Non-brachycephalic dogs with stertor have higher nasopharyngeal collapsibility compared with dogs without stertor and foramen lacerum level is ideal for evaluating nasopharyngeal collapse on dynamic CT.

Stertor, a clinical sign associated with obstructive airway syndrome, is often observed in non-brachycephalic dogs. This prospective, case-control study aimed to compare soft palate dimensions, nasopharyngeal cross-sectional area (CSA), and nasopharyngeal collapsibility at various locations in non-brachycephalic dogs with and without stertor. A total of 50 dogs were recruited and stratified into control (n = 34) and stertor (n = 13) groups. Static and dynamic computed tomography was conducted without tracheal intubation, and the following variables were calculated: normalized soft palate length and thickness, normalized maximum and minimum nasopharyngeal CSAs (rCSAmax and rCSAmin), and nasopharyngeal collapsibility at the level of the cranial end of the soft palate, pterygoid hamulus, foramen lacerum, bony labyrinth, and caudal end of the soft palate. The stertor group demonstrated significantly lower rCSAmax and rCSAmin, as well as higher nasopharyngeal collapsibility compared with the control group, while no significant differences were noted in the soft palate dimension. Evaluating nasopharyngeal collapse at the foramen lacerum level was recommended due to the clear presence of identifiable bony landmarks and lower overlap in the nasopharyngeal collapsibility between dogs with and without stertor. Physical dimensions of the soft palate may not be the primary contributing factor to nasopharyngeal collapse and clinical signs in non-brachycephalic dogs.

Complications of Nasopharyngeal Swabs and Safe Procedures for COVID-19 Testing Based on Anatomical Knowledge.

Nasopharyngeal swabs have been widely to prevent the spread of coronavirus disease 2019 (COVID-19). Nasopharyngeal COVID-19 testing is a generally safe and well-tolerated procedure, but numerous complications have been reported in the media. Therefore, the present study aimed to review and document adverse events and suggest procedural references to minimize preventable but often underestimated risks. A total of 27 articles were selected for the review of 842 related documents in PubMed, Embase, and KoreaMed. The complications related to nasopharyngeal COVID-19 testing were reported to be rarely happened, ranging from 0.0012 to 0.026%. Frequently documented adverse events were retained swabs, epistaxis, and cerebrospinal fluid leakage, often associated with high-risk factors, including severe septal deviations, pre-existing skull base defects, and previous sinus or transsphenoidal pituitary surgery. Appropriate techniques based on sufficient anatomical knowledge are mandatory for clinicians to perform nasopharyngeal COVID-19 testing. The nasal floor can be predicted by the line between the nostril and external ear canal. For safe testing, the angle of swab insertion in the nasal passage should remain within 30° of the nasal floor. The swab was gently inserted along the nasal septum just above the nasal floor to the nasopharynx and remained on the nasopharynx for several seconds before removal. Forceful insertion should be attempted, and alternative examinations should be considered, especially in vulnerable patients. In conclusion, patients and clinicians should be aware of rare but possible complications and associated high-risk factors. The suggested procedural pearls enable more comfortable and safe nasopharyngeal COVID-19 testing for both clinicians and patients.

ANATOMICAL RATIONALE FOR CHOOSING A BLADE FOR POWER-ASSISTED ADENOIDECTOMY IN CHILDREN DEPENDING ON DENTITION.

OBJECTIVE: The aim: To study the anatomic features of the facial skull structures in children of various ages depending on dentition. PATIENTS AND METHODS: Materials and methods: One hundred and forty-four children aged 2-12 years were divided into 4 groups depending on dentition. They underwent anthropometric measure¬ments during adenoidectomy. Based on the cosine theorem, the calculated values were obtained. RESULTS: Results: The distance from choana to the free edge of the retracted soft palate gradually increases from 2.01±0.61 cm in children with stable primary dentition up to 3.09±1.02 cm with mixed dentition. Palato-nasopharyngeal angle in children with stable primary dentition is 126.25±8.76°, in children with aging primary dentition - 132.81±12.21°, and in children with mixed dentition - 120.54±13.72°. CONCLUSION: Conclusions: The optimal configuration of the blade for power-assisted adenoidectomy in children with stable primary dentition has an angle of 53.53±8.76°, and the length of the working part of 2.01±0.61 cm, in children with aging primary dentition - 47.18±12.21° and 2.10±0.71 cm, with mixed dentition - 59.45±13.72° and 3.09±1.02 cm, respectively.

Anatomy of teleost fish immune structures and organs.

The function of a tissue is determined by its construction and cellular composition. The action of different genes can thus only be understood properly when seen in the context of the environment in which they are expressed and function. We now experience a renaissance in morphological research in fish, not only because, surprisingly enough, large structures have remained un-described until recently, but also because improved methods for studying morphological characteristics in combination with expression analysis are at hand. In this review, we address anatomical features of teleost immune tissues. There are approximately 30,000 known teleost fish species and only a minor portion of them have been studied. We aim our review at the Atlantic salmon (Salmo salar) and other salmonids, but when applicable, we also present information from other species. Our focus is the anatomy of the kidney, thymus, spleen, the interbranchial lymphoid tissue (ILT), the newly discovered salmonid cloacal bursa and the naso-pharynx associated lymphoid tissue (NALT).

Aerodynamic characteristics in upper airways among orthodontic patients and its association with adenoid nasopharyngeal ratios in lateral cephalograms.

BACKGROUND: Adenoid hypertrophy among orthodontic patients may be detected in lateral cephalograms. The study investigates the aerodynamic characteristics within the upper airway (UA) by means of computational fluid dynamics (CFD) simulation. Furthermore, airflow features are compared between subgroups according to the adenoidal nasopharyngeal (AN) ratios. METHODS: This retrospective study included thirty-five patients aged 9-15 years having both lateral cephalogram and cone beam computed tomography (CBCT) imaging that covered the UA region. The cases were divided into two subgroups according to the AN ratios measured on the lateral cephalograms: Group 1 with an AN ratio < 0.6 and Group 2 with an AN ratio ≥ 0.6. Based on the CBCT images, segmented UA models were created and the aerodynamic characteristics at inspiration and expiration were simulated by the CFD method for the two groups. The studied aerodynamic parameters were pressure drop (ΔP), maximum midsagittal velocity (Vms), maximum wall shear stress (Pws), and minimum wall static pressure (Pw). RESULTS: The maximum Vms exhibits nearly 30% increases in Group 2 at both inspiration (p = 0.013) and expiration (p = 0.045) compared to Group 1. For the other aerodynamic parameters such as ΔP, the maximum Pws, and minimum Pw, no significant difference is found between the two groups. CONCLUSIONS: The maximum Vms seems to be the most sensitive aerodynamic parameter for the groups of cases. An AN ratio of more than 0.6 measured on a lateral cephalogram may associate with a noticeably increased maximum Vms, which could assist clinicians in estimating the airflow features in the UA.

Nasolaryngeal Distances in the Adult Population and an Evaluation of Commercially Available Nasotracheal Tubes.

BACKGROUND: Preformed nasal endotracheal tubes (NETs) come with a predefined insertion depth due to their curved design. While size indication refers to internal diameter, there is a considerable variability in the corresponding lengths and proportions of same-sized tubes of different manufacturers which is probably based on the lack of data of nasolaryngeal distances (NLDs) in the adult population. Choosing the best-fitting NET is therefore difficult and carries the risk of endobronchial intubation or, on the contrary, cuff inflation at the vocal cord level. The aim of this study was to develop a prediction model for NLD and a selection guide to choose the appropriate NET based on a radiographic description of NLD in comparison to the measurements of available NETs of several manufacturers. METHODS: After institutional ethics board review, 388 computed tomography (CT) scan images of head, neck, and upper thorax in a heterogeneous adult cohort were included. Mean distances from the nares to the lower border of the thyroid cartilage were measured. NETs from different manufacturers were measured and compared to the NLD derived from the radiographic analysis. The patients' sex, body height, and weight were considered as possible covariates in quantile regression models for predicting the NLD. RESULTS: Data from 200 patients were analyzed. NLD was associated with sex, body height, and weight. A simple quantile regression model using the body height as the only covariate sufficed to achieve accurate predictions of NLD. Validation on independent test data showed that 92.8% of the NLD predictions were closer than ±20 mm to the observed NLD values. Measurements of equal-sized NETs varied considerably in outer diameter, proportion, the nasopharyngeal part, and guide marks. Length differences of the bend-to-cuff distance, containing the anatomically NLD, ranged between 218 and 270 mm at same sizes. CONCLUSIONS: A reliable prediction of NLD can be obtained simply by body height, using the formula (Equation is included in full-text article.). As manufacturers' tube lengths vary substantially, additional information about the bend-to-cuff distance as corresponding tube section would allow for more accurate tube selection.

Study of the Anatomical Structure of the Nasopharyngeal Cavity and Distribution of the Air Flow Field.

To build a biomechanical numerical model of the nasopharynx, construct an accurate computerized numerical description of its specific anatomical structures, analyze the distribution of air flow field, starting with the anatomical structure of the pharyngeal recess, correlate its anatomical characteristics with the occurrence and development of nasopharyngeal carcinoma from the perspective of biomechanics. In this study, the nasal and nasopharyngeal cavities of healthy male adult, with the pharyngeal recess in an open state, were scanned by CT to obtain DICOM imaging data. Then, they were imported into Mimics 20.0 to build a model which was recorded in binary STL format. Each file was imported into Geomagic studio 12.0 to construct a 3D model saved in an IGES format. Then, it was imported into ANSYS Workbench for numerical simulation of air flow field. The authors found that:Above all, the causes and pathogenesis of nasopharyngeal carcinoma can be identified from the perspective of biomechanics through the construction of a 3D model and analysis of the characteristics of air flow field. With more in-depth research, it is expected that a more solid scientific foundation will be created for related quantitative analysis.

The impact of tongue dimension on air volume in brachycephalic dogs.

OBJECTIVE: To compare the dimensions and density of the tongue in brachycephalic and mesaticephalic dog breeds and to document the relative extents of the nasopharyngeal and oropharyngeal airways occupied by the tongue and palatal tissues. STUDY DESIGN: Case control study. ANIMALS: Sixteen brachycephalic dogs and 12 mesaticephalic dogs. METHODS: The volume of the tongue was measured with computed tomography in all dogs. Cross-sectional areas of tongue, oropharynx, nasopharynx, and palatal soft tissue were evaluated at two levels, the caudal aspect of the hard palate and the level of the hamulae of the pterygoid. Density of the tongue and soft palate were measured. All variables were compared between brachycephalic and mesaticephalic dogs (P ≤ .05). RESULTS: Absolute tongue volumes did not differ between groups, the volume of the tongue was greater in brachycephalic dogs than in mesaticephalic dogs when expressed relative to (a) body weight (median 5650, interquartile range [IQR] 4833-6522 vs median 4454, IQR 4309-4743, respectively), (b) ratio between skull length/width (70 833, IQR 62490-126 209 vs 48 064, IQR 22984-64 279, respectively), and (c) skull length (689.93, IQR 618.55-970.61 vs 460.04, IQR 288.77-561.69, respectively). The proportion of air (oropharyngeal and nasopharyngeal)/soft tissue (tongue and palatal tissue) in brachycephalic dogs was decreased by approximately 60%, and the tongue was approximately 10 times denser in brachycephalic dogs than in mesaticephalic dogs. CONCLUSION: A relative macroglossia was detected in brachycephalic dogs along with reduced air volume in the upper airway. Tongues of brachycephalic dogs were denser than those of mesaticephalic dogs. CLINICAL SIGNIFICANCE: The relative macroglossia in brachycephalic breeds may contribute to upper airway obstruction.

Evaluation of the pharyngeal recess with cone-beam computed tomography.

PURPOSE: To evaluate the radiological anatomy of the pharyngeal recess (PR) by gender and age. METHODS: Images of patients who underwent cone-beam computed tomography (CBCT) were analyzed retrospectively. A total of 600 PRs (140 male, 160 female) were examined. PR depths, distances between the posterior nasal spine (PNS) and the posterior wall of the pharynx, right and left torus levatorius lengths, and distances between the right and left torus levatorius were measured on the axial plane passing through the PNS-basion point. RESULTS: PR depths differed significantly between age groups (right p = 0.030, left p = 0.047). The PR depths of individuals under 35 years of age were significantly higher than those of individuals aged 35 and over. Further, the distances between the PNS and the posterior wall of the pharynx differed significantly between age groups and between gender groups. The distances between the PNS and the posterior wall of the pharynx were shorter in patients under 35 years of age (p = 0.000). In terms of gender, these distances were significantly longer in males (p = 0.014). The distances between the right and left torus levatorius were also significantly longer in males (p = 0.029). CONCLUSION: The PR is the region in which nasopharyngeal carcinoma originates most frequently and is very important for early diagnosis. The present results indicated that this region can be examined with CBCT.

Comparison of Dimensions of the Nasopharynx and Oropharynx Using Different Anatomical References: Is There Equivalence?

PURPOSE: To evaluate the equivalence of the volumes obtained using different anatomic references to measure the nasopharynx and oropharynx on cone-beam computed tomography (CBCT) scans. We hypothesized that no variations would be found in the nasopharynx and oropharynx dimensions when measured using different measurement methods. MATERIALS AND METHODS: A total of 40 CBCT scans of patients with skeletal Class I (age range, 20 to 50 years) were measured independently by 2 of us. The nasopharynx and oropharynx subregions were volumetrically measured using the adopted limits of 5 different measurement methods (3 for the nasopharynx and 2 for the oropharynx) and InVivoDental software, version 5.4 (Anatomage, San Jose, CA). The minimum area and the minimum area of localization were also evaluated. The intra- and interexaminer concordance for the measurements from the different methods were verified using the interclass correlation coefficient (ICC). The analysis of variance for repeated measures was used to compare the measurements from the 3 nasopharynx methods. The paired t test was used to compare the measurements from the 2 oropharynx methods. The statistical tests were performed at the 5% significance level using SPSS software, version 22.0 (IBM Corp, Armonk, NY). RESULTS: The intra- and interexaminer ICC values were greater than 0.8. We found a statistically significant difference in the volume measurements among the 3 nasopharynx methods (P = .001). However, no differences were found in the minimum area or minimum area of localization comparisons. Statistically significant differences were also observed for the volume, minimum area, and minimum area of localization between the 2 oropharynx methods (P = .001). CONCLUSIONS: Studies that have used different methods of measurement should not be directly compared. The different measurement methods used for nasopharynx and oropharynx evaluations should not be compared.

Cone-beam computed tomography airway measurements: Can we trust them?

INTRODUCTION: Pharyngeal airway space (PAS) assessment has been used in the past for a better understanding of orthodontic and surgical outcomes; however, this analysis could be unreliable. Our objective was to evaluate possible changes in the PAS reading in the same patient from their consecutive cone-beam computed tomography (CBCT) scans. METHODS: We evaluated a total of 27 patients' CBCT scans obtained at 2 time points with the use of a standardized acquisition protocol. The mean age at T0 was 31 years (range 17-62 years) and the follow-up records (T1) were taken after 4-6 months. Dolphin Imaging software was used to measure the volumes of the nasopharynx, oropharynx, and hypopharynx. We also evaluated the craniocervical position with the use of a lateral cephalogram. RESULTS: The variables exhibited high intraclass correlation coefficients (ICCs) when measuring the same CBCT scan twice (T0 and T0). However, The ICC between the measurements performed on the first and second CBCT scans (T0 and T1) showed that the only variable with high reproducibility between the 2 scans was cranial base, with an ICC >0.97. Average differences of 682.1 mm3, 2255.3 mm3, and 517.4 mm3 were found for the nasopharynx, oropharynx, and hypopharynx, respectively. Regarding the cephalometric angles, average differences between T0 and T1 scans were 0.6°, 2.7°, and 0.4° for OPT.CVT, OPT.SN, and cranial base, respectively. CONCLUSIONS: Different CBCT exams with equal scanning and patient positioning protocols can result in different 3D PAS readings. A more careful interpretation of CBCT volumetric data to achieve adequate conclusions of the clinical outcomes is necessary.

Upper airway in children with unilateral cleft lip and palate evaluated with computational fluid dynamics.

INTRODUCTION: Children with unilateral cleft lip and palate (UCLP) exhibit snoring and mouth breathing. They are also reported to show obstructive sleep apnea syndrome. However, their upper airway ventilation condition is not clearly understood. Therefore, this study was performed to evaluate upper airway ventilation condition in children with UCLP with the use of computational fluid dynamics. METHODS: Twenty-one children (12 boys, 9 girls; mean age 9.1 years) with UCLP and 25 children (13 boys, 12 girls; mean age 9.2 years) without UCLP who required orthodontic treatment underwent cone-beam computed tomography (CBCT). Nasal resistance and upper airway ventilation condition were evaluated with the use of computational fluid dynamics from CBCT data. The groups were compared with the use of Mann-Whitney U tests and Student t tests. RESULTS: Nasal resistance of the UCLP group (0.97 Pa/cm3/s) was significantly higher than that of the control group (0.26 Pa/cm3/s; P < 0.001). Maximal pressure of the upper airway (335.02 Pa) was significantly higher in the UCLP group than in the control group (67.57 Pa; P < 0.001). Pharyngeal airway (from choanae to base of epiglottis) pressure in the UCLP group (140.46 Pa) was significantly higher than in the control group (15.92 Pa; P < 0.02). CONCLUSIONS: Upper airway obstruction in children with UCLP resulted from both nasal and pharyngeal airway effects.

The remarkable vocal anatomy of the koala (Phascolarctos cinereus): insights into low-frequency sound production in a marsupial species.

Koalas are characterised by a highly unusual vocal anatomy, with a descended larynx and velar vocal folds, allowing them to produce calls at disproportionately low frequencies. Here we use advanced imaging techniques, histological data, classical macroscopic dissection and behavioural observations to provide the first detailed description and interpretation of male and female koala vocal anatomy. We show that both males and females have an elongated pharynx and soft palate, resulting in a permanently descended larynx. In addition, the hyoid apparatus has a human-like configuration in which paired dorsal, resilient ligaments suspend the hyoid apparatus from the skull, while the ventral parts tightly connect to the descended larynx. We also show that koalas can retract the larynx down into the thoracic inlet, facilitated by a dramatic evolutionary transformation of the ventral neck muscles. First, the usual retractors of the larynx and the hyoid have their origins deep in the thorax. Secondly, three hyoid muscles have lost their connection to the hyoid skeleton. Thirdly, the genioglossus and geniohyoid muscles are greatly increased in length. Finally, the digastric, omohyoid and sternohyoid muscles, connected by a common tendinous intersection, form a guiding channel for the dynamic down-and-up movements of the ventral hyoid parts and the larynx. We suggest that these features evolved to accommodate the low resting position of the larynx and assist in its retraction during call production. We also confirm that the edges of the intra-pharyngeal ostium have specialised to form the novel, extra-laryngeal velar vocal folds, which are much larger than the true intra-laryngeal vocal folds in both sexes, but more developed and specialised for low frequency sound production in males than in females. Our findings illustrate that strong selection pressures on acoustic signalling not only lead to the specialisation of existing vocal organs but can also result in the evolution of novel vocal structures in both sexes.

Reassessing the Anatomic Origin of the Juvenile Nasopharyngeal Angiofibroma.

OBJECTIVE: A modern imaging review is necessary to further define the anatomic origin of the juvenile nasopharyngeal angiofibroma. METHODS: After institutional review board approval, a search from January 1998 to January 2013 yielded 33 male patients (aged 10-23 years) with pathologically proven juvenile nasopharyngeal angiofibroma lesions, as well as pretreatment computed tomography/magnetic resonance imaging. Juvenile nasopharyngeal angiofibroma involvement was assessed in the following regions: sphenopalatine foramen, pterygopalatine fossa, vidian canal, nasopharynx, nasal cavity, sphenoid sinus, choana, pterygomaxillary fissure/masticator space, orbit, and sphenoid bone. RESULTS: The choana and nasopharynx were involved in all 33 patients. In contrast, only 22 lesions involved the pterygopalatine fossa, 24 lesions involved the sphenopalatine foramen, and 28 lesions involved the vidian canal. CONCLUSIONS: Our results suggest that the juvenile nasopharyngeal angiofibroma origin is in the region of the choana and nasopharynx rather than the sphenopalatine foramen or pterygopalatine fossa.

Acoustic Rhinometry for Evaluation of Velopharyngeal Function in Preschool Children Post Palatoplasty.

PURPOSE: To assess the feasibility of acoustic rhinometry for the evaluation of velopharyngeal function in preschool children by detecting changes in nasal cavity volume (NV) and minimal cross-sectional area (MCSA) after palatoplasty. MATERIALS AND METHODS: Sixty-one preschool children with incomplete cleft palate who underwent Sommerlad palatoplasty were examined by acoustic rhinometry. MCSA, distance of the MCSA from the nostril (DMCA), NV, and nasopharyngeal volume (NPV) were measured. Patients were grouped according to velopharyngeal state and lateral cephalographic findings. RESULTS: MCSA, NV, and NPV showed a meaningful difference between the experimental and control groups. DMCA in the experimental group (7.09 ± 1.33 mm) was not markedly different between the 2 sides. NV, NPV, and MCSA in the velopharyngeal insufficiency (VPI) subgroup were obviously larger than those in the velopharyngeal competence (VPC) and marginal VPI subgroups. NV in the VPC group showed no relevant difference from that in the control group. No relevant difference in MCSA, DMCA, and NPV was observed among the 3 subgroups at radiographic evaluation. NV in the noncontact group was markedly larger than in the control group. The curve showed marked constriction in the anterior part but an elevation in the posterior part, especially at a distance of 7.09 cm. CONCLUSION: Acoustic rhinometry is a rapid, noninvasive, and reproducible method that can be used in lieu of lateral cephalography for quantitative evaluation of the NV and MCSA. It can be used to assess postoperative velopharyngeal function in children and has good adaptability.

Critical distance between the cartilaginous Eustachian tube and the internal carotid artery.

During the last decade, endoscopic surgery of the Eustachian tube (ET) has been advocated for ET dilatory dysfunction and for patulous ET. The internal carotid artery (ICA) and the ET are closely related, and knowledge of their surgical anatomy has become essential. This study was designed to establish the anatomical relationships between the endoscopically critical area along the full length of the cartilaginous ET and its closest association with the ICA. The perpendicular distance between the ET lumen and the ICA was measured from head magnetic resonance images (MRI) at three levels: (A) cartilaginous and bony ET junctional point, (B) mid cartilaginous ET point, and (C) the nasopharyngeal orifice of the cartilaginous ET. Totally, 200 sides were reviewed in MRI scans of 229 patients. The mean distances for each level were: A = 4.3 mm (range 1.6-10.4 mm), B = 25 mm (range 9.0-61.6 mm), and C = 62 mm (range 34.3-84.4 mm). The perpendicular distance between ET and ICA at the nasopharyngeal orifice is large, but the distance shortens quickly while moving from the nasopharyngeal orifice of the ET to the junctional point of the ET. The potential for complications to the ICA rises as the surgical field moves closer to the isthmus of the ET because of the decreasing distance between the ET and the ICA.

Size of Velopharyngeal Structures After Primary Palatoplasty.

OBJECTIVE: To describe and compare measures of velar length, velar thickness, and depth of the nasopharynx between two groups of patients with velopharyngeal dysfunction after primary palatoplasty: one received the modified Langenbeck procedure and the other the Furlow procedure. DESIGN: Comparative study involving a convenience sample of videofluoroscopic films established prospectively. SETTING: Surgeries and videofluoroscopic assessments were conducted at a craniofacial center. PARTICIPANTS: Exams from 90 participants were used: 27 (30%) operated with Furlow and 63 (70%) with Langenbeck. Three speech-language pathologists (SLPs) traced the images of the velopharyngeal port to determine the measures of interest. RESULTS: Intrajudge agreement for the SLPs ranged between 0.85 and 0.53, while interjudge agreement ranged between 0.44 and 0.51. The overall measure of velar length was significantly larger (P = .042) for the Furlow group (mean = 26.5) than the Langenbeck group (mean = 24.2 mm). There was no significant difference in velar thickness or depth of the nasopharynx between the two procedures. Although no significant difference was found between the current findings and Subtelny's norms for length, thickness, and depth, the patients presented with an overall depth:length ratio (0.89) significantly greater than Subtelny' ratio (P = .025). CONCLUSION: The findings of this study confirmed the hypothesis that patients who underwent surgery with the Furlow technique may present with significantly longer velums than patients who underwent surgery with the Langenbeck procedure. Information regarding velopharyngeal morphology was predictive of velopharyngeal dysfunction for speech for 80% of the participants and can be useful in documenting outcome of treatment.

Optimal Depth for Nasopharyngeal Temperature Probe Positioning.

BACKGROUND: The nasopharynx is considered 1 of the 4 generally reliable core temperature measurement sites. But curiously, there is no consensus on how far past the nares to insert the probe. Insertion depth is likely to influence the accuracy of nasopharyngeal temperature measurements because probes near the nares will be cooled by ambient air; similarly, probes inserted too far may approach the airway and be cooled by ventilation gases. We thus determined the range of nasopharyngeal probe insertion depths that best approximate reference core temperature measured in the distal esophagus. METHODS: In 36 adults undergoing noncardiac surgery with endotracheal intubation, we inserted a nasopharyngeal thermometer 20 cm past the nares and an esophageal temperature probe 40 cm from the incisors. The nasopharyngeal probe was withdrawn sequentially 2 cm at a time at 5-minute intervals. Pairs of nasopharyngeal and reference distal esophageal temperatures were then compared and summarized by Bland and Altman methods. RESULTS: All nasopharyngeal probe insertion depths between 10 and 20 cm past the nares provided temperatures similar to reference distal esophageal temperatures. At those depths, the bias was typically approximately -0.1°C, with SD of approximately ±0.15°C; the limits of agreement thus were easily within our a priori specified clinically acceptable range of -0.5°C and 0.5°C. CONCLUSIONS: Any nasopharyngeal probe insertion depth between 10 and 20 cm well represents core temperature in adults having noncardiac surgery.

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.

Effects of Le Fort I Osteotomy on the Nasopharyngeal Airway-6-Month Follow-Up.

PURPOSE: The literature discussing the impact of a single Le Fort I osteotomy on nasopharyngeal airways is limited. This study assessed the volumetric changes in the nasopharyngeal airway after a single Le Fort I osteotomy and explored the correlation between these changes and 3-dimensional surgical movements of the upper jaw. MATERIALS AND METHODS: This retrospective study was conducted in 40 patients who had undergone a single Le Fort I (maxillary advancement with or without impaction) to correct Class III malocclusion with maxillary hypoplasia. Preoperative (T1) and 6-month postoperative (T2) cone-beam computed tomographic (CBCT) scans of these patients were used for analysis. Maxillary surgical movements and volumetric changes in the nasopharyngeal airway were measured. The reproducibility of the measurements was evaluated using paired t tests and intraclass correlation coefficients. The Wilcoxon test and Pearson correlation coefficient were applied to evaluate the volumetric changes in the nasopharyngeal airway space and assess the correlations of these changes to the maxillary surgical movements. RESULTS: Six patients were excluded from the study owing to major differences (>5°) in their head and neck posture between the T1 and T2 CBCT scans. The errors of the repeated measurements were insignificant (P > .05), with a high level of agreement (r = 0.99; P < .05) between the repeated digitization of the landmarks. There was a statistically significant impact of a Le Fort I osteotomy on the right maxillary sinus (decreased by 17.8%) and the lower retropalatal space (expanded by 17.3%; P < .05). The correlation between the change in airway volume and the magnitude of surgical maxillary movements was moderate (r = .4). Similarly, there was a moderate correlation between changes in the upper nasopharynx and those in the hypopharynx. CONCLUSION: The single Le Fort I osteotomy was found to increase the retroglossal airway volume. This could be important for the treatment of obstructive sleep apnea in patients with maxillary deficiency. A long-term follow-up assessment of a larger sample with a functional assessment of airway would be beneficial to confirm these findings.