Heterogeneous Presentations and Serologies in Myasthenia Gravis Patients Presenting with Dysphagia.

INTRODUCTION: Myasthenia gravis (MG) is an autoimmune disease that affects the neuromuscular junction. MG patients may present de novo with primary otolaryngology complaints, including swallowing dysfunction. This study describes a range of unique presentations and rare diagnostic serologies, which have not previously been fully described. METHODS: A retrospective review was performed of all patients presenting with primary symptom of dysphagia and subsequently diagnosed with MG. Data collected included demographics, clinical presentation, swallow studies, serology, imaging, treatment, and response. RESULTS: Five patients met the inclusion criteria. Four endorsed dysphagia as primary complaint and one endorsed dysphagia and dysphonia. All patients underwent in-office swallow evaluations that showed vallecular or pyriform sinus residue. Three patients completed modified barium swallow studies that showed pharyngeal weakness and epiglottic dysfunction in all, and upper esophageal sphincter dysfunction in two. One patient with additional symptom of dyspnea was admitted and found to be in myasthenic crisis. Upon serologic evaluation, three patients were positive for acetylcholine receptor (AChR) antibodies only, one for muscle-specific-kinase (MuSK) antibodies only, and one for low density lipoprotein receptor-related protein 4 (LRP4) antibodies only. All patients received neurology evaluation and were treated with steroids, pyridostigmine, plasma exchange, or rituximab. In three patients with over 1 year follow-up, symptoms were significantly improved or resolved. CONCLUSION: MG is an important differential diagnosis in patients with unexplained pharyngeal dysphagia. While workup can include AChR antibody screening, in seronegative patients with persistent symptoms, additional testing for MuSK and LRP4 may lead to diagnosis and effective treatment. LEVEL OF EVIDENCE: Level 4 Laryngoscope, 2024.

Register transitions in an in vivo canine model as a function of intrinsic laryngeal muscle stimulation, fundamental frequency, and sound pressure level.

Phonatory instabilities and involuntary register transitions can occur during singing. However, little is known regarding the mechanisms which govern such transitions. To investigate this phenomenon, we systematically varied laryngeal muscle activation and airflow in an in vivo canine larynx model during phonation. We calculated voice range profiles showing average nerve activations for all combinations of fundamental frequency (F0) and sound pressure level (SPL). Further, we determined closed-quotient (CQ) and minimum-posterior-area (MPA) based on high-speed video recordings. While different combinations of muscle activation favored different combinations of F0 and SPL, in the investigated larynx there was a consistent region of instability at about 400 Hz which essentially precluded phonation. An explanation for this region may be a larynx specific coupling between sound source and subglottal tract or an effect based purely on larynx morphology. Register transitions crossed this region, with different combinations of cricothyroid and thyroarytenoid muscle (TA) activation stabilizing higher or lower neighboring frequencies. Observed patterns in CQ and MPA dependent on TA activation reproduced patterns found in singers in previous work. Lack of control of TA stimulation may result in phonation instabilities, and enhanced control of TA stimulation may help to avoid involuntary register transitions, especially in the singing voice.

Speech and Swallowing Outcomes of Surgically Managed Cervical Chordoma: A Case Series.

OBJECTIVES: Cervical chordoma is a rare, low-grade primary bone tumor occurring in the axial skeleton. Due to challenges in surgical exposure caused by anatomic location, patients may experience dysfunction in speech and swallowing. The objective of this study was to characterize speech and swallowing outcomes for patients undergoing surgical resection of cervical chordoma. Moreover, we detail in-depth two cases with similar initial presentations to compare prognostic factors and management strategies. METHODS: Eleven patients with histologically confirmed cervical chordoma treated between 1993 and 2020 were included in this retrospective case series. Outcomes measured included overall survival, disease-free survival, need for enteral feeds, as well as results of modified barium swallow study (MBSS) and fiberoptic laryngoscopy. RESULTS: The mean age at diagnosis was 55.9 years. The patient population was 81.8% male. Mean survival after diagnosis was 96 months. Four (36.4%) patients required post-operative MBSS and demonstrated aspiration. All four of these patients presented with tumors in the superior cervical spine and received surgeries utilizing anterior approaches. Of the four, 2 required enteral feeds long-term. Four (36.4%) patients endorsed dysphonia. One patient developed post-operative right vocal fold paresis. The remaining three patients experienced stable dysphonia pre- and post-operatively. Additionally, three (27%) patients required tracheostomy placement, two of which remained in place long-term. CONCLUSIONS: Dysphagia is a common side effect of cervical chordoma resection. It is associated with the use of an anterior approach during resection and with tumors located in the superior cervical spine. Patients with postoperative dysphagia should receive early multidisciplinary swallow rehabilitation. LEVEL OF EVIDENCE: 4 Laryngoscope, 2024.

Reconstruction of Vocal Fold Medial Surface 3D Trajectories: Effects of Neuromuscular Stimulation and Airflow.

INTRODUCTION: Analysis of medial surface dynamics of the vocal folds (VF) is critical to understanding voice production and treatment of voice disorders. We analyzed VF medial surface vibratory dynamics, evaluating the effects of airflow and nerve stimulation using 3D reconstruction and empirical eigenfunctions (EEF). STUDY DESIGN: In vivo canine hemilarynx phonation. METHODS: An in vivo canine hemilarynx was phonated while graded stimulation of the recurrent and superior laryngeal nerves (RLN and SLN) was performed. For each phonatory condition, vibratory cycles were 3D reconstructed from tattooed landmarks on the VF medial surface at low, medium, and high airflows. Parameters describing medial surface trajectory shape were calculated, and underlying patterns were emphasized using EEFs. Fundamental frequency and smoothed cepstral peak prominence (CPPS) were calculated from acoustic data. RESULTS: Convex-hull area of landmark trajectories increased with increasing flow and decreasing nerve activation level. Trajectory shapes observed included circular, ellipsoid, bent, and figure-eight. They were more circular on the superior and anterior VF, and more elliptical and line-like on the inferior and posterior VF. The EEFs capturing synchronal opening and closing (EEF1) and alternating convergent/divergent (EEF2) glottis shapes were mostly unaffected by flow and nerve stimulation levels. CPPS increased with higher airflow except for low RLN activation and very dominant SLN stimulation. CONCLUSION: We analyzed VF vibration as a function of neuromuscular stimulation and airflow levels. Oscillation patterns such as figure-eight and bent trajectories were linked to high nerve activation and flow. Further studies investigating longer sections of 3D reconstructed oscillations are needed. LEVEL OF EVIDENCE: N/A, Basic Science Laryngoscope, 134:1249-1257, 2024.

Histologic Examination of Vocal Fold Mucosal Wave and Vibration.

OBJECTIVES: Despite gross anatomic and histologic differences between human and canine vocal folds, similar wave patterns have been described yet not fully characterized. We reconstructed vocal fold (VF) vibration in a canine hemilarynx and performed histologic examination of the same vocal fold. We demonstrate comparable wave patterns while exploring the importance of certain anatomic architectures. METHODS: An in vivo canine hemilarynx was phonated against a glass prism at low and high muscle activation conditions. Vibration was captured using high-speed video, and trajectories of VF medial surface tattooed landmarks were 3D-reconstructed. The method of empirical eigenfunctions was used to capture the essential dynamics of vibratory movement. Histologic examination of the hemilarynx was performed. RESULTS: Oscillation patterns were highly similar between the in vivo canine and previous reports of ex vivo human models. The two most dominant eigenfunctions comprised over 90% of total variance of movement, representing opening/closing and convergent/divergent movement patterns, respectively. We demonstrate a vertical phase difference during the glottal cycle. The time delay between the inferior and superior VF was greater during opening than closing for both activation conditions. Histological examination of canine VF showed not only a thicker lamina propria layer superiorly but also a distinct pattern of thyroarytenoid muscle fibers and fascicles as described in human studies. CONCLUSIONS: Histologic and vibratory examination of the canine vocal fold demonstrated human vocal fold vibratory patterns despite certain microstructural differences. This study suggests that the multilayered lamina propria may not be fundamental to vibratory patterns necessary for human-like voice production. LEVEL OF EVIDENCE: NA (Basic science study) Laryngoscope, 134:264-271, 2024.

Effects of Thyroarytenoid Activation Induced Vibratory Asymmetry on Voice Acoustics and Perception.

INTRODUCTION: Asymmetry of vocal fold (VF) vibration is common in patients with voice complaints and also observed in 10% of normophonic individuals. Although thyroarytenoid (TA) muscle activation plays a crucial role in regulating VF vibration, how TA activation asymmetry relates to voice acoustics and perception is unclear. We evaluated the relationship between TA activation asymmetry and the resulting acoustics and perception. METHODS: An in vivo canine model of phonation was used to create symmetric and increasingly asymmetric VF vibratory conditions via graded stimulation of bilateral TA muscles. Naïve listeners (n = 89) rated the perceptual quality of 100 unique voice samples using a visual sort-and-rate task. For each phonatory condition, cepstral peak prominence (CPP), harmonic amplitude (H1-H2), and root-mean-square (RMS) energy of the voice were measured. The relationships between these metrics, vibratory asymmetry, and perceptual ratings were evaluated. RESULTS: Increasing levels of TA asymmetry resulted in declining listener preference. Furthermore, only severely asymmetric audio samples were perceptually distinguishable from symmetric and mildly asymmetric conditions. CPP was negatively correlated with TA asymmetry: voices produced with larger degrees of asymmetry were associated with lower CPP values. Listeners preferred audio samples with higher values of CPP, high RMS energy, and lower H1-H2 (less breathy). CONCLUSION: Listeners are sensitive to changes in voice acoustics related to vibratory asymmetry. Although increasing vibratory asymmetry is correlated with decreased perceptual ratings, mild asymmetries are perceptually tolerated. This study contributes to our understanding of voice production and quality by identifying perceptually salient and clinically meaningful asymmetry. LEVEL OF EVIDENCE: N/A (Basic Science Study) Laryngoscope, 134:1327-1332, 2024.

Validation and enhancement of a vocal fold medial surface 3D reconstruction approach for in-vivo application.

In laryngeal research, studying the vertical vocal fold oscillation component is often disregarded. However, vocal fold oscillation by its nature is a three-dimensional process. In the past, we have developed an in-vivo experimental protocol to reconstruct the full, three-dimensional vocal fold vibration. The goal of this study is to validate this 3D reconstruction method. We present an in-vivo canine hemilarynx setup using high-speed video recording and a right-angle prism for 3D reconstruction of vocal fold medial surface vibrations. The 3D surface is reconstructed from the split image provided by the prism. For validation, reconstruction error was calculated for objects located at a distance of up to 15 mm away from the prism. The influence of camera angle, changing calibrated volume, and calibration errors were determined. Overall average 3D reconstruction error is low and does not exceed 0.12 mm at 5 mm distance from the prism. Influence of a moderate (5°) and large (10°) deviation in camera angle led to a slight increase in error to 0.16 mm and 0.17 mm, respectively. This procedure is robust towards changes in calibration volume and small calibration errors. This makes this 3D reconstruction approach a useful tool for the reconstruction of accessible and moving tissue surfaces.

Videofluoroscopic Measures of Swallowing After Partial Epiglottidectomy for Dysphagia.

OBJECTIVE: Partial epiglottidectomy has a role in improving dysphagia due to epiglottic obstruction. This study evaluates objective parameters of swallow function in patients who underwent partial epiglottidectomy. STUDY DESIGN: Retrospective study design. SETTING: Tertiary Care University Academic Medical Center. METHODS: A review was performed of patients who underwent CO2 laser partial epiglottidectomy for the treatment of dysphagia at a single tertiary care academic center over a 4-year period. Objective swallowing parameters were evaluated from pre- and postoperative modified barium swallow studies using SwallowTail Advanced Measurement software using blinded reviewers. The postswallow pharyngeal residue (bolus clearance ratio or BCR), spatiotemporal swallowing variables (oropharyngeal [OPT], hypopharyngeal [HPT], and total pharyngeal transit times [TPT]), and airway protection (Penetration-Aspiration Scale [PAS]) were analyzed. Student paired t test was used to determine significant changes in outcome parameters pre- and postsurgery. RESULTS: Forty-three patients (age range 45-92 years, median 70) met the inclusion criteria. A majority (69.8%) had a history of external beam radiation therapy for head and neck cancer. BCR decreased significantly from a mean of 31.7% presurgery to 24.2% (p = .01) postsurgery. OPT, HPT, and TPT did not differ significantly postsurgery. The mean Eating Assessment Tool-10 score improved from 25.1 to 20.2 after treatment (p = .03). PAS score improved by 15.4% and remained stable at 66.2% after surgery. CONCLUSION: Partial epiglottidectomy improves pharyngeal bolus clearance in properly selected patients with dysphagia due to epiglottic obstruction. Patients demonstrated stable swallow function with the benefit of reduced postswallow residue following surgical intervention.

Delayed Tracheal Perforation After Partial Thyroidectomy: A Case Report and Review of the Literature.

Tracheal perforation is an extremely rare and potentially dangerous complication of a partial thyroidectomy. The current case represents a unique presentation of delayed tracheal perforation following an uncomplicated thyroid isthmusectomy for tissue diagnosis of an aggressive appearing thyroid mass in the setting of high-dose steroid administration and recent intubation and self-extubation. While conservative management of tracheal perforation can sometimes be appropriate, our patient was successfully managed via primary closure and infrahyoid muscle transposition flap to cover a 5 mm right lateral tracheal wall defect. We recommend caution be exercised following thyroid surgery in the setting of intubation and high-dose steroids.

3D Reconstruction of Phonatory Glottal Shape and Volume: Effects of Neuromuscular Activation.

INTRODUCTION: Although phonatory glottal posture and airflow pulse shape affect voice quality, studies to date have been limited by visualization of vocal fold (VF) vibration from a superior view. We performed a 3D reconstruction of VF vibratory motion during phonation from a medial view and assessed the glottal volume waveform and resulting acoustics as a function of neuromuscular stimulation. STUDY DESIGN: In vivo canine hemilarynx phonation. METHODS: Across 121 unique combinations of the superior laryngeal nerve (SLN) and recurrent laryngeal nerve (RLN) stimulation, the hemilarynx was excited to the oscillation with airflow. VF medial surface reference points were tracked on high-speed video, mapped into 3D space, and surface shape was restored using cubic spline interpolation. Glottal surface shape, reconstruction-based parameters, and glottal volume waveform were calculated. Fundamental frequency (F0), cepstral peak prominence (CPP), and harmonic amplitude (H1-H2) were measured from high-quality audio samples. RESULTS: The glottis was convergent during opening and divergent during closing. Neuromuscular activation changed phonatory glottal shape and reduced glottal volume. Significant reduction in glottal volume and closing quotient were present with SLN stimulation. RLN stimulation significantly increased F0 and CPP and decreased H1-H2 (constricted glottis), while SLN effects were similar and synergistic with concurrent RLN stimulation. CONCLUSION: 3D reconstruction of in vivo medial surface vibration revealed effects of laryngeal nerve stimulation on glottal vibratory pattern and acoustic correlates of voice quality. SLN activation resulted in significantly quicker glottal closure per cycle, decreased glottal volume, and higher-pitched, less breathy, and less noisy voice. RLN had a similar effect on acoustic measures. LEVEL OF EVIDENCE: NA, Basic Science Laryngoscope, 133:357-365, 2023.

Safety of Platelet-Rich Plasma Subepithelial Infusion for Vocal Fold Scar, Sulcus, and Atrophy.

OBJECTIVE: To demonstrate the safety profile of platelet-rich plasma (PRP) as an injectable therapeutic for the treatment of vocal fold scarring and atrophy. METHODS: Preliminary report on a prospective clinical trial of patients with vocal fold scar or atrophy undergoing unilateral vocal fold subepithelial infusion with autologous PRP. Enrolled patients underwent four subepithelial injections spaced 1 month apart. Adverse events were assessed peri and post-injection at each session. Patient-reported outcomes were collected at every visit using the Voice Handicap Index-10 (VHI-10) and Vocal Fatigue Index (VFI) questionnaires. RESULTS: Twelve patients underwent unilateral vocal fold injection with autologous PRP prepared according to Eclipse PRP® system protocol. Forty-three injections were performed using a peroral or percutaneous approach. An average of 1.57 ± 0.4 cc (range 0.6-2.0 cc) injectate was used. All patients tolerated the procedure without difficulty or peri-procedural complications. The average duration of follow-up was 3.6 ± 1.8 months. No significant inflammatory reactions or adverse events were seen to date. There was statistically significant improvement in patient-reported outcomes at the 3 month follow up (n = 9) follow-up (mean ΔVHI-10 = 10.8, p < 0.001, mean ΔVFI = 18.9, p = 0.01, t test, paired two sample for means, two-tail). All nine patients who completed the series of four injections subjectively (yes/no) reported they were satisfied with the results. CONCLUSION: This prospective study cohort demonstrated a favorable safety profile, with no adverse events or peri-procedural complications. Subjective improvements in vocal quality and reduction in vocal fatigue need to be clinically correlated with further study. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:647-653, 2023.

Control of Pre-phonatory Glottal Shape by Intrinsic Laryngeal Muscles.

OBJECTIVES: Surgical manipulations to treat glottic insufficiency aim to restore the physiologic pre-phonatory glottal shape. However, the physiologic pre-phonatory glottal shape as a function of interactions between all intrinsic laryngeal muscles (ILMs) has not been described. Vocal fold posture and medial surface shape were investigated across concurrent activation and interactions of thyroarytenoid (TA), cricothyroid (CT), and lateral cricoarytenoid/interarytenoid (LCA/IA) muscles. STUDY DESIGN: In vivo canine hemilarynx model. METHODS: The ILMs were stimulated across combinations of four graded levels each from low-to-high activation. A total of 64 distinct medial surface postures (4 TA × 4 CT × 4 LCA/IA levels) were captured using high-speed video. Using a custom 3D interpolation algorithm, the medial surface shape was reconstructed. RESULTS: Combined activation of ILMs yielded a range of unique pre-phonatory postures. Both LCA/IA and TA activation adducted the vocal fold but with greater contribution from TA. The transition from a convergent to a rectangular glottal shape was primarily mediated by TA muscle activation but LCA/IA and TA together resulted in a smooth rectangular glottis compared to TA alone, which caused rectangular glottis with inferomedial bulging. CT activation resulted in a lengthened but slightly abducted glottis. CONCLUSIONS: TA was primarily responsible for the rectangular shape of the adducted glottis with synergistic contribution from the LCA/IA. CT contributed minimally to vocal fold medial shape but elongated the glottis. These findings further refine laryngeal posture goals in surgical correction of glottic insufficiency. LEVEL OF EVIDENCE: NA, Basic science Laryngoscope, 133:1690-1697, 2023.

Reinke's edema management and voice outcomes.

Objectives: Reinke's edema is a chronic disease of the respiratory tract that occurs in adults with a history of chronic smoke exposure. Also known as polypoid corditis, polypoid laryngitis, and polypoid degeneration of the vocal fold, it is strongly associated with smoking, frequently with vocal misuse/abuse, and occasionally with laryngopharyngeal reflux. Reinke's edema remains a cause of chronic dysphonia that is difficult to manage. This review provides perspectives on current and future management of Reinke's edema. Results: Reinke's edema impacts <1% of the population. The excessive mass is seen in polypoid degeneration results in a loss of pitch control and a rough voice. Women are more likely to present for treatment as the characteristic lowering of vocal pitch is more noticeable in women than men. Multiple grading systems have been proposed within the literature. The current standard of care is surgical excision, after smoking cessation. The microflap technique remains the approach of choice for bulky lesions. Surgical management of Reinke's edema has evolved with the introduction of various lasers into otolaryngologic practice; some which can now be used in the office setting. While many management approaches have been described within the literature, there is a little direct comparison and no obvious superior method of Reinke's edema management. Conclusion: To date, the biology of Reinke's edema is not well understood. Additional research is needed further elucidate the role of uncontrolled reflux in the development and recurrence of Reinke's edema.

Solitary Fibrous Tumors of the Head and Neck: A Single-Institution Study of 52 Patients.

Objective: To evaluate the clinicopathologic characteristics of head and neck solitary fibrous tumors and features that may predict tumor recurrence. Study Design: Retrospective review. Setting: University of California-Los Angeles Medical Center. Methods: A single-center retrospective study was conducted on pathologically confirmed cases of head and neck solitary fibrous tumors between 1996 and 2021. Patient demographics, clinical course, and histopathologic features were evaluated. Recurrence-free survival was estimated via Kaplan-Meier analysis. Results: A total of 52 patients were reviewed. The average patient age was 54.7 years (range, 15-89). The most common subsite was the orbit (53.8%, n = 28), but other involved areas included the nasopharynx, paranasal sinuses, and scalp. The median tumor size was 2.95 cm (range, 1.3-11.2). Strong STAT6 (100%) and CD34 (97.9%) expression was observed on immunohistochemistry. Almost all patients were initially managed with wide local excision; 82% of patients (n = 14) had positive margins on pathologic review; and 15% (n = 4) had recurrence at a median 28.5 months (range, 10-113). White patient race was the only significant predictor of tumor recurrence. Patient age (≥55 years), tumor size (≥4), high mitotic rate, and disease subsite were not associated with recurrence. Conclusion: Head and neck solitary fibrous tumors demonstrate a significantly larger local recurrence rate as compared with their rate of metastasis. They can recur many years following initial therapy, warranting long-term surveillance and follow-up to assess for tumor recurrence.

Analysis of vibratory mode changes in symmetric and asymmetric activation of the canine larynx.

Investigations of neuromuscular control of voice production have primarily focused on the roles of muscle activation levels, posture, and stiffness at phonation onset. However, little work has been done investigating the stability of the phonation process in regards to spontaneous changes in vibratory mode of vocal fold oscillation as a function of neuromuscular activation. We evaluated 320 phonatory conditions representing combinations of superior and recurrent laryngeal nerve (SLN and RLN) activations in an in vivo canine model of phonation. At each combination of neuromuscular input, airflow was increased linearly to reach phonation onset and beyond from 300 to 1400 mL/s. High-speed video and acoustic data were recorded during phonation, and spectrograms and glottal-area-based parameters were calculated. Vibratory mode changes were detected based on sudden increases or drops of local fundamental frequency. Mode changes occurred only when SLNs were concurrently stimulated and were more frequent for higher, less asymmetric RLN stimulation. A slight increase in amplitude and cycle length perturbation usually preceded the changes in the vibratory mode. However, no inherent differences between signals with mode changes and signals without were found.

Effects of Laryngeal Vibratory Asymmetry and Neuromuscular Compensation on Voice Quality.

INTRODUCTION: Vibratory asymmetry and neuromuscular compensation are often seen in laryngeal neuromuscular pathology. However, the ramifications of these findings on voice quality are unclear. This study investigated the effects of varying levels of vibratory asymmetry and neuromuscular compensation on cepstral peak prominence (CPP), an analog of voice quality. STUDY DESIGN: In vivo canine phonation model. METHODS: Varying degrees of vocal fold vibratory asymmetry were achieved by stimulating one recurrent laryngeal nerve (RLN) over 11 levels from threshold to maximal muscle activation. For each of these levels, phonation was induced at systematically varied combinations of neuromuscular compensation: three levels each of contralateral RLN stimulation (80%, 90%, and 100% of maximal), superior laryngeal nerve (SLN) activation (0%, 50%, and 100% of maximal), and airflow levels (500, 700, and 900 mL/s). Vocal fold symmetry was determined by assessing the opening phase of the vibratory cycle in high-speed video recordings. Voice quality was estimated acoustically by calculating CPP for each voice sample. RESULTS: Eight hundred twenty-two phonatory conditions with varying degrees of vibratory asymmetry were evaluated. CPP was highest at vibratory symmetry. Increasing levels of asymmetry resulted in significant decreases in CPP. CPP increased significantly with increasing contralateral RLN activation. CPP was significantly higher at 50% SLN activation than 0% or 100% SLN activation. CONCLUSION: Voice quality, as approximated by CPP, is best at vibratory symmetry and deteriorates with increasing degrees of asymmetry. Voice quality may be improved with neuromuscular compensation by increased adduction of the contralateral vocal fold or increased vocal fold tension at mid-levels of SLN activation. LEVEL OF EVIDENCE: NA, Basic Science Laryngoscope, 132:130-134, 2022.

Phonation Threshold Pressure Revisited: Effects of Intrinsic Laryngeal Muscle Activation.

OBJECTIVES/HYPOTHESIS: Phonation threshold pressure (Pth ) is the minimum subglottic pressure required to reach phonation onset and is considered a marker for vocal efficiency and health. We investigated the effects of intrinsic laryngeal muscle (ILM) activation on Pth . STUDY DESIGN: In vivo animal study. METHODS: In an in vivo canine phonation model, laryngeal adductor muscles were activated together by stimulation of the recurrent laryngeal nerves (RLNs) and individually via stimulation of respective terminal nerve branches. Cricothyroid (CT) muscles were activated via stimulation of the superior laryngeal nerves. ILMs were activated in a graded manner at various combinations as transglottal airflow was gradually increased. Aerodynamic and glottal posture parameters were measured at phonation onset. RESULTS: Graded RLN stimulation decreased glottal distance and increased Pth . Thyroarytenoid (TA) muscle activation alone increased Pth . Lateral cricoarytenoid (LCA) muscle activation alone had minimal effects. However, graded TA activation as a function of LCA activation level revealed a synergistic relationship between the two muscles in increasing Pth . Effects of CT activation were dependent on adductor stimulation level: CT activation increased Pth at low RLN stimulation levels and decreased Pth at high RLN levels. CONCLUSIONS: The effects of ILM activation on Pth were consistent with their expected effects on vocal fold stiffness and tension. TA was the primary adductor controlling Pth . While LCA alone had minimal effects on Pth , it enhanced the role of TA in controlling Pth . TA and CT have antagonistic roles in controlling Pth . These relationships should be considered in clinical efforts to improve ease of phonation and vocal efficiency. LEVEL OF EVIDENCE: NA, basic science Laryngoscope, 132:1427-1432, 2022.

Flexible Bronchoscopy Simulation as a Tool to Improve Surgical Skills in Otolaryngology Residency.

OBJECTIVE: To evaluate the benefits of simulation to teach flexible bronchoscopy. STUDY DESIGN: A prospective cohort study to assess the bronchoscopic skills of residents in an otolaryngology training program using a commercially available bronchoscopy simulator. SETTING: Tertiary care otolaryngology residency program. METHODS: Thirty-two otolaryngology residents and 4 expert faculty across 2 academic institutions were assessed on 3 flexible bronchoscopy tasks: diagnostic bronchoscopy, foreign body removal, and tracheal lesion biopsy. Performance was evaluated with a modified version of the validated Bronchoscopy Skills and Tasks Assessment Tool. At 1 of the 2 academic institutions, an additional tool was implemented to evaluate the simulator. RESULTS: There was a correlation between postgraduate training year and time taken to complete tasks, including bronchoscopy, foreign body extraction, and passing through the glottis (P < .001, P = .04, and P < .01, respectively). There was a significant difference between residents and faculty laryngologists for a range of skills and tasks, including percentage of time in middle lumen, contact with bronchial walls, inadvertent esophagus entry, and biopsy of healthy tissue (P < .001, P = .003, P < .001, and P < .001). Additionally, increasing postgraduate level was correlated with a higher percentage of time in the center of the lumen and reduced time to task completion (P = .05 and P < .001). Of 32 residents, 20 evaluated the simulator on its realism, with an average score of 4.1 of 5. CONCLUSION: The commercially available flexible bronchoscopy simulator provides a valid assessment of bronchoscopic skill and is a useful tool for practicing bronchoscopy in a safe, controlled environment. LEVEL OF EVIDENCE: Individual cohort study.