• Sleep Medicine and Psychophysiology
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• v.11 no.1
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• pp.5-9
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• 2004

Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent cessation of breathing due to complete or partial upper airway occlusion during sleep. The incompetent tone of palatal, pharngeal, and glossal muscles which fail to maintain airway patency during sleep causes narrowing of the airway dimension and increased resistance of breathing. The identification of the sites of upper airway obstruction in patients with OSA is important in understanding the pathogenesis and deciding the treatment modality of snoring and/or OSA. Various upper airway imaging modalities have been used to assess upper airway size and precise localization of the sites of upper airway obstruction during sleep. Dynamic imaging modalities enabled assessment of dimensional changes in the upper airway during respiration and sleep. This article focused on reviews of various upper airway imaging modalities, especially dynamic upper airway imaging studies providing important information on the pathogenesis of OSA.

• Korean Journal of Bronchoesophagology
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• v.4 no.1
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• pp.43-51
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• 1998

Background： Three-dementional imaging with spiral CT(3D spiral CT) is a well established imaging modality which has been investigated in various clinical settings. However the 3D spiral CT in upper airway disease is rarely reported and its results are still obscure. Objectives： To access the usefulness of 3D spiral CT imaging in patients with upper airway diseases. Materials and Methods We performed 3D spiral CT in fourteen patients In whom upper airway diseases were clinically suspected. Nine of these patients had upper airway stenosis, two had laryngeal cartilage fracture, and three had laryngo-hypopharyngeal cancer. For evaluation of location and extent of the lesions, we compared the findings of 3D imaging with those of air tracheogram, conventional 2D CT images, endoscopic and operative findings. Results： In case of stenosis, 3D spiral CT provide significant useful information, particularly the site and length of the stenotic segment. But, it was difficult to define the fracture of the laryngeal framework and to detect the cartilagenous invasion by head and neck cancer using the 3D imaging. Conclusion : The 3D spiral CT was an useful adjunctive method to assess some kind of upper airway disease but not in others. So, we should compare the findings of 3D images with those of other diagnostic tools for accurate diagnosis of the upper airway disease.

• Imaging Science in Dentistry
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• v.51 no.4
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• pp.439-446
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• 2021

Purpose: The aim of this study was to identify correlations between the STOP-Bang score and upper airway dimensions using cone-beam computed tomography (CBCT) scans. Materials and Methods: This study included 101 subjects (46 men, 55 women) from dental patients who received CBCT scans from 2014 to 2020. The patients were divided into those with a low obstructive sleep apnoea (OSA) risk (STOP-Bang score<3) and those with an intermediate to high OSA risk (STOP-Bang score≥3), and their upper airway dimensions were then analysed on CBCT scans. Comparisons between the low-risk and intermediate/high-risk groups were conducted using the t-test and the Mann-Whitney test. Correlations between the total STOP-Bang score and upper airway dimension parameters were established using Spearman correlation coefficients. P values≤0.05 were considered to indicate statistical significance. Results: Intermediate/high-risk subjects were predominantly male and over 50 years of age, with a higher body mass index. They had significantly longer upper airways, smaller average airway volumes, and smaller widths and antero-posterior dimensions of the narrowest upper airway segment. The total upper airway length was positively correlated with the STOP-Bang score (r_s=0.278). The average volume (r_s= -0.203) and width of the narrowest upper airway segment(r_s= -0.305) were both negatively correlated with STOP-Bang scores. Conclusion: Subjects with higher STOP-Bang scores had upper airways that were longer, narrower, and smaller in terms of average volume. CBCT scans taken for dental patients as part of investigative procedures could be correlated with STOP-Bang scores to screen for patients at risk of OSA.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.4
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• pp.179-192
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• 2023

Obstructive sleep apnea (OSA) is a common sleep-breathing disorder associated with significant comorbidities and perioperative complications. This narrative review is aimed at comprehensively overviewing preoperative risk evaluation and perioperative management strategies for patients with OSA. OSA is characterized by recurrent episodes of upper airway obstruction during sleep leading to hypoxemia and arousal. Anatomical features, such as upper airway narrowing and obesity, contribute to the development of OSA. OSA can be diagnosed based on polysomnography findings, and positive airway pressure therapy is the mainstay of treatment. However, alternative therapies, such as oral appliances or upper airway surgery, can be considered for patients with intolerance. Patients with OSA face perioperative challenges due to difficult airway management, comorbidities, and effects of sedatives and analgesics. Anatomical changes, reduced upper airway muscle tone, and obesity increase the risks of airway obstruction, and difficulties in intubation and mask ventilation. OSA-related comorbidities, such as cardiovascular and respiratory disorders, further increase perioperative risks. Sedatives and opioids can exacerbate respiratory depression and compromise airway patency. Therefore, careful consideration of alternative pain management options is necessary. Although the association between OSA and postoperative mortality remains controversial, concerns exist regarding adverse outcomes in patients with OSA. Understanding the pathophysiology of OSA, implementing appropriate preoperative evaluations, and tailoring perioperative management strategies are vital to ensure patient safety and optimize surgical outcomes.

• Imaging Science in Dentistry
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• v.46 no.1
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• pp.9-16
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• 2016

Purpose: To evaluate the upper airway dimensions of obstructive sleep apnea (OSA) and control subjects using a cone-beam computed tomography (CBCT) unit commonly applied in clinical practice in order to assess airway dimensions in the same fashion as that routinely employed in a clinical setting. Materials and Methods: This was a retrospective analysis utilizing existing CBCT scans to evaluate the dimensions of the upper airway in OSA and control subjects. The CBCT data of sixteen OSA and sixteen control subjects were compared. The average area, average volume, total volume, and total length of the upper airway were computed. Width and anterior-posterior (AP) measurements were obtained on the smallest axial slice. Results: OSA subjects had a significantly smaller average airway area, average airway volume, total airway volume, and mean airway width. OSA subjects had a significantly larger airway length measurement. The mean A-P distance was not significantly different between groups. Conclusion: OSA subjects have a smaller upper airway compared to controls with the exception of airway length. The lack of a significant difference in the mean A-P distance may indicate that patient position during imaging (upright vs. supine) can affect this measurement. Comparison of this study with a future prospective study design will allow for validation of these results.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.3.1-3.9
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• 2017

Background: The purpose of the study is to compare the effects on the pharyngeal airway space of skeletal anchored face mask with those of tooth-borne facemask. Methods: We used two types of facemask for maxillary protraction, the tooth-borne facemask (TBFM) and the skeletal anchored facemask (SAFM), and evaluated the effects of each facemask on the pharyngeal airway. Twenty-eight patients (mean age 10.3 years) were treated with the TBFM and 24 patients (mean age 11.2 years) were treated with the SAFM. Lateral cephalometric radiographs were taken before treatment (T1) and after treatment (T2) to assess changes in the dimensions of the upper airway. Statistical analysis was performed with independent t tests, matched t tests, Mann-Whitney U tests, and Kruskal-Wallis tests. Results: There were marked increases in upper airway dimensions in both groups following treatment, but the SAFM group had a significantly greater increase in airway dimensions than the TBFM group. Also, the SAFM subgroups showed more improved airway measurements than the TBFM subgroups in both the superior and inferior pharyngeal airways. Conclusions: SAFM is more effective than TBFM in increasing upper airway dimensions.

• Transactions of the KSME C: Technology and Education
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• v.2 no.2
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• pp.73-80
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• 2014

Drug delivery in human upper airway was studied by the numerical simulation of oral airflow. We created an anatomically accurate upper airway model from CT scan data by using a medical image processing software (Mimics). The upper airway was composed of oral cavity, pharynx, larynx, trachea, and second generations of branches. Thin sliced CT data and meticulous refinement of model surface under the ENT doctor's advice provided more sophisticated nasal cavity models. With this 3D upper airway models, numerical simulation was conducted by ANSYS/FLUENT. The steady inspiratory airflows in that model was solved numerically for the case of flow rate of 250 mL/s with drug-laden spray(Q= 20, 40, 60 mL/s). Optimal parameters for mechanical drug aerosol targeting of predetermined areas was to be computed, for a given representative upper airways. From numerical flow visualization results, as flow-rate of drug-laden spray increases, the drag spray residue in oral cavity was increased and the distribution of drug spray in trachea and branches became more homogeneous.

• Tuberculosis and Respiratory Diseases
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• v.70 no.1
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• pp.63-68
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• 2011

Multiple symmetrical lipomatosis (MSL), also called Madelung's disease, is a rare disorder of unknown etiology and characterized by abnormal accumulation of large subcutaneous fatty masses in neck, shoulder, and upper trunk. MSL has known to predominantly affect middle-aged men with a history of alcoholism. Although the clinical course of MSL is considered to be slowly progressive, in advanced stage, fatty masses in the neck may compress the upper aerodigestive tract, resulting in dyspnea and dysphagia. The treatment of MSL is surgical resection, but radical excision is very difficult and recurrence after surgery is frequent. We report the case of 55-year-old man with long lasting MSL, which caused severe airway obstruction. This patient was admitted with progressive dyspnea and massive accumulation of fat around the vocal cord that was detected on a neck CT scan. This abnormal fatty infiltration in supraglottic region caused upper airway obstruction.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.1-11
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• 2021

The purpose of this study is to investigate factors influencing the upper airway dimensions in skeletal Class II children and adolescents. In total, 67 patients were selected. Airway volume and minimal cross-sectional area were three-dimensionally assessed. Craniofacial morphology and skeletal maturity were assessed on generated two-dimensional cephalograms. The measurements were analyzed using Mann-Whitney test, one-way ANOVA, Pearson's correlation, and multiple regression analysis. Upper airway dimensions were significantly smaller in pre-peak stage group, and positively associated with age. Anterior facial height and age were the most relevant factors for airway volume. Mandibular width and age were the most relevant factors for minimal cross-sectional area. Upper airway dimensions were significantly associated with age, skeletal maturity and craniofacial morphology in all three planes.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.547-561
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• 1998

Obstructive sleep apnea (OSA) is a disorder characterized by repetitive episode of upper airway collapse during sleep. Recent studies showed that not only the anatomic factors but the physiologic factors of the upper airway also have effcts on the occurrence of apnea and that the genioglossus muscle also plays an important role in the maintenance of the upper airway. A variety of therapies were performed to treat OSA, and among them the use of mandibular repositioning appliances showed reasonable results. But there is still a lack of research on the structural and physiological mechanism upon the use of mandibular repositioning appliances. The author selected 26(male 17, female 9) OSA patients that came to the Yonsei University Dental Hospital, Department of Orthodontics, and 20 normal adults (male 10, female 10) and took cephalometric radiographs of them in a supine position before and after the placement of the mandibular repositioning appliance to see the structural changes of the upper airway and compare the therapeutic effects between the two groups. We also studied the waking genioglossus muscle activity in OSA patients and investigated the difference in the electromyogram of the genioglosssus muscle upon the change in body posture and the use of mandibular repositioning appliance. Following results were obtained. 1. Among the cephalometric measurements of the upper airway structure, the length of the soft palate, maximum thickness of the soft Palate and SPAS, MAS, VAL, H-H1, MP-H showed statistically significant differences between the normal and OSA groups, but the IAS and EAS showed no statistically significant differences between the two groups. 2. In both the normal and OSA groups, as the epiglottis moved forward on wearing the mandibular repositioning appliance, the epiglottis level of the upper airway increased and the maximum thickness of the soft palate changed and the hyoid bone also moved forward, but the IAS in both groups showed various results and the effect of the mandibular repositioning appliance on the structure of the upper airway was different in the two groups. 3. Upon changing the position, the electromyogram of the genioglossus muscle showed a increasing tendency but there was no statistically significant differences, and when the mandibular repositioning appliance were worn there was a statistically significant increase in the electromyogram of the genioglossus muscle in both the upright and supine positions. The mandibular repositioning appliances not only have an effect on the anatomical structure of the upper airway but also on the physiology of the upper airway. There are different responses to the use of mandibular repositioning appliance between the normal and OSA groups therefore it could be considered to have the different physiology of the upper airway between the two groups.