Site Of Upper Airway Obstruction Research Articles

Differences in salivary microbiome among children with tonsillar hypertrophy and/or adenoid hypertrophy.

Children diagnosed with severe tonsillar hypertrophy display discernible craniofacial features distinct from those with adenoid hypertrophy, prompting illuminating considerations regarding microbiota regulation in this non-inflammatory condition. The present study aimed to characterize the salivary microbial profile in children with tonsillar hypertrophy and explore the potential functionality therein. A total of 112 children, with a mean age of 7.79 ± 2.41 years, were enrolled and divided into the tonsillar hypertrophy (TH) group (n = 46, 8.4 ± 2.5 years old), adenoid hypertrophy (AH) group (n = 21, 7.6 ± 2.8 years old), adenotonsillar hypertrophy (ATH) group (n = 23, 7.2 ± 2.1 years old), and control group (n = 22, 8.6 ± 2.1 years old). Unstimulated saliva samples were collected, and microbial profiles were analyzed by 16S rRNA sequencing of V3-V4 regions. Diversity and composition of salivary microbiome and the correlation with parameters of overnight polysomnography and complete blood count were investigated. As a result, children with tonsillar hypertrophy had significantly higher α-diversity indices (P＜0.05). β-diversity based on Bray-Curtis distance revealed that the salivary microbiome of the tonsillar hypertrophy group had a slight separation from the other three groups (P＜0.05). The linear discriminant analysis effect size (LEfSe) analysis indicated that Gemella was most closely related to tonsillar hypertrophy, and higher abundance of Gemella, Parvimonas, Dialister, and Lactobacillus may reflect an active state of immune regulation. Meanwhile, children with different degrees of tonsillar hypertrophy shared similar salivary microbiome diversity. This study demonstrated that the salivary microbiome in pediatric tonsillar hypertrophy patients had different signatures, highlighting that the site of upper airway obstruction primarily influences the salivary microbiome rather than hypertrophy severity.IMPORTANCETonsillar hypertrophy is the most frequent cause of upper airway obstruction and one of the primary risk factors for pediatric obstructive sleep apnea (OSA). Studies have discovered that children with isolated tonsillar hypertrophy exhibit different craniofacial morphology features compared with those with isolated adenoid hypertrophy or adenotonsillar hypertrophy. Furthermore, characteristic salivary microbiota from children with OSA compared with healthy children has been identified in our previous research. However, few studies provided insight into the relationship between the different sites of upper airway obstruction resulting from the enlargement of pharyngeal lymphoid tissue at different sites and the alterations in the microbiome. Here, to investigate the differences in the salivary microbiome of children with tonsillar hypertrophy and/or adenoid hypertrophy, we conducted a cross-sectional study and depicted the unique microbiome profile of pediatric tonsillar hypertrophy, which was mainly characterized by a significantly higher abundance of genera belonging to phyla Firmicutes and certain bacteria involving in the immune response in tonsillar hypertrophy, offering novel perspectives for future related research.

Advanced Diagnostic Techniques in Obstructive Sleep Apnea

Optimal surgical and medical management of obstructive sleep apnea (OSA) requires clinically reliable identification of patterns and sites of upper airway obstruction. A wide variety of modalities has been used to evaluate upper airway obstruction. Drug-induced sleep endoscopy (DISE) and cine MRI are increasingly used to identify upper airway obstruction sites, to characterize airway obstruction patterns, to determine optimum medical and surgical treatment, and to plan individualized surgical management. Here, the authors provide an overview of the applications of DISE and cine MRI in assessing upper airway obstruction in children and adults with OSA.

Role of ApneaGraph® in the Surgery for Obstructive Sleep Apnoea.

To evaluate the utility of ApneaGraph® AG 200 in diagnosing Obstructive Sleep Apnoea (OSA) as compared to Polysomnography, localization of the site of upper airway obstruction, and the success rate of surgery. A prospective study was conducted including fifteen patients of OSA undergoing surgical treatment. All patients underwent sequential overnight ApneaGraph (AG) and Polysomnogram (PSG) before and after 3 months following surgery. The preoperative and post-operative Apnoea-Hypopnoea Index (AHI) values were compared between AG and PSG. The success of surgery was defined as mean reduction in AHI by ≥ 50% and post-operative AHI < 20. The mean preoperative AHI using PSG was 53.7 and using AG was 44.9 (r = 0.83, p = 0.0001). All patients underwent AG-directed site-specific surgery. The mean postoperative AHI using PSG was 15.3 and using AG was 13.8 (r = 0.67, p = 0.0062). There was significant improvement in AHI post-surgery (p < 0.05, AG & PSG). The surgical success was achieved in 93.3%. The median follow-up was 14 months. ApneaGraph is a reliable alternative to PSG to diagnose OSA with an added advantage to localize the site of obstruction, yielding good surgical outcomes.

Treatment strategies for orofacial myofunctional disorders and malocclusions associated with different sites of upper airway obstruction in children

The impact of respiratory function on children's craniofacial growth has received increasing attention from orthodontists and parents. There is a higher pediatric sleep-disordered breathing risk prevalence in the orthodontic population compared with a general population sample, and orthodontic practitioners need to pay close attention to the respiratory function of their pediatric patients. For children with upper airway obstruction and related dentofacial and functional abnormalities, clinicians should comprehensively consider the site and severity of upper airway obstruction, the clinical feature of malocclusion and other factors to develop an individual, multidisciplinary treatment plan, providing favorable conditions for the development of the children's craniofacial morphology and the whole body.

Sound frequency spectra of snore in relation to the site of obstruction among snorers.

SUMMARYObjectiveThis study aimed to describe the sound frequency of snoring in relation to the site of upper airway vibration among snorers.Methods383 snores from 40 participants who complained of snoring were digitally recorded during natural and induced sleep using a level III polysomnography monitor with a built-in microphone. During drug-induced sleep endoscopy (DISE), the real-time site of upper airway obstruction was assessed, and the sound frequency of snoring was recorded synchronously.ResultsThe mean peak of snoring frequency for unilevel palatal, oropharynx and epiglottis obstruction were 522.5, 482.4 and 300.0 Hz, respectively. Most participants showed multilevel obstruction at the palate and oropharynx, in which the mean for bi-peak snoring frequency were 402.90 Hz and 1086.96 Hz, respectively. Severity of OSA was significantly associated with multilevel obstruction.ConclusionsThere was a significant association between the snoring sound frequency and site of unilevel obstruction. Palatal or oropharyngeal obstruction produced sound at mid-frequency range, while the epiglottis produced a low frequency range. Multilevel obstruction documented a bi-peak snoring frequency.

Real-time prediction of upcoming respiratory events via machine learning using snoring sound signal.

The aim of the study was to inspect the acoustic properties and sleep characteristics of a preapneic snoring sound. The feasibility of forecasting upcoming respiratory events by snoring sound was also investigated. Participants with habitual snoring or a heavy breathing sound during sleep were recruited consecutively. Polysomnography was conducted, and snoring-related breathing sound was recorded simultaneously. Acoustic features and sleep features were extracted from 30-second samples, and a machine learning algorithm was used to establish 2 prediction models. A total of 74 eligible participants were included. Model 1, tested by 5-fold cross-validation, achieved an accuracy of 0.92 and an area under the curve of 0.94 for respiratory event prediction. Model 2, with acoustic features and sleep information tested by Leave-One-Out cross-validation, had an accuracy of 0.78 and an area under the curve of 0.80. Sleep position was found to be the most important among all sleep features contributing to the performance of the 2 models. Preapneic sound presented unique acoustic characteristics, and snoring-related breathing sound could be deployed as a real-time apneic event predictor. The models, combined with sleep information, serve as a promising tool for an early warning system to forecast apneic events. Wang B, Yi X, Gao J, etal. Real-time prediction of upcoming respiratory events via machine learning using snoring sound signal. J Clin Sleep Med. 2021;17(9):1777-1784.

Correlation between the transverse dimension of the maxilla, upper airway obstructive site, and OSA severity.

Acquiring a better comprehension of obstructive sleep apnea physiopathology can contribute to improving patient selection for surgical treatments. We hypothesize that maxillary transverse deficiency restricts the space available for the tongue, leading to upper airway obstruction during sleep. Our primary hypothesis was that maxillary transverse deficiency increases the prevalence of tongue collapse during drug-induced sleep endoscopy (DISE). The secondary hypothesis was that maxillary transverse deficiency will also increase the prevalence of circumferential collapse at the velopharynx. The exploratory hypothesis was that maxillary transverse deficiency is associated with increased obstructive sleep apnea severity. The objectives of this study were to correlate maxillary morphometric measurements with (1) the anatomic level of obstruction during DISE and (2) the apnea-hypopnea index on polysomnography. We made a cross-sectional analysis of patients with obstructive sleep apnea undergoing DISE in search of positive airway pressure alternative treatment. Maxillary measurements were collected from a computed tomography scan (interpremolar distance, intermolar distance [IMD] and sella-nasion A point angle), findings from DISE, and sleep study variables from polysomnography. Correlation between computed tomography, DISE, and polysomnography data was assessed using Pearson's correlation, and receiver operating characteristic curves were determined for each facial measurement. Sixty-nine patients were included in the study. The group with velopharyngeal circumferential collapse had mean IMD = 26.30 mm (25.5-31.45), and the group with anteroposterior collapse had mean IMD = 29.20 mm (26.8-33.10; P = .040). The group with complete tongue-base obstruction had mean interpremolar distance = 26.40 mm (25.1-28) and IMD = 26.30 mm (25.6-28.4), and the group without obstruction had mean interpremolar distance = 28.7 mm (27.2-30; P = .003) and IMD = 34.06 mm (32.1-37; P < .001). The receiver operating characteristic curve determined an IMD cutoff of 29.8 mm for predicting tongue-base obstruction. The maxillary transverse deficiency, identified by reduction in interpremolar distance and IMD, predicted the occurrence of complete tongue-base obstruction, complete concentric collapse at the velopharynx, and multilevel obstruction during DISE. We did not find an association between the maxillary measurements and obstructive sleep apnea severity. These associations hold some promise in ultimately supplanting insights previously available only through DISE.

Surgical treatment of epiglottis collapse in obstructive sleep apnoea syndrome: epiglottis stiffening operation.

SUMMARYThe epiglottis is an important structure that was largely ignored in early research on obstructive sleep apnoea/hypopnoea syndrome (OSAHS). Primary epiglottis collapse (EC) in patients with OSAHS is difficult to treat with conservative therapies, such as oral appliances and CPAP. Therefore, surgical treatment may represent a good option when dealing with EC, although up to now no standardised surgical procedures have been described. Herein, we describe a new surgical procedure that we called “epiglottis stiffening operation” (ESO); the technique is safe, devoid of complications, easy to perform and is effective in treatment of primary EC, which presents as a single or coexistent site of upper airway obstruction without altering fundamental functions of the epiglottis.

Pulmonary function test in upper airway obstruction: a simple yet effective diagnostic test

Upper airway obstruction (UAO) is a dangerous condition that is associated with significant mortality. It is easily diagnosed when its presentation is acute, but subacute or chronic presentation may pose a diagnostic dilemma resulting in disastrous consequences. Clinical evaluation may provide subtle clues towards its presence, whereas pulmonary function test can provide useful information to confirm the presence and site of UAO. Relevant radiological and endoscopic investigation may then be carried out to identify the exact etiology and institute appropriate therapy. We present a case of chronic UAO that was detected with the help of pulmonary function test and confirmed with computed tomography and endoscopy. The etiology was found to be related to fibrosis of the larynx resulting in the immobility of the vocal cords secondary to radiotherapy given to the patient 7 years ago. This is an unusual presentation, as most of the radiotherapy-related fibrosis in the head and neck region present within a few months of the exposure to radiation.

New Options in Pediatric Obstructive Sleep Apnea

To describe the current literature pertaining to the evaluation and management of obstructive sleep apnea (OSA) in children. Newer diagnostic modalities, such as drug-induced sleep endoscopy (DISE) and cine MRI, may be utilized to determine anatomic locations of upper airway obstruction contributing to OSA. Pharmacologic and non-pharmacologic treatments have been studied as primary therapy for OSA or as adjuvant therapy for residual disease after adenotonsillectomy. Surgical therapy for persistent moderate to severe OSA following adenotonsillectomy may be considered for patients who are intolerant of or noncompliant with continuous positive airway pressure (CPAP) therapy and tailored to pertinent anatomic sites of upper airway obstruction. The current body of literature emphasizes evaluation and management for children with recurrent or persistent OSA after adenotonsillectomy. Further studies are needed to determine the long-term effectiveness of various pharmacologic, non-pharmacologic, and surgical therapies.

The aging effect on upper airways collapse of patients with obstructive sleep apnea syndrome

To evaluate, using drug-induced sleep endoscopy (DISE), sites of upper airway obstruction and pattern of collapse in patients over 65years old affected by obstructive sleep apnea. To compare sites and pattern of collapse of elderly patients with a group of patients younger than 65years. A group of 55 patients aged over 65years were enrolled in this prospective study. Fifty patients under 65years old were collected in the control group. Polysomnographic data and clinical parameters such as the daytime sleepiness, and body mass index were evaluated for both groups of patients. All patients underwent DISE examination with VOTE classification. The AHI value increased with aging whereas elderly patients presented a reduction in daytime sleepiness. Elderly patients showed a higher incidence of total collapse in the velum region compared to younger patients (90.9% vs 70%;); the older patients showed a lower degree of total oropharyngeal lateral wall collapse with respect to younger patients, (20% vs 50%). No difference in tongue base collapse emerged between the two subgroups of patients. Elderly patients showed a higher incidence of total collapse in the velum and a lower incidence in the oropharyngeal lateral wall compared to younger patients.

Sleep Disordered Breathing May Signal Laryngomalacia

Background: Pediatric anesthesiologists are often confronted with children with sleep-disordered breathing (SDB) presenting for tonsillectomy and/or anesthesia. The typical patient has symptoms of obstructive sleep apnea (OSA) with enlarged tonsils; however, a subset of patients may have underlying laryngomalacia (LM) without tonsillar hypertrophy. Both OSA and LM significantly increase the risk of intra- and postoperative airway obstruction and sensitivity to narcotics. The prevalence of LM may be underestimated, because direct laryngoscopy (DL) is not routinely performed in the diagnostic evaluation of patients with SDB who lack tonsillar hypertrophy. Aim: To identify the prevalence and DL findings in pediatric patients with SDB without tonsillar hypertrophy. Methods: Retrospective chart review of 108 patients with SDB who underwent general anesthesia for adenotonsillectomy (TA) or adenoidectomy with concomitant DL. The following data were collected: demographic information, medical comorbidities, polysomnography results, anesthetic techniques, and postoperative complications. Results: 94.5% of children had DL findings consistent with LM, including a retropositioned epiglottis and short aryepiglottic folds. Postglottic edema was observed in 42.2%, and these patients were significantly more likely to have a diagnosis of gastroesophageal reflux (P=0.023). 57.8% had vocal cord edema. 75.3% of children who received routine postoperative follow-up care experienced complete symptom resolution. Postoperative complications following discharge from hospital occurred in 12.4% of patients, and 15.7% underwent supraglottoplasty for continued SDB symptoms after TA or adenoidectomy. Conclusion: A substantial proportion of patients with SDB who lacked tonsillar hypertrophy had findings consistent with LM, suggesting that the larynx may be the primary site of upper airway obstruction in these patients. This has significant implications in terms of perioperative management. The majority of patients with SDB had symptomatic improvement following TA or adenoidectomy; however, a subset required further surgical intervention with supraglottoplasty.

Patterns of Upper Airway Obstruction on Drug-Induced Sleep Endoscopy in Patients with Sleep-Disordered Breathing with AHI

ObjectiveTo describe the patterns of upper airway obstruction in patients with sleep-disordered breathing with apnea-hypopnea index (AHI) <5 using drug-induced sleep endoscopy (DISE).Study DesignRetrospective study.SettingTertiary care center.Subjects and MethodsInclusion of patients with sleep-disordered breathing with AHI <5 on polysomnography who underwent DISE. Patients <18 years of age were excluded. DISE findings were reported with the VOTEL classification system: the level of collapse was described as occurring at the velum, oropharynx, tongue base, epiglottis, and the lingual tonsils. The degree of collapse was reported as complete, partial, or none. The pattern of the obstruction was described as anteroposterior, lateral, or concentric when applicable.ResultsA total of 54 patients with sleep-disordered breathing with AHI <5 underwent DISE. Ages ranged from 19 to 65 years. DISE was performed alone in 7% (n = 4) of patients and in conjunction with surgery in 93% (n = 50) of patients. The velum was the most frequent site of upper airway obstruction (85%, n = 46), followed by base of tongue (63%, n = 34), epiglottis (39%, n = 21), lingual tonsils (35%, n = 19), and oropharynx (31%, n = 17). Eighty-three percent (n = 45) of patients had multiple levels of upper airway obstruction, and 15% (n = 8) had a single level of upper airway obstruction.ConclusionPatients with sleep-disordered breathing with AHI <5 have significant upper airway obstruction as seen on DISE. DISE findings indicate that a majority of these patients have multiple levels of upper airway obstruction, which can lead to significant symptoms.

Interventional Drug-Induced Sleep Endoscopy: A Novel Technique to Guide Surgical Planning for Obstructive Sleep Apnea.

One of the challenges of surgery for obstructive sleep apnea (OSA) is identifying the correct surgical site for each patient. The objective of this study was to use drug-induced sleep endoscopy (DISE) and nasopharyngeal tube (NPT) placement to determine the effect of eliminating palatal collapse on the obstruction seen on other segments of the upper airway. Forty-one OSA patients were enrolled in this prospective study. All patients had a polysomnogram followed by DISE. DISE findings were recorded and compared with and without placement of a NPT. Obstruction was graded with a scale that incorporates location, severity, and interval of obstruction. Most patients (83%) demonstrated multilevel obstruction on initial DISE. With the nasopharyngeal airway in place, many patients with multilevel obstruction had at least a partial improvement (74%) and some a complete resolution (35%) of collapse (p < 0.05). Reduction in collapse was observed at the lateral walls (86%), epiglottis (55%), and tongue base (50%). NPT placement did not significantly alter upper airway morphology of patients with incomplete palatal obstruction or mild OSA. To our knowledge, this is the first study to evaluate the effect of soft palatal stenting on downstream pharyngeal obstruction during DISE. Our study provides evidence that reducing soft palatal collapse can reduce negative pharyngeal pressure and thereby alleviate other sites of upper airway obstruction. Taken together, these findings provide a means to identify appropriate candidates for isolated palatal surgery and better direct a minimally invasive approach to the surgical management of OSA.

Multimodality assessment of upper airway obstruction in children with persistent obstructive sleep apnea after adenotonsillectomy.

Children with obstructive sleep apnea (OSA) may have multiple sites of upper airway obstruction (UAO). A wide variety of techniques has been used to evaluate UAO. Our aim was to compare findings of cine magnetic resonance imaging (MRI) and drug-induced sleep endoscopy (DISE) in identifying UAO sites in children with persistent OSA after adenotonsillectomy (AT). Retrospective chart review. The medical records of children who underwent DISE and cine MRI were reviewed. Data pertaining to demographics, past medical history, body mass index, polysomnography, findings of DISE, and cine MRI were obtained. Fifteen children (11 boys, 4 girls; age range, 7-18 years) were identified. Comorbid conditions were Down syndrome in nine patients, cerebral palsy in one, attention deficit hyperactivity disorder in two, and asthma in three. Severity of OSA was moderate in five, and severe in 10. DISE and cine MRI showed the same UAO site in 10 patients: a single site (tongue) in nine and multiple sites (tongue and oropharynx/lateral walls) in one. DISE showed additional UAO sites undetected by cine MRI in three patients. Cine MRI showed additional UAO sites undetected by DISE in one patient. DISE and cine MRI showed different sites of obstruction in one patient. Cine MRI and DISE documented single and multiple sites of UAO in children with persistent OSA after AT. Cine MRI and DISE findings were similar in the majority of the children. Assessment of the sensitivity and specificity of cine MRI and DISE in detecting sites of UAO merits further investigation. 4. Laryngoscope, 127:1224-1230, 2017.

Current Concepts in the Surgical Management of Pediatric OSA

Given that adenotonsillar hypertrophy is a common cause of upper airway obstruction in children with obstructive sleep apnea (OSA), adenotonsillectomy (T&A) has long been the first-line management approach. Despite the positive outcomes associated with this procedure, persistent disease occurs postoperatively in 34 % of children. A number of studies have therefore used drug-induced sleep endoscopy and other methods to identify sites of upper airway obstruction that may be amenable to surgical correction. Research is increasingly focused on the effectiveness of surgical procedures other than T&A, such as suturing of the tonsillar pillars, expansion pharyngoplasty, lingual tonsillectomy, supraglottoplasty, rapid maxillary expansion, and tongue suspension. This article presents an overview of these topics, focusing on current concepts in the surgical management of OSA.

Reoperation on patients with obstructive sleep apnea-hypopnea syndrome after failed uvulopalatopharyngoplasty.

The goals of this study were to explore the reasons after failed uvulopalatopharyngoplasty (UPPP) in some patients with obstructive sleep apnea-hypopnea syndrome (OSAHS), and to observe the efficacy of the second surgery. Twenty-three OSAHS patients with failed UPPP were included in the study. Routine physical exams, electronic endoscopy, computed tomography scan and polysomnography after nasopharyngeal tube insertion were performed to assess the site of upper airway obstruction, and corresponding appropriate surgical treatment was carried out based on the diagnosis. Comprehensive evaluation of the 23 patients revealed that the sites of obstruction after failed UPPP were as follows: 7 cases predominantly in the oropharyngeal area, 2 cases in the nasal, nasopharyngeal and oropharyngeal area, 5 cases predominantly in the glossopharyngeal area and 9 cases in the oropharyngeal and glossopharyngeal areas. Correspondingly, 7 cases underwent improved UPPP alone, 2 cases underwent adenoidectomy or nasal expansion and improved UPPP, 5 cases underwent glossopharyngeal surgery alone and 9 cases underwent improved UPPP and glossopharyngeal surgery. Follow-up for more than 12 months showed that there were four cured cases, 12 cases with marked improvement, and 7 cases with treatment failure. The success rate was 69.6%. After undergoing UPPP, OSAHS patients may still have oropharyngeal airway obstruction. By performing a detailed preoperative assessment on the patient's airway condition and clarifying the site of obstruction, performing the second surgical treatment can still achieve a relatively satisfactory treatment outcome.

Abraham Guz (1929-2014).

How do you describe a giant? As a person of abnormally great stature; above the usual size; or someone with much greater powers than the average person? Abraham Guz (‘Abe’) was not a tall man, but he was a scientific giant with an absolute desire to understand and find the scientific truth. This drive led him to make many original contributions in respiratory and cardiovascular physiology. Indeed, a simple literature search produces over 250 peer reviewed papers spanning some 50 years, the top 25 of which have been quoted over 2500 times. Moreover, most of his outstanding work was published in The Journal of Physiology, and we received it with gratitude because it was always insightful and ahead of its time. Many will argue that counting citations is a poor measure of scientific endeavour and I suspect Abe himself would certainly agree. However, this approach did provide us with a place to start when faced with the task of bringing together Abe's huge and varied scientific contributions.

Comparison of findings of awake and induced sleep fiberoptic nasoendoscopy in cases of snoring and obstructive sleep apnea

BackgroundIdentifying the site of obstruction and the pattern of airway change during sleep are the key points essential to guide surgical treatment decision making for snoring and obstructive sleep apnoea–hypopnoea syndrome (OSAHS) in adults. The use of nasopharyngoscopy during the application of the Müller maneuver is frequently employed to establish the site of upper airway obstruction. The Müller maneuver, however, is used when the patient is awake and therefore may not correlate with obstruction occurring during sleep. Drug-induced sleep endoscopy (DISE) avoids these drawbacks and may provide a more accurate evaluation of the upper airway. ObjectiveThe goal of this study is to compare videoendoscopic findings under induced sleep and those during the awake Müller’s maneuver in order to provide an ideal and objective method for accurate assessment of upper airway in cases of snoring and obstructive sleep apnea. This will facilitate choosing the proper line of treatment and monitoring the effect of management. Design50 adult subjects (42 males and 8 females) with an age range from 21 to 66years complaining of snoring and obstructive sleep apnea underwent nasopharyngoscopy to assess airway during the Müller maneuver while awake and during sleep induced by i.v. propofol infusion 100–150μg/kg/min. comparison between the awake and induced sleep fiberoptic nasoendoscopy findings regarding the degree and shape of airway obstruction at the retropalatal, oropharyngeal and hypopharyngeal levels was done. ResultsThere was statistically significant difference between the two groups regarding the shape of obstruction at the retropalatal and oropharyngeal levels; while there was no statistically significant difference between the two groups regarding the degree of obstruction at the three levels. ConclusionThe drug induced sleep endoscopy was more accurate than the Müller maneuver in assessing the shape of obstruction at the retropalatal and the oropharyngeal level, while it was the same as the Müller maneuver in assessing the degree of obstruction at retropalatal, oropharyngeal and hypopharyngeal levels.

Evaluation of upper airway obstruction in snoring patients using digital video stroboscopy

Stroboscopy is routinely used in voice disorder clinics but its use in studying the mechanisms of upper airway obstruction in patients who snore has not yet been described. This study combines the use of stroboscopy during sleep nasendoscopy to evaluate the oscillations and vibrations observed during snoring in slow motion. In addition, we utilised the multi-dimensional voice programme simultaneously to study some of the acoustic parameters of snoring whilst visualising the dynamics of the upper airway. Forty-five patients with primary snoring or mild obstructive sleep apnoea were recruited at two different centres and underwent sleep nasendoscopy. The simultaneous use of acoustic analysis was included to ascertain whether sound analysis alone could replace the need for using the sedation endoscopy in these patients. The use of a stroboscopic light source indeed enhanced the visualisation during the procedure and some subtle aspects of the mechanisms of upper airway obstruction, such as vibrations of the posterior pharyngeal wall and mucosal waves were identified. Most of the patients in this study exhibited multilevel obstruction and thus acoustic analysis alone would not be sufficient in accurately locating the site of upper airway obstruction in snorers.