Available techniques for objective assessment of upper airway narrowing in snoring and sleep apnea

Polysomnographic Findings Versus Degree of Obstruction During Drug-Induced Sleep Endoscopy and Muller's Maneuver

PURPOSE

To investigate associations between polysomnographic findings and the severity of upper airway obstructions during Muller's Maneuver (MM) and Drug-Induced Sleep Endoscopy (DISE) in patients with obstructive sleep apnea syndrome (OSAS).

METHODS

This was a prospective cohort study. Adult patients newly diagnosed with OSAS in a tertiary sleep center were included consecutively and evaluated by polysomnography and MM. They then underwent DISE in an operating room. The associations between polysomnographic findings and the severity of upper airway obstructions during MM and DISE were assessed. Also, the degree and pattern of obstructions were compared using a modified VOTE questionnaire.

RESULTS

145 patients (mean age 41.5 ± 10.1 years) were enrolled. There were no associations between Respiratory Disturbance Index (RDI), mean and lowest O2 saturation, and body mass index on the one hand, and obstruction degree in MM and DISE (p > 0.05). However, a significant positive correlation was observed between RDI and total VOTE scores in DISE and MM (r = 0.179, p = 0.031 and r = 0.221, p = 0.008 respectively). There were no differences between MM and DISE in diagnosing the degree of obstruction in the velum area (p = 0.687) and the epiglottis (p = 0.50). However, a significant difference was observed between the two techniques in the oropharynx lateral wall (p < 0.001) and tongue base (p = 0.017).

CONCLUSION

Although there was no association between polysomnographic findings and the severity of obstruction in MM and DISE for the separate levels of the upper airway, obstruction severity may be assessed more accurately by total VOTE score, which is representative of RDI severity.

The changes in oral volume and hyoid bone position after maxillomandibular advancement and genioglossus advancement for patients with obstructive sleep apnea

INTRODUCTION

Maxillomandibular advancement (MMA) and genioglossus advancement (GA) are surgeries for patients with obstructive sleep apnea (OSA). Postoperative evaluation is primarily based on the apnea-hypopnea index (AHI) measured by polysomnography. The purpose of this study was to identify the timing of hyoid bone relocation after MMA and GA surgery and to investigate whether or not hyoid bone relocation can be an indicator of postoperative evaluation of OSA.

METHODS

Patients with OSA underwent MMA and GA surgery. Changes in hyoid bone position and tongue-to-oral volume ratio were analyzed on lateral radiographs before, immediately after, and 1 year after surgery. Then, a correlation was verified between these changes and postoperative AHI.

RESULTS

In 18 patients studied, the position of the hyoid bone did not show a constant tendency immediately after surgery. One year after surgery, the bone had moved anteriorly and toward the oral cavity in all patients compared to its preoperative position. And AHI correlated with the movement of the hyoid bone to the oral side.

DISCUSSION

One year after surgery, the tongue was adapted to the newly enlarged oral space, and as a result, the low position of the hyoid bone before the operation was improved. The findings suggest that the degree of lowering of the hyoid bone may be an indicator of the improvement of AHI.

In Situ Investigation of Upper Airway Occlusion in Sleep Disordered Breathing Using Ultrasonic Transducer Arrays

This work presents a novel application of ultrasound for the real-time, non-invasive investigation of occlusion of the upper airway during events of obstructive sleep apnea/hypopnea syndrome. It is hypothesized that ultrasonic pulses applied to the neck during apneic events produce spectral and temporal features that can detect apnea occurrence. Theoretical models of ultrasound propagation and an in vitro test were conducted to test this hypothesis in both transmission and reflection modes. Complete specifications and technical details of the system design and fabrication, which is mounted on each subject's neck, are presented, including the methodology. Nine patients (seven male and two female, mean age of 42 years, with a range of 25 to 56 years, and body mass index 37.6 ± 6.6 kg/m²) were recruited for a full night study, which included simultaneous nocturnal polysomnography for the validation of the results. Nine temporal features and four spectral features were extracted from the envelope of the received pulse waveform. These were used to compute 26 metrics to quantify the changes in the ultrasonic waveforms between normal breathing and apneic events. The statistical analysis of the collected ultrasonic data showed that at least two or more of the proposed features could detect apneic events in all subjects. The findings establish the feasibility of the proposed method as a cost-effective and non-invasive OSAHS screening tool.

Retrospective evaluation of negative-pressure pulmonary edema in dogs (2006-2018): 35 cases

OBJECTIVE

To describe the clinical characteristics and outcomes in a population of dogs with negative-pressure pulmonary edema (NPPE) and to identify the main causes of the disease. To evaluate any associations with morbidity and mortality.

DESIGN

Retrospective study.

SETTING

Three university teaching hospitals and 2 private referral centers in the United Kingdom.

ANIMALS

Thirty-five client-owned dogs presented with NPPE.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: Data collected included patient characteristics, clinical history, clinicopathological abnormalities, radiographic features, treatments, and outcomes. The median age was 4 months (range 2-90) and median weight was 7.1 kg (range 1.7-37.2). There were many causes of NPPE including leash tugs, near hanging, accidental choking, anatomical obstruction to airflow, and purposeful airway obstruction by people. The most common cause of NPPE was accidental choking (40% of cases). Dogs with an anatomical obstruction were older than 24 months. Hypoxemia with an increased alveolar-arterial gradient was common on presentation. The majority of thoracic radiographs (65.7%) showed an alveolar or interstitial pattern in the caudodorsal area as previously described in the literature. Oxygen therapy was administered to 33 (94.3%) dogs. Furosemide was administered to 18 (51.4%) dogs. The median length of hospitalization was 2 days (range 0-14). Twenty-eight (80%) dogs survived to discharge. Seven dogs were mechanically ventilated and only 2 of them (28.6%) survived to discharge. The requirement for mechanical ventilation was the only parameter associated with mortality (P < 0.001).

CONCLUSIONS

Most cases of NPPE occur in juvenile dogs. Different incidents associated with upper airway obstruction can produce an episode of NPPE. Choking on food or toys and near hanging have not been previously described in the veterinary literature as inciting causes of NPPE. The overall prognosis is good.

The interaction of obesity and craniofacial deformity in obstructive sleep apnea

OBJECTIVE

Both obesity and craniofacial deformity are important etiologies of obstructive sleep apnea (OSA). The present research aimed to explore their interaction and different impacts on OSA severity.

METHODS

A total of 207 consecutive OSA patients (169 males, 38 females) were included in the research. Based on the body mass index (BMI) value, patients were divided into 77 normal-weight patients (BMI <24 kg m^-2), 105 overweight patients (24 ≤ BMI<28 kg m^-2) and 26 obese patients (BMI ≥28 kg m^-2). All accepted overnight polysomnography and standard lateral cephalogram. Cephalometric measurements involved 25 cephalometric variables. The correlations between these cephalometric variables, BMI and the apnea-hypopnea index (AHI) were evaluated.

RESULTS

For the whole sample after controlling for gender and age, stepwise regression analysis showed that the factors affecting AHI were increased BMI, narrowing posterior airway space, inferior displacement of hyoid and elongation of the tongue. When grouped by BMI, normal-weight group exhibited with more reduced maxillary length and mandible length, and steeper mandible plane than overweight and obese patients (p < 0.0167). Obese group showed least skeletal restriction and most prominent soft tissues enlargement (p < 0.0167). However, these skeletal indexes were not statistically correlated with AHI.

CONCLUSIONS

Obesity and skeletal malformations were both etiological factors of OSA, but obesity seemed to have a greater influence on AHI severity in all kinds of obese and thin OSA patients. Only in normal-weight group, it was affected by both cephalometric variables and BMI.

Correlation between short-time and whole-night obstruction level tests for patients with obstructive sleep apnea

Identification of obstructive level is crucial for successful surgical outcomes in patients with obstructive sleep apnea (OSA). Unfortunately, most of the dynamic airway evaluations are performed for a short duration under drug-induced sleep; therefore, it is uncertain whether they represent airway events that occur during a whole night of sleep. This study was aimed to evaluate the correlation between obstructive levels that were identified by a short-time and a whole-night test in patients with OSA. Total 101 patients with OSA underwent drug-induced sleep fluoroscopy (DISF) and pressure manometry (PM). For DISF, the obstructive pattern was classified into one of three groups: soft palate, tongue-based, and a combined obstruction. PM was used to measure the proportion of retroglossal events out of total whole-night obstructive events in each patient. The mean age of the patients was 43.8 years. The obstructive pattern was identified as soft palate in 56 patients, combined in 38 patients, and tongue-based in 7 patients following DISF. Results from PM showed that the mean percentage of retroglossal obstructive events was 31.2 ± 30.7%. The average proportion of retroglossal obstructive events that were identified by PM in patients with soft palate, combined, and tongue-based obstruction was 27.2%, 32.1%, and 59.0%, respectively (p = 0.033). There are limitations of evaluating obstructive events that occur during a whole night with short-time tests. Surgeons should be aware the possibility of disagreement in the obstructive level between short-time and whole-night tests.

Relationship between cephalometric parameters and the apnoea-hypopnoea index in OSA patients: a retrospective cohort study

OBJECTIVE

The purpose of this study was to assess the relationship between cephalometric parameters and apnoea-hypopnoea index (AHI) controlling for the effect of gender, age, and body mass index (BMI) on a large sample of patients with obstructive sleep apnoea (OSA).

METHODS

This retrospective cohort study was conducted on the lateral cephalograms of 253 Caucasian adult OSA patients. Cephalometric analyses were performed using 14 parameters for skeletal and soft tissue morphology, including antero-posterior and vertical jaw relationships, hyoid bone position, soft palate length and thickness, airway space, and tongue length and height. A hierarchical regression was run to examine the amount of variability in AHI that cephalometric variables explained after controlling for patients' general characteristics (gender, age, and BMI).

RESULTS

After controlling for gender, age, and BMI, the increase in AHI variance accounted for by cephalometric parameters was equal to 0.103. Among the cephalometric variables, only MP-H and PNS-P were statistically significant (P < 0.05).

LIMITATIONS

Given the retrospective nature of the study, it is difficult to assess whether other confounding variables not considered in the present study could have influenced the relationship between cephalometric parameters and AHI.

CONCLUSIONS

This study revealed the existence of a relationship between OSA severity and some cephalometric parameters. Indeed soft palate length and vertical position of the hyoid bone were significant predictors of AHI in adult Caucasian OSA patients.

Tracking Dynamic Tongue Motion in Ultrasound Images for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA), a breathing disorder characterized by repetitive collapse of the pharyngeal airway during sleep, can cause intermittent hypoxemia and frequent arousal. The evaluation of dynamic tongue motion not only provides the biomechanics and pathophysiology for OSA diagnosis, but also helps doctors to determine treatment strategies for these patients with OSA. The purpose of this study was to develop and verify a dedicated tracking algorithm, called the modified optical flow (OF)-based method, for monitoring the dynamic motion of the tongue base in ultrasound image sequences derived from controls and patients with OSA. The performance of the proposed method was verified by phantom and synthetic data. A common tracking method, the normalized cross-correlation method, was included for comparison. The efficacy of the algorithms was evaluated by calculating the estimated displacement error. All results indicated that the modified OF-based method exhibited higher accuracy in verification experiments. In the human subject experiment, all participants performed the Müller maneuver (MM) to simulate the contour changes of the tongue base with a negative pharyngeal airway pressure in sleep apnea. Ultrasound image sequences of the tongue were obtained during 10 s of a transition from normal breathing to the MM, and these were measured using the modified OF-based method. The results indicated that the displacement of the tongue base during the MM was larger in the controls than in the patients with OSA (p < 0.05); the calculated areas of the tongue in the controls and patients with OSA were 24.9 ± 3.0 and 27.6 ± 3.3 cm², respectively, during normal breathing (p < 0.05), and 24.7 ± 3.6 and 27.3 ± 3.8 cm², respectively, at the end of the MM. The percentage changes in the tongue area were 2.2% and 1.3% in the controls and patients with OSA, respectively. We found that quantitative assessment of tongue motion by ultrasound imaging is suitable for evaluating pharyngeal airway behavior in OSA patients with minimal invasiveness and easy accessibility.

The structural changes of pharyngeal airway contributing to snoring after orthognathic surgery in skeletal class III patients

BACKGROUND

Two-jaw surgery including mandibular and maxillary backward movement procedures are commonly performed to correct class III malocclusion. Bimaxillary surgery can reposition the maxillofacial bone together with soft tissue, such as the soft palate and the tongue base. We analyzed changes of pharyngeal airway narrowing to ascertain clinical correlations with the prevalence of snoring after two-jaw surgery.

METHODS

A prospective clinical study was designed including a survey on snoring and three-dimensional (3D) computed tomography (CT) in class III malocclusion subjects before and after bimaxillary surgery. We conducted an analysis on changes of the posterior pharyngeal space find out clinical correlations with the prevalence of snoring.

RESULTS

Among 67 subjects, 12 subjects complained about snoring 5 weeks after the surgical correction, and examining the 12 subjects after 6 months, 6 patients complained about the snoring. The current findings demonstrated the attenuation of the largest transverse width (LTW), anteroposterior length (APL), and cross-sectional area (CSA) following bimaxillary surgery given to class III malocclusion patients, particularly at the retropalatal level. The average distance of maxillary posterior movements were measured to be relatively higher (horizontal distance 3.9 mm, vertical distance 2.6 mm) in case of new snorers.

CONCLUSIONS

This study found that bimaxillary surgery could lead to the narrowing of upper airway at the retropalatal or retroglossal level as well as triggering snoring in subjects with class III malocclusion. Based on the current clinical findings, we also found that upper airway narrowing at retropalatal level may contribute to increasing the probability of snoring and that polysonography may need to be performed before orthognathic surgery in subjects with class III malocclusion.

Lateral teleradiography of the head as a diagnostic tool used to predict obstructive sleep apnea

OBJECTIVES

To (1) assess the relationship between obstructive sleep apnea (OSA) and craniofacial, pharyngeal anatomy and (2) to submit the recommendations for clinicians for increasing the sensitivity in the diagnostics of OSA.

METHODS

A review of the relevant literature linking OSA in adults with cephalometric analysis was performed. In total, 11 articles with similar procedural criteria were selected. The data were analysed using the Comprehensive Meta-Analysis Software (Biostat Inc., Englewood, NJ) and Statistica 12.0 (StatSoft Inc., Dell Software, Tulsa, OK).

RESULTS

Adults with OSA did not show statistically significant differences in the sagittal and vertical skeletal planes in comparison with the controls (p > 0.05). The patients with OSA had soft palate length, width and area increased accordingly by 4.21, 1.99 mm and 0.86 cm(2), tongue area increased by 2.02 cm(2), the upper posterior pharyngeal space (SPAS) and lower posterior pharyngeal space reduced accordingly by 4.53 and 1.32 mm, mandibular plane to the hyoid bone (MP-H) distance increased by 4.14 mm compared with the controls (p < 0.05). The SPAS parameter of the patients with OSA did not show statistically significant differences between the studies, with the mean value being 5.69 mm.

CONCLUSIONS

Analysed cephalometric data totally supported the concept of soft-tissue abnormalities in subjects with OSA, skeletal-only halfway; MP-H and SPAS being the most reliable parameters. Increased MP-H may serve as a predictor when differentiating normal subjects and patients with OSA. Reduced SPAS width could be a prognostic parameter for suspecting OSA. These two values should be kept in mind by dentists and can also be used as a simple auxiliary method by physicians; nevertheless, it is still underestimated and more studies are needed.

Assessment of Surgical Effects on Patients with Obstructive Sleep Apnea Syndrome Using Computational Fluid Dynamics Simulations

Obstructive sleep apnea syndrome is one of the most common sleep disorders. To treat patients with this health problem, it is important to detect the severity of this syndrome and occlusion sites in each patient. The goal of this study is to test the hypothesis that the cure of obstructive sleep apnea syndrome by maxillomandibular advancement surgery can be predicted by analyzing the effect of anatomical airway changes on the pressure effort required for normal breathing using a high-fidelity, 3-D numerical model. The employed numerical model consists of: 1) 3-D upper airway geometry construction from patient-specific computed tomographic scans using an image segmentation technique, 2) mixed-element mesh generation of the numerically constructed airway geometry for discretizing the domain of interest, and 3) computational fluid dynamics simulations for predicting the flow field within the airway and the degree of severity of breathing obstruction. In the present study, both laminar and turbulent flow simulations were performed to predict the flow field in the upper airway of the selected patients before and after maxillomandibular advancement surgery. Patients of different body mass indices were also studied to assess their effects. The numerical results were analyzed to evaluate the pressure gradient along the upper airway. The magnitude of the pressure gradient is regarded as the pressure effort required for breathing, and the extent of reduction of the pressure effort is taken to measure the success of the surgery. The description of the employed numerical model, numerical results from simulations of various patients, and suggestion for future work are detailed in this paper.

Submental ultrasound measurement of dynamic tongue base thickness in patients with obstructive sleep apnea

Dynamic tongue base thickness (TBT) may be an important anatomic factor in airway narrowing in patients with obstructive sleep apnea (OSA). The development of an accurate clinical assessment of the retroglossal airway in patients with OSA is still evolving. Submental ultrasound was used to investigate the association between measurements of TBT in response to negative airway pressure and the existence of OSA. Twenty OSA patients and 20 control participants underwent ultrasound measurement of TBT on eupneic breathing and with the Mueller maneuver, as well as clinical and polysomnographic assessments. Logistic regression analyses indicated that after adjustment for confounding factors, independent predictors of OSA included TBT in response to negative airway pressure, as measured by submental ultrasound with the Mueller maneuver (odds ratio: 2.11, 95% confidence interval: 1.15-3.87, p < 0.05), and the difference between TBT with the Muller maneuver and that without the Mueller maneuver (odds ratio: 2.47, 95% confidence interval: 1.09-5.58, p < 0.05). Ultrasound measurement of TBT during the Mueller maneuver provides a quantitative assessment of the retroglossal airway in OSA patients with minimal invasiveness and easy accessibility.

Real-time 3D magnetic resonance imaging of the pharyngeal airway in sleep apnea

PURPOSE

To investigate the feasibility of real-time 3D magnetic resonance imaging (MRI) with simultaneous recording of physiological signals for identifying sites of airway obstruction during natural sleep in pediatric patients with sleep-disordered breathing.

METHODS

Experiments were performed using a three-dimensional Fourier transformation (3DFT) gradient echo sequence with prospective undersampling based on golden-angle radial spokes, and L1-norm regularized iterative self-consistent parallel imaging (L1-SPIRiT) reconstruction. This technique was demonstrated in three healthy adult volunteers and five pediatric patients with sleep-disordered breathing. External airway occlusion was used to induce partial collapse of the upper airway on inspiration and test the effectiveness of the proposed imaging method. Apneic events were identified using information available from synchronized recording of mask pressure and respiratory effort.

RESULTS

Acceptable image quality was obtained in seven of eight subjects. Temporary airway collapse induced via inspiratory loading was successfully imaged in all three volunteers, with average airway volume reductions of 63.3%, 52.5%, and 33.7%. Central apneic events and associated airway narrowing/closure were identified in two pediatric patients. During central apneic events, airway obstruction was observed in the retropalatal region in one pediatric patient.

CONCLUSION

Real-time 3D MRI of the pharyngeal airway with synchronized recording of physiological signals is feasible and may provide valuable information about the sites and nature of airway narrowing/collapse during natural sleep.

Computational fluid dynamic analysis of the posterior airway space after maxillomandibular advancement for obstructive sleep apnea syndrome

PURPOSE

This study evaluated the soft tissue change of the upper airway after maxillomandibular advancement (MMA) using computational fluid dynamics.

MATERIALS AND METHODS

Eight patients with obstructive sleep apnea syndrome who required MMA were recruited into this study. All participants underwent pre- and postoperative computed tomography and then MMA by a single oral and maxillofacial surgeon. Upper airway computed tomographic datasets for these 8 patients were created with high-fidelity 3-dimensional numerical models for computational fluid dynamics. The 3-dimensional models were simulated and analyzed to study how changes in airway anatomy affect the pressure effort required for normal breathing. Airway dimensions, skeletal changes, apnea-hypopnea index, and pressure effort of pre- and postoperative 3-dimensional models were compared and correlations were interpreted.

RESULTS

After MMA, laminar and turbulent air flows were significantly decreased at every level of the airway. The cross-sectional areas at the soft palate and tongue base were significantly increased.

CONCLUSIONS

This study showed that MMA increased airway dimensions by increasing the distance from the occipital base to the pogonion. An increase of this distance showed a significant correlation with an improvement in the apnea-hypopnea index and a decreased pressure effort of the upper airway. Decreasing the pressure effort will decrease the breathing workload. This improves the condition of obstructive sleep apnea syndrome.

Magnetic resonance imaging in the evaluation of anatomical risk factors for pediatric obstructive sleep apnoea-hypopnoea: a pilot study

OBJECTIVE

Aim of our study was to identify anatomical risk factors involved in the development of pediatric OSAHS through a MRI-based case-control pilot study.

METHODS

MRI exams of the head and neck of 40 children affected by OSAHS were retrospectively evaluated. 25 indices referring to the air lumen, soft tissues and craniofacial skeleton were measured. Subsequently, the same process of measurement of indices was performed on MRI exams of 40 controls. For each index, then, we calculated in both groups mean, standard deviation, standard error and t value. Comparing the two series we finally calculated the degree of significance of each difference between children with OSAHS and controls through the Student's t-test.

RESULTS

Besides the expected and previously described differences of minimum retropharyngeal cross-sectional area (CSA), nasopharyngeal airway, combined upper airway volume, tonsillar and adenoid cross-sectional and volumetric indices, we found a higher midsagittal CSA of the soft palate and lower position of the hyoid bone, SNB angle and mandibular volume.

CONCLUSIONS

Results from our study population, certainly limited in terms of number of patients and considered age range, showed that not only adeno-tonsillar hypertrophy is important in determining the clinical syndrome: soft palate enlargement and certain skeletal pattern can even assume greater importance in the genesis and in the progression of the obstruction. MRI proved to be an accurate technique in the evaluation of the prevalent risk factor in children affected by OSAHS, leading to the most appropriate surgical approach.

Cephalometric analysis of modifications of the pharynx due to maxillo-mandibular advancement surgery in patients with obstructive sleep apnea

Cephalometry has been used to measure hard and soft facial tissues, as well as the pharyngeal air space for the diagnosis of obstructive sleep apnea (OSA). The changes occurring in the pharynx due to maxillo-mandibular advancement (MMA) have not been established or quantified. The objective of this study was to identify the anatomical changes of the pharynx and of hard tissues that occur in patients with OSA after MMA. 19 patients with a polysomnographic diagnosis of OSA were submitted to cephalometric analysis before and 6 months after surgery in order to evaluate the changes produced by MMA in the pharynx and soft tissues. Cephalometry was standardized in order to obtain descriptive measurements of the dimensions of the airways, the position of the hyoid bone, and maxilla-mandibular relations. The modifications of the pharynx due to MMA showed a significant relation obtained by cephalometry. For each millimeter of maxillary and mandibular bone advancement there was a 0.76mm increase in the retropalatal region and a 1.2mm increase in the pharynx in the retrolingual region. In addition, MMA promoted a significant repositioning of the hyoid bone in the cranial direction.

Subjective, anatomical, and functional nasal evaluation of patients with obstructive sleep apnea syndrome

BACKGROUND

Studies have shown a high occurrence of nasal alterations in patients with obstructive sleep apnea syndrome (OSAS), but no studies have used different methods to evaluate the nose of patients with OSAS. The objective of this study was to evaluate the nose of patients with OSAS, compare them to controls, and correlate the different methods used to evaluate the nose.

METHODS

Forty-seven patients with moderate/severe OSAS and 20 controls who were matched for gender, age, and body mass index were included. Questionnaires regarding sleep and nasal symptoms, physical examination, rhinoscopy, nasofibroscopy, nasal inspiratory peak flow (NIPF), and acoustic rhinometry (AR) measurements were performed.

RESULTS

In the OSAS group, 33 (70.2%) were male, with a mean age of 53.2 ± 9.1 years. In the control group, 13 (65%) were male, with a mean age of 53.7 ± 9.7 years. The OSAS group had a higher score on the nasal symptoms scale (p < 0.01) and a higher frequency of nasal alterations [presence of septal deviation, clinical complaints (p = 0.01) and hypertrophy of the inferior nasal turbinate (p < 0.01)]. The NIPF and AR parameters could not differentiate between the OSAS and control groups. There were no significant correlations among the different methods used to evaluate the nose. Lower NIPF values were capable of predicting higher apnea-hypopnea index scores (p = 0.007).

CONCLUSION

Clinical complaints and nasal alterations as measured by rhinoscopy and nasofibroscopy were associated with the presence of OSAS, which was not the case for the NIPF and AR parameters. The results of different evaluation methods were not correlated with each other.

Does drug-induced sleep endoscopy change the treatment concept of patients with snoring and obstructive sleep apnea?

PURPOSE

Success rates of non-ventilation therapies for sleep disordered breathing (SDB) remain hardly acceptable. Drug-induced sleep endoscopy (DISE) tends to show the level and mechanism of obstruction and helps to specify therapy individually. Therefore, increasing success rates are expected. The objective of this study is to detect whether locations of treatment recommendations given after DISE are different to those made after clinical basic ENT (ear, nose, throat) examination (CBE).

METHODS

This study included patients with obstructive sleep apnea (OSA) and primary snoring who wish or require an alternative therapy to the gold standard, continuous positive airway pressure (CPAP). After CBE, a theoretical treatment recommendation was given comprising surgery (possible surgical target: soft palate, tonsils, tongue base, epiglottis) and mandibular advancement splints (MAS) or both. A second ENT specialist conducted a DISE and independently recommended a second therapy concept without knowing the first one. A third person compared both theoretical locations of treatment recommendations (CBE vs. DISE).

RESULTS

A total of 97 patients (eight female and 89 male, age 30-85 years, AHI 1.9-88.6/h, body mass index [BMI] 20.3-36.3 kg/m²) received two therapy recommendations. Regarding surgical options only, 63.9% of the examined patients got a different recommendation in at least one of four levels. If MAS was included, a change was found in 78.4% of the patients. Subdivided into each type of intervention, the following changes were found in the therapy concept: 24.7% (n = 24/97) soft palate, 12.4% (n = 12/97) tonsils, 33.0% (n = 32/97) tongue base, 27.8% (n = 27/97) epiglottis, 38.1% (n = 37/97) MAS.

CONCLUSIONS

DISE shows a relevant influence on the location of treatment recommendation. Thus, a change in success rates of non-CPAP therapy in OSA and snoring appears possible.

Patient-Specific Geometry Modeling and Mesh Generation for Simulating Obstructive Sleep Apnea Syndrome Cases by Maxillomandibular Advancement

The objective of this paper is the reconstruction of upper airway geometric models as hybrid meshes from clinically used Computed Tomography (CT) data sets in order to understand the dynamics and behaviors of the pre- and postoperative upper airway systems of Obstructive Sleep Apnea Syndrome (OSAS) patients by viscous Computational Fluid Dynamics (CFD) simulations. The selection criteria for OSAS cases studied are discussed because two reasonable pre- and postoperative upper airway models for CFD simulations may not be created for every case without a special protocol for CT scanning. The geometry extraction and manipulation methods are presented with technical barriers that must be overcome so that they can be used along with computational simulation software as a daily clinical evaluation tool. Eight cases are presented in this paper, and each case consists of pre- and postoperative configurations. The results of computational simulations of two cases are included in this paper as demonstration.

Short daytime ApneaGraph for initial case selection of obstructive sleep apnea-hypopnea syndrome before surgery

The aim of this study was to determine whether the 2-h daytime ApneaGraph (dAG) for patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) can be used initially to diagnose and identify the site of obstruction before surgery. Fifty patients with OSAHS diagnosed by polysomnogram were enrolled in this prospective study. Sleep-related parameters, which include the indices for apnea-hypopnea (AHI), apnea index (AI), obstructive, central and mixed AHI (OAHI, CAHI and MAHI, respectively), the lowest oxygen saturation (LSaO₂) and the proportion of upper and lower airway obstruction (UPPER and LOWER, respectively), were measured by both daytime and nocturnal AG (nAG). Different operative techniques were used according to the obstruction site assessed by the nAG. Clinical outcomes were assessed with the Epworth Sleepiness Scale (ESS), visual analog scale (VAS), AI, AHI and LSaO₂. All the indices except LSaO₂ found no significant differences between dAG and nAG; there were significant positive correlations with regard to most indices, but not for CAHI between dAG and nAG. When compared dAG with nAG, most moderate and severe patients had predominant sites of obstructions in the upper level. Postoperative ESS, VAS, AI and AHI decreased significantly, while LSaO₂ significantly increased compared with those preoperative counterparts. dAG may be used as an alternative means for early and low-cost diagnostic evaluation of OSAHS before surgery.

Craniofacial variables in subjects with and without habitual snoring: A cephalometric comparison

OBJECTIVE

The aim of this case control study was to evaluate which cephalometric variables related to craniofacial morphology discriminate between snoring and non-snoring or any other respiratory disease subjects.

MATERIALS AND METHODS

Total 42(21 snoring and 21 non-snoring) cephalometric measurements were determined to study the craniofacial morphology. Non-snoring subjects were matched to snoring subjects by age, sex, and body mass index. Snoring was assessed using a sleep behavior questionnaire administered to the patients. The cephalometric radiographs of the study subjects were traced by a single investigator, and 1 angular measurement and 13 linear measurements of hard and soft tissues were recorded. The paired Student's t test was used to analyze the cephalometric data.

RESULTS

Vertical position of the hyoid (MP-H) was significantly longer (P<0.05) in snoring subjects (23.44±14.892mm) than non-snoring subjects (12.89±4.540mm). Anterior overbite and anterior over-jet of snoring group ((4.81± 3.265 and 5.83±8.59) were significantly higher (P<0.05) than non-snoring group (0.67±1.441 and 0.54±1.138). No significant differences of the other [11] cephalometric variables were found within groups.

CONCLUSION

Snoring subjects appear to present craniofacial factors that differ from those of non-snoring subjects, and we suggest obtaining cephalogram for diagnosis and following up of them.

Differences of Upper Airway Morphology According to Obesity: Study with Cephalometry and Dynamic MD-CT

Objectives

We investigated difference of parameters of polysomnography, cephalometry and dynamic multi-detector computerized tomography (MD-CT) in wake and sleep states according to obesity.

Methods

We evaluated 93 patients who underwent polysomnography and cephalometry. MD-CT was performed in 68 of these 93 patients. Fifty-nine and 34 patients were classified as obese and non-obese, with obesity defined as BMI ≥25. Cephalometry results were analyzed for 12 variables. Using the MD-CT, we evaluated dynamic upper airway morphology in wake and sleep states and divided the upper airway into four parts named as high retropalatal (HRP), low retropalatal (LRP), high retroglossal (HRG), and low retroglossal (LRG). A minimal cross sectional area (mCSA) and collapsibility index (CI) were calculated for each airway level.

Results

Diastolic blood pressure (P=0.0005), neck circumference (P<0.0001), and apnea-hypopnea index (P<0.0001) were statistically significantly different between the obese and non-obese group. Among 12 cephalometric variables, there was a significant difference in only the distance from mandibular plane to hyoid bone (P=0.003). There was statistical difference in CI of HRG and LRG in sleep state (P=0.0449, 0.0281) but no difference in mCSA in wake and sleep states.

Conclusion

The obese group had more severe sleep apnea than the non-obese group. We believe that the increased severity of apnea in the obese group may be have been due to increased collapsibility of the upper airway rather than decreased size of the upper airway.

Effect of an intra-oral nasal dilation appliance on 3-D nasal airway morphology in adults

To determine the effects of a nasal dilation appliance on 3-D nasopharyngeal airway patency. The sample comprised 187 adults (98 males, 89 females) with a history of sleep-disordered breathing. Acoustic rhinometry readings were taken from all patients before and after the intra-oral placement of a nasal dilation appliance (OASYS). The mean left and right nasopharyngeal airways were reconstructed in 3-D, and the data from the right and left nostrils were subjected to principal components analysis (PCA) and finite-element scaling analysis (FESA). Comparing the pre- and post-treatment 3-D mean, left nasopharyngeal airways using PCA, the first two eigenvalues accounted for 96% of the total shape change, and statistical differences were found (p < 0.01). Similarly, for the right side, significant differences were detected between the mean pre- and post-treatment 3-D nasopharyngeal airways (p < 0.01) using PCA. Using FESA to quantify and localize changes after the placement of the nasal dilation appliance, the 3-D mean, normalized, left nasopharyngeal airway was found to be 14% wider in the anterior nasal valve region and 28% wider in the distal regions, while the 3-D mean, normalized, right nasopharyngeal airway was 13% wider in the anterior nasal valve region and 27% wider further distally. The use of an intra-oral nasal dilation appliance may be useful in the management of nasopharyngeal conditions, such as snoring, upper airway resistance syndrome, sleep-disordered breathing, and obstructive sleep apnea, especially in cases where nasal obstruction is demonstrable.

Tongue base ultrasound: a diagnostic tool for predicting obstructive sleep apnea

OBJECTIVES

We assessed the value of an ultrasound (US) examination in the diagnostic workup of patients with sleep-related breathing disorders by correlating US measurements with known parameters for the presence and severity of obstructive sleep apnea.

METHODS

Forty-one male patients who complained of snoring and/or daytime somnolence participated. The diagnostic protocol included history-taking, physical examination, polysomnography, and transcervical US examination of the tongue. The US results were compared with all of the other parameters.

RESULTS

The US imaging was reliable for demonstrating anatomic structures of the tongue base, discriminating between muscle, mucosa, and blood vessels. The lingual arteries were clearly visualized entering the tongue base at its lower lateral borders. There was a significant relationship between the severity of sleep-related breathing disorders (measured by polysomnography) and the width of the lower tongue base (measured as the distance between the lingual arteries). The distance between the lingual arteries also correlated with physical examination findings and patient complaints of daytime somnolence and the sensation of choking during the night.

CONCLUSIONS

Tongue base width, measured by US, may influence the severity of obstructive sleep apnea. This is the first demonstration of the possible role of US examination, an inexpensive, noninvasive, and non-irradiating office procedure, in the diagnostic workup for sleep-related breathing disorders.

Use of Muller's maneuver in the evaluation of patients with sleep apnea - literature review

Sleep apnea-hypopnea syndrome was described twenty years ago, and since then there have been doubts and controversies regarding it. Fiberoptic nasopharyngoscopy with Muller's maneuver, first described by Borowieck and Sassin (1983), is among them.

Aim

Careful literature review on Muller's maneuver, regarding whether it can predict the sucess of uvulopalatopharyngoplasty, location of upper airway obstruction and severity of the disorder.

Discussion and literature rewiew

Literature has shown that there isn't a consensus about the use of Muller's maneuver. In spite of being technically easy, inexpensive and widely used, it is very unespecific and subjective.

Conclusion

The importance of Muller's maneuver in evaluating apneic patients has been questioned, because there are controversies whether it can predict the sucess of uvulopalatopharyngoplasty, location of upper airway obstruction and severity of the disease.

Combination of Bernouilli effect producing maneuver-induced pharyngeal narrowing rate with body mass index as predictive tool for obstructive sleep apnea syndrome

CONCLUSIONS

It is suggested that the combination of the pharyngeal narrowing rate during the Bernouilli effect producing maneuver (BEPM) with the body mass index (BMI) might be a promising predictive method for obstructive sleep apnea syndrome (OSAS).

OBJECTIVES

An attempt was made to clarify the possibility that the dynamic narrowing of the pharynx evaluated by nasopharyngoscopy with BEPM, a forced inspiration through the nose with the mouth closed, might be a reliable clinical daytime predictor for identifying patients at risk of developing OSAS.

SUBJECTS AND METHODS

Subjects were 57 patients complaining of snoring and sleepiness during daytime. Endoscopic images of the retropalatal pharynx were obtained and their area was measured by NIH imaging. The pharyngeal narrowing rate during quiet nasal breathing and that during BEPM were compared to assess pharyngeal dynamics. To increase the sensitivity of this method, BMI was added to the pharyngeal narrowing rate during BEPM.

RESULTS

The criterion of BEPM at a cut-off value of 50% with BMI at a cut-off value of 25 kg/m(2) achieved a sensitivity of 93%, while the specificity was 67% in differentiating simple snorers from OSAS patients (apnea index >5). In addition, the likelihood ratio of the method was found to be 2.81.

Palatal implants for the treatment of snoring and obstructive sleep apnea/hypopnea syndrome

OBJECTIVE

Randomized, double-blinded, placebo-controlled, clinical trial to determine the effectiveness of palatal implants for treatment of mild/moderate obstructive sleep apnea/hypopnea syndrome (OSAHS).

STUDY DESIGN AND SETTING

Sixty-two non-obese adults with history of snoring, daytime sleepiness, and mild/moderate OSAHS, were randomized to receive palatal implants (n = 31) or placebo procedure (n = 31). Complete follow-up including quality of life (QOL, SF-36), snoring visual analog scale (VAS), and Epworth Sleepiness Scale (ESS) data were obtained in 62 patients. Seven patients refused follow-up polysomnography for a total of 55 patients (29 implant and 26 placebo).

RESULTS

The treatment group (change in score of -7.9 +/- 7.7) was significantly improved compared with the placebo group (change in score of 0.9 +/- 4.3) for apnea/hypopnea index (AHI) (P < 0.0001), QOL, SF-36 (P < 0.0001), snoring VAS (P < 0.0001), and ESS (P = 0.0002).

CONCLUSIONS

Palatal implants improve AHI, QOL, snoring intensity, and daytime sleepiness for selected patients with mild/moderate OSAHS.

Use of a sibilant phoneme registration protocol to prevent upper airway collapse in patients with TMD

Patients with temporomandibular dysfunction (TMD) require antero-posterior (AP) correction of mandibular position inter alia. Determination of the limit of the AP correction using a sibilant phoneme registration (SPR) protocol is essential in not increasing muscular tonus. The aim of this study is to investigate the effect of a SPR protocol on the upper airway. Using acoustic pharyngometry data, mean airways of 46 adults undergoing treatment for TMD were reconstructed in 3-D and analyzed using finite element analysis and principal components analysis. When the mean baseline functional residual capacity (FRC) airway was compared to the mean collapsed residual volume (RV) airway, a 25% reduction in the 3-D upper airway was demonstrable (p < 0.01). When the mean baseline FRC airway was compared to the mean airway with SPR (FRC-SPR), a 12% increase was found at the oropharyngeal junction of the 3-D airway, but this finding failed to reach statistical difference. Similarly, when the mean FRC-SPR airway was compared to the mean RV-SPR airway, the amount of collapse was reduced to 16% but again no statistical difference was found. In contrast, when the mean RV airway was compared to the mean RV-SPR airway, a 15-18% increase was found (p < 0.05). It is concluded that the use of a SPR protocol may be useful in improving upper airway RV in patients, during treatment for TMD.

Dental appliance treatment for obstructive sleep apnea

Oral appliances for the treatment of obstructive sleep apnea (OSA) are worn during sleep to maintain the patency of the upper airway by increasing its dimensions and reducing its collapsibility. Oral appliances are a simpler alternative to continuous positive airway pressure (CPAP). Over the last decade, there has been a significant expansion of the evidence base to support the use of oral appliances, with robust studies demonstrating their efficacy. This work has been underpinned by the recognition of the importance of upper airway anatomy in the pathophysiology of OSA. The updated practice parameters of the American Academy of Sleep Medicine now recommend their use for mild-to-moderate OSA, or for patients with severe OSA who are unable to tolerate CPAP or refuse treatment with CPAP. Oral appliances have been shown to have a beneficial impact on a number of important clinical end points, including the polysomnographic indexes of OSA, subjective and objective measures of sleepiness, BP, aspects of neuropsychological functioning, and quality of life. Elucidation of the mechanism of action of oral appliances has provided insight into the factors that predict treatment response and may improve the selection of patients for this treatment modality. Longitudinal studies to characterize the long-term adverse effects of oral appliance use are now beginning to emerge. Although less efficacious than CPAP for improving the polysomnographic indexes of OSA, oral appliances are generally preferred by patients. This has the potential to translate to better patient adherence and may provide an equivalent health outcome.

Obstructive site localization using multisensor manometry versus the Friedman staging system in obstructive sleep apnea

The aim of this study was to find the correlation between an anatomy-based staging system and pressure manometry performed during sleep. A retrospective study of 45 patients with obstructive sleep apnea (OSA) was carried out. All patients were evaluated by polysomnography, and obstruction sites were localized using a multisensor manometer during the full night. Obstruction sites were classified into retropalatal and retroglossal. The patients were also staged by anatomic findings of tonsil size and palate position. The % retroglossal obstruction was 29.4, 33.5 and 48.6% in stages I, II and III, respectively. There was no significant difference between stages. In contrast, when compared according to the Friedman tongue position (FTP), the mean % retroglossal obstruction of FTP grade 3 was significantly higher than that of FTP grade 1 (P = 0.009) although apnea hypopnea index, body mass index and lowest SpO2 were not different among FTP grades. It seems that FTP correlates with retroglossal obstruction and may be used to select patients in need of retroglossal modification of the airway.

The effect of pharyngeal soft tissue components on snoring

OBJECTIVE

To determine the effect of oropharyngeal air column area, parapharyngeal fat pad thickness, pterygoid muscle thickness, and parapharyngeal wall thickness on snoring.

MATERIALS AND METHODS

Fifty-six individuals (35 men, 21 women) complaining of snoring in a questionnaire administered to patients attending the MR unit for cervical MR imaging were enrolled as the study group, and 39 (23 men, 16 women) individuals with no complaint of snoring were enrolled as the control group. Firstly, patients' body mass index (BMI) was determined. Then turbo spin echo T2-weighted MR imaging in the axial plane was performed, from the nasopharynx to the hyoid bone level, in both groups. From the MR images, oropharyngeal air column area, parapharyngeal fat pad thickness, pterygoid muscle thickness and parapharyngeal wall thickness measurements were made. Finally, the results were statistically analysed using SPSS (Statistical Package for Social Sciences) for Windows 10.0. Student's t-test was used as a complementary method in the analysis of the study data. The correlations between BMI and parapharyngeal wall thickness, and BMI and oropharyngeal air column area were determined by Pearson's correlation analysis.

RESULTS

No statistically significant difference was found between study and control groups in terms of mean age, pterygoid muscle thickness, or pharyngeal fat pad thickness (P>.05). Snorers' BMI levels (P<.01) and average parapharyngeal wall thicknesses (P<.05) were statistically significantly higher than those of the control subjects. Snorers' oropharyngeal air column area was significantly narrower than that of the control subjects, statistically (P<.01).

CONCLUSION

As a result of the study, it was concluded that only oropharyngeal air column area and parapharyngeal muscle thickness had an effect on snoring.

Anwendung eines chirurgischen Multi-Level-Konzepts bei obstruktiver Schlafapnoe

BACKGROUND

Obstructive sleep apnea syndrome is a "systemic disease" of the upper airways and the upper digestive tract. The concept of multilevel surgery takes account of the fact that the location of the obstruction frequently cannot be identified precisely.

PATIENTS AND METHODS

In this retrospective study over 4 years, data on 25 patients (median age 49.9 years) with moderate to severe OSAS treated with a surgical multilevel therapy were statistically evaluated. The treatment carried out consisted in reduction of the inferior turbinate, if necessary combined with septum plasty, and conventional uvulopalatopharyngoplasty (UPPP), combined with tonsillectomy and radiofrequency therapy of the base of the tongue if appropriate. Pre- and postoperative clinical and polysomnographical checks were performed.

RESULTS

The mean apnea-hypopnea index (AHI) was 39.2+/-19.7/h before surgery. Postoperatively a highly significant reduction of AHI to 16.5+/-9.9/h (p<0.0001) was seen. In 13 out of 25 patients (52%) the disease was cured (AHI<20 and 50% reduction). In 23 patients the AHI improved. In 15 patients AHI was reduced by more than 50%.

CONCLUSION

Multilevel surgery should be considered as an alternative for patients suffering from OSAS, especially in view of the poor long-term results in patients who receive CPAP therapy or are intolerant to CPAP.

Acoustic rhinometry in the practice of allergy

OBJECTIVE

To provide a comprehensive practical overview of the use of acoustic rhinometry in the practice of allergy.

DATA SOURCES

An all-inclusive PubMed search was conducted for articles on acoustic rhinometry that were published in peer-reviewed journals, between 1989 and 2006, using the keywords acoustic rhinometry, allergic rhinitis, and nasal provocation testing.

STUDY SELECTION

The expert opinion of the authors was used to select studies for inclusion in this review.

RESULTS

Acoustic rhinometry is a sound-based technique used to measure nasal cavity area and volume. It has been validated by comparison to measurements with computed tomography and magnetic resonance imaging. Acoustic rhinometry requires minimal patient cooperation and may be used in adults, children, and infants. It is used by medical practitioners to diagnose and evaluate therapeutic responses in conditions such as rhinitis and to measure nasal dimensions during allergen provocation testing. Acoustic rhinometry also provides a visual reflection of the nasal response to therapy, which may be useful in increasing compliance to prescribed medications.

CONCLUSIONS

Acoustic rhinometry is a safe, noninvasive, objective, and validated measure of nasal obstruction that appears to be of practical use in the diagnosis and management of inflammatory diseases of the upper airways.

Endoscopic evaluation of dynamic narrowing of the pharynx by the Bernouilli effect producing maneuver in patients with obstructive sleep apnea syndrome

OBJECTIVE

To evaluate the dynamic narrowing of the retropalatal pharynx by the Bernouilli effect producing maneuver (BEPM) in patients with obstructive sleep apnea syndrome (OSAS) with computer-assisted analysis of nasopharyngoscopic images.

METHODS

Endoscopic images of the retropalatal pharynx were obtained and their area was measured by NIH imaging. Because changes in distance between the CCD camera of the nasopharyngoscope and the site of pharyngeal narrowing decreased the measurement reliability, the area of the retropalatal pharynx was divided by the square of the uvula's lateral side length for normalization. We calculated both normalized areas: the pharyngeal narrowing during quiet nasal breathing and that during BEPM, which is a forced inspiration through the nose with the mouth closed. The narrowing rate was then calculated as an index of the pharyngeal dynamics.

RESULTS

Nasopharyngoscopy combined with BEPM showed a medial motion of the lateral walls of the pharynx due to the Bernoulli effect, which is an increase in speed and a reduction in pressure of a moving gas passing through a tube constriction. There was a significant correlation between the narrowing rate of the retropalatal pharynx and the apnea index. The decrease in intraluminal pressure at the narrowing combined with the higher atmospheric pressure exercised on the lateral pharyngeal walls would induce the pharyngeal collapse. There was also a significant correlation between the normalized retropalatal are and the apnea index.

CONCLUSION

Nasopharyngoscopy with BEPM suggest that in addition to the static narrowing, the dynamic narrowing of the retropalatal pharynx contributes to the pathophysiology of OSAS. The correlation between the apnea index and both the normalized retropalatal area and the narrowing rate of the retropalatal pharynx due to the Bernoulli effect constitute a quantitative and predictive alternative to the evaluation and understanding of the upper airways changes in OSAS.