Frontal and Lateral Cephalometry in Patients With Sleep-Disordered Breathing

Monitoring of Home Respiratory Polygraphy During Mandibular Distraction Osteogenesis Succeeded by LeFort I Osteotomy in Adult Patients With Obstructive Sleep Apnea

BACKGROUND

Bilateral internal ramus distraction (BIRD) is now part of select protocols for treating obstructive sleep apnea (OSA). Introducing a home monitoring protocol offers a valuable alternative to overnight laboratory polysomnography (PSG).

PURPOSE

The purpose of this study was to evaluate and compare OSA parameters obtained via home respiratory polygraphy (HRP) and hospital PSG in a cohort of patients undergoing mandibular distraction for OSA management.

STUDY DESIGN, SETTING, SAMPLE

Hospital Universitario La Princesa (Madrid) researchers conducted a prospective cohort study with patients diagnosed with moderate (apnea-hypopnea index (AHI) = 15 to 30) to severe (AHI>30) OSA undergoing BIRD followed by LeFort maxillary osteotomy. Exclusion criteria were as follows: severe systemic diseases, central apneas, smoking, poor dental hygiene, or prior OSA interventions.

PREDICTOR VARIABLE

The predictor variable was PSG and HRP techniques.

MAIN OUTCOME VARIABLES

The main outcome variable comprises a collection of OSA parameters, including the AHI, oxygen desaturation index (ODI), and time spent below 90% oxygen saturation (T90). These data were measured both before and after distraction, as well as after 6 mm, 9 mm, and 12 mm of mandibular distraction.

COVARIATES

The covariates were age, sex, cardiovascular risk parameters, and the Epworth sleepiness scale.

ANALYSES

Pearson's correlation analyzed AHI, ODI, and T90 values from PSG and HRP. Wilcoxon Signed Rank-Sum Test compared 2 distraction stages, and the Friedman Test evaluated 3 stages (P < .05). Multiple regression analysis assessed if covariates were independent risk factors for postoperative persistent OSA.

RESULTS

The study included 32 patients (25% with moderate and 75% with severe OSA). Final AHI was 10.9 ± 8.9 (events/hour) with HRP, compared to 15.2 ± 13.4 with PSG (r = 0.7, P < .05). ODI was 9.0 ± 8.1 (des/h) with HRP and 8.7 ± 9.5 with PSG (r = 0.85, P < .05). T90 was 1.6 ± 2.2 with HRP and 1.3 ± 3.0 with PSG (r = 0.6, P < .05). Based on HRP data, AHI improved from D1 (34.0 ± 19.5) to D2 (20.8 ± 14.1) and D3 (12.5 ± 10.4) (P < .05). ODI decreased from D1 (26.1 ± 19.0) to D2 (16.0 ± 12.6) and D3 (9.4 ± 8.8) (P < .05). T90 reduced from D1 (8.2 ± 12.6) to D2 (4.1 ± 5.2) and D3 (1.9 ± 2.8) (P < .05). Multiple regression analysis of comorbidities produced nonsignificant results.

CONCLUSION AND RELEVANCE

Monitoring BIRD through HRP has demonstrated efficacy in yielding results that align with PSG.

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.

Comparison of twin block appliance and Forsus Fatigue Resistant Device therapies on uvulo-glossopharyngeal dimensions: A retrospective study

Objectives:

The aim of this study was to compare the effects of two different functional appliances on skeletal, dental, and uvulo-glossopharyngeal dimensions.

Materials and Methods:

Pre- and post-treatment lateral cephalograms of 50 adolescent Class II patients with a retrognathic mandible were obtained from an archive and divided into two groups according to functional therapy. Twenty-five patients (14 females, 11 males, mean age: 13.5 ± 2.8) who were treated with Forsus Fatigue Resistant Device (FFRD) and 25 patients (17 females, eight males, mean age: 12.5 ± 0.4) who had received functional therapy through the twin block (TWB) were enrolled. Skeletal, dentoalveolar, tongue, uvula, hyoid position, and oropharyngeal airway parameters were measured using the Dolphin software, and uvulo-glossopharyngeal area measurements were performed with the AutoCAD software.

Results:

The TWB group exhibited remarkable mandibular advancement compared to the FFRD group (P < 0.05). Both of the treatments proclined mandibular incisors, and tongue dimensions increased significantly in both groups (P < 0.05). While the hyoid point moved forward and the oropharyngeal area increased significantly in the TWB group, no significant changes were observed in the FFRD group. The comparison of the TWB and FFRD groups with regard to uvulo-glossopharyngeal dimensions showed no significant differences between the groups (P > 0.05).

Conclusion:

Changes in uvulo-glossopharyngeal dimensions did not significantly vary between the two different functional therapies.

Severity evaluation of obstructive sleep apnea based on speech features

PURPOSE

There are upper airway abnormalities in patients with obstructive sleep apnea (OSA), and their speech signal characteristics are different from those of unaffected people. In this study, the severity of OSA was evaluated automatically by machine learning technology based on the speech signals of Chinese people.

METHODS

In total, 151 adult male Mandarin native speakers who had suspected OSA completed polysomnography to assess the severity of the disease. Chinese vowels and nasal sounds were recorded in sitting and supine positions, and the accuracy of predicting the apnea-hypopnea index (AHI) of the participants using a machine learning method was analyzed based on features extracted from the speech signals.

RESULTS

Among the 151 participants, 75 had AHI > 30 events/h, and 76 had AHI ≤ 30 events/h. Various features including linear prediction cepstral coefficients (LPCC) were extracted from the data collected from participants recorded in the sitting and supine positions and by using a linear support vector machine (SVM); we classified the participants with thresholds of AHI = 30 and AHI = 10 events/h. The accuracies of the classifications were both 78.8%, the sensitivities were 77.3% and 79.1%, and the specificities were 80.3% and 78.0%, respectively.

CONCLUSION

This study constructed a severity evaluation model of OSA based on speech signal processing and machine learning, which can be used as an effective method to screen patients with OSA. In addition, it was found that Chinese pronunciation can be used as an effective feature to predict OSA.

No correlation between two-dimensional measurements and three-dimensional configuration of the pharyngeal upper airway space in cone-beam computed tomography

The aim of this study was to evaluate both the 2-dimensional (2D) and 3-dimensional (3D) configuration of the posterior airway space (PAS) in healthy 239 patients using cone-beam computed tomography (CBCT). In particular, we investigated the correlation between the 2D and 3D measurements in view of the potential impact on diagnosis of upper airway obstruction. The pharyngeal airway of each patient was studied at five levels: the level of the posterior nasal spine (PNS), the level of half-height of the PNS and the tip of the soft palate, the level of the tip of the soft palate, the level of the anterior-inferior point of the second vertebra, and at least the level of the top of the epiglottis. At each of these levels, the anterior-posterior dimension as well as the corresponding cross-sectional area was measured. Furthermore we measured the volume of the whole PAS between the first and the last level and compared it with the corresponding 2D values. Differences between genders and age effects were estimated in an analysis of covariance. P values <.05 were considered significant. Linear models were fitted to find the optimal formula to calculate the area or volume from measured distances. Limits of agreement were calculated as 2 ± residual standard deviations. We generated normal 2D and 3D values of the PAS for a normal population. In regard to age, no significant differences were observed. Significant differences were assessed between healthy males and females; however no correlation was observed between the obtained measurements in 2D axial view and the corresponding cross-sectional areas and mean volume in 3D view. In summary, radiologic imaging is a helpful tool to evaluate the airway space in patients with OSAS. However, drawing conclusions from 2D PAS imaging to assess 3D PAS configuration is not reliable, since there is no sufficient correlation between posterior-anterior distances and the corresponding cross-sectional areas.

Inter-examiner agreement of the systematic physical examination in patients with obstructive sleep disorders

PURPOSE

The goal of this study was to investigate the agreement between examiners who were or were not trained in the physical examination of the upper airway (UA) and the craniofacial skeleton of individuals with obstructive sleep disorders (OSD).

METHOD

A systematic assessment of the UA and craniofacial skeleton was performed on 55 individuals with OSD. The participants were consecutively assessed by three otorhinolaryngologists who specialized in sleep medicine for at least 1 year (trained examiners) and two doctors who were attending a residency program in otorhinolaryngology (untrained examiners).

RESULTS

When analyzing all of the parameters assessed, the concordance was better in the trained group (k = 0.694, which is considered "good") compared to the untrained group (k = 0.475, "fair") (p < 0.001). The inter-examiner agreement was also better in the trained compared to the untrained group, as follows: craniofacial (k = 0.643 vs. 0.349), nasal (k = 0.657 vs. 0.614), and pharyngeal (k = 0.729 vs. 0.276) abnormalities (p < 0.05).

CONCLUSION

The overall concordance of the physical examination of the UA and craniofacial skeleton was "good" among the trained specialists and "fair" among examiners without appropriate training, despite its subjectivity.

Craniofacial and upper airway morphology in adult obstructive sleep apnea patients: A systematic review and meta-analysis of cephalometric studies

Obstructive sleep apnea (OSA) is one of the common sleep breathing disorders in adults, characterised by frequent episodes of upper airway collapse during sleep. Craniofacial disharmony is an important risk factor for OSA. Overnight polysomnography (PSG) study is considered to be the most reliable confirmatory investigation for OSA diagnosis, whereas the precise localization of site of obstruction to the airflow cannot be detected. Identifying the cause of OSA in a particular ethnic population/individual subject helps to understand the etiological factors and effective management of OSA. The objective of the meta-analysis is to elucidate altered craniofacial anatomy on lateral cephalograms in adult subjects with established OSA. Significant weighted mean difference with insignificant heterogeneity was found for the following parameters: anterior lower facial height (ALFH: 2.48 mm), position of hyoid bone (Go-H: 5.45 mm, S-H: 6.89 mm, GoGn-H: 11.84°, GoGn-H: 7.22 mm, N-S-H: 2.14°), and pharyngeal airway space (PNS-Phw: -1.55 mm, pharyngeal space: -495.74 mm² and oro-pharyngeal area: -151.15 mm²). Significant weighted mean difference with significant heterogeneity was found for the following parameters: cranial base (SN: -2.25 mm, S-N-Ba: -1.45°), position and length of mandible (SNB: -1.49° and Go-Me: -5.66 mm) respectively, maxillary length (ANS-PNS: -1.76 mm), tongue area (T: 366.51 mm²), soft palate area (UV: 125.02 mm²), and upper airway length (UAL: 5.39 mm). This meta-analysis supports the relationship between craniofacial disharmony and obstructive sleep apnea. There is a strong evidence for reduced pharyngeal airway space, inferiorly placed hyoid bone and increased anterior facial heights in adult OSA patients compared to control subjects. The cephalometric analysis provides insight into anatomical basis of the etiology of OSA that can influence making a choice of appropriate therapy.

The status of cephalometry in the prediction of non-CPAP treatment outcome in obstructive sleep apnea patients

Obstructive sleep apnea syndrome (OSAS) is the most common sleep disordered breathing disorder (SDB) in adults and is characterized by a recurrent partial or complete collapse of the upper airway during sleep. This can be caused by many factors, sometimes interacting, such as skeletal malformations, soft tissue crowding, respiratory instability and the various effects of aging, obesity and gender that dictate craniofacial and upper airway anatomy. Research has demonstrated that the majority of patients exhibit at least one anatomical component such as retrognathia or a narrow posterior airway space that predisposes to the development of OSAS. Within the predisposing elements for OSAS many seem to point to anatomical characteristics. A standardized and relatively simple radiologic technique to evaluate anatomical craniofacial relationships is cephalometry. This has been used already for a long time in orthodontics, but is now gradually being introduced in OSAS treatment to envisage optimal treatment selection as well as to predict treatment outcomes. The purpose of the present review is to evaluate the contribution of cephalometry in the prediction of outcomes from OSAS treatments that depend on the upper airway morphology in their mechanisms of action such as oral appliances that advance the mandible as well as various surgical methods. In addition, an overview of imaging modalities and methods that currently are being used in cephalometric analysis in OSAS patients is provided. The findings indicate that isolated cephalometric parameters cannot be used to reliably predict treatment outcomes from mandibular advancement devices and surgical methods for OSAS. Extreme or outlying values of cephalometric parameters may rather be used as contra-indicators or 'red flags' instead of predictors.

Detection of Obstructive sleep apnea in awake subjects by exploiting body posture effects on the speech signal

Obstructive sleep apnea (OSA) is a common sleep disorder. OSA is associated with several anatomical and functional abnormalities of the upper airway. It was shown that these abnormalities in the upper airway are also likely to be the reason for increased rate of apneic events in the supine position. Functional and structural changes in the vocal tract can affect the acoustic properties of speech. We hypothesize that acoustic properties of speech that are affected by body position may aid in distinguishing between OSA and non-OSA patients. We aimed to explore the possibility to differentiate OSA and non-OSA patients by analyzing the acoustic properties of their speech signal in upright sitting and supine positions. 35 awake patients were recorded while pronouncing sustained vowels in the upright sitting and supine positions. Using linear discriminant analysis (LDA) classifier, accuracy of 84.6%, sensitivity of 92.7%, and specificity of 80.0% were achieved. This study provides the proof of concept that it is possible to screen for OSA by analyzing and comparing speech properties acquired in upright sitting vs. supine positions. An acoustic-based screening system during wakefulness may address the growing needs for a reliable OSA screening tool; further studies are needed to support these findings.

Upper airway imaging in sleep-disordered breathing

Our understanding of sleep-disordered breathing has evolved considerably over the past three decades, and clinical techniques of evaluation have progressed tremendously. Myriad imaging techniques are now available for the physician to approach the dynamic features resulting in turbulent airflow, upper airway narrowing or collapse at different levels. Controversy exists in the choice of investigations, probably because the best evaluation should be a combination of different techniques. Physical, radiographic, endoscopic and acoustic evaluations could be integrated to understand the degree and the levels of airway reduction and/or obstruction in a given patient. This review focuses on cost-effective and easily implemented techniques in daily practice, allowing quality assessment of the dynamic anatomy of sleep-disordered breathing: cephalometry, (sleep-)endoscopy and acoustic reflectometry of the upper airway.

Facial phenotyping by quantitative photography reflects craniofacial morphology measured on magnetic resonance imaging in Icelandic sleep apnea patients

STUDY OBJECTIVES

(1) To determine whether facial phenotype, measured by quantitative photography, relates to underlying craniofacial obstructive sleep apnea (OSA) risk factors, measured with magnetic resonance imaging (MRI); (2) To assess whether these associations are independent of body size and obesity.

DESIGN

Cross-sectional cohort.

SETTING

Landspitali, The National University Hospital, Iceland.

PARTICIPANTS

One hundred forty patients (87.1% male) from the Icelandic Sleep Apnea Cohort who had both calibrated frontal and profile craniofacial photographs and upper airway MRI. Mean ± standard deviation age 56.1 ± 10.4 y, body mass index 33.5 ± 5.05 kg/m(2), with on-average severe OSA (apnea-hypopnea index 45.4 ± 19.7 h(-1)).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Relationships between surface facial dimensions (photos) and facial bony dimensions and upper airway soft-tissue volumes (MRI) was assessed using canonical correlation analysis. Photo and MRI craniofacial datasets related in four significant canonical correlations, primarily driven by measurements of (1) maxillary-mandibular relationship (r = 0.8, P < 0.0001), (2) lower face height (r = 0.76, P < 0.0001), (3) mandibular length (r = 0.67, P < 0.0001), and (4) tongue volume (r = 0.52, P = 0.01). Correlations 1, 2, and 3 were unchanged when controlled for weight and neck and waist circumference. However, tongue volume was no longer significant, suggesting facial dimensions relate to tongue volume as a result of obesity.

CONCLUSIONS

Significant associations were found between craniofacial variable sets from facial photography and MRI. This study confirms that facial photographic phenotype reflects underlying aspects of craniofacial skeletal abnormalities associated with OSA. Therefore, facial photographic phenotyping may be a useful tool to assess intermediate phenotypes for OSA, particularly in large-scale studies.

Velopharyngeal anatomy in patients with obstructive sleep apnea versus normal subjects

PURPOSE

Obesity can cause disturbed breathing and is one of the most significant risk factors for obstructive sleep apnea (OSA). However, the anatomic basis of OSA and, specifically, the anatomic mechanisms leading from obesity to OSA are still unclear. We examined the anatomic features of the velopharynx in patients with OSA versus those without in correlation with the body mass index (BMI), age, history of snoring, and OSA severity and re-evaluated the contribution of adding a frontal view to the cephalometric analysis of patients with OSA.

MATERIALS AND METHODS

Lateral and frontal cephalometric measurements were taken to assess the velopharyngeal anatomic features of 306 men with various degrees of OSA and 64 men without OSA and without a history of snoring. The demographic, polysomnographic, and cephalometric features were compared.

RESULTS

The patients with OSA had an increased pharyngeal length, thicker velum, a thicker posterior pharyngeal wall, a reduced pharyngeal width, and a consequent narrowing of the pharyngeal lumen. As the BMI increased, the OSA severity increased. Also, in parallel, the velum and posterior pharyngeal wall thickness increased and the pharyngeal width decreased. Three types of velopharyngeal narrowing, with an increased occurrence in severe degrees of OSA, were identified: bottle shape, hourglass shape, and tube shape. These aerodynamically unfavorable changes might cause increased upper airway resistance, explaining the development of both OSA and hypoventilation syndrome in obese patients.

CONCLUSIONS

Velopharyngeal thickening and lumen narrowing were shown to be features of obese men with OSA. However, these features developed only above a threshold BMI value. The combination of frontal and lateral cephalometry is important for comprehensive evaluation of patients with OSA.

Pharyngeal airway dimensions: a cephalometric, growth-study-based analysis of physiological variations in children aged 6-17

OBJECTIVE

The aim was to assess pharyngeal airway dimensions and physiological changes based on lateral cephalometric radiographs from healthy untreated children aged 6-17 years.

MATERIALS/METHODS

The sample consisted of 880 lateral cephalograms (412 females and 468 males) of the Zurich Craniofacial Growth Study. Statistical analyses on cephalometric measurements of airway dimensions (distances 'p': shortest distance between soft palate and posterior pharyngeal wall and 't': shortest distance between tongue and posterior pharyngeal wall) and craniofacial parameters were performed. To disclose differences between different age groups, a Kruskal-Wallis test was applied. The influence of gender on 'p' and 't' was analysed by a Mann-Whitney U-test for each age group separately. The Spearman correlation was computed in order to investigate associations between craniofacial parameters. Variables associated with 'p' and 't' were chosen for multiple regression model investigation.

RESULTS

The results demonstrated high interindividual variations. A slight influence of age on 'p' (P = 0.034) could be attested (+1.03 mm) but not on 't' (P = 0.208). With the exception of the 9-year age group, no significant differences between the genders were found. Correlation analysis revealed several statistically significant correlations between 't' or 'p' and antero-posterior cephalometric variables. All correlation coefficients were, however, very low and the adjusted coefficient of determination also revealed the regression model to be very weak.

CONCLUSIONS

The high interindividual variations of 'p' and 't' render the use of reference values problematic. Contrary to other craniofacial structures, neither age-related changes nor sexual dimorphism were found for 'p' and 't'. Any associations to antero-posterior cephalometric characteristics seem low.

Effectiveness of twin-block and Mandibular Protraction Appliance-IV in the improvement of pharyngeal airway passage dimensions in Class II malocclusion subjects with a retrognathic mandible

OBJECTIVE

To test the hypothesis that twin-block and Mandibular Protraction Appliance-IV (MPA-IV) are not effective in improving the pharyngeal airway passage (PAP) dimensions among Class II malocclusion subjects with a retrognathic mandible.

MATERIALS AND METHODS

Eighty-three subjects ranging in age from 8 to 14 years were divided into four groups. Group I included 30 Class I malocclusion subjects (healthy controls); group II consisted of 16 Class II malocclusion subjects (Class II controls); group III had 16 subjects in whom Class II malocclusion was treated by MPA-IV; and the remaining 21 subjects formed group IV, whose Class II malocclusions were corrected by twin-block appliance. Lateral cephalograms recorded at the beginning of orthodontic treatment in group I subjects and at the beginning and end of follow-up/treatment with functional appliance in group II, III, and IV subjects were analyzed to determine the PAP dimensions. Paired t-test, one-way analysis of variance, and Tukey tests were applied for statistical analysis, and a P-value .05 was considered statistically significant.

RESULTS

Soft palate length was decreased significantly in group III (P < .05) and group IV (P < .001) subjects. Soft palate thickness in group IV subjects was increased significantly as compared to group II (P < .05) and group III (P < .01) subjects. The improvement in soft palate inclination in group III and group IV subjects was significant (P < .01). The oropharynx depth was increased significantly in group III (P < .05) and group IV (P < .001) subjects. The depth of the hypopharynx was increased significantly (P < .01) in group IV subjects.

CONCLUSIONS

The twin-block appliance was more efficient than the MPA-IV in the improvement of PAP dimensions among Class II malocclusion subjects with retrognathic mandible.

Lateral cephalometric analysis and the risks of moderate to severe obstructive sleep-disordered breathing in Thai patients

PURPOSES

This cross-sectional study was aimed to compare lateral cephalometric parameters among patients with different severities of obstructive sleep-disordered breathing and to determine if there are radiographic variables that increase risk of moderate to severe obstructive sleep apnea (OSA).

METHODS

Ten linear and 5 angular parameters of lateral cephalometry in 188 adult subjects which included 47 controls and 141 patients with OSA classified by apnea-hypopnea index (AHI) from level-I polysomnography, were analyzed. All radiographs were done under standardized processes and measured twice on separate occasions.

RESULTS

There were statistically significant differences between controls and patients with AHI ≥ 15 in parameters such as a distance from mandibular plane to hyoid (MP-H), posterior airway space (PAS), skull base angle (NSBA), a distance from posterior nasal spine to posterior pharyngeal wall (PNS-PP), and soft palate length (PNS-P), (p < 0.01). However, no significant difference was found between controls and mild OSA. Logistic regression analysis showed that only MP-H with cutoff point of ≥ 18 millimeters, NSBA ≤ 130°, and PAS ≤ 10 millimeters were independent cephalometric variables that increased risk of having AHI ≥ 15 compared to controls with adjusted odds ratio of 17.1, 8.3 and 4.2, respectively. Gender did not significantly associate with OSA severity in this analysis.

CONCLUSIONS

Patients who had longer MP-H, narrower PAS and narrower NSBA than specific cutoff points significantly increased risks of moderate to severe OSA. Treatments that effectively improve these parameters, particularly at tongue base level (MP-H and PAS), may decrease the severity of disease.

Screening and comprehensive evaluation for sleep related breathing disorders

The dentist is well positioned to screen for patients at risk for a sleep disorders, most often a sleep related breathing disorder, and when adequately trained, can treat those diagnosed with sleep apnea using an oral appliance. This treatment requires some degree of training to be able to recognize the symptoms related to the more common sleep disorders. The dentist must determine if the patient is at risk for a sleep disorder through the use of screening questionnaires, reviewing the health history, and additional questioning of the patient.

Cephalometric predictors of therapeutic response to multilevel surgery in patients with obstructive sleep apnea

PURPOSE

The present study investigated whether cephalometric measurements can predict the therapeutic efficacy of multilevel phase I surgery for patients with obstructive sleep apnea (OSA).

PATIENTS AND METHODS

Among 210 patients with OSA who underwent multilevel phase I surgery, 85 were recruited on the basis of the baseline polysomnography, body mass index, and lateral cephalogram recordings. The patients were divided into 2 groups according to the degree of change in the apnea-hypopnea index before and 6 months after multilevel surgery: good responders (>50% decrease in apnea-hypopnea index) and poor responders (0% to 50% decrease or increase in apnea-hypopnea index). Cephalometric analysis was performed to identify the relevant variables, with division into 5 compartments: craniofacial, soft palate, tongue, hyoid bone, and upper airway variables.

RESULTS

In the craniofacial compartment, poor responders represented skeletal Class II with a more retrognathic mandible, and a hyperdivergent vertical pattern with a larger mandibular plane angle, longer lower facial height, and steeper occlusal plane than good responders. In the upper airway compartment, poor responders had narrower middle and inferior airway spaces and a longer upper airway length than good responders. No significant differences were found in the soft palate, tongue, and hyoid measurements between the 2 groups.

CONCLUSION

Some preoperative cephalometric measurements were verified retrospectively to predict the therapeutic response to the multilevel surgery in patients with OSA. This study would contribute not only to establishing selective criteria for the surgical approach to patients with OSA in ear-nose-throat practice but also in deciding on the referral to orthodontists or maxillofacial surgeons.

Cephalometric findings in facioscapulohumeral muscular dystrophy patients with obstructive sleep apneas

PURPOSES

The purposes of the study are: (1) to establish if cephalometry and upper airway examination may provide tools for detecting facioscapulohumeral (FSHD) patients at risk for obstructive sleep apnea syndrome (OSAS); and (2) to correlate cephalometry and otorhinolaryngologic evaluation with clinical and polysomnographic features of FHSD patients with OSAS.

METHODS

Patients were 13 adults affected by genetically confirmed FSHD and OSAS, 11 men, with mean age 47.1 ± 12.8 years (range, 33-72 years). All underwent clinical evaluation, Manual Muscle Test, Clinical Severity Scale for FSHD, Epworth Sleepiness Scale, polysomnography, otorhinolaryngologic evaluation, and cephalometry.

RESULTS

Cephalometric evidence of pharyngeal narrowing [posterior airways space (PAS) < 10 mm] was present in only one patient. The mandibular planus and hyoid (MP-H) distance ranged from 6.5 to 33.1 mm (mean, 17.5 ± 7.8 mm). The mean length of soft palate (PNS-P) was 31.9 ± 4.8 mm (range, 22.2 to 39.7 mm). No patient presented an ANB angle > 7°. There was no significant correlation between cephalometric measures, clinical scores, and PSG indexes. PAS and MP-H were not related to the severity of the disease.

CONCLUSIONS

Upper airway morphological evaluation is of poor utility in the clinical assessment of FSHD patients and do not allow to predict the occurrence of sleep-related upper airway obstruction. This suggests that the pathogenesis of OSAS in FSHD is dependent on the muscular impairment, rather than to the anatomy of upper airways.

Automatic cephalometric evaluation of patients suffering from sleep-disordered breathing

We address the problem of automatically analyzing lateral cephalometric images as a diagnostic tool for patients suffering from Sleep Disordered Breathing (SDB). First, multiple landmarks and anatomical structures that were previously associated with SDB are localized. Then statistical regression is applied in order to estimate the Respiratory Disturbance Index (RDI), which is the standard measure for the severity of obstructive sleep apnea. The landmark localization employs a new registration method that is based on Local Affine Frames (LAF). Multiple LAFs are sampled per image based on random selection of triplets of keypoints, and are used to register the input image to the training images. The landmarks are then projected from the training images to the query image. Following a refinement step, the tongue, velum and pharyngeal wall are localized. We collected a dataset of 70 images and compare the accuracy of the anatomical landmarks with recent publications, showing preferable performance in localizing most of the anatomical points. Furthermore, we are able to show that the location of the anatomical landmarks and structures predicts the severity of the disorder, obtaining an error of less than 7.5 RDI units for 44% of the patients.

Ocena przydatności pomiarów cefalometrycznych w diagnostyce pacjentów z obturacyjnym zespołem snu z bezdechami – doniesienie wstępne

INTRODUCTION

The pathophysiology of OSAS is related with local anatomical predispositions to OSA such as craniofacial anomalies, adenoid and tonsillar hypertrophy, macroglossia, hypertonic oropharyngeal soft tissue, base of tongue proptosis, mandibular hypoplasia, posterior mandibular displacement, maxillary retrusion, enlarged uvula, retrognathia, and inferior positioning of the hyoid. The AIM of the study was to evaluate the usefulness of cephalometric measurements in patients with obstructive sleep apnea syndrome (OSAS).

MATERIAL AND METHODS

Eighteen randomly selected patients with snoring and varying degrees of sleep-disordered breathing were included in this study. All patients underwent completed otolaryngological examination, somnographic test using Poly-Mesam device, cephalometric radiographs and craniofacial CT scans. A control group had the same examinations and cephalometric tests. These patients had no snoring or clinical evidence of sleep-disordered breathing. No patients had prior pharyngeal or maxillomandibular surgery. Lateral cephalometric radiographs were obtained on all subjects in standing position using a standard technique. Each subject had also an awake CT scan in supine position on the back.

RESULTS

According all parameters we gathered from the study, OSAS is associated with significant changes in cephalometric measurements. Cephalometric analysis adds further information regarding the anatomical assessment of OSAS patients however we found craniofacial CT scans easier, more accurate measurements especially applying to soft tissues.

Assessment of lateral cephalometric diagnosis of adenoid hypertrophy and posterior upper airway obstruction: A systematic review

INTRODUCTION

Our objective was to evaluate the capability of lateral cephalograms in diagnosing hypertrophied adenoids and obstructed posterior nasopharyngeal airways.

METHODS

A systematic review of the literature by using several electronic databases (Cochrane Library, Medline, Medline in progress, PubMed, Web of Science, Embase, and Lilacs) was performed with the help of a senior health-sciences librarian. The electronic search was followed up with hand searches. After applying our inclusion-exclusion criteria, the search yielded 11 articles that were then scored based on their methodological validity.

RESULTS

Lateral cephalograms performed reasonably well in evaluating adenoid size; both quantitative measures of adenoid area and subjective grading of adenoid size on lateral cephalograms had reasonable correlations to actual adenoid size (range of r, 0.60 to 0.88). However, evidence suggested that cephalograms were less ideal for evaluating the size of the posterior nasopharyngeal airway. The diagnostic difference is likely because the adenoid is a simpler 3-dimensional structure than the nasopharynx; therefore, it loses less information when compressed into 2 dimensions by the radiograph.

CONCLUSIONS

Being used as a screening tool to determine the need for more rigorous ENT follow-up appears to be the greatest utility of lateral cephalograms. Because no consensus could be reached on what are the most useful landmarks, we recommend that clinicians look for multiple deviant measures of adenoid size rather than one definitive quantification.

Smaller mandibular size in infants with a history of an apparent life-threatening event

OBJECTIVES

To examine small mandibular size and preference for a hand-to-chin posture as salient characteristics in infants with a history of an apparent life-threatening event (ALTE).

STUDY DESIGN

This was a prospective case-control study of term infants, from birth to 6 months of age, admitted post-ALTE and matched 1:2 with healthy control infants (age within 2 weeks and weight within 0.5 kg). Infants with confirmed gastroesophageal reflux and congenital anomalies, including severe micrognathia, were excluded.

RESULTS

Infants with a history of an ALTE (n = 25) were matched to 47 healthy controls. Infants with a history of an ALTE had mandibular indices (larger index indicates a smaller mandible) that were 3.8 mm greater on the left side (95% CI: 2.0-5.6, P < .001) and 4.2 mm greater on the right side (95% CI: 2.7-5.6, P < .001) adjusting for length and non-white race. Controlling for matching and length, a 1-mm increase in the average mandibular index increased the odds of an ALTE by 62% (OR = 1.62, 95% CI: 1.22-2.44, P < .001).

CONCLUSIONS

Smaller mandibular size was associated with ALTE, suggesting airway obstruction as a potential cause of ALTE. The association of this characteristic with ALTE also offers the potential for prospective quantification of ALTE risk.

Relationship between the pharyngeal airway space and craniofacial morphology, taking into account head posture

This study assessed the relationship between craniofacial characteristics and the size of the pharyngeal airway space (PAS), taking into account head posture. Sixty dental students 25-30 years of age (30 men and 30 women) were examined by lateral cephalometry. The data were corrected with the use of appropriate regression equations for the PAS. The PAS significantly correlated with hyoid position, maxillary and mandibular size, maxillary and mandibular prognathism, and mandibular inclination. A large, anteriorly positioned mandible was associated with a large PAS-TP (the most proximal distance between the posterior pharyngeal wall and the tongue base). Uvula length and PNS-Ba (the distance between the most posterior point of the hard palate and the most inferior point of the anterior foramen magnum) correlated with PAS-UP (the most proximal distance between the posterior pharyngeal wall and uvula). Our results suggest that the anteroposterior dimension of the PAS is substantially affected by the size of the enclosure surrounding the PAS, including the maxilla, mandible and soft palate.

Ethnicity and obstructive sleep apnoea

There is a scarcity of adult prevalence studies of OSA outside the Caucasian populations of North America, Europe and Australia, and comparisons have been complicated by methodological differences in sleep study settings, respiratory events definition, measured risk factors and clinical outcomes, and the lack of objective parameters for the measurement of ethnicity itself. Comparing studies with the same methodological design and respiratory events definition, recent large-scale prevalence studies from Hong Kong, Korea and India show similar OSA rates to populations of mainly Caucasian composition. OSA is a very complex disorder determined by several phenotypes such as obesity, craniofacial structure and abnormalities in neuromuscular and ventilatory control. Genetics may partially explain some of the ethnic clustering of these phenotypes, modulated by cultural and environmental factors. The exact contribution of these component phenotypes to overall OSA risk will be determined by their varying prevalence and relative risk conferred across ethnic groups. For lesser degrees of obesity, Asians are at risk for a more severe degree of illness compared with Caucasians. Inter-ethnic studies suggests that African-American ethnicity may also be a significant risk factor for OSA. The increased prevalences of OSA among American Indians and Hispanic adults, and increased severity among Pacific Islanders and Maoris, were mainly explained by increased obesity parameters. Most cephalometric studies have largely been conducted without specific regard to ethnicity and comparisons of findings across studies have been mainly limited by differences in sampling methods and the varying selection and definition of measured cephalometric variables. The limited number of studies with inter-ethnic comparative data suggest cephalometric variables and their degree of contribution to OSA vary across ethnic groups.

Síndrome da apnéia e hipopnéia obstrutiva do sono: análise cefalométrica

A síndrome da apnéia e hipopnéia obstrutiva do sono (SAHOS) caracteriza-se por episódios repetitivos de obstrução das vias aéreas superiores durante o sono, usualmente associada à interrupção do mesmo e queda da saturação da oxihemoglobina. A análise cefalométrica tem sido considerada como importante método diagnóstico fornecendo características craniofaciais, como espaço aéreo posterior da faringe, comprimento da língua e posição do osso hióide os quais podem predispor os pacientes a SAHOS. O propósito dessa revisão é apresentar tópicos anatômicos possíveis de serem observados através da análise cefalométrica e que podem predispor à oclusão das vias aéreas superiores (VAS).

Obstructive sleep apnea and hypopnea syndrome: cephalometric analysis

Obstructive sleep apnea and hypopnea syndrome (OSAHS) are characterized by repeated pauses in breathing during sleep, usually associated with sleep interruption and decreased oxyhemoglobin saturation. Cephalometric analysis has become an important method in diagnosis, reporting specific craniofacial characteristics such as posterior air pharyngeal space, tongue length and hyoid position, which may predispose some people to develop SAHOS. The purpose of this revision is to present several anatomic aspects by cephalometric analysis that may have a predisposition to the development of upper airway occlusion.

Histopathology of the uvula and the soft palate in patients with mild, moderate, and severe obstructive sleep apnea

OBJECTIVE

To study morphometric and qualitative histopathologic changes of the soft palate and uvula in patients with mild, moderate, and severe obstructive sleep apnea.

STUDY DESIGN

A prospective, nonrandomized controlled study.

METHODS

The distal soft palate and uvula were excised during uvulopalatopharyngoplasty from 34 male patients with obstructive sleep apnea. Control specimens were retrieved from 7 male cadavers with no related disorders. All specimens underwent routine processing and the mid-sagittal sections were studied. Morphometric analysis of the relative proportions of the tissue constituents was carried out. Also, a qualitative assessment was performed to detect possible pathologic changes.

RESULTS

The body mass index of patients was significantly higher from that of control subjects. The area fraction occupied by the tissue constituents of the distal portion of the soft palate and uvula in patients with mild, moderate, and severe obstructive sleep apnea and in control subjects was similar, with small and insignificant differences regarding the contents of glands, muscle, fat, blood vessels, and the epithelium. Only the connective tissue was significantly greater in patients with moderate obstructive sleep apnea than in those with severe obstructive sleep apnea and control subjects. The qualitative assessment of the specimens disclosed normal tissue architecture without evidence of destruction. Vascular engorgement, fibrosis, edema, inflammatory cell infiltration, and dilated glandular ducts were observed in a portion of patients and control subjects.

CONCLUSIONS

The structure of the distal soft palate and uvula of patients with obstructive sleep apnea undergoes insignificant changes and is independent of the body mass index levels, indicating that the pathologic changes are probably the sequela of airway obstruction rather than its cause.