Facial morphology and obstructive sleep apnea

Objective:

This study aimed at assessing the relationship between facial morphological patterns (I, II, III, Long Face and Short Face) as well as facial types (brachyfacial, mesofacial and dolichofacial) and obstructive sleep apnea (OSA) in patients attending a center specialized in sleep disorders.

Methods:

Frontal, lateral and smile photographs of 252 patients (157 men and 95 women), randomly selected from a polysomnography clinic, with mean age of 40.62 years, were evaluated. In order to obtain diagnosis of facial morphology, the sample was sent to three professors of Orthodontics trained to classify patients' face according to five patterns, as follows: 1) Pattern I; 2) Pattern II; 3) Pattern III; 4) Long facial pattern; 5) Short facial pattern. Intraexaminer agreement was assessed by means of Kappa index. The professors ranked patients' facial type based on a facial index that considers the proportion between facial width and height.

Results:

The multiple linear regression model evinced that, when compared to Pattern I, Pattern II had the apnea and hypopnea index (AHI) worsened in 6.98 episodes. However, when Pattern II was compared to Pattern III patients, the index for the latter was 11.45 episodes lower. As for the facial type, brachyfacial patients had a mean AHI of 22.34, while dolichofacial patients had a significantly statistical lower index of 10.52.

Conclusion:

Patients' facial morphology influences OSA. Pattern II and brachyfacial patients had greater AHI, while Pattern III patients showed a lower index.

Lateral teleradiography of the head as a diagnostic tool used to predict obstructive sleep apnea

OBJECTIVES

To (1) assess the relationship between obstructive sleep apnea (OSA) and craniofacial, pharyngeal anatomy and (2) to submit the recommendations for clinicians for increasing the sensitivity in the diagnostics of OSA.

METHODS

A review of the relevant literature linking OSA in adults with cephalometric analysis was performed. In total, 11 articles with similar procedural criteria were selected. The data were analysed using the Comprehensive Meta-Analysis Software (Biostat Inc., Englewood, NJ) and Statistica 12.0 (StatSoft Inc., Dell Software, Tulsa, OK).

RESULTS

Adults with OSA did not show statistically significant differences in the sagittal and vertical skeletal planes in comparison with the controls (p > 0.05). The patients with OSA had soft palate length, width and area increased accordingly by 4.21, 1.99 mm and 0.86 cm(2), tongue area increased by 2.02 cm(2), the upper posterior pharyngeal space (SPAS) and lower posterior pharyngeal space reduced accordingly by 4.53 and 1.32 mm, mandibular plane to the hyoid bone (MP-H) distance increased by 4.14 mm compared with the controls (p < 0.05). The SPAS parameter of the patients with OSA did not show statistically significant differences between the studies, with the mean value being 5.69 mm.

CONCLUSIONS

Analysed cephalometric data totally supported the concept of soft-tissue abnormalities in subjects with OSA, skeletal-only halfway; MP-H and SPAS being the most reliable parameters. Increased MP-H may serve as a predictor when differentiating normal subjects and patients with OSA. Reduced SPAS width could be a prognostic parameter for suspecting OSA. These two values should be kept in mind by dentists and can also be used as a simple auxiliary method by physicians; nevertheless, it is still underestimated and more studies are needed.

Comparison of BMI, AHI, and apolipoprotein E ε4 (APOE-ε4) alleles among sleep apnea patients with different skeletal classifications

STUDY OBJECTIVES

This case-control study investigated whether variations within the APOE-ε gene were associated with having a convex facial profile (skeletal Class II) compared to exhibiting a straight or concave facial profile (Class I or Class III) among patients with obstructive sleep apnea (OSA). Associations between the apnea-hypopnea index (AHI) and body mass index (BMI) scores for these OSA patients were also examined in the context of facial profile.

METHOD

OSA patients with an AHI ≥ 15 were recruited from a sleep clinic and classified by facial and dental occlusal relationships based on a profile facial analysis, lateral photographs, and dental examination. Saliva was collected as a source of DNA. The APOE-ε1-4 allele-defining single nucleotide polymorphisms (SNPs) rs429358 and rs7412 were genotyped. A χ(2) analysis was used to assess Hardy-Weinberg equilibrium and for association analysis (significance at p < 0.05). ANOVA and Fisher exact test were also used.

RESULT

Seventy-six Caucasian OSA patients participated in the study-25 Class II cases and 51 non-Class II cases. There was no association of the APOE-ε4 allele with facial profile among these OSA patients. Class II OSA patients had significantly lower BMIs (30.7 ± 5.78) than Class I (37.3 ± 6.14) or Class III (37.8 ± 6.17) patients (p < 0.001), although there was no statistical difference in AHI for Class II patients compared with other groups.

CONCLUSION

OSA patients with Class II convex profile were more likely to have a lower BMI than those in other skeletal groups. In fact 20% of them were not obese, suggesting that a Class II convex profile may influence or be associated with OSA development independent of BMI.

Craniofacial morphological characteristics in children with obstructive sleep apnea syndrome: a systematic review and meta-analysis

BACKGROUND

The authors conducted a systematic review to consolidate the current knowledge regarding craniofacial morphological characteristics associated with obstructive sleep apnea syndrome (OSAS) in nonsyndromic pediatric patients.

TYPES OF STUDIES REVIEWED

The authors included clinical studies in which participants were younger than 18 years, polysomnography was performed to determine the presence and severity of OSAS and the study group was compared with a control group or normative growth center data. The authors excluded studies with syndromic participants or participants who had received orthodontic treatment, orthognathic treatment or both previously.

RESULTS

The authors identified nine articles. They conducted a meta-analyses of the data from all but one of the studies to evaluate the eight most common cephalometric variables in children with OSAS. The I(2) values were 79.53 percent for the angle from the basion point to the sella nasion (SN) line, 89.54 percent for the angle between the SN and palatal plane lines and 96.82 percent for the angle between the mandibular plane and SN lines (MP-SN). Therefore, for these three variables, the authors conducted a random-effect model meta-analysis. For the remaining five variables (MP-SN, the angle from SN to Apoint, the angle from SN to B point [SNB], the angle from A point to nasion point to B point [ANB] and the angle from articulare point to gonion point to gnathion point), I(2) values were all less than 40 percent, and therefore the authors conducted a fixed-effects model meta-analysis. Three of the evaluated cephalometric variables (MP-SN, SNB and ANB) had statistically significant differences in comparison with those in a control group. Although the values of these variables were increased in children with OSAS, results of the meta-analysis should be considered cautiously owing to the limited number of cephalometric variables included.

PRACTICAL IMPLICATIONS

Dentists who identify patients with a craniofacial morphology consistent with pediatric OSAS (retrusive chin, steep mandibular plane, vertical direction of growth and a tendency toward Class II malocclusion) should inquire further into their patients' medical histories. When the craniofacial morphology is accompanied by a history of snoring, inability to breathe through the nose, significant allergies, asthma or obesity, the dentist should refer the patient to an otolaryngologist for assessment.

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.

Obesity and craniofacial structure as risk factors for obstructive sleep apnoea: impact of ethnicity

OSA is the result of structural and functional abnormalities that promote the repetitive collapse of the upper airway during sleep. This common disorder is estimated to occur in approximately 4% of men and 2% of women, with prevalence studies from North America, Australia, Europe and Asia indicating that occurrence is relatively similar across the globe. Anatomical factors, such as obesity and craniofacial morphology, are key determinants of the predisposition to airway collapse; however, their relative importance for OSA risk likely varies between ethnicities. Direct inter-ethnic studies comparing craniofacial phenotypes in OSA are limited. However, available data suggest that Asian OSA populations primarily display features of craniofacial skeletal restriction, African Americans display more obesity and enlarged upper airway soft tissues, while Caucasians show evidence of both bony and soft tissue abnormalities. Our recent comparison of Chinese and Caucasian OSA patients found for the same degree of OSA severity. Caucasians were more obese, and Chinese had more skeletal restriction. However, the ratio of obesity to craniofacial bony size (or anatomical balance, an important determinant of upper airway volume and OSA risk) was similar between Caucasians and Chinese OSA patients. Ethnicity appears to influence OSA craniofacial phenotype but furthermore the relative contribution of the anatomical factors underlying OSA risk. The skeletal restriction craniofacial phenotype may be particularly vulnerable to increasing obesity rates. Better understanding of craniofacial phenotypes encompassing ethnicity may help improve OSA recognition and treatment; however, further studies are needed to elucidate ethnic differences in OSA anatomical risk factors.