Congenital glottic stenosis as a clinical manifestation of FREM1-associated disorders in a neonate with respiratory distress and aphonia

A female infant born at 38 weeks and 2 days via induced vaginal delivery was admitted to the neonatal intensive care unit for respiratory distress soon after birth. Noted to have aphonia on examination, the patient underwent direct laryngoscopy and was diagnosed with an anterior glottic web and subglottic stenosis. The patient underwent a genetic workup including whole exome sequencing which resulted in a diagnosis of a FREM1-associated disorder. Congenital glottic webs and subglottic stenoses have not been previously described as clinical manifestations of FREM1-associated disorders.

Scoping Review of Surgical Rehabilitation of Post Intubation Phonatory Insufficiency

OBJECTIVES

Post intubation phonatory insufficiency (PIPI) or posterior glottic diastasis describes posterior glottic insufficiency (PGI) caused by prolonged intubation causing medial arytenoid ulceration, mucosal scarring, and incomplete cricoarytenoid joint adduction. The purpose of this review is to showcase diagnostic findings, surgical rehabilitation, and gaps in our treatment algorithm of PIPI.

DATA SOURCES

Embase, PubMed, Scopus, Web of Science.

REVIEW METHODS

Two independent reviewers completed a systematic search of the literature studying PIPI. Reported intubation history, laryngeal defect, clinical symptoms, surgical intervention, and outcomes were gathered from included studies.

RESULTS

Nine studies met our inclusion criteria for full review, (45 patients) all of which were case reports/series. All patients had posterior glottic defects, most commonly loss of medial arytenoid tissue, causing varying degrees of PGI. Eleven patients had vocal fold (VF) immobility or hypomobility. Treatment interventions were observation (1), speech therapy (2), VF or posterior glottic injection augmentation (15), medialization laryngoplasty (4), arytenoid repositioning (6), endoscopic (19) or open (3) posterior cricoid reduction, local mucosal rotation flap (11), or free mucosal graft (2) to fill the glottic defect. Observation, voice therapy, and augmentation or type 1 laryngoplasty failed to improve symptoms. Other surgical techniques improved symptoms with varying outcomes.

CONCLUSION

PIPI is a difficult injury to diagnosis and treat. Conservative measures and augmentation/laryngoplasty often fail to fix the PGI. Our review supports symptom improvement with reconstruction of the posterior glottic defect with cricoid reduction or mucosal grafts. Future investigation is needed to better define the diagnosis and successful treatment algorithm. Laryngoscope, 134:2048-2058, 2024.

Double lumen endobronchial tube intubation: lessons learned from anatomy

BACKGROUND

Double lumen endobronchial tubes (DLTs) are frequently used to employ single lung ventilation strategies during thoracic surgical procedures. Placement of these tubes can be challenging even for experienced clinicians. We hypothesized that airway anatomy, particularly of the glottis and proximal trachea, significantly impacts the ease or difficulty in placement of these tubes.

METHODS

Images from 24 randomly selected Positron Emission Tomography - Computed Tomography (PET-CT) scans were evaluated for several anatomic aspects of the upper airway, including size and angulation of the glottis and proximal tracheal using calibrated CT measurements and an online digital protractor. The anatomic issues identified were confirmed in cadaveric anatomic models.

RESULTS

Proximal tracheal diameter measurements in PET-CT scans demonstrated a mean ± standard deviation of 20.4 ± 2.5 mm in 12 males and 15.5 ± 0.98 mm in 12 females (p < 0.001), and both were large enough to accommodate 39 French and 37 French DLTs in males and females, respectively. Subsequent measurements of the posterior angulation of the proximal trachea revealed a mean angle of 40.8 ± 5.7 degrees with no sex differences. By combining the 24 individual posterior tracheal angles with the 16 angled distal tip measurements DLTs (mean angle 24.9 ± 2.1 degrees), we created a series of 384 patient intubation angle scenarios. This data clearly showed that DLT rotation to a full 180 degrees decreased the mean intubation angle between the DLT and the proximal trachea from a mean of 66.6 ± 5.9 to only 15.8 ± 5.9 degrees.

CONCLUSIONS

Rotation of DLTs a full 180 instead of the recommended 90 degrees facilitates DLT intubations.

Scale resolving simulations of the effect of glottis motion and the laryngeal jet on flow dynamics during respiration

BACKGROUND AND OBJECTIVE

The movement of the respiratory walls has a significant impact on airflow through the respiratory tract. The majority of computational fluid dynamics (CFD) studies assume a static geometry which may not provide a realistic flow field. Furthermore, many studies use Reynolds Averaged Navier-Stokes (RANS) turbulence models that do not resolve turbulence structure. Combining the application of advanced scale-resolving turbulence models with moving respiratory walls using CFD will provide detailed insights into respiratory flow structures.

METHODS

This study simulated a complete breathing cycle involving inhalation and exhalation in a nasal cavity to trachea geometry that incorporated moving glottis walls. A second breathing cycle was simulated with static glottis walls for comparison. A recently developed hybrid RANS-LES turbulence model, the Stress-Blended Eddy Simulation (SBES), was incorporated to resolve turbulent flow structures in fine detail for both transient simulations. Transient results were compared with steady-state RANS simulations for the same respiratory geometry.

RESULTS

Glottis motion caused substantial effects on flow structure through the complete breathing cycle. Significant flow structure and velocity variations were observed due to glottal motion, primarily in the larynx and trachea. Resolved turbulence structures using SBES showed an intense mixing section in the glottis region during inhalation and in the nasopharynx during expiration, which was not present in the RANS simulations.

CONCLUSION

Transient simulations of a realistic breathing cycle uncovered flow structures absent in simulations with a constant flow rate. Furthermore, the incorporation of glottis motion impacted airflow characteristics that suggest rigid respiratory walls do not accurately describe respiratory flow. Future research in respiratory airflow should be conducted using transient scale-resolving models in conjunction with moving respiratory walls to capture flow structures in detail.

Simulation of Multiple Source Vocalization in the Larynx: How True Folds, False Folds, and Aryepiglottic Folds May Interact

PURPOSE

This study was a modest beginning to determine dominance and entrainment between three soft tissues in the larynx that can be set into flow-induced oscillation and act as sound sources. The hypothesis was that they interact as coupled oscillators with observable bifurcations as energy is exchanged between them.

METHODOLOGY

The true vocal folds, the ventricular (false) folds, and the aryepiglottic folds were part of a soft-walled airway that produced airflow for sound production. The methodology was computational, based on a simplified Navier-Stokes solution of convective and compressible airflow in a variable-geometry airway.

RESULTS

Three serially connected sources could all produce flow-induced self-oscillation with soft wall tissue and small cross-sectional area. When the glottal cross-sectional areas were similar, bifurcations such as subharmonics, delayed voice onset, and aphonia occurred in the coupled oscillations.

CONCLUSIONS

Closely spaced sound sources in the larynx are highly interactive. They appear to entrain to the source that has the combined advantage of small cross-sectional glottal area and proximity to a downstream vocal tract that supports oscillation with acoustic inertance.

Closed- or open-glottis pushing for vaginal delivery: a planned secondary analysis of the TRAnexamic Acid for Preventing postpartum hemorrhage after vaginal delivery study

BACKGROUND

The effect on obstetrical outcomes of closed- or open-glottis pushing is uncertain among both nulliparous and parous women.

OBJECTIVE

This study aimed to assess the association between open- or closed-glottis pushing and mode of delivery after an attempted singleton vaginal birth at or near term.

STUDY DESIGN

This was an ancillary planned cohort study of the TRAAP (TRAnexamic Acid for Preventing postpartum hemorrhage after vaginal delivery) randomized controlled trial, conducted in 15 French maternity units from 2015 to 2016 that enrolled women with an attempted singleton vaginal delivery after 35 weeks' gestation. After randomization, characteristics of labor and delivery were prospectively collected, with special attention to active second-stage pushing and a specific planned questionnaire completed immediately after birth by the attending care provider. The exposure was the mode of pushing, classified into 2 groups: closed- or open-glottis. The main endpoint was operative vaginal delivery. Secondary endpoints were items of maternal morbidity, including severe perineal laceration, episiotomy, postpartum hemorrhage, duration of the second stage of labor, and a composite severe neonatal morbidity outcome. We also assessed immediate maternal satisfaction, experience of delivery, and psychological status 2 months after delivery. The associations between mode of pushing and outcome were analyzed by multivariate logistic regression to control for confounding bias, with multilevel mixed-effects analysis, and a random intercept for center.

RESULTS

Among 3041 women included in our main analysis, 2463 (81.0%) used closed-glottis pushing and 578 (19.0%) open-glottis pushing; their respective operative vaginal delivery rates were 19.1% (n=471; 95% confidence interval, 17.6-20.7) and 12.5% (n=72; 95% confidence interval, 9.9-15.4; P<.001). In an analysis stratified according to parity and after controlling for available confounders, the rate of operative vaginal delivery did not differ between the groups among nulliparous women: 28.7% (n=399) for the closed-glottis and 27.5% (n=64) for the open-glottis group (adjusted odds ratio, 0.93; 95% confidence interval, 0.65-1.33; P=.7). The operative vaginal delivery rate was significantly lower for women using open- compared with closed-glottis pushing in the parous population: 2.3% (n=8) for the open- and 6.7% (n=72) for the closed-glottis groups (adjusted odds ratio, 0.43; 95% confidence interval, 0.19-0.90; P=.03). Other maternal and neonatal outcomes did not differ between the 2 modes of pushing among either the nulliparous or parous groups.

CONCLUSION

Among nulliparous women with singleton pregnancies at term, the risk of operative vaginal birth did not differ according to mode of pushing. These results will inform shared decision-making about the mode of pushing during the second stage of labor.

Needle Fracture During Injection Medialization Laryngoplasty

OBJECTIVES

Awake injection medialization laryngoplasty is one of the most common therapeutic procedures done by laryngologists in the office or at the bedside. Complications of injection needle fracture are rarely reported.

METHODS

This is a case report of a 59-year-old male inpatient who developed left vocal fold immobility with significant glottic insufficiency after pneumonectomy for a large left-sided lung cancer. During bedside injection medialization using thyrohyoid approach, the 25 G needle fractured at the hub and was embedded partly in pre-epiglottic space and partly extending over rima glottidis.

RESULTS

Fractured needle was successfully retrieved at the bedside with an endoscopic biopsy forcep using flexible bronchoscope.

CONCLUSION

It is imperative to be aware of rare complications of routine procedures like injection laryngoplasty so they can be managed timely and effectively.

A case of antenatally undiagnosed laryngeal atresia with tracheo-esophageal fistula with airway obstruction at birth and its management

Laryngeal atresia is a rare congenital anomaly that is usually diagnosed by antenatal ultrasound, however, if undiagnosed presents with desaturation after birth. A term neonate presented with airway obstruction after birth with multiple failed attempts at intubation and was rescued by proseal laryngeal mask airway (LMA). An esophagoscopy using an Ambuscope utilizing a modified connector assembly revealed an opening on the anterior wall of the esophagus with no esophageal atresia, leading to a diagnosis of H-type tracheo-esophageal fistula (TEF) with laryngeal atresia. The ability to ventilate the neonate via LMA with an absent glottic opening raised the possibility of TEF.

Indirect laryngoscopy is more effective than direct laryngoscopy when tracheal intubation is performed by novice operators: a systematic review, meta-analysis, and trial sequential analysis

PURPOSE

We sought to perform a systematic review and meta-analysis to determine whether indirect laryngoscopy has an advantage over direct laryngoscopy in terms of the tracheal intubation rate, glottic visualization, and intubation time when used by novice operators.

METHODS

We extracted adult prospective randomized trials comparing tracheal intubation with indirect vs direct laryngoscopy in novice operators from electronic databases. We extracted the following data from the identified studies: success rate, glottic visualization, and intubation time. Data from each trial were combined via a random-effects model to calculate the pooled relative risk (RR) or weighted mean difference (WMD) with a 95% confidence interval (CI). We also performed a trial sequential analysis.

RESULTS

We included 15 articles (17 trials) comprising 2,290 patients in the systematic review. Compared with the direct laryngoscopy, indirect laryngoscopy improved success rate (RR, 1.15; 95% CI, 1.07 to 1.24; P = 0.0002; I2 = 88%), glottic visualization (RR, 1.76; 95% CI, 1.36 to 2.28; P < 0.001; I2 = 85%), and intubation time (WMD, -9.06 sec; 95% CI, -16.4 to -1.76; P = 0.01; I2 = 98%) in tracheal intubation. Trial sequential analysis showed that the total sample size was sufficient to analyze the success rate and intubation time.

CONCLUSION

In this systematic review, we found that the tracheal intubation success rate, glottic visualization, and intubation time were improved when novice operators used indirect laryngoscopy rather than direct laryngoscopy. Trial sequential analysis results indicated that the sample size was sufficient for examining the success rate and intubation time.

STUDY REGISTRATION

PROSPERO (CRD42022309045); first registered 4 September 2022.

An unusual cause of hemoptysis and hoarseness due to live leech in the glottis: case report

We performed laryngoscopy on a patient with symptoms such as hoarseness, hemoptysis, cough and intermittent dyspnea, and took out a brown-black foreign body—living leech in the glottis area, no such case has been reported before.

An Unusual Cause of Laryngeal Dyspnea

INTRODUCTION

Medialization laryngoplasty with autologous fat (MLA) is indicated in some patients with glottic insufficiency. The approach is usually safe but long-term complications are poorly described.

CASE REPORT

We present the history of a patient who developed progressive dyspnea and dysphonia two decades after bilateral MLA, which were due to the development of laryngea lipoma into the site of fat injection.

DISCUSSION

The potential relationship between MLA and the development of laryngeal lipoma was discussed. The lipoma may be a long-term survival of too much fat tissue, which was reorganized into a well-limited lipoma over the long-term. Another hypothesis consisted of the injection of fat tissue, including fatty stem cells, and the development of a lipoma over the year through the neovascularization process.

CONCLUSION

We reported the first case of lipoma developed into the laryngeal site of fat injection. Future studies are needed to explore the long-term evolution of injected fat tissue in the context of MLA.

Development and Application of Automated Vocal Fold Tracking Software in a Rat Surgical Model

OBJECTIVE

The rat is a widely used model for studying vocal fold (VF) function after recurrent laryngeal nerve injury, but common techniques for evaluating rat VF motion remain subjective and imprecise. To address this, we developed a software package, called RatVocalTracker1.0 (RVT1.0), to quantify VF motion and tested it on rats with iatrogenic unilateral vocal fold paralysis (VFP).

METHODS

A deep neural network was trained to identify the positions of the VFs and arytenoid cartilages (ACs) in transoral laryngoscope videos of the rat glottis. Software was developed to estimate glottic midline, VF displacement, VF velocity, and AC angle. The software was applied to laryngoscope videos of adult rats before and after right recurrent and superior laryngeal nerve transection (N = 15; 6M, 9F). All software calculated metrics were compared before and after injury and validated against manually calculated metrics.

RESULTS

RVT1.0 accurately tracked and quantified VF displacement, VF velocity, and AC angle. Significant differences were found before and after surgery for all RVT1.0 calculated metrics. There was strong agreement between programmatically and manually calculated measures. Automated analysis was also more efficient than nearly all manual methods.

CONCLUSION

This approach provides fast, accurate assessment of VF motion in rats with minimal labor and allows for quantitative comparison of lateral differences in movement. Through this novel analysis method, we can differentiate healthy movement from unilateral VFP. RVT1.0 is open-source and will be a valuable tool for researchers using the rat model for laryngology research.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:340-346, 2024.

Dosimetric comparison between carotid-sparing IMRT and 3DCRT in early glottic cancer patients treated with definitive radiation therapy

BACKGROUND

The purpose of this study was to evaluate the dosimetric benefits of carotid-sparing IMRT (intensity-modulated radiation therapy) over 3DCRT (three-dimensional conformal radiation therapy) in early glottic cancer patients.

MATERIAL AND METHODS

Ten patients with histologically proven early-stage squamous cell cancer of glottis (T1N0), treated with definitive radiotherapy, were selected retrospectively for the dosimetric analysis. Patients were originally treated with 3DCRT technique. For comparison purpose, IMRT plans were generated for each patient. Dosimetric comparison was done between two techniques (IMRT and 3DCRT) in terms of PTV (planning target volume) coverage, HI (homogeneity index), CI (conformity index), and doses to right carotid artery, left carotid artery, and spinal cord.

RESULTS

V95% for the PTV was higher in IMRT plans (98.26%) as compared to 3DCRT plans (95.12%) (P-value <0.001), whereas V105% for PTV was significantly higher in 3DCRT plans (16.77%) as compared to IMRT plans (0.32%) (P-value 0.11). In terms of both HI and CI, IMRT plans showed better conformity as compared to 3DCRT plans, with statistically significant difference. Both right and left carotid arteries' average mean and maximum doses were significantly lower in IMRT plans as compared to 3DCRT plans (P-value <0.001). IMRT plans resulted in significant carotid-sparing as compared to 3DCRT plans in terms of V35 and V50 (P-value <0.001).

CONCLUSION

Carotid-sparing IMRT resulted in better PTV coverage and lower carotid artery dose as compared to 3DCRT in early glottic cancer patients.

Multivariate Analysis of Vocal Fold Vibrations in Normal Speakers Using High-Speed Digital Imaging

INTRODUCTION

Little is known about the normal variations in vocal fold vibrations. We conducted a prospective study on normal subjects using high-speed digital imaging (HSDI) to elucidate key parameters regarding age/gender-related normal variations.

METHODS

Forty-six healthy adult volunteers were divided into young (aged ≤35 years) male, young female, elderly (aged ≥65 years) male, and elderly female subgroups. HSDI data of sustained phonation of /i/ at a comfortable pitch and loudness were obtained, and vibratory parameters were calculated using the visual-perceptual rating, laryngotopography, digital kymography, and glottal area waveform. Multivariate analysis was then performed on these parameters to clarify the subgroup-specific key parameters.

RESULTS

Four key parameters were identified from a total of 83: one from visual perceptual rating and three from laryngotopography. Subgroup analyses showed that posterior-to-anterior longitudinal phase difference (PD) and high fundamental frequency (F0) were specific to young female participants. A low F0 was specific to young male participants. Large anterior-to-posterior longitudinal PD and its left-right difference were specific to elderly male participants. There were no key parameters for elderly female participants.

CONCLUSIONS

Methods that can assess F0 and longitudinal PD, such as visual-perceptual rating and laryngotopography, were effective in the evaluation of normal vocal fold vibrations and their variations.

Comparison of the Effectiveness of the Miller Laryngoscope and the McGrath-MAC Video Laryngoscope in Direct Visualization of the Glottic Opening

Background and Objective: Placing the laryngoscope blade directly under the epiglottis (known as the direct view (DV) method) during videolaryngoscopy offers a superior view of the glottis when compared to the indirect method of lifting the epiglottis by positioning the Macintosh blade tip over the vallecula. While there are few studies comparing glottic views using Miller and Macintosh blades in pediatric patients, we have not come across such a study in adults. In this study, we aimed to compare the effectiveness and hemodynamic responses of the Miller laryngoscope and the McGrath-MAC videolaryngoscope (VL) in visualizing the glottic opening using the DV method. Material and Methods: A prospective study was conducted between August and December 2022 at XXX Hospital on 85 patients scheduled for surgical procedures involving endotracheal intubation. Patients were divided into two groups: Miller laryngoscope (Group M) and McGrath-MAC videolaryngoscope (Group VL) and intubated using the direct lifting method of the epiglottis. Hemodynamic responses before and after induction, as well as during laryngoscopy, intubation time, number of attempts, Cormack and Lehane (C&L) score, percentage of glottic opening (POGO), duration of the view of the opening, and need for external laryngeal pressure during intubation were recorded. Results: Both laryngoscopes showed similar effectiveness in terms of POGO and C&L score when used with the direct lifting method of the epiglottis. The median POGO values according to the DV method were 80% in Group M and 70% in Group VL (p = 0.099). Hemodynamic responses, intubation time, number of attempts, duration of view of the glottis opening, and the need for external laryngeal pressure were similar between the groups. Conclusions: Due to its ability to provide effective intubation conditions, we believe that the McGrath-MAC VL, when used with the indirect view method, can also be utilized in anesthesia practices alongside the DV method.

Predicting Airflow from Measures Sensitive to Mid-cord Glottal Gap During the COVID-19 Pandemic

OBJECTIVES

To determine if trans-laryngeal airflow, important in assessing vocal function in paresis/paralysis and presbylarynges patients with mid-cord glottal gaps, could be predicted by other measures sensitive to mid-cord glottal gap size but with smaller risks of spreading COVID-19, and if any patient factors need consideration.

METHODS

Four populations were: unilateral vocal fold paresis/paralysis (UVFP, 148), aging and UVFP (UVFP plus aging, 22), bilateral vocal fold paresis/paralysis without airway obstruction (BVFP, 49), and presbylarynges (66). Five measures were selected from the initial clinic visit: mean airflow from repeated /pi/ syllables, longer of 2 /s/ and 2 /z/ productions, higher of 2 cepstral peak prominence smoothed for vowel /a/ (CPPSa), and Glottal Function Index (GFI). S/Z ratios were computed. Stepwise regression models used 3 measures and 5 patient factors (age, sex, etiology, diagnosis, and potentially impaired power source for voicing) to predict airflow.

RESULTS

Log-transformations were required to normalize distributions of airflow and S/Z ratio. The final model revealed age, sex, impaired power source, log-transformed S/Z ratio, and GFI predicted log-transformed airflow (R2 = .275, F[5,278] = 21.1; P < .001).

CONCLUSIONS

The amount of variance explained by the model was not high, suggesting adding other predictive variables to the model might increase the variance explained.

Injection medialisation laryngoplasty: an alternative approach for challenging cases

OBJECTIVE

Conventional injection medialisation laryngoplasty techniques may be compromised by patient-specific factors such as marked kyphosis, an anteriorly positioned larynx or intolerance to nasendoscopy. This paper describes a technique for successful injection medialisation laryngoplasty where conventional methods are precluded, in an 88-year-old man with presbyphonia on a background of Parkinson's disease.

METHODS

After induction of general anaesthesia, a transoral introducing needle, shaped by tactile manipulation to match the curvature of a 'C-MAC' intubating video-laryngoscope 'D-blade' attachment, was introduced until visible above the glottis. The implant material was then injected into the paraglottic space as normal until satisfactory medialisation of the vocal fold was achieved.

RESULTS

When reviewed in the out-patient clinic four weeks later, the patient's post-operative Voice Handicap Index score fell to 6, from a pre-operative score of 21.

CONCLUSION

By utilising commonly available equipment and anaesthetic support to recreate the views and access conventional nasendoscopy and laryngoscopy facilitate, this novel procedure provides a viable and proven alternative in uncommon but challenging cases.

Safety and effectiveness of endotracheal intubation in critically ill emergency patients with videolaryngoscopy

To investigate the safety and efficacy of video laryngoscopy for endotracheal intubation in critically ill patients. A total of 106 critically ill emergency patients treated at our hospital between January 2021 and June 2022 were randomly divided into 2 groups, the visual and direct groups, with 53 patients in each group. Both groups were treated with endotracheal intubation; the visual group was treated with video laryngoscopy, and the direct group was treated with conventional direct laryngoscopy. The Cormack-Lehane grade, percentage of glottic opening score, success rate of one intubation, intubation time, number of intubation attempts, hemodynamic values, and complications were compared between the 2 groups. The success rates of glottis exposure and one-time intubation were significantly higher while the intubation time and number of intubation attempts significantly lower in the visual group than in the direct group. The heart rate, mean arterial pressure (MAP), or blood oxygen saturation did not differ significantly between the 2 groups 10 minutes after entering the room (T0) or after anesthesia induction (T1). MAP was significantly lower in the visual group than in the direct group during immediate intubation (T2). The heart rate and MAP were significantly lower in the visual group than in the direct group 1 minute (T3) and 5 minutes (T4) after intubation. The incidences of intubation-related complications in the visual and direct groups were 7.55% and 22.60%, showing a significant difference. Endotracheal intubation under videolaryngoscopy is safer and more effective for critically ill emergency patients than conventional direct laryngoscopy. This can improve the success rate of intubation, reduce the intubation time, and reduce its effect on hemodynamics. Therefore, it is worthy of further clinical application.

The effects of vocal tract constrictions on aerodynamic measures in a synthetic vocal fold model

According to nonlinear source-filter theory, as the strength of the coupling between the source and filter increases, typically by a decrease in the vocal tract cross-sectional area, the resultant increase in the inertance of the vocal tract yields an increase in the interactions between acoustic pressures within the vocal tract and the changing glottal airflow and/or the vibratory pattern of the vocal folds as noted in Titze [(2008). J. Acoust. Soc. Am. 123(4), 1902-1915]. The purpose of the current research was to examine the effects of parametric vocal tract constrictions mimicking epilaryngeal tube and lip narrowing on aerodynamic measures in a dynamic self-oscillating physical model of the vocal folds and vocal tract. Multilayered silicone vocal fold models were created based on Murray and Thomson [(2011). J. Visualized Exp. 58, e3498] and Murray and Thomson [(2012). J. Acoust. Soc. Am. 132(5), 3428-3438] and mounted to a simple synthetic trachea and supraglottal vocal tract model. Four constriction cross-sectional areas were examined at two locations (i.e., at the epilarynx and lip regions). Phonation threshold pressure and flow were measured at phonation onset and offset using four M5-CONV vocal fold models. Results indicated that both constriction magnitude and location are relevant factors in determining glottal aerodynamics. In general, a narrow epilarynx tube or lip constriction resulted in the lowest onset pressures and airflows while the no vocal tract condition resulted in the highest onset pressures and airflows.

Nasal Breathing Through a Damp Gauze Enhances Surface Hydration of the Vocal Folds and Optimizes Vocal Function

OBJECTIVE

The present study proposes a direct surface hydration system based on nasal breathing through a damp gauze. The goal is to observe whether such direct hydration procedure positively modifies vocal fold functionality by improving voice quality and enhancing the mobility and pliability of the vocal fold mucosa.

METHODS

Sixty-one young adults without voice problems were enrolled and were randomly divided into three double-blinded treatment groups. In the first group (the gauze group), participants breathed through the nose wrapped in a damp gauze for 10 minutes while doing vocal warm-up exercises to facilitate water penetration into the mucosal layers of the vocal folds. The second group (the exercise group) performed the same warm-up exercises as the gauze group for 10 minutes without hydration procedures. The third group (the control group) talked using their normal speaking voice for 10 minutes. The participants were evaluated before and after the treatment tasks with three tests: a laryngostroboscopic examination (ie, the glottic closure, the amplitude of the mucosal wave, and the maximum opening of the glottic space); voice acoustic analysis (multidimensional voice program); and a perceptual voice evaluation (GRBAS scale).

RESULTS

Results showed that after the use of a damp gauze, glottic closure, the amplitude of the mucosal wave, the maximum opening of the glottic space, the shimmer, and the B of GRBAS all improved.

CONCLUSION

Findings showed significantly better vocal results for the participants of the gauze group, suggesting the damp gauze procedure to be an effective, fast, and economical procedure to improve and optimize vocal fold functionality. It can be hypothesized that the obtained results are related to an improvement in vocal folds surface hydration and viscoelasticity.

I-gel Plus acts as a superior conduit for fiberoptic intubation than standard i-gel

The supraglottic airway (SGA) is widely used. I-gel Plus is a next-generation i-gel with some improvements, including facilitation of fiberoptic tracheal intubation (FOI). To compare the performance of i-gel Plus and standard i-gel as conduits for FOI, a Thiel-embalmed cadaveric study was conducted. Twenty-two anesthesiologists were enrolled as operators in Experiment 1. The i-gel Plus and standard i-gel were inserted into one cadaver, and the FOI was performed through each SGA. The primary outcome was time required for FOI. The secondary outcomes were the number of attempts and visual analog scale (VAS) score for difficulty in FOI. Moreover, fiberoptic views of the vocal cords in each SGA were assessed by an attending anesthesiologist using nine cadavers in Experiment 2. The percentage of glottic opening (POGO) score without fiberscope tip upward flexion and upward angle of the fiberscope tip to obtain a 100% POGO score were evaluated as secondary outcomes. The time for FOI through i-gel Plus was significantly shorter than that through standard i-gel (median (IQR), i-gel Plus: 30.3 (25.4-39.0) s, vs standard i-gel: 54.7 (29.6-135.0) s; median of differences, 24.4 s; adjusted 95% confidence interval, 3.0-105.7; adjusted P = 0.040). Although the number of attempts for successful FOI was not significantly different, the VAS score for difficulty in the i-gel Plus group was significantly lower (easier) than that in the standard i-gel group. Moreover, i-gel Plus required a significantly smaller upward angle of the fiberscope tip to obtain a 100% POGO score. FOI can be performed more easily using i-gel Plus than using standard i-gel because of the improved fiberoptic visibility of vocal cords.

Novice residents' endotracheal intubation skill retention on a simulated mannequin after rotating at an anaesthesiology department: a randomized controlled study

OBJECTIVE

To compare the endotracheal intubation skill retention of the McGRATH™ MAC video laryngoscope with that of the Macintosh laryngoscope in first-year residents rotating at an anaesthesiology department.

METHODS

This randomized controlled study enrolled first-year residents who completed a 2-month rotation at an anaesthesiology department. Each rotation group was randomly assigned to the Macintosh laryngoscope (ML) or McGRATH™ MAC video laryngoscope (MML) group. Endotracheal intubation skills were evaluated on a mannequin after the rotation and at 3 and 6 months later. The primary endpoint was the time required for intubation. The secondary endpoint was the percentage of glottic opening (POGO) score.

RESULTS

Forty-six residents participated in this study and were assigned to the ML group (n = 23) or the MML group (n = 23). There were no significant differences between the sex, age and the number of endotracheal intubation procedures performed between the two groups. The time required for intubation was significantly shorter in the MML group compared with the ML group. The POGO scores did not show any significant differences between the two groups.

CONCLUSION

Compared with endotracheal intubation training using the Macintosh laryngoscope, the McGRATH™ MAC video laryngoscope shortened the intubation procedure and its effect remained even after 6 months.

TRIAL REGISTRATION

UMIN-CTR Clinical Trials, UMIN000036643, URL: https://www.umin.ac.jp.

Usefulness of C-curved stylet for intubation with the C-MAC® Miller videolaryngoscope in neonates and infants: a prospective randomized controlled trial

BACKGROUND

Optimizing endotracheal tube (ETT) shape is important for successful videolaryngoscope-aided intubation. This prospective randomized controlled study aimed to compare the tube-handling time between a C-curved and hockey stick-shaped stylet in infants and neonates using the C-MAC® videolaryngoscope Miller blade.

METHODS

A total of 110 infants (age < 1 year) were randomly assigned to either the hockey stick-curved stylet group (group H, n = 53) or the C-curved stylet group (group C, n = 57). The primary outcome was tube handling time after glottis visualization and the secondary outcomes were the total intubation time, incidence of successful intubation, initial tube tip location at the laryngeal inlet, and numerical rating scale for ease of intubation.

RESULTS

Tube insertion time and total intubation duration (both in seconds) were significantly shorter in group C than in group H (13.3 ± 8.9 vs. 25.1 ± 27.0, P = 0.002; 19.9 ± 9.4 vs. 32.8 ± 27.1, P = 0.001, respectively). Group C displayed a higher rate of intubation success within 30 s than group H (87.7% vs. 69.8%, P = 0.029). The initial tube tip was located at the center in 34 children in group C (59.6%) and 12 children in group H (26.1%, P < 0.001). Laryngoscope operators rated intubation as easier when provided with a C-curved stylet.

CONCLUSIONS

In neonates and infants, modification of the ETT shape into a C-curve may reduce tube handling time compared to the conventional hockey stick-shaped tube during intubation using a C-MAC® video laryngoscope Miller blade.

Domain adaptive Sim-to-Real segmentation of oropharyngeal organs

Video-assisted transoral tracheal intubation (TI) necessitates using an endoscope that helps the physician insert a tracheal tube into the glottis instead of the esophagus. The growing trend of robotic-assisted TI would require a medical robot to distinguish anatomical features like an experienced physician which can be imitated by utilizing supervised deep-learning techniques. However, the real datasets of oropharyngeal organs are often inaccessible due to limited open-source data and patient privacy. In this work, we propose a domain adaptive Sim-to-Real framework called IoU-Ranking Blend-ArtFlow (IRB-AF) for image segmentation of oropharyngeal organs. The framework includes an image blending strategy called IoU-Ranking Blend (IRB) and style-transfer method ArtFlow. Here, IRB alleviates the problem of poor segmentation performance caused by significant datasets domain differences, while ArtFlow is introduced to reduce the discrepancies between datasets further. A virtual oropharynx image dataset generated by the SOFA framework is used as the learning subject for semantic segmentation to deal with the limited availability of actual endoscopic images. We adapted IRB-AF with the state-of-the-art domain adaptive segmentation models. The results demonstrate the superior performance of our approach in further improving the segmentation accuracy and training stability.

Acoustic Screening of the "Wet voice": Proof of Concept in an ex vivo Canine Laryngeal Model

BACKGROUND

Current protocols for bedside swallow evaluation have high rates of false negative results. Though experts are not consistently able to screen for aspiration risk by assessing vocal quality, there is emerging evidence that vocal acoustic parameters are significantly different in patients at risk of aspiration. Herein, we aimed to determine whether the presence of material on the vocal folds in an excised canine laryngeal model may have an impact on acoustic and aerodynamic measures.

METHODS

Two ex vivo canine larynges were tested. Three liquids of different viscosities (1:100 diluted glycerin, pure glycerin, and honey-thick Varibar) were placed on the vocal folds at a constant volume. Acoustic and aerodynamic measures were obtained in both adducted and abducted vocal fold configurations. Intraglottal high-speed imaging was used to approximate the maximum divergence angle of the larynges in the studied conditions and examine its relationship to vocal efficiency (VE) and acoustic measures.

RESULTS

In glottic insufficiency conditions only, we found that several acoustic parameters could predict the presence of material on the vocal folds. Based on the combination of the aerodynamic and acoustic data, we found that decreased spectral energy in the higher harmonics was associated with decreased VE in the presence of material on the vocal folds and/or glottic insufficiency.

CONCLUSION

Decreased spectral energy in the higher harmonics of the voice was found to be a potential biomarker of swallowing dysfunction, as it correlates with decreased vocal efficiency due to material on the vocal folds and/or glottic insufficiency, both of which are known risk factors for aspiration.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:2517-2524, 2023.

Direct versus indirect epiglottis elevation in cervical spine movement during videolaryngoscopic intubation under manual in-line stabilization: a randomized controlled trial

BACKGROUND

During videolaryngoscopic intubation, direct epiglottis elevation provides a higher percentage of glottic opening score than indirect epiglottis elevation. In this randomized controlled trial, we compared cervical spine movement during videolaryngoscopic intubation under manual in-line stabilization between the two glottis exposure methods.

METHODS

Videolaryngoscopic intubation under manual in-line stabilization was performed using C-MAC® D-blade: direct (n = 51) and indirect (n = 51) epiglottis elevation groups. The percentage of glottic opening score was set equally at 50% during videolaryngoscopic intubation in both groups. The primary outcome measure was cervical spine movement during videolaryngoscopic intubation at the occiput-C1, C1-C2, and C2-C5. The secondary outcome measures included intubation performance (intubation success rate and intubation time).

RESULTS

Cervical spine movement during videolaryngoscopic intubation was significantly smaller at the occiput-C1 in the direct epiglottis elevation group than in the indirect epiglottis elevation group (mean [standard deviation] 3.9 [4.0] vs. 5.8 [3.4] °, P = 0.011), whereas it was not significantly different at the C1-C2 and C2-C5 between the two groups. All intubations were successful on the first attempt, achieving a percentage of glottic opening score of 50% in both groups. Intubation time was longer in the direct epiglottis elevation group (median [interquartile range] 29.0 [24.0-35.0] vs. 22.0 [18.0-27.0] s, P < 0.001).

CONCLUSIONS

When performing videolaryngoscopic intubation under manual in-line stabilization, direct epiglottis elevation can be more beneficial than indirect epiglottis elevation in reducing cervical spine movement during videolaryngoscopic intubation at the occiput-C1.

TRIAL REGISTRATION

Clinical Research Information Service (number: KCT0006239, date: 10/06/2021).

Using a vertical three-mass computational model of the vocal folds to match human phonation of three adult males

Computer models of phonation are used to study various parameters that are difficult to control, measure, and observe in human subjects. Imitating human phonation by varying the prephonatory conditions of computer models offers insight into the variations that occur across human phonatory production. In the present study, a vertical three-mass computer model of phonation [Perrine, Scherer, Fulcher, and Zhai (2020). J. Acoust. Soc. Am. 147, 1727-1737], driven by empirical pressures from a physical model of the vocal folds (model M5), with a vocal tract following the design of Ishizaka and Flanagan [(1972). Bell Sys. Tech. J. 51, 1233-1268] was used to match prolonged vowels produced by three male subjects using various pitch and loudness levels. The prephonatory conditions of tissue mass and tension, subglottal pressure, glottal diameter and angle, posterior glottal gap, false vocal fold gap, and vocal tract cross-sectional areas were varied in the model to match the model output with the fundamental frequency, alternating current airflow, direct current airflow, skewing quotient, open quotient, maximum flow negative derivative, and the first three formant frequencies from the human production. Parameters were matched between the model and human subjects with an average overall percent mismatch of 4.40% (standard deviation = 6.75%), suggesting a reasonable ability of the simple low dimensional model to mimic these variables.

The Management in Patients With Bilateral Vocal Fold Immobility: 15 Years' Experience at a Tertiary Centre

OBJECTIVE

In order to correct the varying vocal fold positions to meet the various clinical requirements in patients with bilateral vocal fold immobility, we present pertinent surgical methods to treat them.

MATERIALS AND METHODS

From 2005 to 2020, 115 patients diagnosed with bilateral vocal fold immobility were addressed for ventilation in 89 patients and for phonation in 26 patients. In the ventilation surgery group, all the neurogenic subjects received mere suture lateralization (SL) procedures and the mechanical ones underwent arytenoid release (AR) plus SL procedures if the cricoarytenoid joint fixation (CAJF) could be confirmed before operation. In the phonation group, neurogenic subjects received nonsurgical treatment and the mechanical ones underwent AR plus arytenoid adduction (AA) procedure. The decannulation rate and respiratory comfort rate for each subgroup will be calculated and the phonatory tests were conducted.

RESULTS

In the ventilation group, 55% (49/89) of subjects received related surgeries. Mere SL offered 40 successful decannulation or respiratory comfort in 42 neurogenic subjects (95.2%). The single episode rate was high as 95%. An AR plus SL procedure also obtained 100% of decannulation or respiratory comfort with a single episode of surgical procedure if the CAJF could be confirmed preoperatively. In the phonation group, 15% (4/26) of subjects received appropriate surgeries. Single AR plus AA procedures also led to 100% (4/4) of the appropriate candidates serviceable sound.

CONCLUSION

SL procedure keeping intact laryngeal mucosa usually offered permanent glottis enlarging effect or decannulation with a single episode of procedure. The use of arytenoid release for CAJF has led to remarkable advances in the ultimate surgical outcomes of both the ventilation and phonation in terms of decreasing revision surgeries.

LEVELS OF EVIDENCE

level 4.

Fundamental frequency disturbances in female and male singers' pitch glides through long tube with varied resistances

Source-filter interaction can disturb vocal fold vibration frequency. Resonance frequency/bandwidth ratios (Q-values) may affect such interaction. Occurrences of fundamental frequency (fo) disturbances were measured in ascending pitch glides produced by four female and five male singers phonating into a 70 cm long tube. Pitch glides were produced with varied resonance Q-values of the vocal tract + tube compound (VT + tube): (i) tube end open, (ii) tube end open with nasalization, and (iii) with a piece of cotton wool in the tube end (conditions Op, Ns, and Ct, respectively). Disturbances of fo were identified by calculating the derivative of the low-pass filtered fo curve. Resonance frequencies of the compound VT+tube system were determined from ringings and glottal aspiration noise observed in narrowband spectrograms. Disturbances of fo tended to occur when a partial was close to a resonance of the compound VT+tube system. The number of such disturbances was significantly lower when the resonance Q-values were reduced (conditions Ns and Ct), particularly for the males. In some participants, resonance Q-values seemed less influential, suggesting little effect of source-filter interaction. The study sheds light on factors affecting source-filter interaction and fo control and is, therefore, relevant to voice pedagogy and theory of voice production.

Difficult glottis: Diagnostic dilemma in viewof the clinical presentation

<br><b>Introduction:</b> The taxonomy of vocal fold lesions has been refined, and it serves as a common descriptive language for diagnosis, treatment algorithms, and reporting of outcomes. However, we observe rare cases when numerous pathologies overlap, resulting in an unclear and complicated clinical presentation of the glottis.</br> <br><b>Aim:</b> The aim of this paper is to present cases of overlapping etiopathological factors which poses a challenge when making a diagnosis and referring a patient for adequate treatment.</br> <br><b>Material and method:</b> The study presents different photographs of the glottis, including some unique and unusual images in which overlapping pathologies were captured. The photographs are accompanied by case descriptions, comments, and pathological analyses.</br> <br><b>Results:</b> Four selected photographs showed a bunch of exophytic growth lesions with foci of whitish plaques, covered by yellowish crusts, with thinned, reddened vocal folds presenting foci of leukoplakia. The study discussed possible causes of vocal folds edema, diffuse erythema, presence of crusts or exudate, whitish debris/plaques or development of leukoplakia, non-neoplastic ulceration, as well as injected and reddened mucous membrane. Chronic infectious laryngitis, idiopathic ulcerative laryngitis, and drug-induced laryngitis were also mentioned. The study also raised the issues concerning diabetics and patients treated with inhaled corticosteroids, including candidiasis and primary aspergillosis of the larynx.</br> <br><b>Conclusions:</b> To conclude, everyday clinical practice involves encountering cases of unclear onset and course, with complicated presentation of the glottis. Therefore, comprehensive history-taking and thorough investigation of systemic causes are of immense importance. Recommended management includes conducting the most meticulous differential diagnosis, implementing treatment for the most likely cause, and, whenever possible, refraining from biopsy in order to avoid permanent damage to vocal cords.</br>.

Classifying Vocal Folds Fixation from Endoscopic Videos with Machine Learning

Vocal folds motility evaluation is paramount in both the assessment of functional deficits and in the accurate staging of neoplastic disease of the glottis. Diagnostic endoscopy, and in particular videoendoscopy, is nowadays the method through which the motility is estimated. The clinical diagnosis, however, relies on the examination of the videoendoscopic frames, which is a subjective and professional-dependent task. Hence, a more rigorous, objective, reliable, and repeatable method is needed. To support clinicians, this paper proposes a machine learning (ML) approach for vocal cords motility classification. From the endoscopic videos of 186 patients with both vocal cords preserved motility and fixation, a dataset of 558 images relative to the two classes was extracted. Successively, a number of features was retrieved from the images and used to train and test four well-grounded ML classifiers. From test results, the best performance was achieved using XGBoost, with precision = 0.82, recall = 0.82, F1 score = 0.82, and accuracy = 0.82. After comparing the most relevant ML models, we believe that this approach could provide precise and reliable support to clinical evaluation.Clinical Relevance- This research represents an important advancement in the state-of-the-art of computer-assisted otolaryngology, to develop an effective tool for motility assessment in the clinical practice.

Optical Flow Glottovibrogram for the examination of vocal fold pathology

Laryngeal high-speed video endoscopy is performed to examine the cycles of vocal fold vibrations in detail and to diagnose voice abnormalities. One of the recent image processing techniques for visualizing vocal fold vibration is optical flow-based playbacks, which include optical flow kymograms (OFKG) for local dynamics, optical flow glottovibrogram (OFGVG) and glottal optical flow waveforms (GOFW) for global dynamics. In recent times, various optical flow computing algorithms have been developed. In this paper, we used four well-known optical flow algorithms Horn Schunk, Lucas Kanade, Gunnar Farneback, and TVL1 to construct the optical flow playbacks. The proposed playback reliability is examined by comparing them to traditional representations such as Phonovibrogram (PVG). Since PVG and OFGVG are interconnected, a comparison study was carried out to better comprehend their interaction.Clinical Relevance- Both OFGVG and PVG add to the precision of interpreting pathological conditions by offering complementary information to the conventional spatiotemporal representations.

Goldenhar syndrome complicated with subglottic airway stenosis: a case report

BACKGROUND

Goldenhar syndrome is a congenital disease that involves an absence or underdevelopment of structures that arise from the first and second pharyngeal arches and more or less severe extracranial anomalies. A variety of supraglottic malformations may be observed, including mandibular hypoplasia, mandibular asymmetry and micrognathia. Subglottic airway stenosis (SGS), which can cause difficulties in airway management during the perioperative period, is seldom emphasized in literature descriptions of Goldenhar syndrome, but can be clinically significant.

CASE PRESENTATION

An 18-year-old female with a history of Goldenhar syndrome presented for placement of a right mandibular distractor, right retroauricular dilator, and stage I transfer of a prefabricated expanded flap under general anesthesia. During tracheal intubation, the endotracheal tube (ETT) met resistance unexpectantly when attempting to pass through the glottis. Subsequently, we attempted the procedure with a smaller size ETT but again met resistance. With fiberoptic bronchoscope, we found that the whole segment of the trachea and bilateral bronchi were obvious narrow. Given the finding of unexpected severe airway stenosis and the associated risks with proceeding with the surgery, the operation was cancelled. We removed the ETT once the patient was fully awake.

CONCLUSIONS

Anesthesiologists should be aware of this clinical finding when evaluating the airway of a patient with Goldenhar syndrome. Coronal and sagittal measurements on computerized tomography (CT) and three-dimensional image reconstruction can be used to evaluate the degree of subglottic airway stenosis and measure the diameter of the trachea.

Difficult endotracheal intubation due to a large epiglottic cyst: A case report

RATIONALE

An epiglottic cyst is a type of benign tumor that is formed due to the obstruction of the mucinous duct and the retention of glandular secretion. In such cases, the glottis is not visible as it is covered by the enlarged epiglottic cyst. When conventional anesthesia is administered in such patients, they might have difficulty ventilation since the epiglottic cyst can easily form a flap and move with external pressure changes and can cause the blockage of the glottis due to the loss of consciousness and the relaxation of the throat muscles of the patient. If endotracheal intubation is not initiated and effective ventilation is not established, the patient may suffer from hypoxia and other accidents.

PATIENT CONCERNS

A 48-year-old male presented to the otolaryngology department with a foreign body sensation in the throat.

DIAGNOSES

A large epiglottic cyst was diagnosed.

INTERVENTIONS

The patient was planned to undergo epiglottis cystectomy under general anesthesia. After induction of anesthesia, the cyst severely covered the glottis and made endotracheal intubation difficult. The anesthesiologist rapidly adjusted the position of the laryngeal lens; thus, the endotracheal intubation was successful under the visual laryngoscope.

OUTCOMES

The endotracheal intubation was successful under the visual laryngoscope and the operation went well.

LESSONS

Patients with epiglottic cysts are more likely to have difficult airways after induction of anesthesia. Anesthesiologists should take preoperative airway assessment seriously, efficiently handle difficult airway and intubation failure, and make quick and correct choices to ensure patient safety.

Primary site of constriction during the compression phase of cough in healthy young adults

Glottal closure has been considered as the primary constriction point during the compression phase (CP); however, vocal fold adduction alone cannot resist the high pressures, providing motivation to explore other mechanisms contributing to that resistance. The goal of this study was to identify site(s) and degree of constriction during the CP of cough of varying types in healthy young adults. Twenty-five healthy young participants participated in this study. The experimental protocol was comprised of: 1) baseline pulmonary function measures; 2) cough practice to establish weak, moderate and strong coughs; 3) voluntary and reflex cough assessments with fluoroscopy and airflow measures. We used a repeated measures ANOVA to identify whether there are differences in constriction ratio between cough types. There was a significant difference in constriction of varying cough types. Degree of constriction in all cough strengths showed that the glottis was the most constricted area, followed by the laryngeal vestibule, nasopharynx, hypopharynx, oropharynx, and cervical trachea, in order, but stronger cough resulted in more constriction in all areas compared to weaker cough. Degree of constriction in reflex cough showed a similar pattern though there was greater constriction in the oropharynx than the hypopharynx. Airflow measures in voluntary cough were consistent with previous findings. Differences in upper airway constriction during the compression phase of cough may be attributed to differences in motor control between reflex and voluntary cough, and the increased constriction seen during strong cough may reflect increased muscle recruitment during that task. In the future, we can use this knowledge to develop novel methods for cough rehabilitation.

To compare the influence of blind insertion and up-down optimized glottic exposure manoeuvre on oropharyngeal leak pressure using SaCoVLM™ video laryngeal mask among patients undergoing general anesthesia

To compare the potential influences of blind insertion and up-down optimized glottic exposure manoeuvre on the oropharyngeal leak pressure (OPLP) in using SaCoVLM™ video laryngeal mask (VLM) among patients undergoing general anesthesia. A randomized self-control study controlled was conducted to investigate the effect of two insertion techniques on OPLP. A total of 60 patients (male or female, 18-78 years, BMI 18.0-30.0 kg m-2 and ASA I-II) receiving selective surgery under general anesthesia were randomly recruited. After induction of anesthesia, the SaCoVLM™ was inserted by blind insertion manoeuvre. The glottic exposure grading(V1) of the SaCoVLM™ visual laryngeal mask and the OPLP(P1) were recorded. And the glottic exposure grading(V2) and OPLP(P2) of SaCoVLM™ were recorded again when the glottic exposure grading was optimal. The glottis exposure grading and OPLP were compared before and after different insertion manoeuver. The glottic exposure grading (V2) obtained by using up-down optimized glottic exposure manoeuvre was better than that obtained by using blind insertion manoeuvre (V1)(P < 0.001). The OPLP was significantly lower in the blind insertion manoeuvre (P1) than in the up-down optimized glottic exposure manoeuvre (P2) (32.4 ± 5.0 cmH2O vs. 36.3 ± 5.2 cmH2O, P < 0.001). In using SaCoVLM™, higher OPLP and better glottic exposure grading were achieved through up-down optimized glottic exposure manoeuvre, protecting the airway while real-time monitoring of conditions around the glottis, which significantly improves airway safety. Our results suggests that up-down optimized glottic exposure manoeuver may be a useful technique for SaCoVLM™ insertion.Trial registration: ChiCTR, ChiCTR2000028802. Registered 4 January 2020, http://www.chictr.org.cn/ChiCTR2000028802.

Differences in Glottal Closure and Visibility of the Anterior Commissure during Rigid-90°, Rigid-70°, and Flexible Laryngostroboscopy

INTRODUCTION

The conventional rigid-90° and rigid-70° laryngostroboscopy has been so far considered the gold standard in assessing the vibratory behavior of the vocal folds and the glottal closure configuration during phonation. Meanwhile, this rigid laryngostroboscopy is more and more replaced by flexible chip-on-tip systems. The aim of this study was to evaluate the influence of these different endoscopic techniques on glottal closure configuration and on visibility of the complete focal fold length including anterior commissure during phonation.

METHODS

Twenty-one euphonic subjects were enrolled (mean age 34.6 ± 9.5; m = 10, f = 11). They were examined with the three laryngoscopic techniques (conventional rigid-90°, rigid-70°, and flexible chip-on-tip laryngoscopy during low and high voice pitch with soft and loud voice intensity). For evaluating the degree of glottal closure, a modified classification of Södersten et al. was applied and the visibility of the anterior commissure was evaluated. The correlation of the three endoscopic techniques was assessed with Cohen and Fleiss' kappa.

RESULTS

In even low loud phonation, the rigid-90° and rigid-70° endoscopies revealed a complete closure of the glottis in only 47.6% of subjects but with flexible endoscopy in 81%. The complete vocal fold length with anterior commissure was best visible with flexible endoscopy in 90.5% in low-soft and high-soft phonation. The rigid-90° endoscopy showed a slight agreement in comparison with the flexible endoscopy in regard to the types of vocal fold closure with a Cohen's kappa coefficient k = 0.199. The rigid-90° endoscopy showed an almost perfect agreement with k = 0.84 when compared to the rigid-70° endoscopy. The flexible endoscopy compared to the rigid-70° endoscopy showed a fair agreement with k = 0.346.

CONCLUSION

We found mainly corresponding results in both rigid-90° and rigid-70° endoscopic techniques which can be explained by the same transoral approach with the tongue pulled out, whereas the flexible transnasal endoscopy mainly gives a better view on the anterior commissure. The influence of transorally or transnasally guided endoscopic techniques needs to be considered in interpretation of laryngostroboscopic parameters like vocal fold closure and supraglottal hyperactivity.

Change in glottic view during intubation using a KoMAC videolaryngoscope: A retrospective analysis

Intubation with videolaryngoscopy has become popular in various clinical settings. However, despite the use of a videolaryngoscope, difficult intubation still exists and intubation failure has been reported. This retrospective study assessed the efficacy of the 2 maneuvers in improving the glottic view during videolaryngoscopic intubation. The medical records of patients who underwent videolaryngoscopic intubation and whose glottal images were stored in electronic medical charts were reviewed. The videolaryngoscopic images were divided into 3 categories according to the applied optimization techniques as follows: conventional method, with the blade tip located in the vallecular; backward-upward-rightward pressure (BURP) maneuver; and epiglottis lifting maneuver. Four independent anesthesiologists scored the visualization of the vocal folds using the percentage of glottic opening (POGO, 0-100%) scoring system. A total of 128 patients with 3 laryngeal images were analyzed. The glottic view was the most improved in the epiglottis lifting maneuver among all the techniques. The median POGO scores were 11.3, 36.9, and 63.1 in the conventional method, BURP, and epiglottis lifting maneuver, respectively (P < .001). There were significant differences in the distribution of POGO grades according to the application of BURP and epiglottis lifting maneuvers. In the POGO grades 3 and 4 subgroups, the epiglottis lifting maneuver was more effective than the BURP maneuver in improving the POGO score Inadequate visualization of the vocal folds occurred even when intubation was performed using a videolaryngoscope. The application of optimization maneuvers, such as BURP and epiglottis lifting by the blade tip, could improve the glottic view.

An Ex-vivo Model Examining Acoustics and Aerodynamic Effects Following Medialization With and Without Arytenoid Adduction

OBJECTIVES/HYPOTHESIS

Quantify differences in acoustics and intraglottal flow fields between Thyroplasty Type 1 (TT1) with and without arytenoid adduction (AA) using excised canine larynx model.

STUDY DESIGN

Basic science experiments using excised larynges.

METHODS

Surgical procedures were implemented in eight excised canine larynges. Acoustics and intraglottal flow measurements were taken at low and high subglottal pressures in each experimental setup.

RESULTS

In all larynges, vocal efficiency (VE) and cepstrum peak prominence (CPP) were higher, and the mean phonatory flow rate was lower in TT1 with AA than without AA. The glottal asymmetry is reduced with AA and promotes the formation of stronger vortices in the glottal flow during the closing phase of the vibrating folds.

CONCLUSIONS

Findings suggest a clear acoustic and aerodynamic benefit to the addition of AA when performing TT1. It shows significant improvement in CPP, translating to decreased breathiness and dysphonia and increased VE, leading to easier and more sustainable phonation. Stronger intraglottal vortices are known to be correlated with the loudness of voice produced by phonation.

LEVEL OF EVIDENCE

N/A Laryngoscope, 133:621-627, 2023.

Efficacy of Intermittent and Continuous Subglottic Secretion Drainage in Preventing the Risk of Ventilator-Associated Pneumonia: A Meta-Analysis of Randomized Control Trials

Ventilator-associated pneumonia (VAP) is hospital-acquired pneumonia that develops 48 h or longer following mechanical ventilation. However, cuff pressure fluctuates significantly due to patient or tube movement, which might result in microaspiration. Subglottic secretion drainage (SSD) has been suggested as a method for VAP prevention bundles. This systematic review and meta-analysis aims to investigate the efficacy and safety of subglottic SSD in preventing VAP. The secondary outcomes of this study are to investigate the intensive care unit (ICU) stay length and mortality rate regarding VAP. This study followed the Preferred Reporting Item for Systematic Review and Meta-Analysis guidelines. A thorough search of PubMed, Embase, and the Web of Science was conducted between June and August 2022. The study analysis used the Mantel-Haenszel method, and the quality of the included study was assessed using the Cochrane Risk of Bias 2. Eighteen randomized controlled trials with a total of 2537 intubated patients were included. It was found that SSD was associated with a lower risk of VAP (RR 1.44; 95% CI; 1.20-1.73; p < 0.0001). The subgroup analysis (utilizing intermittent and continuous methods) found no statistically significant difference between the two groups (p = 0.28). The secondary endpoints showed that there was no significant difference in mortality (RR 1.02; 95% CI; 0.87-1.20; p = 0.83), but there were substantial differences in ICU stays (mean difference, 3.42 days; 95% CI; 2.07-4.76; p < 0.00001) in favor of the SSD group. This was based on a very low certainty of evidence due to concerns linked to the risk of bias and inconsistency. The use of SSD was associated with a reduction in VAP incidence and ICU stay length, but there was no significant difference in the mortality rate.

GlottisNetV2: Temporal Glottal Midline Detection Using Deep Convolutional Neural Networks

High-speed videoendoscopy is a major tool for quantitative laryngology. Glottis segmentation and glottal midline detection are crucial for computing vocal fold-specific, quantitative parameters. However, fully automated solutions show limited clinical applicability. Especially unbiased glottal midline detection remains a challenging problem. We developed a multitask deep neural network for glottis segmentation and glottal midline detection. We used techniques from pose estimation to estimate the anterior and posterior points in endoscopy images. Neural networks were set up in TensorFlow/Keras and trained and evaluated with the BAGLS dataset. We found that a dual decoder deep neural network termed GlottisNetV2 outperforms the previously proposed GlottisNet in terms of MAPE on the test dataset (1.85% to 6.3%) while converging faster. Using various hyperparameter tunings, we allow fast and directed training. Using temporal variant data on an additional data set designed for this task, we can improve the median prediction accuracy from 2.1% to 1.76% when using 12 consecutive frames and additional temporal filtering. We found that temporal glottal midline detection using a dual decoder architecture together with keypoint estimation allows accurate midline prediction. We show that our proposed architecture allows stable and reliable glottal midline predictions ready for clinical use and analysis of symmetry measures.

Comparison of one-dimensional and three-dimensional glottal flow models in left-right asymmetric vocal fold conditions

While the glottal flow is often simplified as one-dimensional (1D) in computational models of phonation to reduce computational costs, the 1D flow model has not been validated in left-right asymmetric vocal fold conditions, as often occur in both normal and pathological voice production. In this study, we performed three-dimensional (3D) and 1D flow simulations coupled to a two-mass model of adult male vocal folds and compared voice production at different degrees of left-right stiffness asymmetry. The flow and acoustic fields in 3D were obtained by solving the compressible Navier-Stokes equations using the volume penalization method with the moving vocal fold wall as an immersed boundary. Despite differences in the predicted flow pressure on vocal fold surface between the 1D and 3D flow models, the results showed reasonable agreement in vocal fold vibration patterns and selected voice outcome measures between the 1D and 3D models for the range of left-right asymmetric conditions investigated. This indicates that vocal fold properties play a larger role than the glottal flow in determining the overall pattern of vocal fold vibration and the produced voice, and the 1D flow simplification is sufficient in modeling phonation, at least for the simplified glottal geometry of this study.

Describing the Acoustic and Vocal Production Characteristics of the Irrintzi: Feasibility of Its Use for the Treatment of Voice Disorders

PURPOSE

The aims of this study were to analyze and characterize the irrintzi (a folkloric shout emitted in a single breath used by the Basque people) acoustically and to describe the mechanism by which it is emitted.

METHOD

Thirty-six sound samples of 12 female volunteers were analyzed. Acoustic analysis included primarily fundamental frequency (f _o), spectral analysis in the time domain with a narrowband filter, and the use of linear predictive coding (LPC). Laryngeal and pharyngeal movements while emitting an irrintzi were studied by fiberoptic nasal endoscopy. Postural and mandible movements were observed and video recorded. Movements of the larynx and the vocal tract were also studied by lateral pharyngo-laryngeal radioscopy.

RESULTS

The central part of an irrintzi spectrogram contains a peculiar, repeated M-shaped motif unseen in the spectrogram of any other human vocal emission, and intensity was over 90 dB SPL in all cases. f _o was very high (1487 Hz) especially at the end of the irrintzi. Fiberoptic nasal endoscopy consistently revealed considerable elevation of the glottis, with the larynx swinging forward and retraction of the ventricular bands. Lateral radioscopy showed a very high larynx and a high tongue dorsum.

CONCLUSIONS

The irrintzi is a sound emitted in a single breath and characterized by its shrillness and loudness, qualities that make it audible in noisy environments and over large distances and the vocal technique observed when it is produced can be explained by the Estill voice model (Steinhauer et al., 2017). The use of this technique may help in the treatment of voice disorders and improve efficiency in singers, teachers, actors, and people who use their voice at high volume or at high frequency.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.20779405.

Correlating Perceptual Voice Quality in Adductor Spasmodic Dysphonia With Computer Vision Assessment of Glottal Geometry Dynamics

PURPOSE

This study examined the relationship between voice quality and glottal geometry dynamics in patients with adductor spasmodic dysphonia (ADSD).

METHOD

An objective computer vision and machine learning system was developed to extract glottal geometry dynamics from nasolaryngoscopic video recordings for 78 patients with ADSD. General regression models were used to examine the relationship between overall voice quality and 15 variables that capture glottal geometry dynamics derived from the computer vision system. Two experts in ADSD independently rated voice quality for two separate voice tasks for every patient, yielding four different voice quality rating models.

RESULTS

All four of the regression models exhibited positive correlations with clinical assessments of voice quality (R ²s = .30-.34, Spearman rho = .55-.61, all with p < .001). Seven to 10 variables were included in each model. There was high overlap in the variables included between the four models, and the sign of the correlation with voice quality was consistent for each variable across all four regression models.

CONCLUSION

We found specific glottal geometry dynamics that correspond to voice quality in ADSD.