310), BMI (P < .001, r (2) = -0.404), and anthropometric findings (waist circumference P = .005, r (2) = -0.281, hip circumference P < .001, r (2) = -0.353, neck circumference P = .010, r (2) = -0.261). There were no significant differences between the OSA and non-OSA groups with respect to age (P = .178), gender (P = .189), or ultrasonographic findings for subcutaneous fat tissue thickness adjacent to the submandibular gland (P = .480), thyroid isthmus (P = .311), suprasternal notch (P = .950), umbilicus (P = .691), or hyoid (P = .159). Neck circumference (P = .039) and BMI (P = .014) were significantly higher in the OSA group.

CONCLUSION

These indicate that anterior neck and umbilical subcutaneous fat tissue thickness may not contribute to the severity of OSA.