Lateral Collapse Research Articles

Pharyngoplasty in the Treatment of Sleep Apnea: Efficacy of Surgical Techniques

In sleep apnea/hypopnea syndrome (SAHS) a superior airway collapse can occur in the anteroposterioror lateral direction. The primary or secondary decrease in the tone of the dilating muscles of the pharynx, due to the negative pressure produced by the contraction of the diaphragm cause the collapse. Pharyngoplasty surgical techniques try to improve lateral collapse by repositioning the muscles that constitute the pharyngeal lateral wall, mainly the palatopharyngeal (PP), palatoglossal (PG) and upper constrictor (UC).

International Pediatric Otolaryngology Group (IPOG) consensus recommendations: Management of suprastomal collapse in the pediatric population

IntroductionSuprastomal Collapse (SuStCo) is a common complication of prolonged tracheostomy in children. There is a paucity of literature on this subject, especially regarding how to manage significant suprastomal collapse that prevents safe decannulation. ObjectiveProvide a definition, classification system, and recommend management options for significant suprastomal collapse in children with tracheostomy. MethodsMembers of the International Pediatric Otolaryngology Group (IPOG) who are experts in pediatric airway conditions were surveyed and results were refined using a modified Delphi method. ResultsConsensus was defined as > 70% agreement on a subject. The experts achieved consensus:•on a standard definition of Suprastomal Collapse•that there is clinical importance between significant and insignificant collapse•that the gold standard diagnostic modality is endoscopic examination under anesthesia•that the severity of collapse is a major determinant in the surgical approach•that surgical intervention is the first line management in combined anterior and lateral Suprastomal Collapse. ConclusionThis consensus statement provides recommendations for medical specialists who manage infants and children with tracheostomies with significant Suprastomal Collapse. It provides a classification system to facilitate diagnosis and treatment options for this condition.

The correlation between drug-induced sleep endoscopy findings and severity of obstructive sleep apnea

ObjectiveThis study aimed to assess the relationship between anthropometric data, drug-induced sleep endoscopy (DISE) findings, and severity of obstructive sleep apnea (OSA). MethodsFrom August 2016 to August 2017, a total of 147 surgically naïve adult patients with OSA underwent DISE. Factors that were analyzed included anthropometric data and DISE findings. ResultsWhen anthropometric data and DISE findings were analyzed with AHI by univariate analysis, the results showed that Epworth Sleepiness Scale (ESS), body mass index (BMI), neck circumference, concentric collapse of the velum, lateral oropharyngeal collapse, and anterior-posterior collapse of the tongue base were considered potentially independent predictors (p = 0.024, p < 0 .001, p < 0 .001, p < 0.001, p < 0.001, p < 0 .001, respectively, by Spearman correlation). When all important factors were evaluated in a stepwise multiple linear regression analysis, BMI, lateral oropharyngeal collapse, and anterior-posterior collapse of the tongue base were identified as significant predictors for the severity of OSA. The final model was listed as below:AHI score = 2.19 BMI + 7.56 Oropharynx/Lateral degree + 8.23 Tongue base/ Anterior-Posterior degree – 40.59. ConclusionBy analyzing anthropometric data and DISE findings with AHI score, the results indicated that BMI, lateral oropharyngeal collapse, and anterior-posterior collapse of the tongue base were important factors associated with the severity of OSA.

Editorial: Flank dynamics, sector collapses, lahars, and rockfalls: analysis, monitoring, and modelling of small to large scale volcanic slope instability

Slope dynamics in volcanic environments comprise a wide spectrum of phenomena, from large lateral collapse to shallow debris remobilization, which may represent a major threat for human communities and infrastructures. Many volcanos built up from the ocean floor and large portions of the volcano edifice are submerged. In these settings, only the edifice’s summit can be investigated by terrestrial remote sensing and in-situ approaches. Growth and destruction, including tectonics and gravitational phenomena, affect entire volcano flanks and are not limited to the physical boundary of the sea level but could comprise their subaqueous parts

Flow-Identified Site of Collapse During Drug-Induced Sleep Endoscopy: Feasibility and Preliminary Results

Flow-Identified Site of Collapse During Drug-Induced Sleep Endoscopy: Feasibility and Preliminary Results

Drug-induced sleep endoscopy: techniques, interpretation and implications.

The purpose of this article is to highlight recent advances in the burgeoning field of drug-induced sleep endoscopy (DISE). One of the first studies to investigate the correlation of DISE findings and natural sleep endoscopy found good agreement in clinically significant obstruction. Previous studies have shown good agreement of DISE findings with the use of different sedative agents implying that the choice of sedative may not be crucial. However, recent studies show variable patterns of collapse, especially at the tongue base, with the use of different sedative agents. A universally accepted classification scheme for drug-induced sleep endoscopy is lacking. A new DISE classification system, termed Palate, Tonsils, Lateral pharyngeal wall, Tongue base, Epiglottis, was introduced this year with the noted advantage of being able to better differentiate between clinically relevant tonsillar and lateral pharyngeal wall collapse. Despite recent advances in the field, there remains no general consensus that DISE findings predict surgical success but may aid in the identification of patients who will respond well to oral appliance therapy. Drug-induced sleep endoscopy is a structure-based evaluation of the upper airway that more closely resembles the natural sleep state compared with awake evaluation.

Layered gabbros and peridotites from Piton des Neiges volcano, La Réunion Island

We conducted a petrological study of the layered gabbros and peridotites outcropping in the cirque of Salazie, combining field investigations, geochemistry, petrography and, mineralogy to constrain the magmatic evolution of Piton des Neiges volcano (La Réunion). Three new hectometer-long outcrops are reported here (Sites 1, 2 and 3) in addition to the gabbroic series (hereafter named Site 4) previously described in the literature. The Sites 1 and 2 are located in the upper parts of the Mât River and show dunite and wehrlite units with no apparent foliation, lineation, or layering. The Sites 3 and 4 are located in the lower parts of the river and are made of olivine-gabbro, gabbro and ferrogabbro units showing marked foliation and lineation, and abundant layering. The mean composition of primary phases varies between Sites 1–2 and Sites 3–4: Fo89.5 to Fo69.8 in olivine, Mg# of 90 to 69 in clinopyroxene, and Mg# of 44 to 0 in Cr-spinel, titanomagnetite and, ilmenite, respectively. Here we show that the layered gabbros and peridotites exposed at the four sites represent multiple levels of magma storage. Based on the results of previous gravimetric studies and a drill hole related to geothermal exploration, we propose that the gabbroic series belongs to a magmatic system predating the building of Piton des Neiges and centered underneath the cirque of Salazie. The high volume of erupted materials in the NE quadrant of the volcanic edifice, and the southward magmatic flow direction in the layered gabbros suggest that the initial eruptive center of Proto-Piton des Neiges was above the cirque of Salazie, ~3 km north of the present-day summit. The landscape of Piton des Neiges may have changed when its NE flank experienced a major lateral collapse, after complete solidification of the gabbroic bodies. The magmatic activity, then, shifted southward after the flank collapse. Finally, we suggest that peridotites outcrops are associated with the present-day Piton des Neiges.

Factors Affecting Optimal Titration Pressure of Continuous Positive Airway Pressure Device in Patients with Obstructive Sleep Apnea Syndrome.

To assess the effects of anatomical, clinical parameters, and pulmonary respiratory function on the therapeutic titration pressure of continuous positive airway pressure (CPAP) device in obstructive sleep apnea syndrome (OSAS). The study comprised 41 OSAS patients whose optimum CPAP titration pressures were measured. Each patient underwent an otorhinolaryngologic and thoracic examination, and data was recorded for height, weight, body mass index, neck-waist circumferences, Mallampati classification, tonsillar hypertrophy, hypopharyngeal collapse, soft palate-tongue base obstruction scores, peak nasal inspiratory flow and acoustic rhinometry measures, and CPAP device therapeutic pressures. Forced vital capacity, forced expiratory volume, FEV1/FVC ratio and peak expiratory flow values were noted. Median CPAP optimal pressure cut-off value was determined as 9 mmH2O. Statistical analysis was made in two groups as CPAP titration optimal pressure ≤9 and >9 mmH2O. In the optimal pressure >9 group, neck and waist circumferences, hypopharyngeal collapse score, retropalatal and retrolingual lateral wall collapse scores were significantly higher (p<0.05). In multivariate and univariate model analysis, neck and waist circumferences, hypopharyngeal collapse score, retropalatal and retrolingual lateral wall collapse scores were observed to be significant in predicting high and low pressures in univariate model. For the prediction of optimal CPAP titration pressure in OSAS treatment, wide neck and waist circumferences, high hypopharyngeal collapse score and retropalatal and retrolingual lateral wall collapse grades may be determinative.

Association Between Breathing Route, Oxygen Desaturation, and Upper Airway Morphology.

This study aimed to assess the role of capnography in objectively evaluating breathing routes during drug-induced sleep endoscopy (DISE) and further elucidate the relationship between breathing route, obstructive sleep apnea (OSA) severity, and DISE findings. Prospective observational study. Nighty-five patients with established OSA were recruited for this study from May 2017 to May 2019. DISE was performed in the operating room. Sedation was maintained with propofol using a target-controlled infusion system and the depth of sedation was monitored based on the bispectral index. The breathing routes, which included oral breathing, oronasal breathing, and nasal breathing, were detected using capnography. DISE findings were recorded using the VOTE (velum, oropharynx, base of tongue, and epiglottis) classification. Patients with mouth breathing were associated with increased OSA severity, worse oximetric variables, and higher body mass index in comparison with those with other breathing routes. Mouth breathing was associated with a higher degree and higher prevalence of lateral pharyngeal wall collapse and tongue base collapse during DISE. Mouth breathing was significantly associated with worse oxygen desaturation and increased degree of upper airway collapse. Therefore, patients with mouth breathing during propofol-based intravenous anesthesia should be carefully monitored. 4 Laryngoscope, 131:E659-E664, 2021.

0674 Association Between Lateral Wall Collapse On Drug-induced Sleep Endoscopy And MRI Findings In Hypoglossal Nerve Stimulator Patients

Abstract Introduction Hypoglossal nerve stimulator (HNS) is an effective and safe alternative therapy for obstructive sleep apnea (OSA) in selected patients. Emerging evidence demonstrates that the outcome of HNS is variable, especially for patients with lateral wall collapse on drug-induced sleep endoscopy (DISE). Awake magnetic resonance imaging (MRI) offers detailed visualization of soft tissue. The aim of this study was to determine whether lateral wall collapse on DISE is associated with awake MRI findings in prospective HNS patients. Methods Patients from the ADHERE Registry, an international outcomes study for UAS were used for this study. At baseline, awake, supine MRI scans of each subject’s head and neck region were collected. The distance between the lateral walls was measured at the level of the hard palate, located by the appearance of the posterior nasal spine, using axial T2 turbo spin echo MRI. DISE assessments of the upper airway were recorded using the VOTE classification. All statistical analyses were performed using SPSS IBM 19.0 software program. Kendall’s Tau-b was performed to compare the association between VOTE scoring and MRI findings. Results Twenty-seven patients (N = 3 female, AHI = 28.8±10.5, BMI = 28.8 ±3.8 kg/m2, age = 53±9.9 years) were included in this study. The mean overall VOTE score and lateral wall score was 5.6±1.1 and 0.5±0.5, respectively. The mean lateral wall distance was 18.8±3.2 mm. A significant, inverse association was found between MRI lateral wall measurement and oropharyngeal lateral wall scoring on DISE (T=-.332,p=0.042) but not other anatomic subsites on DISE. Conclusion In our study, greater lateral wall collapse on DISE corresponded to narrower lateral airway distance on MRI. The utility of static imaging modalities such as MRI as patient selection tools for HNS warrants further study. Support Drs. Dedhia and Schwab receive related support for this project from the National Institutes of Health (NHBLI R01HL144859)

Investigation of Structural Stability for Monolithic Nano Bridges on Micro Apertures

The instability of polymeric membranes with nano- and micro-sized apertures has been regarded as one of the main reasons behind realizing ultra-thin membranes with apertures. As is well known, when the thickness of the membrane gets thinner or the aperture size gets smaller, the possibility of geometrical deformation or structural damage by collapse or fracture increases. Herein, we suggest the design rules for the stability of polymeric membranes possessing 1D nano-line patterns monolithically constructed on micro-aperture supporting layers. The proposed theoretical model, which has been thoroughly demonstrated and analyzed based on both theoretical and experimental approaches, provides stability criteria for lateral collapse and vertical fracture of ultra-thin membranes with apertures.

Managing obstructive sleep apnea patients with CPAP failure with a novel Lateral Pharyngoplasty as a stand-alone procedure.

Obstructive sleep apnea syndrome (OSAS) is caused by a complete or partial obstruction of the upper airway. A new Cahali lateral pharyngoplasty as a stand-alone procedure for the treatment of OSA patients, whatever the level and pattern of airway obstruction in patients with CPAP failure or non-compliant patients, is it? 40 patients with known OSAS non-compliant with CPAP or CPAP failures included. BMI, Stop-Bang score, and sleep study parameters were reported before and after the new Cahali pharyngoplasty operation. Preoperative DISE was done for all cases. There were 28 (70%) cases with successful operation outcomes, and 12 (30%) failed cases. Postoperative Stop Bang score, AHI, snoring index were significantly reduced in comparison to preoperative data (p-value <0.001); however, minimal SpO2 and baseline SpO2 were significantly increased in comparison to preoperative data. There was a significant improvement in AHI postoperative. Patients collapse at the level of lateral wall hypopharynx, high tongue collapse, laryngeal collapse, tongue palate interaction, all significantly predict failure outcome of the operation (p-value=0.022). However, the absence of laryngeal collapse (L0) had a successful prediction outcome. The high snoring index significantly predicts operation failure. However, preoperative high baseline SpO2 predicts operation success significantly. The new Cahali lateral pharyngoplasty can be used as a stand-alone procedure in the absence of lateral wall collapse at the level of the hypopharynx (LH), high tongue base collapse (TH), laryngeal collapse (L1) or tongue palate interaction.

Expansion sphincter pharyngoplasty: analyzing the technique based on anatomy.

The purpose of this study is to evaluate the effect of the different surgical techniques of expansion sphincter pharyngoplasty (ESP) on the dimensions of the oropharyngeal airway. The techniques that were evaluated included the preservation and transection of the palatopharyngeus (PP) and superior pharyngeal constrictor (SPC) muscle attachment and transposition of the PP muscle to the hamulus of the medial pterygoid plate and the palatal musculature. Surgical techniques were applied in twenty half heads. The preservation of the PP-SPC attachment inhibited the transposition of the PP muscle to the hamulus and resulted in comparable enlargement in the medial-lateral dimension in the oropharyngeal airway when the PP muscle was transposed to the palatal musculature. After transection of the PP-SPC attachment, significant enlargement was observed in anterior-posterior and medial-lateral directions in the oropharyngeal airway when the PP muscle was transposed both to the hamulus and the palatal musculature. The distances measured after both the transposition techniques were similar. The present study is a basic study demonstrating how different techniques of ESP affect the position of the soft palate. The PP-SPC attachment can be transected in the patients with anterior-posterior palatal and lateral wall collapse to pull the soft palate anteriorly in addition to prevent the lateral wall collapse. The PP-SPC attachment can be preserved in the patients with only lateral wall collapse. Nevertheless, the clinical consequences of these static changes need to be evaluated in clinical studies.

Parameter Calibration of Soil in the Poyang Lake Region Based on Discrete Element Method

In order to obtain the soil parameters of Poyang Lake Region before direct seeding, the soil properties of Duchang County, Poyang County and Xinjian District recollected and the discrete element method model is established. The angle of repose of paddy soil is 53.00° tested by the lateral wall collapse method. Eleven parameters are used to establish EDEM simulation model with the Hertz-Mindlin and the Johnson-Kendall-Roberts (JKR) contact model. Based on the Plackett-Burman experiment, the Steepest ascent experiment and Box-Behnken experiment are carried out to study the factors affecting the angle of repose and the regression equation is established. Thus The optimal parameters are obtained with the deviation of 2.23%. Then the furrow width and depth are introduced to verify the soil model and the comprehensive error is 11.60%. Therefore, the soil model before direct seeding can be used to optimize the structure of mechanical direct seeding in Poyang lake region, so as to achieve the purpose of reducing resistance and increasing efficiency.

Kinked rebar configurations for improving the progressive collapse behaviours of RC frames under middle column removal scenarios

For reinforced concrete (RC) frame structures, applying more continuous longitudinal bars in the beams is the most effective way to improve the progressive collapse resistance. However, an RC frame has the possibility to experience multiple collapse mechanisms. An RC frame may not only experience progressive collapse caused by critical column removal but may also experience lateral collapse under strong earthquakes. The strong column-weak beam (SCWB) requirement in seismic design does not allow excessive longitudinal reinforcement in the beams. To solve this contradiction, a previous study proposed a novel kinked rebar (KB) configuration to enhance both the seismic and progressive collapse resistances of RC frames. This study was carried out to conduct further experimental validation and investigation of progressive collapse behaviours of RC frames with KB configurations. First, a quasi-static progressive collapse test involving 9 RC frame substructures was carried out. The test results indicated that the application of KBs could increase both the loading and deformation capacities under the catenary mechanism of RC substructures. For RC substructures, the influences on progressive collapse behaviours from various structural parameters were also investigated. Second, finite-element simulations were carried out to model the behaviours of the test specimens. This study experimentally verified that the KB configuration can improve the progressive collapse resistances of RC frame structures and clarified the progressive collapse mechanism of novel RC frame substructures with KB configurations.

Introducing a new classification for drug-induced sleep endoscopy (DISE): the PTLTbE system.

A new classification system is proposed to help the interpretation of drug-induced sleep endoscopy (DISE). The purpose is to create a classification system that improves upon existing systems designed to assess suitability of lateral wall surgery such as expansion pharyngoplasty whilst improving the reliability of the classification. A qualitative study into the difficulties trainees had with existing systems was used to identify key issues that needed to be addressed. A visual description of the palate, tonsils, lateral pharyngeal wall, tongue base, epiglottis (PTLTbE) classification was developed. Preliminary data on the inter-rater reliability of PTLTbE were collected. Twenty junior doctors were asked to interpret 5 DISE videos using the PTLTbE classification, and the kappa and percentage agreement were calculated. The Krippendorff alpha ranged between 0.56 and 0.86 for individual DISE videos which compared favourably with the results from those who also completed the VOTE classification (range 0.31 to 0.66). The overall percentage agreement for PTLTbE was 90.1%. There are a number of advantages of the PTLTbE system over other existing DISE classifications. (1) Tonsillar obstruction is separated from lateral pharyngeal wall collapse. (2) Interobserver reliability is improved, critical to improve communication, patient outcomes and future research. (3) The learning curve to use this system is short. Most doctors did not need to refer to the classification images as an aide-memoire after a few uses of the PTLTbE system. A fuller examination of the reliability of the PTLTbE system is underway along with examination of its use in clinical settings.

Tsunami and tephra deposits record interactions between past eruptive activity and landslides at Stromboli volcano, Italy

Abstract Devastation associated with tsunamis is well known on the global scale. Flank collapse at volcanic islands is among the mechanisms triggering tsunamis, but very few examples document interaction between landslides and volcanic activity. The study of three well-preserved medieval tsunami deposits recently discovered along the coast of Stromboli volcano (Aeolian Islands, southern Italy) enabled a detailed characterization of the tsunami sequences intercalated with volcaniclastic deposits and primary tephra and allowed reconstruction of the likely sequence of volcanic events. In one case, a violent explosion possibly preceded the tsunami, whereas in the youngest event, the lateral collapse of the volcano flank triggered a tsunami wave that was rapidly followed by sustained explosive magmatic activity and ensuing prolonged ash venting. The hypothesized tsunami-triggering dynamics suggests a close link between volcanic activity and flank collapse, further confirming that the persistent activity at Stromboli makes the volcano particularly susceptible to tsunami generation.

Preoperative Predictors of Response to Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea.

Hypoglossal nerve stimulation (HGNS) is an effective treatment for patients with obstructive sleep apnea (OSA) who fail continuous positive airway pressure (CPAP). We assessed the relationship between patient characteristics and response to HGNS. Retrospective cohort study. Single tertiary care institution. This study included CPAP-intolerant patients with moderate to severe OSA after HGNS system implantation from November 2015 to December 2017. Patient measures, drug-induced sleep endoscopy (DISE) findings, and apnea-hypopnea indices (AHIs) were recorded. Forty-eight patients underwent implantation with the following median measures: age, 66 years; body mass index, 28.6; and neck circumference, 41.0 cm. Patients were classified by Friedman tongue position (II, 27%; III, 56%; IV, 17%) and Mallampati grade (I, 25%; II, 50%; III, 23%; IV, 2%). By DISE, 71% had anterior-posterior palatal collapse. Additionally, 38% had lateral oropharynx collapse; 50%, tongue base collapse; and 27%, epiglottis collapse. Following implantation, median AHI improved from 38.5 to 2.7 (P < .001), and 92% of patients had no worse than mild OSA (8% moderate). Patients with Friedman tongue position grade II/III experienced greater change in AHI as compared with grade IV (94.2% vs 73.8%, P < .001). Patients with Mallampati score I/II experienced greater improvement versus score III/IV (94.7% vs 66.5%, P < .001). No DISE findings, including any obstruction or collapse, were associated with change in AHI. This study further confirms HGNS as an effective treatment of CPAP-intolerant OSA. Office measures such as Friedman tongue position IV and Mallampati III/IV were associated with mildly decreased response. DISE findings were not associated with patient response.

Mapping Recent Shoreline Changes Spanning the Lateral Collapse of Anak Krakatau Volcano, Indonesia

We use satellite imagery to investigate the shoreline changes associated with volcanic activity in 2018–2019 at Anak Krakatau, Indonesia, spanning a major lateral collapse and period of regrowth through explosive activity. The shoreline changes have been analyzed and validated through the adaptation of an existing methodology based on Sentinel-2 multispectral imagery and developed on Google Earth Engine. This work tests the results of this method in a highly dynamic volcanic environment and validates them with manually digitized shorelines. The analysis shows that the size of the Anak Krakatau Island increased from 2.84 km2 to 3.19 km2 during 15 May 2018–1 November 2019 despite the loss of area in the 22 December 2018 lateral collapse. The lateral collapse reduced the island area to ~1.5 km2 but this was followed by a rapid increase in area in the first two months of 2019, reaching up to 3.27 km2. This was followed by a period of little change as volcanic activity declined and then by a net decrease from May 2019 to 1 November 2019 that resulted from erosion on the SW side of the island. This history of post-collapse eruptive regrowth and coastal erosion derived from the shoreline changes illuminates the potential for satellite-based automated shoreline mapping to provide databases for monitoring remote island volcanoes.

Role of drug-induced sleep endoscopy in evaluation of positional vs non-positional OSA

BackgroundThe study aimed to evaluate the anatomical differences between positional and non-positional OSA, and to identify the potential predictors for distinguishing between these two types of OSA.MethodsA cross-sectional study of 230 consecutive patients with OSA undergoing DISE (Drug-induced Sleep Endoscopy) was carried out at a tertiary academic medical center. The factors correlating with positional and non-positional OSA were analyzed, including clinical characteristics, polysomnography data, and DISE findings.ResultsUnivariate analysis revealed that non-positional dependency was correlated with a higher BMI (p < 0.001), neck circumference (p < 0.001), modified Mallampati score (p = 0.003), AHI (p < 0.001), degree of velum concentric collapse (p = 0.004), degree of oropharyngeal lateral wall collapse (p < 0.001), and degree of tongue base anteroposterior collapse (p = 0.004). Multivariate analysis revealed that oropharyngeal lateral wall collapse (OR = 1.90, p = 0.027) was the only anatomical factor significantly predicted non-positional dependency in OSA patients. AHI (OR = 1.04, p < 0.001), although significant, made only a marginal contribution to the prediction of non-positional dependency.ConclusionsOropharyngeal lateral wall collapse was identified as the only anatomical predictor for non-positional dependency in OSA patients. Therefore, further treatment modalities should address the distinct anatomical trait between positional and non-positional OSA.Graphical abstract