Intranasal delivery of Duox2 DNA using cationic polymer can prevent acute influenza A viral infection in vivo lung.

We studied the contribution of Duox2 in mucosal host defense against influenza A virus (IAV) infection in in vivo lung. We found that Duox2 was required for the induction of type I and III interferon (IFN)s and transient Duox2 overexpression using cationic polymer polyethyleneimine (PEI) leads to suppression of IAV infection in in vivo lung. Twenty mice (C57BL/6J) were anesthetized and challenged by intranasal administration of 213 pfu/30 µl of IAV (WS/33/H1N1), and IAV-infected mice were euthanized at 1, 3, 5, 7, 10, 14 days post infection (dpi). Duox2 small hairpin RNA (shRNA) and pCMV-Duox2 formulated with PEI were inoculated to mice to assess the regulatory mechanism between Duox2 and IFN secretion. Following intranasal IAV inoculation, viral infection was significantly aggravated from 3 dpi in in vivo lung and viral titer was highest at 7 dpi. Consistent with this, Duox2 messenger RNA (mRNA) and protein expressions were significantly induced from 3 dpi in the lung tissue of IAV-infected mice. Viral titer was much higher in IAV-infected mice that were inoculated with Duox2 shRNA accompanied with lower survival rate and extensive lung pathologies. Interestingly, severe lung pathologies in IAV-infected mice were not observed and viral titer was significantly reduced in mice with pulmonary administration of pCMV-Duox2 formulated with PEI before IAV inoculation. Both mRNA and secreted protein levels of IFN-ß and IFN-λ2/3 were highly elevated in IAV-infected mice with pCMV-Duox2 formulated with PEI. Duox2 is necessary for the regulation of IFN secretion in in vivo lung, and pulmonary administration of Duox2 DNA using cationic polymer triggers the induction of type I and III IFNs resulting in more complete suppression of IAV infection.

Soft palate cephalometric changes with a mandibular advancement device may be associated with polysomnographic improvement in obstructive sleep apnea.

PURPOSE: It is unclear whether soft palate-associated changes in cephalometry associated with a mandibular advancement device (MAD) are independently associated with improvements in polysomnography (PSG) respiratory parameters in obstructive sleep apnea (OSA). METHODS: This retrospective review aimed to identify the association between soft palate-associated changes in cephalometry and PSG changes after application of an MAD. Korean patients diagnosed with OSA who underwent cephalometry with or without an MAD were enrolled. All the patients were evaluated after undergoing full-night PSG twice: once with an MAD and once without. Cephalometric findings were measured using an image analyzer. RESULTS: Mean apnea-hypopnea index significantly decreased with an MAD from 36.4/h to 14.7/h (p < 0.001). Retropalatal airway space significantly increased with an MAD from 6.6 to 7.3 mm (p = 0.013). Soft palate length also significantly decreased with an MAD from 43.6 to 42.3 mm (p = 0.02). Although these findings were shown by responders (patients with a reduction of apnea-hypopnea index by more than 50%), there were no significant changes in non-responders. However, retroglossal airway space did not significantly increase with an MAD even in responders. CONCLUSIONS: Improvement of OSA with an MAD can be predicted with soft palate-associated upper airway changes shown in cephalometry.

Adenotonsillar hypertrophy as a risk factor of dentofacial abnormality in Korean children.

No studies for the role of adenotonsillar hypertrophy in development of dentofacial abnormalities have been performed in Asian pediatric population. Thus, we aimed to investigate the relationship between adenotonsillar hypertrophy and dentofacial abnormalities in Korean children. The present study included consecutive children who visited a pediatric clinic for sleep-disordered breathing due to habitual mouth breathing, snoring or sleep apnea. Their palatine tonsils and adenoids were graded by oropharyngeal endoscopy and lateral cephalometry. Anterior open bite, posterior crossbite, and Angle's class malocclusions were evaluated for dentofacial abnormality. The receiver-operating characteristic curve analysis was used to identify age cutoffs to predict dentofacial abnormality. A total of 1,083 children were included. The presence of adenotonsillar hypertrophy was significantly correlated with the prevalence of dentofacial abnormality [adjusted odds ratio = 4.587, 95% CI (2.747-7.658)] after adjusting age, sex, body mass index, allergy, and Korean version of obstructive sleep apnea-18 score. The cutoff age associated with dentofacial abnormality was 5.5 years (sensitivity = 75.5%, specificity = 67%) in the children with adenotonsillar hypertrophy and 6.5 years (sensitivity = 70.6%, specificity = 57%) in those without adenotonsillar hypertrophy. In conclusion, adenotonsillar hypertrophy may be a risk factor for dentofacial abnormalities in Korean children and early surgical intervention could be considered with regards to dentofacial abnormality.

Evaluation of coblation lingual tonsil removal technique for obstructive sleep apnea in Asians: preliminary results of surgical morbidity and prognosticators.

Retroglossal obstruction is one of the etiologies causing obstructive sleep apnea (OSA) and can be addressed by removing some tissues of the tongue base. However, because of its deep-seated location, its surgical removal is still challenging. Although coblation technique has been introduced, its efficacy and morbidity need further evaluation, particularly in Asians. This study aimed to assess its safety and effectiveness and to identify outcome prognosticators. Forty-seven OSA patients who underwent coblation lingual tonsil removal were included. Retroglossal obstruction was confirmed by drug-induced sleep videofluoroscopy. Attended full-night polysomnography was performed twice; before and 6 months after surgery in 27 patients. The tongue base was fully exposed with three deep-seated traction sutures, visualized with a 30° or 70° endoscope, and ablated using a coblator. Surgical success was defined with postoperative apnea hypopnea index (AHI) <20 and reduction >50 %. Postoperative morbidities were evaluated. Demographic and polysomnographic parameters between success and failure groups were compared. None of the patients had immediate postoperative hemorrhage. Postoperatively, one patient had delayed hemorrhage and one patient severe respiratory difficulty. Taste loss, tongue dysmotility, dental injury or severe oropharyngeal stricture were absent. A mean AHI decreased from 37.7 ± 18.6 to 18.7 ± 14.8/h (P < 0.001). The success rate was 55.6 %. Their mean minimal oxygen saturation was significantly lower (P = 0.004) in the failure group. Coblation lingual tonsil removal technique showed minimal morbidity and favorable outcome in Koreans. The surgical outcome might be associated with the severity of single respiratory events.

Influencing factors on the effect of mandibular advancement device in obstructive sleep apnea patients: analysis on cephalometric and polysomnographic parameters.

BACKGROUND: The purposes of this study were to evaluate clinical outcome of mandibular advancement device (MAD) for obstructive sleep apnea (OSA) patients and to estimate influencing factors on MAD effect. METHODS: From the patients who were diagnosed as OSA by polysomnography at Seoul National University Bundang Hospital from January 2007 to February 2009, the patients who chose MAD as initial treatment option were included. All the patients' data were collected by reviewing and analyzing medical record and radiograph retrospectively. RESULTS: Eighty-six patients (76 males and 10 females; mean age of 51.5 ± 9.8 years) with OSA were included in this study. Total success rate of MAD treatment was 47.7% (41/86 patients). Among cephalometric parameters, lower facial height (35.61 ± 4.26 vs. 38.19 ± 4.89) showed significant difference between success group and non-success group. From the polysomnographic parameters, apnea index (19.79 ± 17.32 vs. 30.08 ± 23.28), average oxygen saturation (95.03 ± 1.42 vs. 94.32 ± 1.56), lowest oxygen saturation (81.44 ± 6.64 vs. 76.87 ± 7.98), oxygen saturation under 90% (4.47 ± 5.90 vs. 9.01 ± 9.29), and oxygen desaturation index (23.58 ± 17.46 vs. 37.16 ± 22.35) showed significant difference between groups. CONCLUSIONS: From the results, it was proved that MAD was an effective treatment option for the OSA patients. Some cephalometric and polysomnographic parameters including posterior lower facial height, apnea index, average oxygen saturation, lowest oxygen saturation, oxygen saturation under 90 %, and oxygen desaturation index could be influencing factors on MAD effect.

Cardiopulmonary coupling analysis: changes before and after treatment with a mandibular advancement device.

PURPOSE: The aim of this study is to 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 reevaluated after 3-month use of a MAD. At baseline, apnea-hypopnea index (AHI) was 33.6±17.0, Epworth sleepiness scale was 10.5±4.8, and Pittsburgh sleep quality index was 5.8±2.8. The CPC parameters were extracted from single-lead electrocardiography of polysomnography. We compared CPC parameters at baseline with those after 3-month use of a MAD. RESULTS: All respiratory indices improved with the use of MAD. However, there were no differences in the sleep architectures except N3 sleep (3.7±4.3 to 6.9±6.4%, p<0.001). The CPC parameters showed a significant improvement with the use of MAD. Low-frequency coupling (59.5±16.1 to 47.7±14.8%, p<0.001) and elevated low-frequency coupling (44.6±18.4 to 32.6±15.7%, p<0.001) significantly decreased. High-frequency coupling (28.6±16.0 to 36.5±15.7%, p=0.004) and very low frequency coupling (11.7±7.2 to 15.3±6.6%, p=0.028) 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<0.001) and positively correlated with low-frequency and elevated low-frequency coupling changes (r=0.604 and 0.497, respectively; p<0.001 in both). However, the changes of Epworth sleepiness scale and Pittsburgh sleep quality index after MAD therapy showed no significant correlation with the changes in the CPC parameters. CONCLUSIONS: To our knowledge, this is the first study to evaluate the quality of sleep in patients using a MAD for their OSA based upon CPC analysis. 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.

Dental implant as a potential risk factor for maxillary sinus fungus ball.

Fungus ball is the most common form of non-invasive fungal sinusitis, and maxillary sinus is the most commonly involved site. Maxillary sinus fungus ball (MFB) accounts for a considerable proportion of unilateral maxillary sinusitis. The prevalence of MFB has recently increased; however, its contributing factors are unclear. This study analyzed the association between MFB and dental implants. One hundred one patients who underwent unilateral maxillary sinus surgery were divided into two groups based on surgical biopsy results: unilateral bacterial sinusitis (UBS, n = 45) and MFB (n = 56). Stratified random sampling of 30 patients from each group was performed to adjust for age. The number of dental implants on maxillary teeth and degree of penetration into the maxillary sinus was radiologically evaluated. The number of patients with dental implants was greater (P = 0.085) and the number of implants was significantly higher (P = 0.031) in the MFB group. Dental implant can be a potential risk factor for MFB development. Therefore, dental implant surgeons should take caution in penetrating the maxillary sinus floor during implant insertion and otolaryngologists should consider the possibility of fungus ball when assessing patients with sinusitis who have dental implants.

Effects of surgical vs. nonsurgical therapy on erectile dysfunction and quality of life in obstructive sleep apnea syndrome: a pilot study.

INTRODUCTION: Obstructive sleep apnea syndrome (OSAS) is associated with erectile dysfunction (ED). The improvement of ED after medical therapy including continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs) is still controversial. Furthermore, the efficacy of surgical treatment has been little investigated. AIM: The aim of this nonrandomized prospective study was to evaluate the effects of surgical (uvulopalatopharyngoplasty [UPPP]) and nonsurgical approaches (CPAP and MAD) on ED and quality of life (QOL) in OSAS. METHODS: OSAS patients underwent UPPP (N = 30), CPAP (N = 16), or MAD (N = 10) and completed the Korean versions of the International Index of Erectile Function questionnaire (KIIEF-5) and the Calgary Sleep Apnea Quality of Life Index (SAQLI) before and after a median of 7 months of treatment (interquartile range, 4-15 months). All patients underwent a full-night in-laboratory polysomnography at baseline and follow-up. MAIN OUTCOME MEASURE: The main outcome measures are the KIIEF-5 and SAQLI scores. RESULTS: CPAP group showed older age, higher body mass index, and more severe OSAS than other groups. Apnea-hypopnea index and lowest oxygen saturation level improved significantly in all groups, but Epworth Sleepiness Scale score decreased significantly in UPPP and MAD groups. Significant increase of KIIEF-5 was observed in patients who underwent UPPP (P = 0.039, paired t-test), but not in nonsurgical treatment group. All groups had the tendency of better QOL after treatment, but statistical significance was found only in MAD group. Neck circumference (r = 0.360, P = 0.006) and KIIEF-5 score (r = -0.484, P < 0.001) at baseline were significantly related to the improvement of KIIEF-5. CONCLUSIONS: This study demonstrated that ED in OSAS may improve following UPPP. Better disease-specific QOL was observed after both surgical and nonsurgical therapies in OSAS. These findings suggest that interventions for OSAS can provide the alleviation of ED and increase QOL in OSAS patients with ED, especially if they had pronounced complaints of ED and wide neck circumferences.

Treatment outcomes and compliance according to obesity in patients with obstructive sleep apnea.

The objective of this study was to assess treatment outcomes and compliance according to obesity among groups of patients with obstructive sleep apnea (OSA) receiving different treatments. A total of 297 patients with OSA treated between 2006 and 2009 underwent pre- and post-treatment polysomnography. One hundred and fifty-one patients were treated with continuous airway positive pressure (CPAP), 76 with mandible advancement device (MAD), and 70 with oropharyngeal surgery. All patients were classified according to obesity. Treatment success rate and compliance of CPAP were analyzed according to obesity. For each treatment modality, the overall treatment success rate was not significantly different between obese and non-obese patients. However, the oxygen desaturation index was different in patients who were treated with MAD and surgery. Additionally, obese patients with severe OSA showed an unfavorable response to CPAP treatment. For CPAP compliance, obese patients showed a tendency to be highly compliant with CPAP treatment at 12 months than non-obese patients. This study showed that obesity might be a factor in determining the success or failure of treatment. Additionally, obesity may be a predictive factor to determine CPAP compliance.

Comparison between mono-bloc and bi-bloc mandibular advancement devices for obstructive sleep apnea.

Although mandibular advancement device (MAD) is widely used, there are a few papers comparing the efficacy and compliance at the same time according to the type of MAD. The aim of this study is to compare the efficacy and compliance between mono-bloc and bi-bloc MAD in the treatment of obstructive sleep apnea (OSA). Ninety-three patients who treated with mono-bloc MAD and 60 patients with bi-bloc MAD from January 2007 through September 2011 were retrospectively enrolled. All the patients underwent full-night polysomnography(PSG) before and 3 months after MAD was applied. The response rate was significantly higher in the patients using mono-bloc than those using bi-bloc MAD (77.4 vs. 58.3 %; P = 0.012). In contrast, the compliance rate of MAD use was significantly higher in the patients using bi-bloc than those using mono-bloc MAD (68.8 vs. 83.3 %; P = 0.044) at 1 year. According to the severity of OSA, the response rate was significantly higher in severe OSA than in mild to moderate OSA (P = 0.033 for mono-bloc MAD and P = 0.048 for bi-bloc MAD). However, there was no difference in the compliance between mild to moderate OSA and severe OSA. Our study showed that mono-bloc MAD was superior to bi-bloc MAD in efficacy while bi-bloc MAD is superior to mono-bloc MAD in compliance. We propose that both the efficacy and compliance should be considered in using MAD for treatment of OSA.

Radiographic and histologic characterization of tongue base tissues obtained by transoral robotic surgery in patients with obstructive sleep apnea.

OBJECTIVE: Our aim was to radiographically and histologically characterize the tongue base tissues removed after robotic surgery and to analyze their relationship with polysomnographic measurements in obstructive sleep apnea. METHODS: Medical records, radiographs and histologic specimen of the patients who underwent transoral robotic tongue base reduction surgery were retrospectively reviewed. Findings in computed tomography (CT) images, histopathological features of the removed tongue base tissues, and respiratory parameters in polysomnography were compared and analyzed. RESULTS: Surgical specimens and CT images were available from 13 patients (aged 29-61 years). Histologic examination showed that the removed tissues comprised four layers-epithelial, lymphoid follicular, glandular, and muscle tissue. The median (interquartile range) thickness of the epithelial, lymphoid, and glandular layers was 0.29 (0.24-0.44) mm, 3.37 (1.67-4.75) mm, and 3.75 (3.45-4.10) mm, respectively. The lymphoid layer thickness on CT was correlated with that in the histologic section (r=0.967, p<0.001). However, the thickness of each layer had no significant correlation with the polysomnographic parameters. CONCLUSION: The tongue base tissue removed by transoral robotic surgery in OSA patients comprised four distinctive layers including epithelial, lymphoid follicular, glandular and muscular layers. These layered structures could also be discriminated in the CT images.

Comparison of success criteria based on long-term symptoms and new-onset hypertension in mandibular advancement device treatment for obstructive sleep apnoea: observational cohort study.

OBJECTIVE: To identify adequate criteria to determine the success or failure of mandibular advancement device (MAD) treatment for obstructive sleep apnoea (OSA) based on long-term symptoms and new-onset hypertension. DESIGN: Observational cohort study. SETTING: A tertiary care hospital setting in South Korea. PARTICIPANTS: Patients (age >18 years) who were diagnosed with OSA by a polysomnography (PSG) or Watch peripheral arterial tonometry (PAT), and who had been treated with MAD between January 2007 and December 2014 were enrolled. PRIMARY AND SECONDARY OUTCOME MEASURES: Patients underwent PSG or Watch PAT twice; before and 3 months after the application of MAD. The patients were categorised into success and failure groups using seven different criteria. MAD compliance, witnessed apnoea and snoring, Epworth Sleepiness Scale score and occurrence of new-onset hypertension were surveyed via telephonic interview to determine the criteria that could identify success and failure of MAD. RESULTS: A total of 97 patients were included. The mean follow-up duration was 60.5 months, and the mean apnoea-hypopnoea index (AHI) was 35.5/hour. Two of the seven criteria could significantly differentiate the success and failure groups based on long-term symptoms, including (1) AHI<10/hour with MAD and (2) AHI<10/hour and AHI reduction of >50% with MAD. Kaplan-Meier survival analysis showed that one criterion of AHI<15/hour with MAD could differentiate the success and failure groups based on new-onset hypertension (p=0.035). The receiver operating characteristic curve analysis indicated that the cut-off AHI for new-onset hypertension was 16.8/hour (71.4% sensitivity and 75.0% specificity). CONCLUSION: Our long-term follow-up survey for symptoms and new-onset hypertension suggested that some of the polysomnographic success criteria, that is, AHI<10/hour with MAD, AHI<10/hour and AHI reduction of >50% with MAD and AHI<15/hour with MAD may be useful in distinguishing the success group from failure one. Further prospective longitudinal studies are warranted to validate these criteria.

Influencing factors on CPAP adherence and anatomic characteristics of upper airway in OSA subjects.

Although continuous positive airway pressure (CPAP) is the most effective treatment modality, poor adherence still remains a problem for obstructive sleep apnea (OSA) treatment and there is little evidence regarding how this might be improved. This study aims to analyze the anatomic and clinical factors of OSA subjects who failed to comply with CPAP therapy.The medical records of 47 OSA subjects who received CPAP therapy as a first-line treatment modality were retrospectively reviewed. The medical records were reviewed for demographic and polysomnographic data and anatomic findings of the nasal cavity and oropharynx.24 patients who adhered to CPAP therapy and 23 patients who were nonadherent were enrolled in the study. There were no statistically significant differences in sleep parameters between CPAP-adherent patients and CPAP nonadherent subjects. Mean body mass index of CPAP nonadherent group was significantly higher than CPAP adherent group. Higher grades of septal deviation and hypertrophic change of the inferior turbinate were observed more in the CPAP nonadherent group. In addition, CPAP nonadherent subjects showed considerably bigger tonsils and higher grade palatal position comparing with the CPAP adherent subjects. Subjective discomfort including inconvenience, mouth dryness, and chest discomfort were the main problems for OSA subjects who did not comply with CPAP therapy.Excessive upper airway blockage in the nasal cavity and oropharynx was predominant in CPAP nonadherent subjects, which might cause the reported subjective discomfort that reduces CPAP compliance. Therefore, resolution of these issues is needed to enhance CPAP compliance for control of OSA.

A Single Primary Site Obstruction May Lead to Sleep-Disordered Breathing in Multiple Sites: An Animal Model.

OBJECTIVES: This study aimed to investigate the dynamic upper airway changes occurring in an obstructive sleep apnea (OSA) rabbit model using dynamic computerized tomography (CT). METHODS: In this study, 2.5 U of botulinum toxin type A was injected into the genioglossus to paralyze the tongue in the OSA group (n = 7). The control group was injected with normal saline (n = 7). Apnea-hypopnea index was measured using ApneaLink at baseline and at 1, 2, 3, 4, 6, and 8 weeks post-injection. Anterior to posterior (AP) and transverse diameters at the levels of the palate and tongue base were measured using a dynamic CT at baseline and at 1 and 2 weeks post-injection. RESULTS: The success rate of OSA induction was higher in the OSA group (P = .02). In the OSA group, transverse and AP diameters at the palate level and AP diameter at the tongue base level significantly decreased 2 weeks post-injection (P = .01). CONCLUSIONS: A single obstruction site may constitute the primary pathogenesis in some OSA patients, even when the involvement of multiple sites is indicated. These findings may contribute to the identification of OSA pathogenesis and improve the planning of treatment based on the primary cause of OSA.

A Comparison of Different Success Definitions in Non-Continuous Positive Airway Pressure Treatment for Obstructive Sleep Apnea Using Cardiopulmonary Coupling.

STUDY OBJECTIVES: The definition and the criteria for the successful treatment of obstructive sleep apnea vary, depending on the study. This study aimed to compare different success criteria of non-continuous positive airway pressure (non-CPAP) treatment for obstructive sleep apnea in terms of sleep quality by using cardiopulmonary coupling. METHODS: We included 98 patients who had been treated with sleep surgery or with a mandibular advancement device at our sleep clinic from January 2011 to March 2013. The success and failure groups were divided by 6 criteria that have been used in the literature. The validity of each of the 6 criteria was evaluated by cardiopulmonary coupling-based sleep quality. RESULTS: The parameters of cardiopulmonary coupling indicated that sleep quality improved with non-CPAP treatment: low-frequency coupling decreased from 57.4% ± 17.7% to 46.9% ± 16.5%, whereas high-frequency coupling increased from 30.2% ± 17.1% to 37.4% ± 16.7%. In multiple regression analysis, only the criterion of a reduction in the apnea-hypopnea index greater than 50% was significantly associated with sleep quality improvement (p = 0.016; 95% confidence interval, 1.008-1.076 in the high-frequency coupling increment; p = 0.001; 95% confidence interval, 1.025-1.099 in the low-frequency coupling decrement). CONCLUSIONS: Cardiopulmonary coupling analysis showed that a reduction in the apnea-hypopnea index of more than 50% might be the optimal criterion to determine the success or failure of non-CPAP treatment in terms of sleep quality.

Therapeutic outcomes of mandibular advancement devices as an initial treatment modality for obstructive sleep apnea.

Although continuous positive airway pressure (CPAP) is a highly efficacious treatment for obstructive sleep apnea (OSA), there is a need for alternative treatment options, such as sleep surgeries and mandibular advancement devices (MADs), to overcome the limitations of CPAP.This study aimed to analyze the therapeutic outcomes of OSA subjects who were treated with a MAD, and to estimate the clinical impact of MAD as a first-line treatment for OSA.Forty-seven patients diagnosed with OSA received an adjustable MAD as an initial treatment. Drug-induced sleep endoscopic findings and sleep parameters (both pre-MAD and post-MAD treatment), such as apnea index, oxygen saturation, and degree of daytime sleepiness, were assessed retrospectively.The MAD treatment resulted in a significant reduction in apnea-hypopnea index, and also a significant elevation in lowest oxygen saturation. Satisfactory results of MAD treatment as a first treatment modality were observed in 27 patients, and a successful outcome was reached in approximately 72% of patients. The OSA patients who had lower body mass index and upper airway narrowing at the level of palate and tongue base showed relatively higher rates of a satisfactory outcome even in cases of moderate or severe OSA.These results suggest that the use of a MAD may be an alternative treatment option in OSA patients with retropalatal and retroglossal area narrowing regardless of disease severity. Additionally, MADs can be recommended as an initial treatment modality, and the effectiveness of MADs in achieving success may not be inferior to CPAP.

The effect of positional dependency on outcomes of treatment with a mandibular advancement device.

OBJECTIVE: To evaluate retrospectively the efficacy of the mandibular advancement device (MAD) in patients with obstructive sleep apnea in terms of positional dependency. DESIGN: Retrospective analysis. SETTING: Academic tertiary referral center. PATIENTS: One hundred patients with obstructive sleep apnea treated with the MAD at the Department of Otorhinolaryngology sleep clinic were included from January 1, 2005, through December 31, 2010. INTERVENTIONS: All patients underwent nocturnal full-night polysomnography before and at least 3 months after intraoral MAD application. MAIN OUTCOME MEASURES: Treatment results and prognostic factors deciding the success of MAD application. RESULTS: Of the 100 patients, 80 showed positional dependency and 20 showed nondependency. In the position-dependent obstructive sleep apnea group, the median (interquartile range) apnea-hypopnea index (AHI) decreased from 32.1 (24.4-41.9) to 8.6 (3.7-13.8) (P < .001); in the nondependent group, from 56.4 (26.2-71.5) to 15.7 (6.8-30.7) (P < .001). The success rate (AHI reduction ≥50% and AHI <10) was 57.5% and 30.0% in position-dependent and position-nondependent groups, respectively (P = .04). CONCLUSION: Identifying patients with obstructive sleep apnea as position dependent or nondependent may have important therapeutic implications in predicting the outcome of MAD treatment.

Determinants of treatment outcome after use of the mandibular advancement device in patients with obstructive sleep apnea.

OBJECTIVE: To determine the predictors affecting treatment outcome after application of the mandibular advancement device (MAD). DESIGN: Retrospective analysis. SETTING: Tertiary care university hospital. PATIENTS: A total of 76 patients (68 men and 8 women) who were treated with the MAD for obstructive sleep apnea (OSA) were included from September 2005 through August 2008. All the subjects underwent cephalometry, nocturnal polysomnography, and sleep videofluoroscopy (SVF) before and at least 3 months after receipt of a custom-made MAD. Sleep videofluoroscopy was performed before and after sleep induction and was analyzed during 3 states of awakeness, normoxygenation sleep, and desaturation sleep. Subjects were divided into success and nonsuccess groups depending on treatment outcome. MAIN OUTCOME MEASURES: Multiple variables from cephalometry and SVF including the length of the soft palate, retropalatal space, retrolingual space, and mouth opening angle were evaluated during sleep events with or without the MAD between success and nonsuccess group. RESULTS: The soft palate was significantly longer in the nonsuccess group than in the success group. The retropalatal and retrolingual airway spaces and mouth opening angle were not different between 2 groups. Application of the MAD increased the retrolingual space and decreased the length of the soft palate and the mouth opening angle significantly in both success and nonsuccess groups. However, retropalatal space was widened only in the success group, which showed that retropalatal space may be important in determining treatment response of the MAD. CONCLUSION: The length of the soft palate showed a difference between success and nonsuccess groups, and widening of retropalatal space might be an important factor for successful outcome with MAD application.