Myoung Su Choi

Background and Objectives Positive airway pressure (PAP) therapy is the gold-standard treatment for obstructive sleep apnea (OSA), yet a substantial proportion of patients discontinue treatment, with underlying causes potentially differing by dropout timing. This study aimed to compare clinical characteristics, polysomnography (PSG) findings, and reasons between early dropouts (ED; ≤3 months) and late dropouts (LD; >3 months), and to identify factors associated with dropout timing.Subjects and Method This retrospective study included 106 OSA patients who discontinued PAP therapy (ED, n=62; LD, n=44), classified by the Korean National Health Insurance 3-month adherence evaluation cutoff. Dropout causes were extracted from structured nursing records and categorized into four mechanistic domains.Results Baseline demographics and PSG parameters were compared between groups. Device discomfort (52.5% vs. 14.0%, p<0.001) and expiratory pressure resistance (22.6% vs. 0%, p<0.001) predominated in ED, whereas lack of perceived treatment effect (8.2% vs. 44.2%, p<0.001) and lack of disease awareness (1.6% vs. 15.9%, p=0.008) characterized LD. The Firth’s penalized logistic regression indicated that device discomfort was independently associated with ED (penalized odds ratio=3.65, 95% confidence interval: 1.34-9.99, p=0.012).Conclusion PAP dropout mechanisms differ qualitatively by timing. ED is driven by device-related physiological barriers, suggesting that early-phase management should prioritize device adaptation and pressure optimization, while long-term retention requires disease awareness reinforcement and objective efficacy feedback.

Background and Objectives While the apnea-hypopnea index (AHI) is the standard for obstructive sleep apnea (OSA) classification, it only measures event frequency. It fails to account for the duration and depth of desaturation. In contrast, hypoxic burden (HB) addresses this by integrating the area under the nocturnal desaturation curve. This study aimed to characterize patients with moderate AHI who exhibit a disproportionately high HB.Subjects and Method This retrospective study analyzed overnight polysomnography data from 319 adults (AHI ≥15 events/h). HB was estimated using an approximated formula (approximated HB, aHB). Patients with moderate OSA were stratified into a moderate-low (ML; aHB <60 %·min/h, n=111) group and a moderate-high (MH; aHB ≥60 %·min/h, n=14) group. A severe subgroup (SS; AHI 30.0-47.7/h, n=98), comprising the lower 50th percentile of severe OSA patients by AHI, served as the comparison group.Results Despite similar AHI levels, MH and ML exhibited markedly different aHB (MH 70.3±7.4 %·min/h vs. ML 26.3±12.9 %·min/h; p<0.001). Critically, the aHB of MH was statistically equivalent to that of SS (p=0.401). After adjusting for AHI, age, and body mass index in multivariable regression, neck circumference was not a significant predictor of aHB (β=-0.071, p=0.936).Conclusion A subtype of moderate OSA patients with high aHB (≥60 %·min/h) exhibits a nocturnal desaturation profile statistically equivalent to that of early severe OSA, characterized by prolonged apneic events and greater desaturation depth.

Achieving stable nasal tip projection in Asian rhinoplasty is frequently limited by insufficient septal cartilage, particularly in cases of age-related ossification or post-traumatic septal change. We describe an endonasal technique in which the posterior nasal septum is harvested as a single integrated cartilage-bone unit, preserving the native bone-cartilage junction without separation, and used as an extended columellar strut for tip augmentation. The integrated bony component provides structural rigidity that pure cartilage alone may not offer, reducing the need for supplementary cap grafting and preserving a natural infratip lobule-to-nostril proportion. Candidate selection is guided by preoperative CT assessment of bony thickness and junction integrity at the planned harvest site. Key technical principles include controlled incremental drilling, precise pocket dissection, and avoidance of tensioned fixation to the lower lateral cartilages. We present an illustrative case of a 40-year-old male with post-traumatic partial septal ossification and low nasal tip deformity; we applied this technique and observed satisfactory aesthetic outcome at the 3-month follow-up. This report describes the operative concept and technical approach; however, it does not include outcome data nor does it claim comparative superiority.

Background and Objectives The aim of this study was to investigate the prevalence, risk factors, and possible causes of residual excessive daytime sleepiness (EDS) in patients with obstructive sleep apnea (OSA) who were treated with positive airway pressure (PAP) machines.Subjects and Method We retrospectively analyzed medical records of 108 patients diagnosed with OSA from July 2021 to July 2023. PAP compliance, the presence of EDS, and EDS risk factors were assessed using the Epworth Sleepiness Scale and telephone interviews with patients who had received PAP treatment for more than 6 months.Results The overall prevalence of residual EDS was 17.6% (19/108 patients). Among them, 8 cases (42.1%) had explainable causes such as lack of sleep, depression, and chronic diseases, while 11 cases (57.9%) had idiopathic EDS. A high depression score (odds ratio [OR]=1.159, p=0.010) and the use of PAP for less than 4 hours (OR=4.554, p=0.018) significantly increased the risk of residual EDS.Conclusion Through this study, we found that the risk factors for residual EDS in OSA patients were high depression scores and insufficient PAP usage time.

Background and Objectives The purpose of this study was to determine whether smartwatch (SW) data measured over several nights at home could effectively predict obstructive sleep apnea (OSA).Subjects and Method Patients suspected of having OSA and scheduled for polysomnography (PSG) were asked to wear a SW at home for 7 nights before undergoing PSG. After obtaining the SW data, it was compared and analyzed with the PSG.Results A total 59 people including 42 OSA patients and 17 normal control were included in the study. The sensitivity and specificity for predicting apnea-hypopnea index (AHI) ≥5/h using the SW lowest oxygen saturation of 85% were 85.7% and 70.6%. The area under curve (AUC) for the receiver operating characteristic (ROC) curve was 0.901 (p<0.001). The sensitivity and specificity for predicting AHI ≥15/h using the SW lowest oxygen saturation of 82% were 80.6% and 67.9%. The AUC for the ROC curve was 0.866 (p<0.001).Conclusion This study showed that the OSA can be predicted fairly accurately using data obtained from wearing a SW for several nights in an environment similar to daily life rather than a hospital laboratory.

Background and Objectives The aim of this study was to investigate the compliance and treatment effects of both rapid eye movement sleep related obstructive sleep apnea (REM_ OSA) and non-stage specific OSA (NS_OSA) patients prescribed with positive airway pressure (PAP) therapy.Subjects and Method Medical records of 223 patients diagnosed with OSA from July 2021 to March 2023 were retrospectively analyzed. Six-month PAP compliance, symptoms questionnaires were compared for 60 patients in the REM_OSA group and 163 in the NS_OSA group.Results For patients in mild NS_OSA, mild REM_OSA, moderate NS_OSA, moderate REM_ OSA, severe NS_OSA, and severe REM_OSA groups, the compliance of six-month PAP was 50.0%, 33.3% (p=0.467), 69.6%, 58.3% (p>0.999), 70.7%, and 0% (p=0.023), respectively. In the NS_OSA group, PAP led to significant daytime sleepiness score improvement (7.3±3.4 to 5.7±3.6, p=0.022). In contrast, the scores for the REM_OSA group changed insignificantly (8.4±4.7 to 6.8±2.9, p=0.332).Conclusion This study revealed that PAP therapy compliance of the REM_OSA group was not lower than that of the NS_OSA group, except for the severe subgroup. However, REM_OSA was found to be less effective in improving daytime sleepiness symptoms than NS_OSA after PAP therapy.

Sleep apnea has emerged as a significant health issue in modern society, with self-diagnosis and effective management becoming increasingly important. Among the most renowned methods for self-diagnosis, the STOP-BANG questionnaire is widely recognized as a simple yet effective tool for diagnosing and assessing the risk of sleep apnea. However, its sensitivity and specificity have limitations, necessitating the need for tools with higher performance. Consequently, this study aimed to enhance the accuracy of sleep apnea diagnoses by integrating machine learning with the STOP-BANG questionnaire. Research through actual cases was conducted based on the data of 262 patients undergoing polysomnography, confirming sleep apnea with a STOP-BANG score of ≥3 and an Apnea–Hypopnea Index (AHI) of ≥5. The accuracy, sensitivity, and specificity were derived by comparing Apnea–Hypopnea Index scores with STOP-BANG scores. When applying machine learning models, four hyperparameter-tuned models were utilized: K-Nearest Neighbor (K-NN), Logistic Regression, Random Forest, and Support Vector Machine (SVM). Among them, the K-NN model with a K value of 11 demonstrated superior performance, achieving a sensitivity of 0.94, specificity of 0.85, and overall accuracy of 0.92. These results highlight the potential of combining traditional STOP-BANG diagnostic tools with machine learning technology, offering new directions for future research in self-diagnosis and the preliminary diagnosis of sleep-related disorders in clinical settings.

Background and Objectives Obstructive sleep apnea (OSA) is associated with various health risks, including hypertension, cerebrovascular disease, myocardial infarction, diabetes, cognitive impairment, and all-cause mortality. While overnight polysomnography (PSG) is the gold standard for diagnosing OSA, it is costly and time-consuming. The STOP-Bang questionnaire is a convenient tool for OSA screening, but its high sensitivity comes at the expense of low specificity. The purpose of this study was to investigate the usefulness of combining the STOP-Bang questionnaire and a smartwatch capable of measuring oxygen saturation in screening for OSA.Subjects and Method Of the patients scheduled for PSG due to OSA, 109 patients voluntarily participated in the study by filling out a STOP-Bang questionnaire during their first visit and wearing a smartwatch during PSG.Results There were 80 males and 29 females, with the patients’ mean age of 45±13.3 years. Based on the apnea-hypopnea index (AHI), 19 patients (17.4%) were normal, 28 (25.7%) had mild OSA, 23 (21.1%) had moderate OSA, and 39 (35.8%) had severe OSA. When using the AHI threshold of AHI ≥15/h, the STOP-Bang alone showed sensitivity of 85.5% and specificity of 61.7%. Combining the STOP-Bang questionnaire with a smartwatch resulted in a slight decrease in sensitivity and a significant increase in specificity, yielding the values of 80.5% and 84.4%, respectively.Conclusion A two-step approach using the STOP-Bang and a smartwatch was implemented to enhance the diagnostic accuracy of screening OSA.

Background and Objectives Obstructive sleep apnea (OSA) is a complex sleep-related respiratory disorder with various pathophysiology and clinical manifestations. Diagnosis and treatment considering only the number of respiratory events, such as sleep duration, may have limitations. The purpose of this study is to analyze the clinical and polysomnography (PSG) characteristics of patients with severe OSA in whom slow wave sleep (SWS) was well-maintained.Subjects and Method This study retrospectively analyzed 203 patients who underwent PSG due to suspected OSA. Severe OSA patients were classified into a SWS maintained group (SWS≥15%) and a SWS reduced group (SWS<15%), and their clinical records, PSG results, and heart rate variability (HRV) were compared.Results The SWS maintained group (n=27), compared to the SWS reduced group (n=58), had a significantly longer total sleep time (p=0.027) and lower wake after sleep onset (p=0.001), rapid eye movoement (REM) latency (p=0.007), non-supine apnea-hypopnea index (AHI, p=0.006), non-REM AHI (p<0.001), arousal index (p<0.001) and Epworth Sleepiness Scale (p=0.048). In addition, the SWS maintained group had a significantly low value in very low frequency in HRV than that of the SWS reduced group (p=0.046).Conclusion The SWS maintained group in the severe OSA showed better PSG and HRV results and reduced daytime sleepiness than those of the SWS reduced group.

Peritonsillar abscess (PTA) is the most common deep neck infection of the head and neck, but pharyngeal edema extending behind or below the tonsil and spreading to the larynx is atypical. Accurate diagnosis and prompt treatment are required because airway obstruction, descending mediastinitis, or thrombophlebitis may result. We evaluated surgical outcomes of inferiorly extended PTA (IEPTA) using an endoscope and a radiofrequency device for intraoral drainage. We retrospectively reviewed the medical records of 56 patients with IEPTA who underwent incisional drainage between 2013 and 2021. Two experienced surgeons performed intraoral drainage using an endoscope and a radiofrequency device (endoscopic group [EG]) or without such devices (WEG). Thirty (male: 26, female: four; mean age: 51.3 years), and 26 (male: 21, female: five; mean age: 55.9 years) patients in the EG and WEG, respectively, were evaluated. The mean hospitalization durations were 6.7 and 14.5 days for the EG and WEG, respectively (p<0.01). There were significant between-group differences regarding the number of tracheostomies conducted to secure an airway or surgical field (EG: four (13.3%); WEG: 16 (61.5%); p<0.01. The hospitalization duration for patients undergoing tracheostomy was significantly shorter in the EG than in the WEG (9.3 vs. 18.5 days, respectively; p=0.01). No significant difference in the mean hospital stay was observed for patients who did not undergo tracheostomy ([EG: 6.3, WEG: 8.2] days; p=0.081). IEPTA drainage using an endoscope and a radiofrequency instrument can reduce duration of hospitalization and tracheostomy procedures compared with the conventional method.