Woo-Hyun Lee

Regrowth of the adenoids after coblation adenoidectomy: Cephalometric analysis

To analyze the prevalence of adenoid regrowth at 1 year after coblation adenoidectomy using cephalometric radiography.

Mortality of Patients with Obstructive Sleep Apnea in Korea

BACKGROUND Obstructive sleep apnea (OSA) is associated with diverse health risks, including death. However, the role of OSA as a risk factor for death has never been studied in Asians. This study is aimed at evaluating the influence of OSA on the mortality in Korean sleep clinic population. METHODS A total of 2,240 patients who underwent in-laboratory full-night polysomnography due to snoring or sleep apnea were included. The patients were categorized based on apnea-hypopnea index (AHI)/hour. Death records were provided from the Statistics Korea. A Cox-proportional hazard regression model and Kaplan-Meier survival curve were used for analysis and demonstration of the all-cause mortality and cardiovascular mortality. RESULTS The all-cause mortality risk adjusted for age, sex, body mass index, diabetes, hypertension, cardiovascular diseases, and previous history of stroke was significantly associated with the increased severity of OSA. The adjusted hazard ratio (HR) for all-cause mortality in the severe OSA group (AHI ≥ 30) vs. reference group (5 < AHI) was 2.47 (95% confidence interval [CI], 1.09-5.57) and the adjusted HR for cardiovascular mortality was 4.66 (CI 1.03-21.08). After adjusting for whether the patients were treated or untreated, the HR for all-cause and cardiovascular mortality in the severe OSA group vs. reference group were 2.14 (p = 0.079) and 4.19 (p = 0.076), respectively. CONCLUSIONS The present study showed that the increased mortality was also associated with the increased severity of OSA in Koreans as shown in the studies performed in the Western countries.

Establishment of a Rabbit Model of Obstructive Sleep Apnea by Paralyzing the Genioglossus

IMPORTANCE This study presents an innovative method for developing a neuromuscular model of obstructive sleep apnea (OSA). OBJECTIVE To establish a new OSA animal model simulating real upper airway conditions during sleep. DESIGN AND SETTING In vivo animal study at an academic tertiary referral center. SUBJECTS A total of 27 New Zealand white male rabbits were used. INTERVENTION Sleep was induced by intramuscular injection of 0.3 mL/kg of tiletamine hydrochloride plus zolazepam hydrochloride and 0.2 mL/kg of xylazine. Upper airway obstruction was induced by injecting botulinum toxin type A (2.5 U in 8 rabbits, 5.0 U in 10 rabbits, and 7.5 U in 1 rabbit) into the genioglossus. Eight rabbits were injected with normal saline as a control. MAIN OUTCOMES AND MEASURES Drug-induced sleep was evaluated using a portable polysomnography device for electroencephalography, electrooculography, chin electromyography, nasal airflow, breathing efforts, and pulse oxymetry. Respiratory events (apneas or hypopneas) during sleep were evaluated using a sleep-screening tool. RESULTS All the rabbits showed no apneas or hypopneas before injection of botulinum toxin type A. In the control rabbits injected with normal saline, apneas or hypopneas were not found. The respiratory events were observed in 5 of 8 rabbits injected with 2.5 U of botulinum toxin type A, whereas they were observed in 7 of 10 rabbits injected with 5.0 U of botulinum toxin type A. The median (interquartile range) apnea hypopnea index was 9.6 (5.3-14.8) per hour and 45.6 (21.5-70.5) per hour in the rabbits injected with 2.5 U and 5.0 U of botulinum toxin type A, respectively (P = .03). CONCLUSIONS AND RELEVANCE An animal model of OSA could be developed by paralyzing the genioglossus in rabbits. This model may contribute to identifying the pathogenesis of upper airway obstruction in OSA and to developing new diagnostic or treatment devices targeting specific obstruction sites.

Prevalence of nasal polyps and its risk factors: Korean National Health and Nutrition Examination Survey 2009-2011.

Background Although nasal polyps (NPs) are thought to be a common otorhinolaryngologic disease, there have been few population-based epidemiologic studies on the prevalence of NPs. The aim of this study is to evaluate the prevalence of NPs and the risk factors in the general Korean population. Methods The data were obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) (2009-2011), which was a cross-sectional survey of noninstitutionalized populations all around the country (n = 28,009). Among them, 19,152 participants (age more than or equal to 20 years) completed medical interviews, physical examinations and endoscopic examination. Analyses were performed using a complex sample design to identify the prevalence and its risk factors. Results The weighted prevalence of NPs was 2.5%. The increased prevalence was associated with increasing age. In the multivariate analyses, male sex [adjusted odds ratio (OR) = 1.68, 95% confidence interval (CI) = 1.25-2.26], low education level (adjusted OR = 1.57, CI = 1.16-2.13), obesity (adjusted OR = 1.49, CI = 1.19-1.87), asthma (adjusted OR = 1.80, CI = 1.24-2.62), and thyroid cancer (adjusted OR = 2.98, CI = 1.26-7.09) were associated with NPs. Among those with NPs, the proportion of symptomatic NPs was 34.4% and asthma was the only significant associated risk factor. Conclusion The prevalence of NPs in the Korean general population was not low despite advances in medical and surgical treatment and two thirds of the subjects with NPs were asymptomatic. Further investigation is needed to exhibit the causal relationship between the associated risk factors identified and NPs.

Interrater reliability of sleep videofluoroscopy for airway obstruction in obstructive sleep apnea

Sleep videofluoroscopy (SVF) has been introduced to identify upper airway obstruction. This study was aimed to determine the interrater reliability of SVF in patients with obstructive sleep apnea (OSA).

Cardiopulmonary Coupling Analysis: Changes before and after Treatment with a Mandibular Advancement Device

Objectives: Evaluate the changes of sleep quality in patients using a mandibular advancement device (MAD) for obstructive sleep apnea (OSA) based upon cardiopulmonary coupling (CPC). Methods: A total of 52 patients (mean age, 53.7 ± 9.6 years; range, 33-74 years) were included in this study. Of them, there were 47 males (90.4%). All subjects were diagnosed with OSA after in-laboratory full-night polysomnography and re-evaluated after 3-month use of a MAD. At baseline, apnea-hypopnea index (AHI) was 33.6 ± 17.0. We compared CPC parameters at baseline with those after 3 month use of a MAD. Results: Low frequency coupling (59.5 ± 16.1 to 47.7 ± 14.8%, P < .001) and elevated low frequency coupling (44.6 ± 18.4 to 32.6 ± 15.7%, P < .001) significantly decreased. High frequency coupling (28.6 ± 16.0 to 36.5 ± 15.7%, P = .004) and very low frequency coupling (11.7 ± 7.2 to 15.3 ± 6.6%, P = .028) significantly increased. The change of AHI significantly correlated with changes of the CPC parameters: negatively correlated with high frequency coupling change (r = –0.572, P < .001); positively correlated with low frequency and elevated low frequency coupling changes (r = 0.604 and 0.497, respectively; P < .001 in both). Conclusions: Low frequency coupling decreased as AHI improved while high frequency coupling increased as AHI improved. The CPC parameters showed that the sleep quality was improved by MAD therapy.

Neurogenic Model of Obstructive Sleep Apnea in Rabbits

Objectives: An animal model of obstructive sleep apnea (OSA) can be helpful for evaluating the pathophysiology of OSA and application of novel treatment modalities. This study aimed to establish new OSA animal model simulating real upper airway conditions during sleep. Methods: A total of 27 New Zealand white male rabbits were used. Sleep was induced by intramuscular injection of 0.3 ml/kg of Zoletil and 0.2 ml/kg of Rompun. Drug-induced sleep was evaluated using Embletta X100 for electroencephalography, electrooculography, chin electromyography, nasal airflow, breathing efforts, and pulse oxymetry. Upper airway obstruction was induced by injecting botulinum toxin into the genioglossus. Respiratory events (apneas or hypopneas) during sleep were evaluated using ApneaLink. Results: All the rabbits showed no apneas or hypopneas before injection of botulinum toxin. In the control rabbits injected with normal saline, apneas or hypopneas were not found. The respiratory events were observed in 5 of 8 rabbits injected with 2.5 units of botulinum toxin whereas they were observed in 7 of 10 rabbits injected with 5.0 units of botulinum toxin. The median AHI was 9.6 (5.3 – 14.8)/h and 45.6 (21.5 – 70.5)/h in the rabbits injected with 2.5 units and 5.0 units of botulinum toxin, respectively (P = .028). Conclusions: The animal model of OSA could be developed by paralyzing the genioglossus in rabbits.