Cephalometric studies on the upper airway space in normal Chinese

Pharyngeal airway subdivisions in 3-dimensional analysis: Differences between anterior and posterior anatomic boundaries

INTRODUCTION

This study aimed to evaluate if there were differences between anterior and posterior anatomic boundaries used for the 3-dimensional determination of pharyngeal airway.

METHODS

The sample included 150 cone-beam computed tomography scans from healthy patients divided according to (1) age: 6-11, 12-16, and ≥16 years; (2) sex: female and male; (3) anteroposterior skeletal pattern: Class I, II, and III; (4) vertical pattern: brachyfacial, mesofacial, and dolichofacial; and (5) craniocervical inclination (CCI): natural head posture, head flexion, and head extension. Anatomic regions were created to determine the correspondences between structures anteriorly and posteriorly to the pharyngeal airway.

RESULTS

The location of the epiglottis, vallecula, hyoid, C2, and C3 were statistically different according to the CCI, and the location of vallecula, C3, and C4 were different according to sex. However, no statistically significant differences were observed between the frequencies of anterior and posterior anatomic region locations among age and different anteroposterior and vertical skeletal patterns. Posterior landmarks tend to be located below the anterior ones; consequently, the anatomic subregion they define will also be located below.

CONCLUSIONS

Anterior and posterior structures and vertical and anteroposterior skeletal patterns may determine upper airway limits regardless of age. However, the studies must be paired according to sex, and CCI must be standardized.

A surgery-first approach using single-jaw rotational mandibular setback in low-angle mandibular prognathism

For the treatment of low-angle mandibular prognathism, rotational mandibular setback surgery is usually performed with Le Fort I maxillary osteotomy to rotate the maxillomandibular complex simultaneously. However, this maxillary surgery can be replaced with the orthodontic intrusion of maxillary posterior teeth. Single-jaw rotational mandibular setback surgery can be done with a surgery-first approach by planning orthodontic rotation of the maxillary occlusal plane with the simulation of the postsurgical forward mandibular rotation. This case report describes this approach applied to a 19-year-old female patient with low-angle mandibular prognathism but without maxillary deficiency. A Class II open bite was formed by the rotational setback surgery. During postsurgical orthodontic treatment, the maxillary total arch was distalized with maxillary molar intrusion using palatal mini-implants and lever. This case report demonstrates that orthodontic rotation of the maxillary occlusal plane and simulation of mandibular rotation can replace maxillary surgery and enable single-jaw rotational mandibular setback surgery with a surgery-first approach.

Evaluation of Changes in the Pharyngeal Airway Space as a Sequele to Mandibular Advancement Surgery: A Cephalometric Study

PURPOSE

To evaluate effect of mandibular advancement on pharyngeal airway space using lateral cephalogram.

MATERIALS AND METHODS

Twenty patients who were diagnosed with class II skeletal malocclusion and underwent surgical intervention for the correction of their dentofacial deformity following orthodontic treatment were included. The soft tissue changes in the pharyngeal space were brought about by the surgical intervention, and the changes that had occurred in increasing the airway were evaluated by using cephalogram.

RESULTS

The results of this study showed that following mandibular advancement surgery, the pharyngeal airway space increased along with an increase in the length and thickness of the uvula with a reduction in the angulation. All the changes remained stable in the late postoperative phase.

CONCLUSION

Patients who underwent mandibular advancement showed a significant increase in the pharyngeal airway space and that remained stable during the evaluation period. As a consequence, mandibular advancement seems to be the most stable surgical movement in relation to airway dimensional gains.

Cephalometric Evaluation of the Upper Airway in Different Skeletal Classifications of Jaws

BACKGROUND

Respiratory system is an important section in development of maxillofacial components and many studies indicated its effect on normal growth of the jaws. The aim of this study is to evaluate upper airway in different skeletal classifications of jaws in lateral cephalogram and its relation to age and gender.

MATERIALS AND METHODS

Study samples were 105 digital cephalometric radiographies, 72 females and 33 males. Lateral cephalograms were hand traced and based on Stainer analysis, there were 30 samples in Class I, 30 samples in Class II and 45 samples in Class III subgroup. Vertical linear measurements, horizontal linear measurements, and angular measurement, proportions and space measurements of the airway in the Cephalograms were analyzed by AutoCAD software.

RESULTS

Data were analyzed using SPSS software version 20. Two horizontal linear measurement (the hypo pharyngeal airway depth, the nasopharyngeal airway depth) and one space measurement (soft palate space) were significantly different in skeletal classes. Vertical and horizontal linear measurements in the 3 groups were increased significantly in men rather than women. The developmental age of groups showed some significant differences.

CONCLUSION

Upper airway dimension is different in different skeletal classes, developmental ages, and gender.

Reliability of lateral cephalometric radiographs in the assessment of the upper airway in children: A retrospective study

OBJECTIVES

To test the reliability of Lateral cephalometric radiographs (LCRs) for use in the assessment of the upper airway, hyoid bone, soft palate, and tongue.

MATERIALS AND METHODS

The records of 57 healthy Chinese children from a nonhospital population (mean age = 12.6 years, SD = 0.5, 28 males and 29 females) who received two consecutive LCRs in the natural head posture were retrospectively analyzed. Fifteen linear, angular, and area measurements were used to describe the airway, hyoid bone, soft palate, and tongue. The reliability between the two LCRs was assessed with the intraclass correlation coefficient (ICC) and F-test. Errors were estimated with the Dahlberg and Bland-Altman method, and intra- and inter-assessor agreements were determined.

RESULTS

Measurements of upper airway and hyoid bone had excellent method reliability, intra-assessor reliability, and inter-assessor reliability (ICC > 0.8). However, the method reliability and the inter-assessor reliability for soft palate and tongue was less favorable (ICC from 0.60 to 0.96). Soft palate area and thickness were the most critical parameters. Intra-assessor reliability was greater than both method reliability and inter-assessor reliability (which were similar).

CONCLUSIONS

The measurement of upper airway morphology, defined as the intramural space, and of the hyoid bone position were highly reliable on LCRs of children. However, the limited reliability in the assessment of tongue and soft palate area may compromise the diagnostic application of LCRs to these structures.

Relationships between the obstructive character of the tonsils and the type of ventilation and lip posture

INTRODUCTION

The role of obstructive tonsils in ventilatory disorders and abnormal lip posture is widely discussed in the literature but remains controversial. The data reported on the probable relationship between obstructive tonsils and an existing breathing disorder or lip incompetence were subjective. The purpose of this study was to evaluate the relationship between the obstructive character of the tonsils and the type of ventilation and lip posture.

MATERIALS AND METHODS

This is a cross-sectional study performed in children aged from 6 to 12 years old. The subjects were divided into two groups (A and B) according to the obstructive or non-obstructive character of the palatal tonsils. Type of ventilation and lip posture at rest were recorded for each child. The collected data were analysed using the SPSS 20.0 software (for Windows). A Student's t-test and a Chi² test were respectively used to compare quantitative and qualitative variables according to the obstructive character of the tonsils for each group. The level of significance is fixed at P=0.05.

RESULTS

The subjects in group B with obstructive palatal tonsils were significantly more likely to oral breathing and lip incompetence than the subjects with non-obstructive tonsils (group A).

CONCLUSION

The clinical examination of children with ventilatory and postural disorders with lip incompetence must be directed towards the search for associated obstructive palatal tonsils in order to plan an early etiological treatment. This would allow to avoid subsequent problems in the dentofacial structures.

[Comparison of the dental measurements according to the obstructive character of the tonsils]

INTRODUCTION

The role of obstructive tonsils in dental arches abnormalities is widely discussed in the literature but remains controversial. Data on the probable relationship between obstructive tonsils and the presence of these orthodontic abnormalities are subjective. The objective of this study is to quantify the relationship between the obstructive character of the tonsils and the dental arches measurements.

MATERIALS AND METHODS

A cross-sectional study was performed in children aged between 6 to 12 years divided into 2 groups (A and B) according to the obstructive character of the tonsils. Dental intra- and inter-arches measurements are recorded on each child. Data is analyzed using SPSS 20.0 for Windows. A t Student and chi square tests are respectively used to compare quantitative and qualitative variables according to the obstructive character of the tonsils. The level of significance is fixed at p = 0.05.

RESULTS

The upper dental arch depth is significantly more important in subjects with obstructive tonsils (group B). Dental arches widths are significantly more important in subjects without obstructive tonsils (group A). Group B subjects are significantly more likely to have class II malocclusions, open bite and posterior cross bite with mandibular lateral deviation than group A subjects.

CONCLUSION

Early evaluation of children with obstructive tonsils can prevent dental intra- and inter-arches abnormalities caused by upper airway obstruction. Thus late and more aggressive treatments which are not always as efficient as when they were performed during childhood will be avoided.

Gender-related difference in the upper airway dimensions and hyoid bone position in Chinese Han children and adolescents aged 6-18 years using cone beam computed tomography

OBJECTIVE

To investigate the gender-related differences in upper airway dimensions and hyoid bone position in Chinese Han children and adolescents (6-18 years) using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

CBCT-scans of 119 boys and 135 girls were selected and divided into four groups (group 1: 6-9 years; group 2: 10-12 years; group 3: 13-15 years; group 4: 16-18 years). The airway dimensions including the cross-sectional area (CSA), anteroposterior (AP) and lateral (LAT) width, length (L), mean CSA and volume (VOL) of upper airway segmentations and hyoid bone position including 11 linear and three angular measurements were investigated using Materialism's interactive medical image control system (MIMICS) 16.01 software. Gender-related differences were analyzed by two independent sample t-tests.

RESULTS

No gender-related difference was found in values of the facial morphology, airway dimensions and hyoid bone position for group 1 (p > 0.05). The children and adolescents in groups 2, 3 and 4 showed significant gender-related differences in the measurement results of facial morphology, airway dimensions and hyoid bone positions (p < 0.05). What's more, the measurement values of boys were obviously larger than those of girls except some measurements in group 2.

CONCLUSIONS

The measurements of airway dimensions and hyoid bone positions have gender-related differences in children and adolescents aged 10-18 years. These results could be taken into consideration during orthodontic diagnosis and treatment.

Influence of tonsil size on sagittal cephalometric measurements

INTRODUCTION

The role of tonsils in the origin of sagittal skeletodental abnormalities has been widely discussed in the literature but remains controversial. Data on the probable relationship between enlarged tonsils and the presence of these abnormalities were subjective. The aim of this study was to quantify the relationship between the space occupied by the palatine tonsils and sagittal cephalometric measurements.

MATERIALS AND METHODS

A cross-sectional study was performed on a group of children divided into 5 subgroups according to the standardized tonsillar hypertrophy grading scale. Cephalometric measurements were recorded for each child. Data were analyzed using SPSS 20.0 for Windows. The strength of the association between tonsil grades and quantitative variables was assessed using Spearman's rank correlation coefficient (Rho). The level of significance was fixed at P=0.05.

RESULTS

Lengths SN, t2-p3, h-Gn and Xi-pm, and angles I/F, I/SN, i/M, SNB, SNPog and SNGn were significantly and negatively correlated with grades. The ANB angle, the sagittal position of the pogonion and the angle of facial convexity were significantly and positively correlated with grades.

CONCLUSION

Early evaluation of tonsil size can prevent certain skeletodental abnormalities in the sagittal plane caused by upper airway obstruction. Thus, more aggressive late treatments, which are not always as effective as when they are performed during childhood, can be avoided.

Measurements of normal upper airway assessed by 3-dimensional computed tomography in Chinese children and adolescents

OBJECTIVE

To establish normative data of upper airway dimensions in Chinese children and adolescents by age and sex.

METHODS

CT-scans of 281 Chinese children and adolescents (140 girls, 141 boys) aged from 6 to 18 years (yr) were selected among the patients who visited in Department of Oral and Maxillofacial Surgery from September 2009 to August 2010. Child was defined as 6-12 yr, and adolescent as 13-18 yr. All the subjects were divided into 4 groups according to age as 6-9, 10-12, 13-15 and 16-18. The upper airway was divided into four distinct anatomic regions: the nasopharynx, the palatopharynx, the glossopharynx and the epiglottic region. Using 3-dimension image processing software, the minimal cross-sectional area with its sagittal diameter and transversal diameter, length and volume of upper airway segmentations were measured.

RESULTS

There was no difference in all parameters of segmentations between genders in children. In adolescents the differences of airway parameters were evident between genders. Male adolescents' upper airway were bigger and longer than female's. Volumes and lengths of segmentations were increased with age in male and female respectively.

CONCLUSIONS

Norms for upper airway in Chinese children and adolescents assessed by 3-D reconstruction computed tomography have been established. Volume and other dimension of upper airway are increased with age. Significant sex dimorphisms in upper airway dimension are evident in adolescents.

Ultrasonographic evaluation of geniohyoid muscle movement during swallowing: a study on healthy adults of various ages

Our purpose in this study was to investigate the application of B+M-mode ultrasound (B/M-mode) imaging as a new approach to quantifying activity patterns of the geniohyoid muscles during swallowing and to assess how these patterns differ according to age and gender. Sixty healthy volunteers (30 men, 30 women) were divided into three age groups (20-39, 40-59, 60-79 years). The subjects were then given 10 ml of mineral water. Ultrasonographic imaging was repeated 5 times and measurements were averaged. Simultaneous B/M-mode images were captured at two regions along the lateral geniohyoid muscle wall. All geniohyoid muscle movement was recorded by real-time B/M-mode. In all cases, ultrasonographic images of the geniohyoid muscle movement during swallowing were easily visualized with the use of real-time B/M-mode. The average moving distance and the duration of movement of the geniohyoid muscle during contraction increased gradually with age. There was a significant difference in ultrasonic measurements of the moving distance and the duration of movement during swallowing between males and females in the three age groups (P < 0.05). B/M-mode imaging provides a simple, noninvasive technique for visual assessment of the lateral geniohyoid muscle wall and may provide a clinical method for evaluating swallowing.

A comparison study of upper airway among different skeletal craniofacial patterns in nonsnoring Chinese children

OBJECTIVE

Patients with OSAS (obstructive sleep apnea syndrome) demonstrate decreased upper airway dimension and craniofacial skeletal abnormalities. The study was performed to analyze whether upper airway dimensions differed among Chinese nonsnoring children of different sagittal and vertical skeletal facial morphologies.

MATERIALS AND METHODS

Lateral cephalometric records were used to measure the dimensions of the upper airway. Two groups of subjects were studied. A group of subjects with a normodivergent facial pattern (n = 190; FH-MP angle between 23.5 degrees and 30.5 degrees ) was divided into three subgroups according to ANB angle (Class I, II, or III). A second group of subjects with a normal sagittal facial pattern (n = 180; ANB angle between 0.7 degrees and 4.7 degrees ) was divided into three subgroups according to the FH-MP angle (low angle, normal angle, or high angle). All subgroups were matched for age and sex.

RESULTS

In the group of subjects with a normodivergent facial pattern, a significant tendency for reduced upper airway dimension in the inferior part (palatopharyngeal and hypopharynx) was found in the Class III, Class I, and Class II subgroups, in that order. In the group of subjects with a normal sagittal facial pattern, the superior part of the airway (nasopharyngeal and palatopharyngeal) decreased with increasing mandibular plane angle.

CONCLUSION

The sagittal and vertical skeletal patterns may be contributory factors for the variation of the inferior and superior part of the upper airway, respectively. Skeletal deficiency of nonsnoring Chinese children may predispose them to upper airway obstruction.

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.

Cephalometric analysis in obese and nonobese patients with obstructive sleep apnea syndrome

STUDY OBJECTIVES

The aims of this study were to comprehensively evaluate the cephalometric features of patients with obstructive sleep apnea syndrome (OSAS), and to elucidate the relationship between cephalometric variables and severity of the apnea-hypopnea index (AHI).

PATIENTS

The study population consisted of 62 male patients with OSAS, classified into 33 obese patients (body mass index [BMI] >or= 27) and 29 nonobese patients (BMI < 27), and 13 male simple snorers (AHI < 5 events per hour).

METHOD

and measurements: Diagnostic polysomnography and measurements of 22 cephalometric variables were carried out for all patients and simple snorers.

RESULTS

Patients with OSAS in both subgroups showed several significant cephalometric features compared with simple snorers: (1) inferiorly positioned hyoid bone, (2) enlarged soft palate, and (3) reduced upper airway width at soft palate. More extensive and severe soft-tissue enlargements including anteriorly positioned hyoid bone and a longer tongue were found in the obese patients. In the nonobese patients, the anteroposterior distances of the bony nasopharynx and oropharynx were significantly smaller than those of simple snorers and obese patients. Stepwise regression analysis showed that anterior displacement of the hyoid bone and retroposition of the mandible were the dominant overall determinants for AHI in patients with OSAS, and that narrowing of the bony oropharynx and inferior displacement of the hyoid bone were dominant determinants for AHI in nonobese patients. A significant regression model for AHI using cephalometric variables could not be obtained for the obese patients, but the BMI proved to be the most significant determinant.

CONCLUSION

Characteristics of the craniofacial bony structure such as narrowing of the nasopharynx and oropharynx and enlargement of the soft tissue in the upper airway may be important risk factors for the development of OSAS in nonobese patients. In obese patients, the deposition of adipose tissue in the upper airway may aggravate the severity of OSAS.

Obstructive sleep apnea syndrome: a comparison between Far-East Asian and white men

OBJECTIVES

To investigate the possible differences between Far-East Asian men and white men in obstructive sleep apnea syndrome (OSAS).

STUDY DESIGN

Prospective nonrandomized controlled study.

METHODS

This study compared consecutive Far-East Asian men with OSAS (n = 50) with two selected groups of White men with OSAS (n = 50 in each group). One group of white men was controlled for age, respiratory disturbance index (RDI), and minimum oxygenation saturation (LSAT). Another group was controlled for age and body mass index (BMI). Cephalometric analysis was performed on all subjects.

RESULTS

The majority of the Far-East Asian men were found to be nonobese (mean BMI, 26.7 +/- 3.8) but had severe OSAS (mean RDI, 55.1 +/- 35.1). When controlled for age, RDI, and LSAT, the white men were substantially more obese (mean BMI, 29.7 +/- 5.8, P = .0055). When controlled for age and BMI, the white men had less severe illness (RDI, 34.1 +/- 17.9, P = .0001). Although the posterior airway space and the distance from the mandibular plane to hyoid bone were less abnormal in the Far-East Asian men, the cranial base dimensions were significantly decreased.

CONCLUSIONS

The majority of the Far-East Asian men in this study were found to be nonobese, despite the presence of severe OSAS. When compared with white men, Far-East Asian men were less obese but had greater severity of OSAS. There may be differences in obesity and craniofacial anatomy as risk factors in these two groups.