Linear dimensions of the upper airway structure during development: assessment by magnetic resonance imaging

The effect of pharyngeal structures on the severity of obstructive sleep apnea

BACKGROUND/OBJECTIVE

Obstructive sleep apnea (OSA) is characterized by complete or partial cessation of breathing during sleep. The tongue is suggested as a possible anatomical site causing airway obstruction. However, the role of other pharyngeal structures in the development of OSA remains unclear. We designed a study using both the apnea-hypopnea index (AHI) and the oxygen saturation measurements to assess the severity of OSA. We aimed to identify critical anatomical structures of the upper airway that correlate with the severity of OSA and to evaluate the utility of magnetic resonance imaging (MRI) markers to detect possible OSA in patients without overt symptoms.

MATERIALS AND METHODS

The study included participants referred to the neurology outpatient clinic from the check-up unit. Participants were grouped as controls, mild, moderate, or severe OSA according to the AHI. A cranial MRI with a field of view (FOV) encompassing the upper airway structures was obtained from all participants. The areas of the tongue and the uvula were measured on the sagittal images by drawing the boundaries of the tissues manually. The posterior air space (PAS) area was evaluated from regions of interest in five parallel planes.

RESULTS

Of 105 participants, 30 were controls, 27 had mild, 25 had moderate, and 23 had severe OSA. The moderate and severe OSA groups did not differ in oxygen saturation levels during sleep. Therefore, patients with moderate and severe OSA were combined into one group (moderate/severe OSA). The area of the tongue was significantly larger in the moderate/severe OSA group compared to the control group. Both the tongue and the uvula areas showed a significant positive correlation with the AHI.

CONCLUSION

Our findings suggest that the tongue and uvula have prominent roles in the severity of OSAS. It may be useful to measure these structures with MRI to screen for at-risk individuals without overt OSA symptoms.

Comparison of weight-based and pinna size method for ProSeal laryngeal mask airway size selection in children receiving general anesthesia: A randomized clinical study

Background and Aims

Several methods are in use for LMA ProSeal™ size selection in pediatric patients. Weight-based method is most commonly used. Pinna size-based method is a promising new technique for accurate size selection.

Material and Methods

A total of 146 children aged between 6 months and 12 years undergoing surgery under general surgery were included. They were randomized into either pinna-based group (group X) or weight-based group (group Y). Both groups were compared for accurate placement of ProSeal™ laryngeal mask airway (PLMA), ease of insertion, number of attempts needed, and peak airway pressures.

Results

A Comparable number of patients had a Brimacombe score of 3 and above, indicating correct placement in both groups (P = 0.407). PLMA was easily inserted in 79.5% and 87.7% of patients of groups X and Y, respectively (P = 0.180). Insertion was found to be difficult in 20.5% of patients in group X, whereas it was difficult in only 12.3% of patients of group Y (P = 0.180). The two groups were comparable as per the number of attempts needed for insertion (P = 0.161). Mean peak airway pressures too were comparable between both groups. Ease of insertion too, was statistically insignificant between both groups.

Conclusions

Pinna size-based estimation of LMA size is an effective alternative method to weight-based selection.

Guedel oropharyngeal airway: The validation of facial landmark-distances to estimate sizing in children - Visualisation by magnetic resonance imaging (GUEDEL-I): A prospective observational study

OBJECTIVE

To validate the ERC-recommended facial landmark-distance for oropharyngeal airway sizing in children.

METHODS

We conducted a prospective observational study in anaesthetised, spontaneously breathing children ≤12 years undergoing cranial MRI. Oropharyngeal airways were inserted following the distance from the maxillary incisors to the mandibular angle. Primary outcome was the rate of properly sized oropharyngeal airways on MRI, defined as the distal end positioned within 10 mm from the epiglottis without contacting it. Secondary outcomes were the occurrence of tongue protrusion, oropharyngeal airways clinical efficacy, and related adverse events. Furthermore, we calculated probabilities for the estimation of proper size when considering five facial landmark-distances and optimal rules based on biometric parameters.

RESULTS

In 94 children with a mean (SD) age of 4.7 (±3) years, 47.9% [95%-CI 38%-57.9%] oropharyngeal airways were properly sized, while 23.4% [95%-CI 15.9%-33%] were undersized, and 28.7% [95%-CI 20.5%-38.7%] oversized. Tongue protrusion occurred in 59.1% [95%-CI 38.2%-77.2%] of undersized and 15.6% [95%-CI 7.6%-29.2%] of properly sized oropharyngeal airways. No oropharyngeal airway required replacement. Comparing probabilities for five landmark-distances, "maxillary incisors to the angle of the mandible" proved superior for proper sizing at 41.2% [95%-CI 32%-51.7%]. The best-fit formula was "22.43 + 17.54 × log(weight[kg])" with a probability of 61.7% [95%-CI 51.5%-70.9%].

CONCLUSION

Although the facial landmark-distance "maxillary incisors to the angle of the mandible" does not reliably predict oropharyngeal airway size, no clinical problems have been encountered. Since it can be considered the least inaccurate facial landmark-distance, it can serve as an approximation, but the efficacy of oropharyngeal airways should be evaluated clinically.

REGISTERED CLINICAL TRIAL

German Clinical Trials Register; DRKS00025918.

Morphological and acoustic modeling of the vocal tract

In speech production, the anatomical morphology forms the substrate on which the speakers build their articulatory strategy to reach specific articulatory-acoustic goals. The aim of this study is to characterize morphological inter-speaker variability by building a shape model of the full vocal tract including hard and soft structures. Static magnetic resonance imaging data from 41 speakers articulating altogether 1947 phonemes were considered, and the midsagittal articulator contours were manually outlined. A phoneme-independent average-articulation representative of morphology was calculated as the speaker mean articulation. A principal component analysis-driven shape model was derived from average-articulations, leading to five morphological components, which explained 87% of the variance. Almost three-quarters of the variance was related to independent variations of the horizontal oral and vertical pharyngeal lengths, the latter capturing male-female differences. The three additional components captured shape variations related to head tilt and palate shape. Plane wave propagation acoustic simulations were run to characterize morphological components. A lengthening of 1 cm of the vocal tract in the vertical or horizontal directions led to a decrease in formant values of 7%-8%. Further analyses are required to analyze three-dimensional variability and to understand the morphological-acoustic relationships per phoneme. Average-articulations and model code are publicly available (https://github.com/tonioser/VTMorphologicalModel).

Palatine Tonsil Measurements and Echogenicity during Tonsillitis Using Ultrasonography: A Case-Control Study

This case-control study aimed to assess the size and echogenicity of inflamed tonsils using ultrasonography. It was carried out at different hospitals, nurseries, and primary schools in Khartoum state. About 131 Sudanese volunteers between 1 and 24 years old were recruited. The sample included 79 volunteers with normal tonsils and 52 with tonsillitis according to hematological investigations. The sample was divided into groups according to age-1-5 years old, 6-10 years old, and more than ten years. Measurements in centimeters of height (AP) and width (transverse) of both tonsils (right and left) were taken. Echogenicity was assessed according to normal and abnormal appearances. A data collection sheet containing all the study variables was used. The independent samples test (t-test) showed an insignificant height difference between normal controls and cases with tonsillitis. The transverse diameter increased significantly with inflammation (p-value < 0.05) for both tonsils in all groups. Echogenicity can differentiate between normal and abnormal tonsils (p-value < 0.05 using the chi-square test) for samples from 1-5 years and 6-10 years. The study concluded that measurements and appearance are reliable indicators of tonsillitis, which can be confirmed with the use of ultrasonography, helping physicians to make the correct diagnosis and decisions.

Study of pharyngeal airway morphology with CBCT: Benefits of four premolar extraction orthodontic treatments

BACKGROUND AND AIM

Four premolars extractions are routine procedures for correction of malocclusion, but will inevitably lead to a reduction of tongue space, whether this will weaken the pharyngeal airway remains a controversy.

PATIENTS AND METHODS

Cone-beam computed tomography (CBCT) radiographs of 80 patients who completed four premolar extraction orthodontic treatments were collected and divided into three anteroposterior skeletal groups according to the ANB (angle subspinale to nasion to supramentale) value. Linear, angular, cross-sectional area, and volumetric dimensions of the pharyngeal airway were measured using Dolphin Imaging 11.9 software. One-way analysis of variance and Pearson's correlation coefficient test were performed to assess the intergroup comparisons. Treatment changes were evaluated with two-sample t-tests.

RESULTS

In intergroup comparisons, vertical linear and cross-sectional area differences were identified in S-Go/N-Me, VD1, VD1/N-Me, VD2/N-Me, AA, OAA and OMINI (p<0.05), while other measurements showed no significant differences. Angle2, the tilting degree of the pharyngeal airway, showed a positive correlation with ANB (p<0.05). As for the treatment changes, a significant increase was found in the pharyngeal airway in the Class I group (OUA p<0.05, VD1 p<0.001, VD2 p<0.05) and Class II group (VD1 p<0.001. VD2, p<0.05), and inversely, a significant decrease was found in the pharyngeal airway in the Class III group (OAA p<0.05, OMINI p<0.05, OUA p<0.05). No volumetric difference was identified. Interestingly, regarding the preoperative pharyngeal airway size, values trended to the mean value significantly.

CONCLUSION

Four premolar extraction orthodontic treatments did not affect the pharyngeal airway volume except for the vertical liner and cross-sectional area dimensions. The trend of the gold standard suggested a positive influence of four premolar extraction orthodontic treatments.

Target insertion depth of nasopharyngeal temperature probes in children: A prospective observational study analyzing magnetic resonance images

BACKGROUND

Core temperature monitoring is indispensable to prevent children from perioperative thermal perturbations. Although nasopharyngeal measurements are commonly used in anesthesia and considered to reflect core temperature accurately, standardized target depths for probe insertion are unknown in children.

AIMS

Our primary goal was to determine a target depth of nasopharyngeal temperature probe insertion in children by measuring distances on magnetic resonance imaging (MRI). Secondary aims were to correlate these measurements with biometric variables and facial landmark-distances to derive formulas estimating target depth.

METHODS

We conducted a prospective observational study in children ≤12 years undergoing cranial MRI with anesthesia. We documented patient characteristics and measured the landmark-distances nostril-mandible, nostril-tragus, and philtrum-tragus on patient's faces. On MRI, the target point for the probe tip was considered to be the site of the nasopharyngeal mucosa with the closest proximity to the internal carotid artery. After its determination in the transverse axis and triangulation to the sagittal axis, we measured the distance to the nostril. This distance, defined as target insertion depth, was correlated with the patient characteristics and used for univariate and multiple linear regression analysis.

RESULTS

One hundred twenty children with a mean age of 4.5 years were included. The target insertion depth ranged from 61.8 mm in infants to 89.8 mm in 12-year-old children. Height correlated best (ρ = 0.685, 95%-CI: [0.57-0.77]). The best-fit estimation in millimeters, "40.8 + height [cm] × 0.32,″ would lead to a placement in the target position in 67% of cases. A simplified approach by categories of 50-80, 80-110, 110-130, and >130 cm height with target insertion depths of 60, 70, 80, and 85 mm, respectively, achieved similar probabilities.

CONCLUSIONS

Height-based formulas could be a valuable proxy for the insertion depth of nasopharyngeal temperature probes. Further clinical trials are necessary to investigate their measurement accuracy.

Correlation of cephalometric variables with obstructive sleep apnea severity among children: a hierarchical regression analysis

OBJECTIVE

To evaluate the correlation between cephalometric parameters and apnea-hypopnea index (AHI) after controlling gender, body mass index (BMI), and adenoid size in children with obstructive sleep apnea (OSA).

METHODS

Sixty-four children with OSA (40 males, 24 females, 8.72 ± 0.899 years) were chosen by simple random sampling for a cross-sectional study from January 2018 to March 2022. They were diagnosed with OSA, assessed by Obstructive Sleep Apnea-18 questionnaire and home polysomnography and underwent lateral cephalograms.

RESULTS

Hierarchical regression analysis indicated that cephalometric parameters (except adenoid size) were associated with OSA severity, explaining 18.1% of the AHI variance. Among cephalometric measurements, AHI was positively associated with H-RGn and N-Go-Me angle (p < 0.05) and negatively associated with NP (p < 0.05).

CONCLUSION

The sagittal diameter of the oropharynx, lower gonial angle, and hyoid position are significant AHI predictors in children with OSA, independent of demographic characteristics and adenoid size.

Evaluation of Skeletal, Dentoalveolar, and Sagittal Airway Changes Induced by the Mandibular Anterior Repositioning Appliance (MARA) in Class II Malocclusion: A Retrospective Controlled Study on Lateral Cephalograms

The aim of the study was to evaluate the changes in skeletal, dentoalveolar, and airway dimensions induced by the mandibular anterior repositioning appliance (MARA) in the treatment of Class II malocclusion. A group of 24 Class II patients treated with MARA was evaluated with lateral cephalograms at the start (13.8 ± 2 years) and at the end of treatment (15.7 ± 1.9 years) and compared with a matched untreated Class II group of 20 subjects selected from the archive of the AOOF Legacy. Statistical comparisons were performed with the Student’s t-test. No significant differences were observed for the sagittal airway dimensions. The MARA group showed a significant improvement of Wits (−1.4 mm; p = 0.009) and ANB angle (−0.6°; p = 0.038), a reduction in the overjet (−1.9 mm; p = 0.001), of the overbite (−1.5 mm; p = 0.005), an improvement of molar relationship (1.8 mm; p = 0.000) and a proclination of the lower incisors (2.7°; p = 0.012). During active treatment, MARA did not produce significant favorable changes in the sagittal airway dimensions in Class II subjects when compared with untreated controls. Clinically, these findings highlighted that MARA was able to provide an effective correction of Class II malocclusion with favorable dentoskeletal changes.

Pediatric Obstructive Sleep Apnea: What’s in a Name?

Obstructive sleep apnea is a highly prevalent disease across the lifespan and imposes substantial morbidities, some of which may become irreversible if the condition is not diagnosed and treated in a timely fashion. Here, we focus on the clinical and epidemiological characteristics of pediatric obstructive sleep apnea, describe some of the elements that by virtue of their presence facilitate the emergence of disrupted sleep and breathing and its downstream consequences, and also discuss the potential approaches to diagnosis in at-risk children.

Assessment of event-related evoked potentials and China-Wechsler intelligence scale for cognitive dysfunction in children with obstructive sleep apnea

OBJECTIVE

To explore the relationship between obstructive sleep apnea (OSA) and cognitive impairment by combining event-related evoked potentials (ERPs) and China-Wechsler Younger Children Scale (C-WISC) in children with sleep-disordered breathing (SDB) with vs. without OSA.

METHODS

This was a retrospective case-control study of all consecutive children (n = 148) with adenoid tonsil hypertrophy between July 2017 and March 2019 at the Hospital.

RESULTS

The children were divided into the OSA (n = 102) and non-OSA (n = 46) groups. The apnea-hypopnea index (AHI), obstructive apnea index (OAI), and obstructive apnea-hypopnea index (OAHI) in the OSA group were elevated compared with those of the non-OSA group (all P < 0.001). The mean oxygen saturation (SaO₂) and SaO₂ nadir were lower in the OSA group compared with the non-OSA group (both P < 0.001). The respiratory arousal index (RAI) values in the OSA group were larger than those of the non-OSA group (P < 0.001). The P300 and N100 latencies in the OSA group were longer than those of the non-OSA group (both P < 0.001). Pearson's correlation analysis revealed correlations of the P300 peak latency with full-scale intelligence quotient (FIQ) (P < 0.001 and r = -0.527), verbal intelligence quotient (VIQ) (P < 0.001 and r = -0.448), and performance intelligence quotient (PIQ) (P < 0.001 and r = -0.515). There was a correlation between the N100 peak latency and PIQ (P = 0.026 and r = -0.183).

CONCLUSION

ERPs, as an objective measurement, might help assess cognitive impairment in children with OSA.

Speech production in Mandarin-speaking children with cochlear implants: a systematic review

OBJECTIVE

This study aimed to systematically review and critically appraise the literature describing the phonetic characteristics and accuracy of the consonants, vowels and tones produced by Mandarin-speaking children with cochlear implants (CIs).

DESIGN

The protocol in this review was designed in conformity with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. EBSCOhost, PubMed, Scopus, PsycINFO, ProQuest Central databases were searched for relevant articles which met the inclusion criteria.

STUDY SAMPLE

A total of 18 journal papers were included in this review.

RESULTS

The results revealed that Mandarin-speaking children with CIs perform consistently more poorly in their production of consonants, in particular on fricatives, have a smaller and less well-defined vowel space, and exhibit greater difficulties in tone realisation, notably T2 and T3, when compared to their normal-hearing (NH) peers. The results from acoustic and accuracy analyses are negatively correlated with CI implantation age, but largely positively correlated with hearing age.

CONCLUSIONS

Findings of this review highlight the factors that influence consonant, vowel and tone production in Mandarin-speaking children with CIs, thereby providing critical information for clinicians and researchers working with this population.

Correlation between craniofacial structures, anthropometric measurements, and nasopharyngeal dimensions in black adolescents

OBJECTIVES

To evaluate the correlation between craniofacial structures, anthropometric measurements, and bony and soft tissue nasopharyngeal dimensions in African Black adolescents.

METHODS

This retrospective cross-sectional study was conducted on 483 healthy adolescents (250 females and 233 males), randomly selected from one dental clinic. The inclusion criteria were skeletal and dental Class I, Black ethnicity, pubertal growth period as determined by the Greulich and Pyle atlas criteria, and no history of orthodontic treatment. Anthropometric measurements (stature, upper body height, lower body height, and BMI) and radiographic records (hand-wrist radiographs, and lateral cephalograms) were obtained. One investigator traced and analysed all cephalograms to determine three skeletal craniofacial parameters (maxillary length [Ar- ANS], mandibular length [Ar-Gn], and lower anterior facial height [ANS-Me]), and 14 (8 skeletal and 6 soft tissue) nasopharyngeal parameters. Pearson correlation coefficients and stepwise multiple linear regression analyses were conducted.

RESULTS

The mean skeletal ages of females and males were 11.31±2.31y and 12.66±1.85y, respectively. Multiple linear regression analyses showed that stature, posterior height of nasal cavity (S-PNS), length of nasal floor (AA-PNS), and mean area of bony nasopharynx (Area 1) were significantly correlated with maxillary length, P<.001. Stature, BMI, S-PNS, vertical angle of nasopharynx (Ba-S-PNS), Area 1, adenoid height (AD), and linear hyoid bone measurements (H-AA, H-RGN, H-Ax) were all correlated with mandibular length, P<.05. Lower facial height showed sexual dimorphism and was significantly associated with vertical nasopharyngeal measurements, BMI and upper body height.

CONCLUSIONS

Craniofacial structures were significantly associated with stature and upper body height. Maxillary growth was associated with bony nasopharyngeal variables. Mandibular growth and lower facial height were associated with bony and soft tissue nasopharyngeal variables. The sexual dimorphism in lower facial height warrants future studies to fully understand and manage the craniofacial complex and nasopharyngeal airway in African Black adolescents.

Advanced interdisciplinary treatment protocol for pediatric obstructive sleep apnea including medical, surgical, and orthodontic care: a narrative review

OBJECTIVE

To suggest an updated interdisciplinary treatment protocol for pediatric obstructive sleep apnea (POSA) based on the integration of craniofacial growth modification into medical and surgical sleep practice.

METHODS

PubMed, Scopus, and Cochrane library were searched up to February 2020 using keywords. Among 184 articles, 80 studies were finally included. An integrated treatment protocol for POSA encompassing craniofacial skeletal management as well as medical and surgical care was attempted.

RESULTS

A differential diagnostic workflow for identifying the phenotype of POSA was suggested, and a phenotype-based treatment protocol for POSA was proposed. Despite the lack of high level of evidence, timely skeletal growth modification in three dimensions using craniofacial growth potential could be valuable treatment for upper airway development in POSA patients with craniofacial phenotypic cause.

CONCLUSION

A novel precision treatment protocol will advance clinicians to determine the primary option or to apply the combined strategy for POSA patients.

Sleep-disordered breathing and comorbidities: role of the upper airway and craniofacial skeleton

Obstructive sleep-disordered breathing (SDB), which includes primary snoring through to obstructive sleep apnea syndrome (OSAS), may cause compromise of respiratory gas exchange during sleep, related to transient upper airway narrowing disrupting ventilation, and causing oxyhemoglobin desaturation and poor sleep quality. SDB is common in chronic disorders and has significant implications for health. With prevalence rates globally increasing, this condition is causing a substantial burden on health care costs. Certain populations, including people with sickle cell disease (SCD), exhibit a greater prevalence of OSAS. A review of the literature provides the available normal polysomnography and oximetry data for reference and documents the structural upper airway differences between those with and without OSAS, as well as between ethnicities and disease states. There may be differences in craniofacial development due to atypical growth trajectories or extramedullary hematopoiesis in anemias such as SCD. Studies involving MRI of the upper airway illustrated that OSAS populations tend to have a greater amount of lymphoid tissue, smaller airways, and smaller lower facial skeletons from measurements of the mandible and linear mental spine to clivus. Understanding the potential relationship between these anatomical landmarks and OSAS could help to stratify treatments, guiding choice towards those which most effectively resolve the obstruction. OSAS is relatively common in SCD populations, with hypoxia as a key manifestation, and sequelae including increased risk of stroke. Combatting any structural defects with appropriate interventions could reduce hypoxic exposure and consequently reduce the risk of comorbidities in those with SDB, warranting early treatment interventions.

Correlations between obstructive sleep apnea and adenotonsillar hypertrophy in children of different weight status

The present study aimed to evaluate the relationship between OSA and adenotonsillar size in children of different weight status. A total of 451 patients aged 2–13 years with suspected OSA were retrospectively enrolled in the study. Correlations between the apnea-hypopnea index (AHI) and adenotonsillar size in different weight status were investigated. The adenoidal/nasopharyngeal (A/N) ratio of underweight children was significantly higher than that of normal-weight children (P = 0.027). Both adenoid and tonsil size were positively correlated with logAHI in children of normal weight (r = 0.210, P = 0.001; and r = 0.212, P = 0.001) but uncorrelated in the other groups. Gender (OR = 1.49, 95% CI: 1.01–2.20, P = 0.043), obese (OR = 1.93, 95% CI: 1.10–3.40, P = 0.012), A/N ratio (OR = 1.55, 95% CI: 1.28–1.88, P < 0.001) and tonsil size (OR = 1.36, 95% CI: 1.18–1.57, P < 0.001) were all associated with the severity of OSA. Adenotonsillar hypertrophy contributed to OSA in normal-weight children. In children of abnormal weight, instead of treatment for adenotonsillar hypertrophy, appropriate treatments for other factors are required.

Comparison of weight-based and pinna size-based selection of ProSeal laryngeal mask airway in paediatric population - A prospective exploratory trial

Background and Aims

Weight-based selection of ProSeal laryngeal mask airway (PLMA) size may be unreliable in some situations. The aim of this study was to compare the ventilation parameters using PLMA during controlled ventilation between weight-based size selection and pinna size-based selection in children.

Methods

A total of 204 patients were randomised to receive either pinna size-based (Group P) or weight-based (Group W) size selection of PLMA. We tested the hypothesis that pinna size-based selection of PLMA was better than weight-based selection of PLMA in paediatric patients during controlled ventilation under general anaesthesia in terms of oropharyngeal sealing pressure (the primary end-point) and Brimacombe score. Cuff pressure was maintained at 60 cm of H₂O during the study. Secondary outcomes included the number of attempts for successful placement of PLMA, peak airway pressure, gastric tube placement, traumatic insertion, and complications were also compared. Parametric variables were analysed using unpaired t-test and categorical variables were analysed using Mann-Whitney and Chi-square test.

Results

In all, 200 patients were analysed. The mean oropharyngeal sealing pressure in Group P was 25.4 ± 3.5 cmH₂O and 24.9 ± 3.8 cmH₂O in Group W, (P = 0.34). There was no significant difference between the two groups in any of the secondary outcomes. There were no traumatic insertion or complications reported in both the groups.

Conclusion

Pinna-based size selection method can be used in PLMA placement in the paediatric population for positive pressure ventilation and it serves as an alternative method to weight-based selection.

Linear dimensions of normal upper airway structure by magnetic resonance imaging in Chinese Han infants and preschool children

OBJECTIVES

To establish normative data of upper airway structure in Chinese Han infants and preschool children.

METHODS

Magnetic resonance imaging (MRI) scans of 521 Chinese Han infants and preschool children (225 girls, 296 boys) aged from 1 day to 72 months were selected from the children who underwent head MRI at the Capital Institute of Pediatrics Affiliated Children Hospital, Beijing, China. No subjects had sleep-disordered breathing or associated conditions that may have affected the upper airway anatomy. The upper airway dimensions and surrounding soft tissue sizes were measured along the mid-sagittal and axial images.

RESULTS

On images from the mid-sagittal image, the normative values of the following were obtained for all age group: thickness of the adenoid and nasopharyngeal area, length and thickness of the soft palate, length and height of the tongue, length of upper airway, distance between the mental spine and clivus, and the adenoid oblique width, soft palate oblique width, and tongue oblique width along the mental spine-clivus line. Normative values of the mean tonsillar width and intertonsillar space on the axial images were also obtained. There were no differences in any measurements between boys and girls in either infants or preschool children. Older children had larger airway dimensions, as expected.

CONCLUSION

Normative values for upper airway structure in Chinese Han infants and preschool children assessed by MRI were established. The upper airway dimension and surrounding soft tissues size, including soft palate, adenoid, tongue, and tonsils, were increased with age. There were no gender differences during the first six years of life. These data may prove useful when studying airway disease in Chinese Han children.

Transcervical ultrasonographic examination of palatine tonsil size and its correlation with age, gender and body-mass index in healthy children

OBJECTIVE

Our aim was to assess the palatine tonsil size with transcervical ultrasonography in healthy children and to analyze whether the palatine tonsil size is correlated with age, gender and body-mass index (BMI).

METHODS

This series consisted of 680 healthy children (340 females, 340 males) who underwent transcervical ultrasonography for evaluation of palatine tonsil size. A total of seventeen age groups (range: 1-17 years) comprised of 40 children (20 females, 20 males) were constituted. Demographic data including gender, height, weight and BMI were noted. Correlation between baseline descriptive data and tonsil volume was investigated.

RESULTS

The average age was 102.51 ± 59.24 months (range: 12 to 204) and body-mass index was 17.50-5.16 kg/m2 (min: 12.4-max:25.8). The average tonsil volume was 1819.5-2023.5 mm³ (min:601, max: 4007). The tonsil volume did not differ significantly between females and males (p = 0.108). However, there was a significant difference between tonsil volumes of various age groups (p < 0.001). Tonsil size seemed to be greater in parallel with advancement of age (p < 0.001) and increased BMI (p < 0.001).

CONCLUSION

Transcervical ultrasonography can be an accurate, safe, cheap, non-invasive and accessible measure for evaluation of the size of tonsils objectively. There were strongly positive correlations between age, BMI and palatine tonsil size in healthy children and variability with respect to descriptive characteristics must be considered during diagnostic procedures and preoperative evaluation.

ADVANCES IN KNOWLEDGE

In our study, we suggest that transcervical ultrasonography can be an accurate, safe, cheap, non-invasive and accessible measure for evaluation of the size of tonsils. There were positive correlations between age, BMI and palatine tonsil size in healthy children.

Urine cysteinyl leukotriene levels in children with sleep disordered breathing before and after adenotonsillectomy

OBJECTIVES

Obstructive sleep apnea (OSA) is a common problem in children and is associated with increased cardiovascular, neurobehavioral and somatic growth consequences. Cysteinyl leukotrienes (CysLTs) play a major role with local and systemic relations to the pathophysiology of OSA. The level of CysLTs in urine, blood, exhaled breath and adenotonsillar tissue of OSA children are increased. However it remains unclear whether inflammatory marker levels are alleviated after adenotonsillectomy. Therefore, we compare the urine leukotriene E4 (uLTE4) levels in children before and after adenotonsillectomy and evaluate clinical outcomes on resolution of OSA.

METHODS

Children under 15 years who suspected OSA with planned adenotonsillectomy were recruited. Sleep questionnaires, quality of life assessment by OSA-18, physical examination, lateral neck radiographs, overnight SpO₂ monitoring and uLTE4 levels were collected. 4 ± 2 weeks post-surgery, OSA-18 was reevaluated and urine was collected again.

RESULTS

Thirty-three children with sleep disordered breathing (SDB) were included (mean age 8.1 ± 2.8 years). After adenotonsillectomy, the uLTE₄ levels decreased from 961.9 (684.8-1438.2) to 708.6 (538.2-1038.8) pg/mg Cr (P = 0.009). The post-surgery score from sleep questionnaire, OSA-18 questionnaire were significant improved (P < 0.001). Obese children demonstrated an improved quality of life post-surgery, but results were poorer than normal-weight children (P = 0.01). The uLTE4 no obvious improved in obese children.

CONCLUSIONS

Adenotonsillectomy remains an effective treatment for SDB children that not only alleviated the severity of SDB and improved quality of life; it also decreased levels of the systemic inflammatory marker, uLTE4. However, benefits were more obvious in non-obese children.

Investigation of the Upper Airway Anatomy With Ultrasound

OBJECTIVE

The aims of this study were to describe the relationship between the scanning planes and appearance of the upper airway on sonography and to demonstrate the reliability and reproducibility of sonographic measurements of the upper airway.

METHODS

Airway sonoanatomy was recognized by comparing the airway images and the corresponding cadaver's anatomical specimens. Systemic sonographic examination of 267 healthy volunteers was conducted to obtain the sonographic measurement of airway lumen. The reliability and reproducibility studies were conducted in 40 healthy volunteers.

RESULT

The air-filled upper airway appeared as a bright heterogeneous hyperechoic line. During deep inspiration, the upper airway lumen expanded to the highest anterior-posterior dimension, whereas during deep expiration, the lateral dimension tended to increase. The sonographic measurements had good reproducibility, with intraclass correlation coefficient ranging from 0.722 to 0.887 and 0.727 to 0.882 for interobserver and intraobserver reliability, respectively.

CONCLUSIONS

Ultrasonography can determine the anatomy of the upper airway and perform the quantitative analysis of the upper airway lumen during respiration. The results were encouraging and support the utility of ultrasonography in future airway disorder studies.

The use of magnetic resonance imaging in the evaluation of upper airway structures in paediatric obstructive sleep apnoea syndrome: a systematic review and meta-analysis

OBJECTIVES

A systematic review was conducted to assess the effectiveness of MRI in evaluating upper airway structures in children affected by obstructive sleep apnoea syndrome (OSAS).

METHODS

A literature search was performed in the Cochrane Central Register of Controlled Trials, Web of Science, Scopus and PubMed databases from their inception to 31/03/2016, including available randomized controlled trials and controlled clinical trials published in English assessing the use of MRI integrated with traditional polysomnography (PSG) among children up to 15 years of age affected by OSAS. The primary outcome to be evaluated was the efficacy of MRI in analyzing the upper airway total volume among healthy children compared with children affected by OSAS. Secondary outcomes were to compare the efficacy of MRI in analyzing the upper airway cross-sectional area in the areas adjacent to the adenoids and tonsils, adenoid and tonsil volume, and soft-tissue and maxillofacial bone parameters in the same sample. Results were expressed using a random-effects model and mean differences (MD) with 95% confidence intervals (CI).

RESULTS

The search yielded 1005 titles in total; the selection process narrowed to 3 titles, which were all assessed as indicating an unclear level of risk of bias. The meta-analysis found evidence of MRI effectiveness in evaluating differences in the upper airway total volume between paediatric patients affected by OSAS and paediatric patients not affected by OSAS (MD -0.56 cm(3); 95% CI: -1.05 to -0.07).

CONCLUSIONS

Although MRI could be considered effective in evaluating upper airway structures in children affected by OSAS, based on the present evidence, PSG is still the golden standard and further studies are required to verify MRI reliability.

MR Image Analytics to Characterize the Upper Airway Structure in Obese Children with Obstructive Sleep Apnea Syndrome

Purpose

Quantitative image analysis in previous research in obstructive sleep apnea syndrome (OSAS) has focused on the upper airway or several objects in its immediate vicinity and measures of object size. In this paper, we take a more general approach of considering all major objects in the upper airway region and measures pertaining to their individual morphological properties, their tissue characteristics revealed by image intensities, and the 3D architecture of the object assembly. We propose a novel methodology to select a small set of salient features from this large collection of measures and demonstrate the ability of these features to discriminate with very high prediction accuracy between obese OSAS and obese non-OSAS groups.

Materials and Methods

Thirty children were involved in this study with 15 in the obese OSAS group with an apnea-hypopnea index (AHI) = 14.4 ± 10.7) and 15 in the obese non-OSAS group with an AHI = 1.0 ± 1.0 (p<0.001). Subjects were between 8–17 years and underwent T1- and T2-weighted magnetic resonance imaging (MRI) of the upper airway during wakefulness. Fourteen objects in the vicinity of the upper airways were segmented in these images and a total of 159 measurements were derived from each subject image which included object size, surface area, volume, sphericity, standardized T2-weighted image intensity value, and inter-object distances. A small set of discriminating features was identified from this set in several steps. First, a subset of measures that have a low level of correlation among the measures was determined. A heat map visualization technique that allows grouping of parameters based on correlations among them was used for this purpose. Then, through T-tests, another subset of measures which are capable of separating the two groups was identified. The intersection of these subsets yielded the final feature set. The accuracy of these features to perform classification of unseen images into the two patient groups was tested by using logistic regression and multi-fold cross validation.

Results

A set of 16 features identified with low inter-feature correlation (< 0.36) yielded a high classification accuracy of 96% with sensitivity and specificity of 97.8% and 94.4%, respectively. In addition to the previously observed increase in linear size, surface area, and volume of adenoid, tonsils, and fat pad in OSAS, the following new markers have been found. Standardized T2-weighted image intensities differed between the two groups for the entire neck body region, pharynx, and nasopharynx, possibly indicating changes in object tissue characteristics. Fat pad and oropharynx become less round or more complex in shape in OSAS. Fat pad and tongue move closer in OSAS, and so also oropharynx and tonsils and fat pad and tonsils. In contrast, fat pad and oropharynx move farther apart from the skin object.

Conclusions

The study has found several new anatomic bio-markers of OSAS. Changes in standardized T2-weighted image intensities in objects may imply that intrinsic tissue composition undergoes changes in OSAS. The results on inter-object distances imply that treatment methods should respect the relationships that exist among objects and not just their size. The proposed method of analysis may lead to an improved understanding of the mechanisms underlying OSAS.

CD1c-Related DCs that Express CD207/Langerin, but Are Distinguishable from Langerhans Cells, Are Consistently Present in Human Tonsils

Several subsets of dendritic cells (DCs) are present in the oropharyngeal tonsillar tissues and are thought to behave as major actors in development and regulation of immunity by acting as a first line of recognition for airborne and alimentary antigens. We previously discovered in human adult tonsils infected with Epstein–Barr virus (EBV), a subset of DCs that expressed langerin/CD207, a lectin usually recognized as a hallmark of epidermal Langerhans cells (LCs). In the present study, we analyzed the content of several child and adult tonsils in order to characterize in more detail the phenotype of these tonsillar CD207-expressing DCs (tCD207 DCs) and to compare it with that of other human DC subsets. We showed that all the human tonsils studied (n = 12) contained significant proportions of tCD207 DCs among tonsillar cells expressing HLA-DR. Moreover, the presence of tCD207 DCs in tonsils from young children free of EBV infection indicated that these cells could be established early in the tonsil independently of EBV infection. We also showed that tCD207 DCs, that were found mainly located within the tonsillar lymphoid stroma, were distinguishable from LCs by the level of expression of CD1a and EpCAM, and also from human inflammatory DCs by the lack of CD1a, CD206, and CD14 expression. Detailed analysis of cell surface DC markers showed that tCD207 DCs were unrelated to CD141⁺ DCs or macrophages, but defined a subtype of tonsillar DCs closely related to myeloid resident CD1c DCs. Since it was established that blood CD1c myeloid DCs exhibit plasticity and are capable of expressing CD207 notably in the presence of inflammatory cytokines, it is tempting to speculate that CD207⁺ CD1c⁺ DCs may play a specific immune role.

An Evaluation of Thyromental Distance-based Method or Weight-based Method in Determining the Size of the Laryngeal Mask Airway Supreme: A Randomized Controlled Study

The successful placement of Laryngeal Mask Airway (LMA) Supreme in adults largely depends on right selection of its size. Most anesthesiologists determine the size of LMA according to patients' body weight, which does not always work well. An alternative method should be established to guarantee higher efficacy of ventilation through LMA Supreme placement. This controlled study was designed to compare the efficacy of LMA Supreme placement, when the size of it is determined by body weight or by thyromental distance. Eighty healthy individuals with American Society of Anesthesiologists physical status 1 to 2 scheduled for elective ambulatory surgery were randomly allocated into 2 groups: thyromental distance-based group (n = 40) and weight-based group (n = 40). Efficacy of controlled ventilation through LMA, easy of device placement, and pharyngeal sealing were evaluated between the groups. The tidal volume under 10 cm H2O pressure-controlled ventilation in thyromental distance-based group was significantly higher than that in weight-based group (523.9 ± 135.4 vs 477.1 ± 185.6; P = 0.031). The number of patients who achieved "excellent" tidal volume (>8 mL/kg) were significantly more in the thyromental distance-based group (24/40 vs 13/40; P = 0.019). Among overweight patients (body mass index >23), those who achieved "excellent" tidal volume (>8 mL/kg) under 10 cm H2O pressure-controlled ventilation were also more in thyromental distanced-based group than in weight-based group (11/24 vs 2/24; P = 0.031). The time taken for successful insertion was shorter with the thyromental distance-based group compared with the weight-based group (54.6 ± 33.6 vs 87.8 ± 98.9; P = 0.021). Oropharyngeal leak pressure was pretty close between the 2 groups (26.4 ± 5.1 vs 25.0 ± 5.7 cm H2O; P = 0.180). In terms of guaranteeing better positive pressure ventilation, facilitating device placement, and reliable pharyngeal sealing, thyromental distance-based method can be a better option compared with the weight-based method for LMA Supreme size selection.

Understanding the anatomic basis for obstructive sleep apnea syndrome in adolescents

RATIONALE

Structural risk factors for obstructive sleep apnea syndrome (OSAS) in adolescents have not been well characterized. Because many adolescents with OSAS are obese, we hypothesized that the anatomic OSAS risk factors would be more similar to those in adults than those in children.

OBJECTIVES

To investigate the anatomic risk factors in adolescents with OSAS compared with obese and lean control subjects using magnetic resonance imaging (MRI).

METHODS

Three groups of adolescents (age range: 12-16 yr) underwent MRI: obese individuals with OSAS (n = 49), obese control subjects (n = 38), and lean control subjects (n = 50).

MEASUREMENTS AND MAIN RESULTS

We studied 137 subjects and found that (1) obese adolescents with OSAS had increased adenotonsillar tissue compared with obese and lean control subjects; (2) obese OSAS adolescents had a smaller nasopharyngeal airway than control subjects; (3) the size of other upper airway soft tissue structures (volume of the tongue, parapharyngeal fat pads, lateral walls, and soft palate) was similar between subjects with OSAS and obese control subjects; (4) although there were no major craniofacial abnormalities in most of the adolescents with OSAS, the ratio of soft tissue to craniofacial space surrounding the airway was increased; and (5) there were sex differences in the pattern of lymphoid proliferation.

CONCLUSIONS

Increased size of the pharyngeal lymphoid tissue, rather than enlargement of the upper airway soft tissue structures, is the primary anatomic risk factor for OSAS in obese adolescents. These results are important for clinical decision making and suggest that adenotonsillectomy should be considered as the initial treatment for OSAS in obese adolescents, a group that has poor continuous positive airway pressure adherence and difficulty in achieving weight loss.

Impact of orthodontic appliances on the quality of craniofacial anatomical magnetic resonance imaging and real-time speech imaging

AIMS

The aim of this work was to investigate the effects of commonly used orthodontic appliances on the magnetic resonance (MR) image quality of the craniofacial region, with special interest in the soft palate and velopharyngeal wall using real-time speech imaging sequences and anatomical imaging of the temporomandibular joints (TMJ) and pituitaries.

METHODS

Common orthodontic appliances were studied on 1.5 T scanner using standard spin and gradient echo sequences (based on the American Society for Testing and Materials standard test method) and sequences previously applied for high-resolution anatomical and dynamic real-time imaging during speech. Images were evaluated for the presence and size of artefacts.

RESULTS

Metallic orthodontic appliances had different effects on image quality. The most extensive individual effects were associated with the presence of stainless steel archwire, particularly if combined with stainless steel brackets and stainless steel molar bands. With those appliances, diagnostic quality of magnetic resonance imaging speech and palate images will be most likely severely degraded, or speech imaging and imaging of pituitaries and TMJ will be not possible. All non-metallic, non-metallic with Ni/Cr reinforcement or Ni/Ti alloys appliances were of little concern.

LIMITATIONS

The results in the study are only valid at 1.5 T and for the sequences and devices used and cannot necessarily be extrapolated to all sequences and devices. Furthermore, both geometry and size of some appliances are subject dependent, and consequently, the effects on the image quality can vary between subjects. Therefore, the results presented in this article should be treated as a guide when assessing the risks of image quality degradation rather than an absolute evaluation of possible artefacts.

CONCLUSIONS

Appliances manufactured from stainless steel cause extensive artefacts, which may render image non-diagnostic. The presence and type of orthodontic appliances should be always included in the patient's screening, so the risks of artefacts can be assessed prior to imaging. Although the risks to patients with fixed orthodontic appliances at 1.5 T MR scanners are low, their secure attachment should be confirmed prior to the examination.

Intraoperative long range optical coherence tomography as a novel method of imaging the pediatric upper airway before and after adenotonsillectomy

BACKGROUND/OBJECTIVES

While upper airway obstruction is a common problem in the pediatric population, the first-line treatment, adenotonsillectomy, fails in up to 20% of patients. The decision to proceed to surgery is often made without quantitative anatomic guidance. We evaluated the use of a novel technique, long-range optical coherence tomography (LR-OCT), to image the upper airway of children under general anesthesia immediately before and after tonsillectomy and/or adenoidectomy. We investigated the feasibility of LR-OCT to identify both normal anatomy and sites of airway narrowing and to quantitatively compare airway lumen size in the oropharyngeal and nasopharyngeal regions pre- and post-operatively.

METHODS

46 children were imaged intraoperatively with a custom-designed LR-OCT system, both before and after adenotonsillectomy. These axial LR-OCT images were both rendered into 3D airway models for qualitative analysis and manually segmented for quantitative comparison of cross-sectional area.

RESULTS

LR-OCT images demonstrated normal anatomic structures (base of tongue, epiglottis) as well as regions of airway narrowing. Volumetric rendering of pre- and post-operative images clearly showed regions of airway collapse and post-surgical improvement in airway patency. Quantitative analysis of cross-sectional images showed an average change of 70.52mm(2) (standard deviation 47.87mm(2)) in the oropharynx after tonsillectomy and 105.58mm(2) (standard deviation 60.62mm(2)) in the nasopharynx after adenoidectomy.

CONCLUSIONS

LR-OCT is an emerging technology that rapidly generates 3D images of the pediatric upper airway in a feasible manner. This is the first step toward development of an office-based system to image awake pediatric subjects and thus better identify loci of airway obstruction prior to surgery.

Tongue fat and its relationship to obstructive sleep apnea

STUDY OBJECTIVES

The objective of this study was to determine whether tongue fat is increased in obese sleep apneics compared to obese subjects without sleep apnea. We hypothesized that excess fat is deposited in the tongue in obese patients with sleep apnea.

DESIGN

Case-control design.

SETTING

Academic medical center.

PATIENTS

We examined tongue fat in 31 obese controls (apnea-hypopnea index, 4.1 ± 2.7 events/h) and 90 obese apneics (apnea-hypopnea index, 43.2 ± 27.3 events/h). Analyses were repeated in a subsample of 18 gender-, race-, age-, and BMI-matched case-control pairs.

INTERVENTIONS

All subjects underwent a MRI with three-point Dixon magnetic resonance imaging. We used sophisticated volumetric reconstruction algorithms to study the size and distribution of upper airway fat deposits in the tongue and masseter muscles within apneics and obese controls.

MEASUREMENTS AND RESULTS

The data supported our a priori hypotheses that after adjustment for age, BMI, gender, and race, the tongue in apneics was significantly larger (P = 0.001) and had an increased amount of fat (P = 0.002) compared to controls. Similar results were seen in our matched sample. Our data also demonstrate that within the apneic and normal tongue, there are regional differences in fat distribution, with larger fat deposits at the base of the tongue.

CONCLUSIONS

There is increased tongue volume and deposition of fat at the base of tongue in apneics compared to controls. Increased tongue fat may begin to explain the relationship between obesity and obstructive sleep apnea.

Computational fluid dynamics endpoints for assessment of adenotonsillectomy outcome in obese children with obstructive sleep apnea syndrome

BACKGROUND

Improvements in obstructive sleep apnea syndrome (OSAS) severity may be associated with improved pharyngeal fluid mechanics following adenotonsillectomy (AT). The study objective is to use image-based computational fluid dynamics (CFD) to model changes in pharyngeal pressures after AT, in obese children with OSAS and adenotonsillar hypertrophy.

METHODS

Three-dimensional models of the upper airway from nares to trachea, before and after AT, were derived from magnetic resonance images obtained during wakefulness, in a cohort of 10 obese children with OSAS. Velocity, pressure, and turbulence fields during peak tidal inspiratory flow were computed using commercial software. CFD endpoints were correlated with polysomnography endpoints before and after AT using Spearman׳s rank correlation (rs).

RESULTS

Apnea hypopnea index (AHI) decreases after AT was strongly correlated with reduction in maximum pressure drop (dPTAmax) in the region where tonsils and adenoid constrict the pharynx (rs=0.78, P=0.011), and with decrease of the ratio of dPTAmax to flow rate (rs=0.82, P=0.006). Correlations of AHI decrease to anatomy, negative pressure in the overlap region (including nasal flow resistance), or pressure drop through the entire pharynx, were not significant. In a subgroup of subjects with more than 10% improvement in AHI, correlations between flow variables and AHI decrease were stronger than in all subjects.

CONCLUSIONS

The correlation between change in dPTAmax and improved AHI suggests that dPTAmax may be a useful index for internal airway loading due to anatomical narrowing, and may be better correlated with AHI than direct airway anatomic measurements.

Quantitative upper airway endoscopy with swept-source anatomical optical coherence tomography

Minimally invasive imaging of upper airway obstructions in children and adults is needed to improve clinical decision-making. Toward this goal, we demonstrate an anatomical optical coherence tomography (aOCT) system delivered via a small-bore, flexible endoscope to quantify the upper airway lumen geometry. Helical scans were obtained from a proximally-scanned fiber-optic catheter of 820 μm outer diameter and >2 mm focal length. Coupled with a long coherence length wavelength-swept light source, the system exhibited an SNR roll-off of < 10 dB over a 10 mm range. Operating at 10 rotations/s, the average accuracy of segmented cross-sectional areas was found to be -1.4 ± 1.0%. To demonstrate the capability of this system, aOCT was performed on a pediatric airway phantom and on ex vivo swine trachea. The ability for quantitative endoscopy afforded by this system can aid in diagnosis, medical and surgical decision making, and predictive modeling of upper airway obstructive disorders.

Interspeaker variability in hard palate morphology and vowel production

PURPOSE

Differences in vocal tract morphology have the potential to explain interspeaker variability in speech production. The potential acoustic impact of hard palate shape was examined in simulation, in addition to the interplay among morphology, articulation, and acoustics in real vowel production data.

METHOD

High-front vowel production from 5 speakers of American English was examined using midsagittal real-time magnetic resonance imaging data with synchronized audio. Relationships among hard palate morphology, tongue shaping, and formant frequencies were analyzed. Simulations were performed to determine the acoustical properties of vocal tracts whose area functions are altered according to prominent hard palate variations.

RESULTS

Simulations revealed that altering the height and position of the palatal dome alters formant frequencies. Examinations of real speech data showed that palatal morphology is not significantly correlated with any formant frequency but is correlated with major aspects of lingual articulation.

CONCLUSION

Certain differences in hard palate morphology can substantially affect vowel acoustics, but those effects are not noticeable in real speech. Speakers adapt their lingual articulation to accommodate palate shape differences with the potential to substantially affect formant frequencies, while ignoring palate shape differences with relatively little acoustic impact, lending support for acoustic goals of vowel production.

Computational fluid dynamics endpoints to characterize obstructive sleep apnea syndrome in children

Computational fluid dynamics (CFD) analysis may quantify the severity of anatomical airway restriction in obstructive sleep apnea syndrome (OSAS) better than anatomical measurements alone. However, optimal CFD model endpoints to characterize or assess OSAS have not been determined. To model upper airway fluid dynamics using CFD and investigate the strength of correlation between various CFD endpoints, anatomical endpoints, and OSAS severity, in obese children with OSAS and controls. CFD models derived from magnetic resonance images were solved at subject-specific peak tidal inspiratory flow; pressure at the choanae was set by nasal resistance. Model endpoints included airway wall minimum pressure (Pmin), flow resistance in the pharynx (Rpharynx), and pressure drop from choanae to a minimum cross section where tonsils and adenoids constrict the pharynx (dPTAmax). Significance of endpoints was analyzed using paired comparisons (t-test or Wilcoxon signed rank test) and Spearman correlation. Fifteen subject pairs were analyzed. Rpharynx and dPTAmax were higher in OSAS than control and most significantly correlated to obstructive apnea-hypopnea index (oAHI), r = 0.48 and r = 0.49, respectively (P < 0.01). Airway minimum cross-sectional correlation to oAHI was weaker (r = -0.39); Pmin was not significantly correlated. CFD model endpoints based on pressure drops in the pharynx were more closely associated with the presence and severity of OSAS than pressures including nasal resistance, or anatomical endpoints. This study supports the usefulness of CFD to characterize anatomical restriction of the pharynx and as an additional tool to evaluate subjects with OSAS.

Tonsillotomy versus tonsillectomy--a randomized trial regarding dentofacial morphology and post-operative growth in children with tonsillar hypertrophy

OBJECTIVES

The primary aim of this study was to analyse two different methods of tonsil surgery, tonsillectomy (TE) and tonsillotomy (TT), regarding post-operative dentofacial growth in children with tonsillar hypertrophy. A secondary aim was to analyse these results in relation to cephalometric standards.

MATERIAL AND METHODS

The study group consisted of 64 subjects (39 boys and 25 girls), mean age 4.8 years ± 4 months. They were randomized to a complete removal of the pharyngeal tonsil, TE, (n = 31) or a partial removal, TT, (n = 33). Pre-operative and 2 years post-operative study material were obtained and analysed. The results were compared with cephalometric standards.

RESULTS

Pre-operative, children with hypertrophic tonsils displayed an increased vertical relation (P < 0.05) compared with cephalometric standards. Post-operative, no significant difference could be detected between the two surgical procedures regarding dentofacial growth. Mandibular growth with an anterior inclination was significant (P < 0.001/TE, P < 0.01/TT) for both groups. An increased upper and lower incisor inclination was noted (P < 0.01/TE,TT). The vertical relation decreased (P < 0.001/TE, P < 0.05/TT) as well as the mandibular angle (P < 0.01/TE, P < 0.001/TT). Reduction was also significant for the sagittal intermaxillar (P < 0.001/TE,TT) relation. These post-operative results, together with a more prognatic mandible (P < 0.05/TE,TT) and chin (P < 0.001/TE, P < 0.01/TT), might indicate a more horizontal direction of mandibular growth.

CONCLUSION

TE and TT yielded equal post-operative dentofacial growth in children treated for hypertrophic tonsils. This result should be considered when deciding upon surgical technique.

Morphological variation in the adult hard palate and posterior pharyngeal wall

PURPOSE

Adult human vocal tracts display considerable morphological variation across individuals, but the nature and extent of this variation has not been extensively studied for many vocal tract structures. There exists a need to analyze morphological variation and, even more basically, to develop a methodology for morphological analysis of the vocal tract. Such analysis will facilitate fundamental characterization of the speech production system, with broad implications from modeling to explaining interspeaker variability.

METHOD

A data-driven methodology to automatically analyze the extent and variety of morphological variation is proposed and applied to a diverse subject pool of 36 adults. Analysis is focused on two key aspects of vocal tract structure: the midsagittal shape of the hard palate and the posterior pharyngeal wall. Result Palatal morphology varies widely in its degree of concavity but also in anteriority and sharpness. Pharyngeal wall morphology, by contrast, varies mostly in terms of concavity alone. The distribution of morphological characteristics is complex, and analysis suggests that certain variations may be categorical in nature.

CONCLUSION

Major modes of morphological variation are identified, including their relative magnitude, distribution, and categorical nature. Implications of these findings for speech articulation strategies and speech acoustics are discussed.

Sagittal area of the vocal tract in young female children

OBJECTIVE

To measure the sagittal areas of the front and back cavities of the vocal tract in children acquiring speech.

PATIENTS AND METHODS

Ten female children were selected from the Serial Experimental collection of the Burlington Growth Centre in Toronto, Canada. Each of the 10 children was seen annually from ages 3 through 8. Data collections included lateral cephalograms in occlusion. We traced those cephalograms and identified landmarks to delineate the front and back cavities. The sagittal areas of the front and back cavities were calculated. A measure of the angle of the head to the cervical vertebrae was made.

RESULTS

Front cavities were larger and grew faster. For both front and back cavities, age, angle measure, and the interaction of age and angle measure were significant.

CONCLUSION

Space available for the tongue to maneuver is greater anteriorly than posteriorly even when the jaw is maximally elevated.

Age-dependent changes in the size of adenotonsillar tissue in childhood: implications for sleep-disordered breathing

OBJECTIVE

To analyze age-associated changes in linear and cross-sectional area (CSA) measurements of adenoid, tonsils, and pharyngeal lumen.

STUDY DESIGN

Measurements were completed in head magnetic resonance imaging examinations performed for diagnostic purposes. Linear and nonlinear regression models were applied to describe the effect of age on the size of soft tissues and upper airway.

RESULTS

Magnetic resonance imaging data were analyzed in 149 children without snoring (aged 0-15.9 years) and in 33 children with snoring (aged 1.6-15 years). In the children without snoring, adenoid size increased during the first 7-8 years of life and then decreased gradually [% (adenoid oblique width/mental spine-clivus length) = 11.38 + 1.52 (age) - 0.11 (age)(2), R(2) = 0.22, P < .01; adenoid CSA = 90.75 + 41.93 (age) - 2.47 (age)(2); R(2) = 0.50; P < .01]. Nasopharyngeal airway CSA increased slowly up to age 8 years and rapidly thereafter. Similar patterns were noted for the tonsils and oropharyngeal airway. In contrast, in children with snoring, adenoid and tonsils were large irrespective of age, and nasopharyngeal airway size increased slowly with age.

CONCLUSIONS

In children without snoring, growing adenotonsillar tissue narrows the upper airway lumen to variable degrees only during the first 8 years of life. In contrast, in children with snoring, appreciable pharyngeal lymphoid tissue enlargement is present during the preschool years and persists beyond the eighth birthday.

Pediatric upper airway obstruction: interobserver variability is the road to perdition

PURPOSE

The purposes of the study are to determine the interobserver variability in the clinical assessment of pediatric upper airway obstruction (UAO) and to explore how variability in assessment of UAO may contribute to risk factors and incidence of postextubation UAO.

MATERIALS

This is a prospective trial in 2 tertiary care pediatric intensive care units. Bedside practitioners performed simultaneous, blinded UAO assessments on 112 children after endotracheal extubation.

RESULTS

Agreement among respiratory therapists, pediatric intensive care nurses, and pediatric intensive care physicians was poor for cyanosis (κ = 0.01) and hypoxemia at rest (κ = 0.14) and fair for consciousness (κ = 0.27), air entry (κ = 0.32), hypoxemia with agitation (κ = 0.27), and pulsus paradoxus (κ = 0.23). When looking at "stridor" and "retractions," defined using more than 2 grades of severity from the Westley Croup Score, the interrelater reliability was moderate (κ = 0.43 and κ = 0.47, respectively). This could be improved marginally by dichotomizing the presence or absence of stridor (κ = 0.54) or retractions (κ = 0.53). The overall incidence of UAO after extubation (stridor plus retractions) could range from 7% to 22%, depending on how many providers were required to agree.

CONCLUSIONS

Physical findings routinely used for UAO have poor interobserver reliability among bedside providers. This variability may contribute to inconsistent findings regarding incidence, risk factors, and therapies for postextubation UAO.

Relationship between adenoid size and severity of obstructive sleep apnea in preschool children

OBJECTIVE

To investigate the contributions of adenoid and tonsil sizes to obstructive sleep apnea syndrome (OSAS) in normal-weight children in two age categories: preschool and schoolchildren.

METHODS

Fifty-eight normal-weight (body mass index z-score<2) symptomatic children with OSAS (apnea-hypopnea index ≥ 2) were evaluated. The patients were divided into two age categories: preschool (age<6; n=33) and schoolchildren (age ≥ 6; n=25). Polysomnographic findings and adenoid and tonsil sizes were compared. The relative contributions of body mass index and adenoid and tonsil sizes were also investigated with a regression analysis.

RESULTS

Adenoid grade and apnea index correlated significantly in preschool children (r=0.45, p<0.01). On regression analysis, adenoid grade was a significant predictor of the apnea index in preschool children. The influence of adenoid hypertrophy decreased from preschool to schoolchildren. Tonsil size had little influence on the apnea index in either group.

CONCLUSION

Adenoid hypertrophy was a major contributor to OSAS in normal-weight preschool children. The upper airway morphology of younger children with OSAS differed from that of older children with OSAS.

A novel method for laryngeal mask airway size selection in paediatric patients

CONTEXT

The successful use of the laryngeal mask airway in children partly depends on the correct selection of size. Most anaesthesiologists rely on the weight-based table which is often difficult to remember. A simple method allowing an adequate choice of the correct size may be highly desirable.

OBJECTIVES

To test the hypothesis that the size of the external ear (pinna) of the child may be used as proxy for the required size of laryngeal mask airway.

DESIGN

A descriptive study.

SETTING

King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.

PATIENTS

Two hundred and ten paediatric patients aged 6 months to 15 years, of either sex, American Society of Anesthesiologists (ASA) 1-2 and scheduled for routine ophthalmological procedures from 1 March to 31 December 2010. Emergency cases, patients with a full stomach or with a history of any oropharyngeal lesion other than tonsillar hypertrophy were excluded.

MAIN OUTCOME MEASURES

The size of the external ear was measured with a ruler in vertical and horizontal dimensions in the first 30 patients, and visually evaluated for the remaining patients. For all, the nearest corresponding size of partially inflated laryngeal mask airway was chosen and inserted after induction. The correct placement was assessed using predefined criteria.

RESULTS

Insertion and good ventilation was achieved in 196 (93.3%) on first attempt. Fourteen patients (6.7%) required a second attempt and the main reason for failure was an audible leak because of smaller size.

CONCLUSION

Choosing the size of the laryngeal mask airway in children according to the size of the external ear was associated with a success rate of 93% which is comparable with that reported in the literature when the tables are used. This simple method may allow a rapid choice of the correct size of laryngeal mask airway and may eliminate the need to remember different tables or formulae.

Obstructive sleep apnea syndrome in children

The clinical syndrome of obstructive sleep apnea (OSAS) in children is a distinct, yet somewhat overlapping disorder with the condition that occurs in adults, such that the clinical manifestations, polysomnographic findings, diagnostic criteria and treatment approaches need to be considered in an age-specific manner. Childhood OSAS has now become widely recognized as a frequent disorder and as a major public health problem. Pediatric OSAS, particularly when obesity is concurrently present, is associated with substantial end-organ morbidities and increased healthcare utilization. Although adenotonsillectomy (T&A) remains the first line of treatment, evidence in recent years suggests that the outcomes of this surgical procedure may not be as favorable as expected, such that post-T&A polysomnographic evaluation may be needed, especially in high-risk patient groups. In addition, incorporation of nonsurgical approaches for milder forms of the disorder and for residual OSAS after T&A is now being investigated.

Estimation of teeth-to-vallecula distance for prediction of optimal oropharyngeal airway length in young children

BACKGROUND

Estimation of teeth-to-vallecula distance would facilitate the selection of properly sized oropharyngeal airways in young children. The aims of the present study were to measure the teeth-to-vallecula distance and to create an algorithm to predict this distance based on anatomical landmarks and patient characteristics in children.

METHODS

Two hundred children, aged 1-9 yr, undergoing elective surgery were investigated. After induction of general anaesthesia, the distance from the teeth to the vallecula was measured using a laryngoscope with a straight blade. After intubation, the distances from the mouth angle to the mandible angle and the tragus of the ear were measured with a tape measure.

RESULTS

The teeth-to-vallecula distance was significantly correlated with the age, weight, height, and external measurements (P<0.001). By stepwise multiple linear regression analysis, a formula was obtained for the teeth-to-vallecula distance (cm) = 3.998 + 0.017 × age (months)+the mouth-to-mandible distance × 0.286 with a high coefficient of determination (r²=0.764).

CONCLUSIONS

The teeth-to-vallecula distance can be predicted using the age and the mouth-to-mandible distance in young children.