Assessment of obstruction level and selection of patients for obstructive sleep apnoea surgery: an evidence-based approach

The Use of Middle Latency Auditory Evoked Potentials (MLAEP) as Methodology for Evaluating Sedation Level in Propofol-Drug Induced Sleep Endoscopy (DISE) Procedure

To analyze the middle latency auditory evoked potential index (MLAEPi), compared to the standard bispectral index (BIS), as a method for evaluating the sedation level in drug-induced sleep endoscopy (DISE). In this controlled clinical study on a sample of 99 obstructive sleep apnea (OSA) or snoring patients, we compared the MLAEPi with the BIS after propofol infusion during the standard DISE technique in order to define the MLAEPi values within the observational window of the procedure. The DISE procedure was divided into eight steps, and we collected both MLAEPi and BIS data values from the same patient in every step. The MLAEPi showed a faster response than the BIS after propofol infusion during DISE. Therefore, the clinical use of the MLAEPi in evaluating the sedation level seems to be a good alternative to the current technological standards.

Reduction of postural nasal resistance following oropharyngeal surgery in patients with moderate-severe obstructive sleep apnea

BACKGROUND

Patients with obstructive sleep apnea (OSA) have elevated nasopharyngeal resistances due to increased turbulent airflow. The study aims to investigate the effect of oropharyngeal surgery on nasal resistance in patients with various severity levels of OSA.

METHODOLOGY

Patients with greater or equal to 5 events hourly on the apnea-hypopnea index (AHI) were enrolled. Patients with retropalatal obstruction underwent uvulopalatopharyngoplasty, while patients with concurrent retrolingual obstruction under- went uvulopalatopharyngoplasty (UPPP) plus tongue base suspension. Before surgery and after surgery, subjective outcomes were assessed using a visual analog scale (VAS), and objective outcomes were assessed using overnight polysomnography and rhinomanometry. The limitation of the study was that UPPP instead of expansion sphincter pharyngoplasty was performed in this study.

RESULTS

Sixty-two patients were enrolled, while 30 patients were diagnosed as mild OSA (group Mild) and 32 patients were mo- derate-severe OSA (group MS). The preoperative VAS of nasal obstruction in recumbency during sleep was significantly reduced after surgery in group MS. However, no significant differences between preoperative and postoperative VAS were found in group Mild. The postoperative anterior and posterior total nasal resistances (TNR) in sitting and supine positions were not significantly different from those before surgery in group. In contrast, the postoperative posterior TNR in supine position was 0.292±0.301(Pa/ cm3/s), compared with 0.425±0.343(Pa/cm3/s) preoperatively.

CONCLUSIONS

Oropharyngeal surgery improves nasal obstruction during sleep and lowers the supine TNR measured in poste- rior rhinomanometry in patients with moderate-severe OSA. Oropharyngeal surgery is a possible treatment for postural nasal obstruction in patients with moderate-severe OSA.

A New Technological Advancement of the Drug-Induced Sleep Endoscopy (DISE) Procedure: The "All in One Glance" Strategy

To illustrate a new technological advance in the standard drug-induced sleep endoscopy (DISE) model, a new machine was used, the Experimental 5 Video Stream System (5VsEs), which is capable of simultaneously visualizing all the decisional parameters on a single monitor, and recording and storing them in a single uneditable video. The DISE procedure was performed on 48 obstructive sleep apnea (OSA) or snoring patients. The parameters simultaneously recorded on a single monitor are (1) the pharmacokinetics and pharmacodynamics of propofol (through the target controlled infusion (TCI) pump monitor), (2) the endoscopic upper airway view, (3) the polygraphic pattern, and (4) the level of sedation (through the bispectral index (BIS) value). In parallel to the BIS recording, the middle latency auditory evoked potential (MLAEP) was also recorded and provided. Recorded videos from the 5VsEs machine were re-evaluated six months later by the same clinician and a second clinician to evaluate the concordance of the therapeutic indications between the two. After the six-month period, the same operator confirmed all their clinical decisions for 45 out of 48 videos. Three videos were no longer evaluable for technical reasons, so were excluded from further analysis. The comparison between the two operators showed a complete adherence in 98% of cases. The 5VsEs machine provides a multiparametric evaluation setting, defined as an “all in one glance” strategy, which allows a faster and more effective interpretation of all the simultaneous parameters during the DISE procedure, improving the diagnostic accuracy, and providing a more accurate post-analysis, as well as legal and research advantages.

Comparison of upper airway obstruction during zolpidem-induced sleep and propofol-induced sleep in patients with obstructive sleep apnea: a pilot study

STUDY OBJECTIVES

Drug-induced sleep endoscopy (DISE) using propofol is commonly used to identify the pharyngeal structure involved in collapse among patients with obstructive sleep apnea. DISE has never been compared with zolpidem-induced sleep endoscopy. We hypothesized that propofol at recommended sedation levels does not influence upper airway collapsibility nor the frequency of multilevel pharyngeal collapse as compared with zolpidem-induced sleep.

METHODS

Twenty-one patients with obstructive sleep apnea underwent polysomnography and sleep endoscopy during zolpidem-induced sleep and during DISE with propofol. A propofol target-controlled infusion was titrated to achieve a bispectral index between 50 and 70. Airway collapsibility was estimated and compared in both conditions by peak inspiratory flow and the magnitude of negative effort dependence. Respiratory drive was estimated by the difference between end-expiratory and peak-negative inspiratory pharyngeal pressure (driving pressure). Site and configuration of pharyngeal collapse during zolpidem-induced sleep and DISE with propofol were compared.

RESULTS

The frequency of multilevel collapse during zolpidem-induced sleep was similar to that observed during DISE with propofol (72% vs 86%, respectively; difference: 14%; 95% confidence interval: -12% to 40%; P = .453). The endoscopic classification of pharyngeal collapse during both conditions were similar. Peak inspiratory flow, respiratory drive (effect size: 0.05 and 0.03, respectively), and negative effort dependence (difference: -6%; 95% confidence interval: -16% to 4%) were also similar in both procedures.

CONCLUSIONS

In this pilot study, recommended propofol doses did not significantly increase multilevel pharyngeal collapse or affect upper airway collapsibility and respiratory drive as compared with zolpidem-induced sleep.

CLINICAL TRIAL REGISTRATION

Registry: clinicaltrials.gov; Name: Natural and Drug Sleep Endoscopy; URL: https://clinicaltrials.gov/ct2/show/study/NCT03004014; Identifier: NCT03004014.

TORS for OSA: a practice, pitfalls and literature review

PURPOSE

Trans-oral robotic surgery (TORS) is increasingly employed in obstructive sleep apnoea (OSA) management. Objective outcomes are generally assessed through polysomnography. Pre-operative magnetic resonance imaging (MRI) can be a useful adjunct in objective upper airway assessment, in particular the tongue base, providing useful information for surgical planning and outcome assessment, though care must be taken in patient positioning during surgery. The purpose of this paper is to identify pitfalls in this process and suggest a protocol for pre-operative MRI scanning in OSA.

DESIGN/METHODOLOGY/APPROACH

This study is a four-patient prospective case-series and literature review. Outcome measures include pre- and post-operative volumetric changes in the pharynx as measured on MRI and apnoea-hypopnea indices (AHI), with cure being OSA resolution or a 50 per cent reduction in AHI.

FINDINGS

All patients achieved AHI reduction and/or OSA cure following TORS, despite a decrease in pharyngeal volume measurements at the tongue base level. This study and others lacked standardisation in the MRI scanning protocol, which resulted in an inability to effectively compare pre- and post-operative scans. Pitfalls were related to variation in head/tongue position, soft-tissue marker usage and assessed area boundary limits.

PRACTICAL IMPLICATIONS

TORS appears to be effective in OSA management. A new protocol for patient positioning and anatomical landmarks is suggested.

ORIGINALITY/VALUE

The findings could provide directly comparable data between scans and may allow correlation between tongue base volumetric changes and AHI through subsequent and historical study meta-analysis.

Real-Time Identification of Upper Airway Occlusion Using Electrical Impedance Tomography

STUDY OBJECTIVES

Real-time monitoring of upper airway collapse during sleep could be instrumental for studies in biomechanics of obstructive sleep apnea (OSA) and selecting individualized treatment modalities. Although some imaging techniques are used under sedated sleep, none are available during the entire natural sleep process. We hypothesized that electrical impedance tomography (EIT) can be used for noninvasive continuous imaging of the upper airway during natural sleep and quantifying upper airway collapse in terms of its size.

METHODS

After determining surface landmarks to attach the electrodes for monitoring the retroglossal airway, EIT was conducted in 10 healthy participants. As a feasibility test of EIT in detecting upper airway collapse, transient airway closure was induced by the swallowing maneuver. These EIT images were confirmed by simultaneous magnetic resonance imaging (MRI) scans. Subsequently, EIT scans were conducted in 7 healthy participants and 10 patients with OSA under nonsedated sleep to determine whether it could identify upper airway narrowing or collapse. Respiratory events were identified by concurrent polysomnography (PSG).

RESULTS

Swallowing-induced airway closure was identified successfully in all 10 participants on simultaneous EIT and MRI scans. Sizes and positions of the upper airway closures in reconstructed EIT images were well correlated with those in magnetic resonance images. Obstructive hypopnea and apnea were detected successfully by EIT in 10 patients with OSA, and no significant changes in EIT data were observed in 7 healthy participants during concurrent EIT and PSG tests. Additionally, conductivity changes in the airway were greater during obstructive apnea than during hypopnea (64.3% versus 26.3%, respectively; P < .001) compared with those during baseline respiration.

CONCLUSIONS

EIT could be a useful real-time monitoring device for detecting upper airway narrowing or collapse during natural sleep in patients with OSA. Currently, changes in the upper airway size can be estimated with good accuracy, but shape estimation needs future improvements in the EIT image quality.

European position paper on drug-induced sleep endoscopy: 2017 Update

BACKGROUND

The first edition of the European position paper (EPP) on drug-induced sleep endoscopy (DISE) was published in 2014 with the aim to standardise the procedure, to provide an in-depth insight into the main aspects of this technique and to have a basis for future research. Since 2014, new studies have been published concerning new sedative agents or new insights into the pattern/levels of the obstruction depending on the depth of sedation. Therefore, an enlarged group of European experts in the field of sleep breathing disorders (SBD), including the most of the first DISE EPP main authors, has decided to publish an update of the European position paper on DISE, in order to include new evidence and to find a common language useful for reporting the findings of this endoscopic evaluation in adult population affected by SBD.

METHODS

The authors have evaluated all the available evidence reported in the literature and have compared experience among various departments in leading European centres in order to provide an update regarding the standardisation of the DISE procedure and an in-depth insight into the main aspects of this technique.

RESULTS

After the first European Position Consensus Meeting on DISE and its update, consensus was confirmed for indications, required preliminary examinations, where to perform DISE, technical equipment required, staffing, local anaesthesia, nasal decongestion, other medications, patient positioning, basics and special diagnostic manoeuvres, drugs and observation windows. So far, no consensus could be reached on a scoring and classification system. However, regarding this aim, the idea of an essential classification, such as VOTE with the possibility of its graded implementation of information and descriptions, seems to be the best way to reach a universal consensus on DISE classification at this stage. A common DISE language is mandatory, and attempts to come to a generally accepted system should be pursued.

Robotics in otorhinolaryngology - head and neck surgery

A look at the past, present and future.

Drug induced sleep endoscopy: its role in evaluation of the upper airway obstruction and patient selection for surgical and non-surgical treatment

Sleep related breathing disorders cause obstruction of the upper airway which can be alleviated by continuous positive airway pressure (CPAP) therapy, oral devices or surgical intervention. Non-surgical treatment modalities are not always accepted by patients and in order to attain successful surgical outcomes, evaluation of the upper airway is necessary to carefully select the patients who would benefit from surgery. There are numerous techniques available to assess the upper airway obstruction and these include imaging, acoustic analysis, pressure transducer recording and endoscopic evaluation. It is essential to note that the nocturnal obstructive upper airway has limited muscle control compared to the tone of the upper airway lumen during wakefulness. Thus, if one were to attempt to identify the anatomical segments contributing to upper airway obstruction in sleep related breathing disorders; it must be borne in mind that evaluation of the airway must be performed if possible when the patient is awake and asleep albeit during drug induced sleep. This fact as such limits the use of imaging techniques for the purpose. Drug induced sleep endoscopy (DISE) was pioneered at Royal National Throat, Nose and Ear Hospital, London in 1990 and initially introduced as sleep nasendoscopy. The nomenclature and the technique has been modified by various Institutions but the core value of this evaluation technique remains similar and extremely useful for identifying the anatomical segment responsible for obstructing the upper airway during sleep in patients with sleep related breathing disorders. There have been numerous controversies that have surrounded this technique but over the last two decades most of these have been addressed and it now remains in the forefront of methods of evaluating the upper airway obstruction. A variety of sedative agents and different grading systems have been described and efforts to unify various aspects of the technique have been made. This article will look at its usefulness and advantages and will discuss some important contributions made to the field of evaluation of the upper airway using DISE.

Drug-induced sedation endoscopy (DISE) classification systems: a systematic review and meta-analysis

PURPOSE

Drug-induced sedation endoscopy (DISE) classification systems have been used to assess anatomical findings on upper airway obstruction, and decide and plan surgical treatments and act as a predictor for surgical treatment outcome for obstructive sleep apnoea management. The first objective is to identify if there is a universally accepted DISE grading and classification system for analysing DISE findings. The second objective is to identify if there is one DISE grading and classification treatment planning framework for deciding appropriate surgical treatment for obstructive sleep apnoea (OSA). The third objective is to identify if there is one DISE grading and classification treatment outcome framework for determining the likelihood of success for a given OSA surgical intervention.

METHODS

A systematic review was performed to identify new and significantly modified DISE classification systems: concept, advantages and disadvantages.

RESULTS

Fourteen studies proposing a new DISE classification system and three studies proposing a significantly modified DISE classification were identified. None of the studies were based on randomised control trials.

CONCLUSION

DISE is an objective method for visualising upper airway obstruction. The classification and assessment of clinical findings based on DISE is highly subjective due to the increasing number of DISE classification systems. Hence, this creates a growing divergence in surgical treatment planning and treatment outcome. Further research on a universally accepted objective DISE assessment is critically needed.

Drug-Induced Sedation Endoscopy (DISE) DATA FUSION system: clinical feasibility study

Drug-induced sleep endoscopy (DISE) is a diagnostic technique for 3D dynamic anatomical visualisation of upper airway obstruction during sedated sleep. There is a lack of standardised procedure and objective measurement associated with information capture, information management, evaluation of DISE findings, treatment planning, and treatment outcomes. The objective of this study is to present clinical feasibility results using a DISE DATA FUSION system for capturing, merging, displaying and storing anatomical data from an endoscopic imaging system and cardiorespiratory data from an anaesthesiological monitoring system simultaneously in real-time during DISE. This prospective cohort study included 20 patients presenting with symptoms of sleep related breathing disorders undergoing drug-induced sedation endoscopy and had volunteered for DISE DATA FUSION system to be used during their DISE assessment. The DISE DATA FUSION system was used to capture, merge, display, and store anatomical changes from an endoscopic imaging system and cardiorespiratory changes from an anaesthesiological monitoring system simultaneously in real time during drug-induced sedation endoscopy assessment. In all 20 patients, anatomical obstructions at different levels of the pharyngeal lumen (soft palate, velum, tonsils, oropharynx lateral wall, base of tongue, and epiglottis) with a different obstruction configuration and severity were captured simultaneously in real time with its associated cardiorespiratory parameters. Furthermore, a composite video consisting of an anatomical image, blood oxygen level, pulse rate, blood pressure, and timestamp was created for every obstructive event. Our system provides a useful and better way of capturing, merging, visualising, and storing anatomical data/physiological data simultaneously during DISE in real time. Furthermore, it enhances the understanding of the impact of the anatomical severity due to the simultaneous display of the cardiovascular parameters at that specific time of anatomical obstruction for optimising surgical decision based on DISE.

Is transoral robotic surgery a safe and effective multilevel treatment for obstructive sleep apnoea in obese patients following failure of conventional treatment(s)?

A best evidence topic was written according to a structured protocol. The question addressed was whether TransOral Robotic Surgery (TORS) is a safe and effective multilevel treatment for Obstructive Sleep Apnoea (OSA) in obese patients following failure of conventional treatment(s). A total of 39 papers were identified using the reported searches of which 5 represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Existing treatments for OSA - primarily CPAP - though highly effective are poorly tolerated resulting in an adherence often lower than 50%. As such, surgery is regaining momentum, especially in those patients failing non-surgical treatment (CPAP or oral appliances). TORS represents the latest addition to the armamentarium of Otorhinolaryngologists - Head and Neck Surgeons for the management of OSA. The superior visualisation and ergonomics render TORS ideal for the multilevel treatment of OSA. However, not all patients are suitable candidates for TORS and its suitability is questionable in obese patients. In view of the global obesity pandemic, this is an important question that requires addressing promptly. Despite the drop in success rates with increasing BMI, the success rate of TORS in non-morbidly obese patients (BMI = 30-35kgm^-2) exceeds 50%. A 50% success rate may at first seem low, but it is important to realize that this is a patient cohort suffering from a life-threatening disease and no option left other than a tracheostomy. As such, TORS represents an important treatment in non-morbidly obese OSA patients following failure of conventional treatment(s).

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There is a paucity of evidence on the subject with complete absence of RCTs.

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The literature supports TORS as a safe multilevel treatment for OSA.

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The effectiveness of TORS for OSA drops with increasing BMI.

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TORS represents an important treatment for OSA in non-morbidly obese patients after failure of conventional treatment(s).

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There is no role for TORS as an OSA treatment in morbidly obese patients.

uDISE model: a universal drug-induced sedation endoscopy classification system-part 1

Drug-induced sedation endoscopy (DISE) classification systems play a significant role in clinical analysis based on DISE findings, treatment decision process, treatment planning process and fundamentally in treatment outcomes. However, there is a major problem: there is no universally agreed DISE classification system. Hence, for the same DISE examination different DISE classification systems can be used to: assess anatomic findings, decide and plan different treatments. Hence, this leads to different treatment outcomes. The key objective of this study is to propose uDISE model: universal drug-induced sedation endoscopy (DISE) classification system. Set theory and relational mapping was used to develop a DISE classification system based on anatomical structures/level; degree of severity; and configuration of obstruction and its relationship with existing DISE classification systems. uDISE model consists of seven anatomical sites (nose, velum, tonsils, lateral pharyngeal wall/oropharynx, tongue base, epiglottis and larynx), three degrees of obstructive severity (none, partial and complete), three configurations of obstruction (anteroposterior, lateral and circumferential) and a severity index. uDISE model was mapped to four existing DISE classification systems: Pringle and Croft grading system, VOTE, NOHL and P-T-L-Tb-E. uDISE model provides a methodology for mapping different DISE findings based on different classification systems into one common DISE assessments format. This provides a framework for comparing different DISE assessments, treatment plan and treatment outcome irrespective of DISE classification system used. Further research is required to establish a complete relational mapping between uDISE model and other existing DISE classification systems.

Surgical Management of Obstructive Sleep Apnea

Surgical management of snoring and obstructive sleep apnea is indicated when a surgically correctable abnormality is believed to be the source of the problem. Many patients opt for surgical treatment after noninvasive forms of treatment have been proven ineffective or difficult to tolerate. With increasing frequency, functional rhinoplasty, septoplasty, turbinoplasty, palatal surgery, and orthognathic surgery are being used in the management of snoring and obstructive sleep apnea. Plastic surgeons' experience with aesthetic nasal surgery, nasal reconstruction, palatal surgery, and craniofacial surgery puts them at the forefront of performing surgery for snoring and sleep apnea. The role of functional septorhinoplasty, turbinoplasty, palatal surgery, genioglossal advancement, and orthognathic surgery is indispensable in the surgical management of obstructive sleep apnea. Multidisciplinary management of these patients is critical, and plastic surgeons are encouraged to work collaboratively with sleep medicine clinicians and centers.

Modified barbed soft palatal posterior pillar webbing flap palatopharyngoplasty

BACKGROUND

The soft palate and the lateral pharyngeal walls contribute to the collapse of the upper airway in patients with snoring and obstructive sleep apnea. In this study, the original soft palatal webbing flap palatopharyngoplasty for both soft palatal and oropharyngeal lateral wall collapse has been modified to include all tonsil grades and to apply the barbed suture technique.

METHODS

Twenty-one adults with significant soft palatal webbing, lateral pharyngeal wall collapse, and tonsil hypertrophy of any grade were selected for the study with a minimum follow-up period of 6 months.

RESULTS

Snoring was improved with snoring scale reduced from 9.4 ± 1.6 to 1.7 ± 3.2 (p < 0.005). The preoperative to postoperative apnea-hypopnea index (AHI) statistically improved from 45.7 ± 2.6 to 12.3 ± 3.9 (p < 0.005) and lowest O2 saturation from 73.8 ± 3.6 to 89.4 ± 1.9 % (p < 0.005). Postoperative endoscopic findings showed significant improvement in soft palatal and lateral pharyngeal wall collapse. There were no significant intraoperative or postoperative complications.

CONCLUSION

Modified barbed soft palatal webbing flap palatopharyngoplasty provided objective improvement of obstructive sleep apnea (OSA) in adults with soft palatal, lateral pharyngeal wall collapse and tonsillar hypertrophy, with no significant complications and has the potential to serve as an effective alternative for these cases.

Otorhinolaryngological aspects of sleep-related breathing disorders

Snoring and obstructive sleep apnoea (OSA) are disorders within a wide spectrum of sleep-related breathing disorders (SRBD). Given the obesity epidemic, these conditions will become increasingly prevalent and continue to serve as a large economic burden. A thorough clinical evaluation and appropriate investigations will allow stratification of patients into appropriate treatment groups. A multidisciplinary team is required to manage these patients. Patient selection is critical in ensuring successful surgical and non-surgical outcomes. A wide range of options are available and further long term prospective studies, with standardised data capture and outcome goals, are required to evaluate the most appropriate techniques and long term success rates.

Outcome of TORS to tongue base and epiglottis in patients with OSA intolerant of conventional treatment

PURPOSE

Transoral robotic surgery (TORS) of the tongue base with or without epiglottoplasty represents a novel treatment for obstructive sleep apnea (OSA). The objective was to evaluate the clinical efficacy of TORS of the tongue base with or without epiglottoplasty in patients who had not tolerated or complied with conventional treatment (continuous positive airway pressure or oral appliance).

METHODS

Four-year prospective case series. The primary outcome measure was the apnea-hypopnea index (AHI) in combination with the Epworth Sleepiness Score (ESS). Mean oxygen saturation levels (SaO2) before and after TORS on respective sleep studies were also recorded. Secondary outcome measures included operative time and complications. Patient reported outcome measures (PROMs) assessed included voice, swallow and quality of life.

RESULTS

Fourteen patients underwent TORS for tongue base reduction with ten having additional wedge epiglottoplasty. A 64 % success rate was achieved with a normal post-operative sleep study in 36 % of cases at 6 months. There was a 51 % reduction in the mean AHI (36.3 ± 21.4 to 21.2 ± 24.6, p = 0.02) and a sustained reduction in the mean Epworth Sleepiness Score (p = 0.002). Mean SaO2 significantly increased after surgery compared to pre-operative values (92.9 ± 1.8 to 94.3 ± 2.5, p = 0.005). Quality of life showed a sustained improvement 3 months following surgery (p = 0.01). No major complications occurred.

CONCLUSIONS

TORS of the tongue base with or without epiglottoplasty represents a promising treatment option with minimal morbidity for selected patients with OSA. Long-term prospective comparative evaluation is necessary to validate the findings of this study.

Diagnostic Role of Magnetic Resonance Imaging in Obstructive Sleep Apnea Syndrome

We aim to review the diagnostic role of magnetic resonance (MR) imaging in obstructive sleep apnea syndrome (OSAS). Basic background about sleep apnea, MR anatomy of the pharyngeal airway, and MR imaging sequences applied in obstructive sleep apnea are discussed. Static and dynamic MR imaging is used in the assessment of patients with OSAS. Magnetic resonance imaging can detect the level, degree, and cause of obstruction in the upper airway that guide the clinical diagnosis and treatment. Imaging is used for prediction of treatment outcome and monitoring and follow-up of patients with OSAS after therapy.

Radiofrequency ablation in snoring surgery: local tissue effects and safety measures

Radiofrequency ablation is now widely used in the treatment of patients with snoring and obstructive sleep apnoea. It is well suited to the multilevel approach typically required in snoring surgery and can be used interstitially or in cutting mode. However, no research has been performed to analyse the collateral local tissue damage or size of lesions induced by radiofrequency application. This is the first study of the histological effects of interstitial radiofrequency. We studied the size of tissue lesions generated at differing power settings with and without local anaesthetic application in human tonsils and chicken breast tissue. The size of the lesion was independent of power setting and local anaesthetic infiltration. The typical effect was an oval-shaped lesion centred on the active electrode, 6-7 mm in width and 7-8 mm in length. This was confirmed histopathologically, with smaller lesions generated in the submucosa (2 × 3 mm) but with no collateral tissue damage beyond this distinct zone of injury. To avoid complications, we recommend placing contiguous radiofrequency applications at least 8 mm apart. Post-nasal space packing raises and tautens the soft palate. The use of local anaesthetic increases interstitial volume, thereby reducing the risk of incorrect probe placement and resultant ulceration or fistulation.

European position paper on drug-induced sedation endoscopy (DISE)

BACKGROUND

Although drug-induced sedation endoscopy (DISE) represents the most widespread diagnostic tool for upper airway endoscopic evaluation of snoring and obstructive sleep apnea hypopnea syndrome (OSAHS), many controversies exist about how to perform the sedation, the indications for DISE, and how to report DISE findings. The present position paper reports on a consensus as proposed by a group of European experts in the field of DISE after discussion during a recent dedicated meeting.

METHODS

The authors have evaluated all the available evidence reported in the literature and have compared experience among various departments in leading European centers in order to provide a standardization of the DISE procedure and an in-depth insight in the main aspects of this technique.

RESULTS

A proposal of the DISE procedure standardization has been achieved with a general agreement concerning the terminology, indications, contraindications, required preliminary examinations, setting, technical equipment required, staffing, local anesthesia and nasal decongestion, patient positioning, basis and special diagnostic maneuvers, and the applied sedation drugs and observation windows. Otherwise, no consensus has been reached on a scoring and classification system.

CONCLUSIONS

Although consensus has been reached on several aspects of the DISE procedure, some topics remain open to future research, such as a better analysis of the importance of positional aspects during DISE and a further comparison of the differences in degree, level and pattern of upper airway collapse observed during DISE versus during natural sleep and awake endoscopy. Finally, a universally accepted scoring and classification system is lacking.

Multilevel radiofrequency ablation to the soft palate and tongue base: tips and pitfalls

The objective of the study is to increase awareness and understanding of the techniques and safety measures to minimise complications and improve patient outcomes. Literature review using MedLine and keywords snoring; obstructive sleep apnoea; radiofrequency ablation; electrosurgery; palate; tongue base was conducted. There is no accepted gold standard technique for radiofrequency ablation; to date, there is no published literature regarding common tips and pitfalls in radiofrequency application specifically for superficial applications and second-stage surgery. Surgery for snoring and obstructive sleep apnoea is typically multilevel. Pre-operative patient assessment and selection are critical to ensure good outcomes. Radiofrequency is generally safe and efficacious in this subset of patients. However, as with all surgery, it is operator-dependent. In particular, we emphasise the methodology for second-stage surgery, optimising visualisation and avoiding ulceration/fistulation of the soft palate, which are previously undescribed in the literature.

Reviewing the Systematic Reviews in OSA Surgery

Objective

There is an extensive amount of literature on surgeries as treatment for obstructive sleep apnea syndrome on adults. Previous systematic reviews have been performed to summarize the outcomes for sleep surgeries, with conflicting results. The objective of this study was to critically evaluate these systematic reviews to provide an overview of their quality, strengths, and conclusions.

Data Sources

MEDLINE, Scopus, and the Cochrane Collaboration databases were searched from inception to April 2013.

Review Methods

An overview of systematic reviews was undertaken. Studies included in this review are the systematic reviews whose primary objective was to evaluate the outcomes of sleep apnea surgery on adults. The methodological quality of the studies was analyzed with AMSTAR checklist, and the quality of evidence was evaluated using the GRADE assessment tool. Primary outcome measures assessed the effect of surgery on snoring, sleepiness, and the apnea-hypopnea index.

Results

A total of 11 studies were included in this study, and the pooled overview includes 378 studies. The systematic reviews were mostly graded as low quality using the GRADE tool and low to moderate according to the AMSTAR checklist. Outcome for apnea-hypopnea index demonstrated substantial variation leading to conflicting results. Despite a high amount of heterogeneity, outcomes for sleepiness and snoring demonstrated significant improvement across included reviews.

Conclusions

Although obstructive sleep apnea surgery is associated with improved outcomes in most studies, the level and quality of evidence reviews requires improvement.

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.

Validation of sleep nasendoscopy for assessment of snoring with bispectral index monitoring

Bispectral index (BIS) monitor is a neurophysiological monitoring device which continually analyses a patient's electroencephalogram during sedation and general anaesthesia to assess the level of consciousness and depth of anaesthesia. BIS monitoring, whilst performing sleep nasendoscopy (using midazolam and propofol), has helped validate depth of sedation and allowed comparison with levels of sedation of control patients during natural sleep. A prospective study of 30 patients with snoring undergoing sleep nasendoscopy with BIS monitoring was conducted. BIS monitoring was recorded throughout the procedure and assessment of snoring was made at the appropriate level of sedation and snoring. BIS values were compared with control patients. The 30 patients undergoing sleep nasendoscopy had average BIS values ranging from 50.72 to 61.2. Similar results were seen with BIS and oxygen saturation in the control group. BIS monitoring provides an adjunct to the assessment of sleep nasendoscopy in determining the level of sedation required for snoring assessment. Comparable BIS values and oxygen saturation levels were obtained between controls and patients during sedation-induced sleep, thus validating the role of sleep nasendoscopy.

The role of the nose in snoring and obstructive sleep apnoea: an update

Multilevel anatomic obstruction is often present in snoring and obstructive sleep apnoea (OSA). As the nose is the first anatomical boundary of the upper airway, nasal obstruction may contribute to sleep-disordered breathing (SDB). A number of pathophysiological mechanisms can potentially explain the role of nasal pathology in SDB. These include the Starling resistor model, the unstable oral airway, the nasal ventilatory reflex and the role of nitric oxide (NO). Clinically, a number of case–control studies have shown that nasal obstruction is associated with snoring and mild SDB. However, there is not a linear correlation between the degree of nasal obstruction and the severity of SDB, while nasal obstruction is not the main contributing factor in the majority of patients with moderate to severe OSA. Randomised controlled studies have shown that in patients with allergic rhinitis or non-allergic rhinitis and sleep disturbance, nasal steroids could improve the subjective quality of sleep, and may be useful for patients with mild OSA, however, they are not by themselves an adequate treatment for most OSA patients. Similarly, nasal surgery may improve quality of life and snoring in a subgroup of patients with mild SDB and septal deviation, but it is not an effective treatment for OSA as such. On the other hand, in patients who do not tolerate continuous positive airway pressure (CPAP) well, if upper airway evaluation demonstrates an obstructive nasal passage, nasal airway surgery can improve CPAP compliance and adherence.