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

Evaluation of upper airway volume and craniofacial volumetric structures in obstructive sleep apnoea adults: A descriptive CBCT study

OBJECTIVE

The aim of this investigation was to assess, with a descriptive three-dimensional evaluation, the volume of upper airway (UAWV) and the volume of craniofacial structures in adult patients suffering from obstructive sleep apnoea (OSA) and compare them to the corresponding findings in adults with no sleep disorders.

MATERIALS AND METHODS

The sample consisted of 54 adult males, 27 suffering from OSA diagnosed by means of the Apnoea Hypopnea Index and 27 with no history of sleep disorders. All subjects had a cone beam computerized tomography scan performed with the same head position. UAWV was assessed with the Amira® software, and craniofacial volumes by means of a specially developed data-processing program, which allowed the construction of tetrahedrons using anatomical landmarks. Assessed volumes were naso-maxillary, cranium upper anterior, oral cavity, post-oral cavity, hyoid to mandible, and post-hyoid. SPSS (version 19.0) was used for the statistical analysis. The Levene's test for Equality of Variance, the t-test for Equality of Means and the Mann-Whitney test were used to evaluate the variables. The level of significance was set at P ≤ 0.05.

RESULTS

The mean value of UAWV was smaller in the OSA group. The post-hyoid volume, the calculated posterior volume, and the ratio of posterior to total volume showed differences between the groups.

CONCLUSIONS

Craniofacial structures did not show significant differences between the groups, but in the OSA group the posterior space released for upper airway was significantly bigger and UAWV was significantly smaller.

Further Development of P4 Approach to Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a heterogeneous disorder. Cluster analysis has identified different physiologic subtypes with respect to symptoms. A difference exists in cardiovascular risk from OSA between the 7 subtypes identified. There are 3 basic subtypes replicated in multiple studies: (a) a group where insomnia is the main symptom; (b) an asymptomatic group; (c) a group with marked excessive sleepiness. The symptomatic benefit from treatment with nasal CPAP varies between these 3 subtypes. Data from the Sleep Heart Health Study reveal that the increased risk of cardiovascular disease from OSA occurs only in the excessively sleepy group.

Continuous positive airway pressure alters brain microstructure and perfusion patterns in patients with obstructive sleep apnea

OBJECTIVES

To assess the effects of continuous positive airway pressure (CPAP) treatment on brain structure and function in patients with obstructive sleep apnea (OSA).

METHODS

A prospective study of seven OSA patients recruited from the sleep center at our institution was carried out. Patients were treated with six weeks of CPAP treatment. Pre-treatment and post-treatment magnetic resonance imaging (MRI) perfusion scans were obtained and compared to assess for treatment-induced changes. Microstructural changes were quantified using functional anistrophy (FA) and mean diffusivity (MD), and brain perfusion was quantified using cerebral blood flow (CBF) and cerebral blood volume (CBV).

RESULTS

Of the seven patients included the in study, six (85.7%) were male, and the mean age was 51 years (standard deviation = 13.14). Increased FA and decreased MD were found in the hippocampus, temporal lobes, fusiform gyrus, and occipital lobes. Decreased FA and increased MD were found in frontal regions for all patients (p < 0.05). Increased CBF and CBV were also observed following treatment (p < 0.05).

CONCLUSION

In addition to symptom resolution, CPAP treatment may allow for healing of OSA-induced brain damage as seen by restoration of brain structure and perfusion.

Robot-assisted Tongue Base Resection ensures favorable therapeutic outcome to Obstructive Sleep Apnea patients with Lingual tonsil hypertrophy

Tongue base (TB) narrowing is recognized as a significant site of upper airway collapse during sleep in obstructive sleep apnea (OSA) patients and robot technology is expected to have promising clinical utility in OSA patients with TB narrowing. The purpose of our study is to demonstrate the better therapeutic conditions and favorable indications of robot-assisted TB resection (TBR) in OSA. We performed robot-assisted TBR combined with nasal and palatal surgery in 16 OSA patients with any of the following characteristics: severe TB narrowing (over grade II) and moderate or severe OSA. The preoperative median AHI was 48.8/hr and the median lowest SaO₂ was 82.0%. The median AHI decreased to 18.7/hr and ten patients (62.5%) were included in the responder group following robot-assisted TBR combined with nasal and palatal surgery. The lowest SaO₂ improved to 90.5% and the posterior airway space (PAS) was significantly increased following robot-assisted TBR. Cephalometric results showed that wider PAS were observed in responders compared to non-responders prior to robot-assisted TBR. Interestingly, there was greater improvement in the objective parameters including PAS in the OSA patients with lingual tonsilar hypertrophy than they were in those without and all patients with lingual tonsillar hypertrophy (n = 6) responded to robot-assisted TBR. Robot-assisted TBR exhibited minimal morbidity and postoperative complications in OSA patients. Robot-assisted TBR can be considered a promising and innovative surgical option to reduce TB volume and improve sleep parameters in OSA patients with TB narrowing. OSA patient with TB narrowing due to lingual tonsil hypertrophy shows greater therapeutic outcome and lingual tonsil hypertrophy appears to be most favorable surgical indications of robot-assisted TBR.

Mandibular width as a novel anthropometric measure for assessing obstructive sleep apnea risk

Craniofacial abnormalities are a known obstructive sleep apnea (OSA) risk factor, but still need to be better characterized. This study investigates the relationship between mandibular width and the risk of developing OSA.We retrospectively analyzed 3D reconstructions of head and neck computed tomography (CT) scans at our institution for mandibular width, neck circumference, neck fat volume (NFV), airway volume (AWV), and NFV:AWV ratio. Age, gender, and BMI were also documented. Patients were contacted to complete a STOP-BANG survey to assess OSA risk. Only patients with reconstructable scans and completed STOP-BANG questionnaires were included in the study. Survey results were analyzed to assess the correlation between mandible width and STOP-BANG. Mandible association was also compared to the associations of the other known risk factors.The final analysis included 427 patients with a mean age of 58.98 years (standard deviation = 16.77), 56% of whom were male. Mandibular width was found to positively correlate with STOP-BANG score (r = .416, P < .001). Statistically significant differences between mandible size for each risk group was seen (P < .001). After controlling for age and sex, mandible size was significantly different only for the low risk vs. high risk groups (odds ratio = 1.11; 95% confidence interval = 1.03-1.20; P = .007). Furthermore, when stratified according to mandible size, the small mandible group (<77.50 mm) predominantly consisted of low risk patients; the medium size mandible group (77.50-84.40 mm) was predominated by intermediate risk patients, and large mandible (>84.40 mm) was predominantly seen in high risk patients. Mandible width expressed a stronger association than NFV:AWV ratio, but neck circumference and NFV had stronger associations than did mandible width.In addition to previously documented OSA risk factors, mandibular width is positively correlated with OSA as an independent risk factor. Observation of a wide mandible (jaw) should raise awareness of OSA risk and increase screening methods when appropriate.

Is sleep apnea underdiagnosed in adult patients with osteogenesis imperfecta? -a single-center cross-sectional study

BACKGROUND

Patients with Osteogenesis imperfecta (OI) suffer from increased bone fracture tendency generally caused by a mutation in genes coding for type I collagen. OI is also characterized by numerous co-morbidities, and recent data from questionnaire studies suggest that these may include increased risk for sleep apnea, a finding that lacks clinical evidence from cohort studies. In this cross-sectional study, 25 adults with OI underwent clinical otorhinolaryngology examination as well as overnight polysomnography to address the question. The participants were aged between 19 and 77 years, and ten of them had mild clinical OI phenotype, seven had a moderately severe phenotype, and eight had a severe phenotype.

RESULTS

We found obstructive sleep apnea (apnea hypopnea index ≥5/h) in as many as 52% of the OI patients in the cohort. Unexpectedly, however, no correlation was present between sleep apnea and daytime sleepiness, experienced bodily pain, severity of OI, Mallampati score, or neck circumference.

CONCLUSIONS

Seeing that the usual predictors showed no association with occurrence of sleep apnea, we conclude that obstructive sleep apnea may easily be left as an undetected disorder in individuals with OI. Recurrent nocturnal hypoxia due to episodes of apneas can even affect bone metabolism, thereby further aggravating bone fragility in patients with OI.

Prevalence of malocclusion in children with obstructive sleep apnoea

OBJECTIVES

To describe the prevalence of malocclusions in 2- to 10-year-old children suffering from obstructive sleep apnoea (OSA) and to evaluate the association between occlusal variables and OSA.

SETTING AND SAMPLE POPULATION

A total of 2101 consecutive patients referred to an otorhinolaryngology unit were considered for the study. One hundred and fifty-six children (range 2-10 years) with suspected OSA were selected for a sleep study. The final sample consisted of 139 children suffering from OSA and a control group of 137 children.

MATERIALS AND METHODS

All patients included in the study underwent a clinical orthodontic examination to record the following occlusal variables: primary canine relationship, presence of a posterior crossbite, overjet and overbite. Odds ratios and 95% confidence intervals, comparing the demographic characteristics and dental parameters in OSA vs non-OSA children, were computed. Multivariable logistic regression models were developed to compare independent variables associated with OSA to non-OSA children.

RESULTS

The prevalence of malocclusions in children with OSA was 89.9% compared to 60.6% in the control group (P < 0.001). Factors independently associated with OSA compared to the control group were posterior crossbite (OR = 3.38; 95%CI:1.73-6.58), reduced overbite (OR = 2.43; 95%CI:1.15-5.15.), increased overbite (OR = 2.19; 95%CI:1.12-4.28) and increased overjet (OR = 4.25; 95%CI:1.90-9.48).

CONCLUSIONS

This study showed a high prevalence of malocclusion in children with OSA compared to the control group. The posterior crossbite and deviations in overjet and overbite were significantly associated with OSA. The presence of these occlusal features shows the importance of an orthodontic evaluation in screening for paediatric OSA.

[The nose, an orthodontic-surgical marker]

INTRODUCTION

Inthe quest for a universal marker to describe the physiological function of facialmechanics, the author has found nasal ventilation at rest to be a major factor to beborne in mind.

MATERIALS AND METHODS

Factors related to embryology, anatomyand respiratory physiology, along with analysis of the literature in the relevantareas, now enable us to view the nose in a different light.

CONCLUSION

The authorconcludes that nasal ventilation at rest constitutes a mandatory objective in theperformance of all types of therapy.

Apnea-Hypopnea Index in Healthy Class III Patients Treated With Intraoral Vertical Ramus Osteotomy: A Prospective Cohort Study

PURPOSE

The study purpose was to assess whether mandibular setback surgery by intraoral vertical ramus osteotomy (IVRO) induces obstructive apnea and hypopnea in healthy Class III patients without a history of respiratory dysfunction. We hypothesized that the apnea-hypopnea index (AHI) would not exceed 5 events per hour after surgery.

PATIENTS AND METHODS

A prospective cohort study was conducted. The sample was composed of healthy Class III patients without a history of obstructive sleep apnea treated with isolated mandibular setback surgery by the IVRO procedure at a university hospital. In-home respiratory sleep recordings (Nox T3; Nox Medical, Reykjavik, Iceland) and self-administered questionnaires were obtained before and at least 3 months after surgery. The AHI was the primary outcome variable. Other study variables were as follows: peripheral capillary oxygen saturation, oxygen desaturation index, snore index, body mass index, Epworth Sleepiness Scale, and Oral Impact on Daily Performance index. Descriptive and bivariate statistics were computed, and the significance level was set at .05.

RESULTS

The sample was composed of 8 patients. The mean age at surgery was 23.2 years (range, 18.2 to 33.4 years). The mean amount of surgical setback was 4.3 mm (range, 2.5 to 7.4 mm). The mean body mass index was 24.2 kg/m² (standard error [SE], 1.3 kg/m²) and 23.9 kg/m² (SE, 1.4 kg/m²) at the presurgical and postsurgical sleep recordings, respectively. The mean AHI was 1.3 events per hour (SE, 0.3; range, 0.1 to 2.5) before surgery and 1.8 events per hour (SE, 0.4; range, 0.3 to 3.3) after surgery. No statistically significant changes in AHI (P = .412), peripheral capillary oxygen saturation (P = .443), oxygen desaturation index (P = .194), snore index (P = .363), or Epworth Sleepiness Scale (P = .812) were observed. The patients' self-reported oral health-related quality of life was statistically significantly improved after surgery (P = .034).

CONCLUSIONS

Mandibular setback surgery with the IVRO procedure in the range of 2.5 to 7.4 mm did not induce obstructive sleep apnea, measured as an AHI above 5 events per hour, in the 8 healthy, young adult Class III patients presented in this study. More studies including larger patient samples are needed.

Craniofacial Phenotyping in Chinese and Caucasian Patients With Sleep Apnea: Influence of Ethnicity and Sex

STUDY OBJECTIVES

Craniofacial abnormalities are a risk factor for obstructive sleep apnea (OSA). We have previously shown that phenotypic information derived from craniofacial photographs predict OSA in sleep clinic populations. However, there are likely ethnic and sex differences in craniofacial phenotypes related to OSA. We aimed to assess the use of craniofacial photography to identify interactions between OSA, ethnicity, and sex in craniofacial phenotype.

METHODS

Frontal and profile craniofacial photographs were analyzed from two sleep clinic populations of different ethnicity (Hong Kong Chinese, Australian Caucasians). OSA was defined as apnea-hypopnea index (AHI) > 10 events/h. Ten craniofacial measurements (three angles relating to jaw position and seven ratios describing proportions of the face) were examined for interactions between OSA status and sex or ethnicity) using factorial analysis of variance.

RESULTS

A total of 363 subjects (25% female) were included (n = 200 Chinese, n = 163 Caucasian), of which 33% were controls. There were two-way interactions for OSA with both sex (mandibular plane angle [F = 7.0, P = .009], face / eye width ratio [F = 4.7, P = .032], maxillary / mandibular volume ratio [F = 9.2, P = .003]) and ethnicity (face / nose width ratio [F = 4.0, P = .045], mandibular width / length ratio [F = 5.1, P = .024], maxillary / mandibular volume ratio [F = 11.0, P = .001]).

CONCLUSIONS

We provide evidence of ethnic and sex differences in facial phenotype related to OSA. Furthermore, we demonstrate that craniofacial photography can be used as a phenotypic tool to assess these differences and allow investigation of OSA phenotypes in large samples. This has relevance to personalizing OSA recognition strategies across different populations.

The effect of tongue base suspension with uvulopalato-pharyngoplasty on sleep quality in obstructive sleep apnea

The objective was to investigate whether tongue base suspension with uvulopalatopharyngoplasty (UPPP) is beneficial on polysomnography analysis for sleep quality in patients with obstructive sleep apnea (OSA) anatomically classified as Fujita type III (small tonsils and a bulky tongue base). In the retrospective study, the charts of 36 patients with OSA that underwent tongue base suspension with UPPP from 2012 through 2015 were reviewed. The surgical outcome measured according to Sher’s classification (AHI reduction > 50% and AHI < 20 per hour as success group, otherwise as failure group). The pre- and post-operative sleep quality parameters were evaluated, and the total sleep time changes were evaluated based on electroencephalography study, slow wave sleep, sleep efficiency, rapid eye movement sleep percentile, and Epworth sleep scale scores. Respiratory, the outcomes of polysomnography analysis were then compared between the successful surgery and surgical failure groups during a 1-year follow up. Total arousals and reduced respiratory arousal indices, along with unchanged periodic leg movement and spontaneous electroencephalography arousal indices, were observed in the successful surgery group but not in the surgical failure group. There were 66% resulted in surgical success by this surgery, and 34% as in failure group according to Sher’s criteria. Patient sleep quality was further improved by reducing the respiratory arousal index and increasing the rapid eye movement sleep percentile during the 1-year follow up.

Soft palate cephalometric changes with a mandibular advancement device may be associated with polysomnographic improvement in obstructive sleep apnea

PURPOSE

It is unclear whether soft palate-associated changes in cephalometry associated with a mandibular advancement device (MAD) are independently associated with improvements in polysomnography (PSG) respiratory parameters in obstructive sleep apnea (OSA).

METHODS

This retrospective review aimed to identify the association between soft palate-associated changes in cephalometry and PSG changes after application of an MAD. Korean patients diagnosed with OSA who underwent cephalometry with or without an MAD were enrolled. All the patients were evaluated after undergoing full-night PSG twice: once with an MAD and once without. Cephalometric findings were measured using an image analyzer.

RESULTS

Mean apnea-hypopnea index significantly decreased with an MAD from 36.4/h to 14.7/h (p < 0.001). Retropalatal airway space significantly increased with an MAD from 6.6 to 7.3 mm (p = 0.013). Soft palate length also significantly decreased with an MAD from 43.6 to 42.3 mm (p = 0.02). Although these findings were shown by responders (patients with a reduction of apnea-hypopnea index by more than 50%), there were no significant changes in non-responders. However, retroglossal airway space did not significantly increase with an MAD even in responders.

CONCLUSIONS

Improvement of OSA with an MAD can be predicted with soft palate-associated upper airway changes shown in cephalometry.

Genetic Ancestry for Sleep Research: Leveraging Health Inequalities to Identify Causal Genetic Variants

Recent evidence has highlighted the health inequalities in sleep behaviors and sleep disorders that adversely affect outcomes in select populations, including African-American and Hispanic-American subjects. Race-related sleep health inequalities are ascribed to differences in multilevel and interlinked health determinants, such as sociodemographic factors, health behaviors, and biology. African-American and Hispanic-American subjects are admixed populations whose genetic inheritance combines two or more ancestral populations originating from different continents. Racial inequalities in admixed populations can be parsed into relevant groups of mediating factors (environmental vs genetic) with the use of measures of genetic ancestry, including the proportion of an individual's genetic makeup that comes from each of the major ancestral continental populations. This review describes sleep health inequalities in African-American and Hispanic-American subjects and considers the potential utility of ancestry studies to exploit these differences to gain insight into the genetic underpinnings of these phenotypes. The inclusion of genetic approaches in future studies of admixed populations will allow greater understanding of the potential biological basis of race-related sleep health inequalities.

Obstructive sleep apnea: current perspectives

The prevalence of obstructive sleep apnea (OSA) continues to rise. So too do the health, safety, and economic consequences. On an individual level, the causes and consequences of OSA can vary substantially between patients. In recent years, four key contributors to OSA pathogenesis or "phenotypes" have been characterized. These include a narrow, crowded, or collapsible upper airway "anatomical compromise" and "non-anatomical" contributors such as ineffective pharyngeal dilator muscle function during sleep, a low threshold for arousal to airway narrowing during sleep, and unstable control of breathing (high loop gain). Each of these phenotypes is a target for therapy. This review summarizes the latest knowledge on the different contributors to OSA with a focus on measurement techniques including emerging clinical tools designed to facilitate translation of new cause-driven targeted approaches to treat OSA. The potential for some of the specific pathophysiological causes of OSA to drive some of the key symptoms and consequences of OSA is also highlighted.

Upper Airway Areas, Volumes, and Linear Measurements Determined on Computed Tomography During Different Phases of Respiration Predict the Presence of Severe Obstructive Sleep Apnea

PURPOSE

The objective of this study was to analyze the potential of using low-dose volumetric computed tomography (CT) during different phases of respiration for identifying patients likely to have severe obstructive sleep apnea (OSA), defined as a respiratory disturbance index (RDI) higher than 30.

PATIENTS AND METHODS

A prospective study was undertaken at the Ramathibodi Hospital (Bangkok, Thailand). Patients with diagnosed OSA (N = 82) were recruited and separated into group 1 (RDI, ≤30; n = 36) and group 2 (RDI, >30; n = 46). The 2 groups were scanned by low-dose volumetric CT while they were 1) breathing quietly, 2) at the end of inspiration, and 3) at the end of expiration. Values for CT variables were obtained from linear measurements on lateral scout images during quiet breathing and from the upper airway area and volume measurements were obtained on axial cross-sections during different phases of respiration. All CT variables were compared between study groups. A logistic regression model was constructed to calculate a patient's likelihood of having an RDI higher than 30 and the predictive value of each variable and of the final model.

RESULTS

The minimum cross-sectional area (MCA) measured at the end of inspiration (cutoff point, ≤0.33 cm²) was the most predictive variable for the identification of patients likely to have an RDI higher than 30 (adjusted odds ratio [OR] = 5.50; 95% confidence interval [CI], 1.76-17.20; sensitivity, 74%; specificity, 72%,), followed by the MCA measured at the end of expiration (cutoff point, ≤0.21 cm²; adjusted OR = 3.28; 95% CI, 1.05-10.24; sensitivity, 70%; specificity, 68%).

CONCLUSION

CT scanning at the ends of inspiration and expiration helped identify patients with an RDI higher than 30 based on measurement of the MCA. Low-dose volumetric CT can be a useful tool to help the clinician rapidly identify patients with severe OSA and decide on the urgency to obtain a full-night polysomnographic study and to start treatment.

Pharyngeal Airway Dimensions and Head Posture in Obstructive Sleep Apnea Patients with and without Morphological Deviations in the Upper Cervical Spine

Objectives

The aim of the study was to analyse differences in pharyngeal airway dimensions and head posture between obstructive sleep apnea patients with and without morphological deviations in the upper cervical spine and to analyse associations between pharyngeal airway dimensions and head posture in the total sample.

Material and Methods

The sample comprised 53 obstructive sleep apnea (OSA) patients of which 32.1% had upper spine morphological deviations. Accordingly two groups were defined: 17 OSA patients with morphological deviations in the upper spine and 36 without upper spine deviations. Pharyngeal airway dimensions in terms of distances, cross-sectional areas and volume and upper spine morphological deviations were evaluated on cone-beam computed tomography. Head posture was evaluated on two-dimensional generated lateral cephalograms. Differences were analysed and adjusted for age and gender by multiple linear regression analysis.

Results

OSA patients with upper spine morphological deviations had a significantly more backward and curved neck posture (OPT/HOR, P < 0.01; OPT/CVT, P < 0.05) compared to OSA patients without spine deviations. No significant differences were found in airway dimensions between patients with and without upper spine deviations. In the total group significant associations were found between head posture and pharyngeal airway distances and cross-sectional area at the nasal floor, epiglottis and hyoid bone level (P < 0.05, P < 0.01, P < 0.001). No significant association was found between head posture and airway volume.

Conclusions

The results may contribute to differentiate obstructive sleep apnea patients and thereby may prove valuable in diagnosis and treatment planning of obstructive sleep apnea patients.

"Silent" Sleep Apnea in Dentofacial Deformities and Prevalence of Daytime Sleepiness After Orthognathic and Intranasal Surgery

PURPOSE

The purposes of this study were to determine the occurrence of undiagnosed "silent" obstructive sleep apnea (OSA) in dentofacial deformity (DFD) patients at initial surgical presentation and to report on the level of daytime sleepiness in DFD patients with OSA and chronic obstructive nasal breathing (CONB) after undergoing bimaxillary, chin, and intranasal surgery.

MATERIALS AND METHODS

A retrospective cohort study of patients with a bimaxillary DFD and CONB was implemented. Patients were divided into those with no OSA (group I) and those with OSA (group II). Group II was further subdivided into patients referred with polysomnogram (PSG)-confirmed OSA (group IIa) and those with a diagnosis of OSA only after surgical consultation, airway evaluation, and a positive PSG (group IIb). Group II patients were analyzed at a minimum of 1 year after surgery (range, 1 to 10 years) for daytime sleepiness with the Epworth Sleepiness Scale. Patients with postoperative excessive daytime sleepiness were assessed for risk factors and continued need for OSA treatment. Patients in group II were studied to determine which DFD patterns were most associated with OSA. We compared the prevalence of OSA between our study population and the general population.

RESULTS

Two hundred sixty-two patients met the inclusion criteria. Of these, 23% (60 of 262) had PSG-confirmed OSA (group II). This rate was much higher than that found in the general population. Of the patients, 7% (19 of 262) were known to have OSA at initial surgical consultation (group IIa). An additional 16% (41 of 262) were later confirmed by PSG to have OSA (group IIb). Patients with primary mandibular deficiency and short face DFDs were most likely to have OSA (P < .001 and P = .001, respectively). In group II, 91% (55 of 60) rated their daytime sleepiness as "not sleepy" at a minimum of 1 year after surgery. A significant association was found between group II patients with postoperative excessive daytime sleepiness ("sleepy" or "very sleepy") and a preoperative body mass index category of overweight (P = .026).

CONCLUSIONS

Our study found silent OSA to be frequent in the DFD population. The prevalence of OSA in DFD patients exceeded that estimated in the general population, with retrusive jaw patterns most affected. In DFD patients also presenting with OSA and CONB, we confirmed low levels of daytime sleepiness long-term after simultaneous bimaxillary orthognathic, chin, and intranasal surgery.

Quantitation of Mandibular Symphysis Bone as Source of Bone Grafting: Description in Class I and Class III Skeletal Conditions

The aim of this study was to quantify the cortical and cancellous bone in the mandibular symphysis and relate it to the teeth and to the skeletal class. A descriptive study was conducted using cone beam computerized tomography (CBCT). Class I and class III subjects were included, defined according to dental occlusion and cephalogram results. Linear measurements were taken on the CBCT of the mandibular canines, lateral incisors, and central incisors, where the analysis was related to the axial and apical axes considering the bone in relation to the dental area. With previous definitions, an observer took 2 measurements of the height of the mandibular symphysis, cortical bone of the buccal and lower region, and thickness of cancellous bone at different levels; the correlation coefficient between the first and second measurement was 0.99 and presented P = .001. The results were analyzed with analysis of variance and Tukey's honest significant difference test, with P < .05 being statistically significant. The symphysis height was significantly greater in class III subjects. The cortical bone was an average 1.67 ± 0.44 mm in vertical distance in the skeletal class I group and 1.74 ± 0.47 mm in the class III group. The cancellous bone had an average width of 5.03 ± 1.94 mm in the skeletal class I group and 4.74 ± 2.05 mm in the class III group. It was observed that cancellous bone was significantly thicker at the incisor level than at the canine level. There were anatomical differences between skeletal class I and class III subjects, although the clinical significance may be questionable. With the values from these analyses, it may be concluded that there are no significant differences in quantitation of the cortical and cancellous bone in the anterior mandibular symphysis.

Facial phenotype in obstructive sleep apnea-hypopnea syndrome: a systematic review and meta-analysis

This systematic review and meta-analysis explores the association between facial phenotype and obstructive sleep apnea-hypopnea syndrome in adults. A comprehensive electronic (Medline via Ovid, Scopus, and Embase) database and reference search were undertaken in relation to imaging modalities for surface craniofacial assessments in subjects with sleep apnea. The outcome measures were surface facial dimensions, morphology and profile. The quality of studies was assessed and a meta-analysis conducted. The studies were weighted using the inverse variance method, and the random effects model was used to analyse data. This systematic review identified eight case-control studies. In five studies (906 participants), adults with sleep apnea showed increased weighted mean differences in neck circumference by 1.26 mm (P = 0.0001) with extensive heterogeneity between studies (I² = 93%). Only two studies (467 participants) shared the following outcomes: mandible length, lower facial height, mandible width and anterior mandible height parameters. The pooled results demonstrated obstructive sleep apnea syndrome was associated with larger parameters than controls. In conclusion, the surface facial assessment was able to demonstrate some characteristic morphological features, facilitating a meta-analysis, in adults with obstructive sleep apnea-hypopnea syndrome. The strength of these findings, however, was limited by the heterogeneity of the studies precluding the identification of a clear phenotype.

Obstructive sleep apnoea pathogenesis from mild to severe: Is it all the same?

Obstructive sleep apnoea (OSA) is a common disorder caused by not only an impaired upper airway anatomy (i.e. anatomically narrow/collapsible airway), but also by several non-anatomical factors. In this review, we summarise what is known about how each of the pathological factors that cause OSA vary according to disease severity as measured by the apnoea-hypopnoea index. Our synthesis of the available literature indicates that most of the key factors that cause OSA vary with disease severity. However, there is substantial heterogeneity such that the relative contribution of each of these traits varies both between patients and within different severities of disease. These differences likely contribute to variable efficacy of many non-continuous positive airway pressure treatments and inconsistencies in responses with regard to different OSA severities at baseline.