Tremor Makes a Difference: A Comparative Study of the Demographics and Treatment Outcomes in Patients With Adductor Spasmodic Dysphonia With or Without Vocal Tremor.

OBJECTIVES: This study aims to evaluate the demographic differences between those with adductor spasmodic dysphonia with vocal tremor (AdSD(+)VT) and those without vocal tremor (AdSD(-)VT) and to analyze their response to treatment with botulinum neurotoxin (BoNT-A). STUDY DESIGN: Retrospective cohort study. METHODS: A database review of all spasmodic dysphonia patients treated with BoNT from 1989 to 2018 at the Mayo Clinic in Arizona was performed. Only patients who had received ≥4 injections of BoNT-A for AdSD were included. Patients were divided into two cohorts: those with coexistent vocal tremor (AdSD(+)VT) and those without vocal tremor (AdSD(-)VT). RESULTS: The final analysis included 398 patients, with 210 AdSD(+)VT patients (53%) and 188 AdSD(-)VT patients (47%). The length of follow-up and median number of treatments were similar between cohorts. AdSD(+)VT patients were more likely to be female (P < 0.001), and older at onset (P < 0.001) and first injection (P < 0.001). The mean maximal benefit was significantly lower for the AdSD(+)VT cohort (P < 0.01), however the mean length of benefit was similar (P = 0.70). CONCLUSIONS: Demographic differences exist between AdSD(+)VT and AdSD(-)VT patients. AdSD(+)VT patients benefit from BoNT-A treatment; however, our analysis suggests that the degree of their maximal benefit is less than in those without VT.

Idiopathic Subglottic Stenosis Is Associated With More Frequent and Abnormal Squamous Metaplasia.

OBJECTIVES: Gain insights into the pathophysiology of idiopathic subglottic stenosis (iSGS) by investigating differences in transcriptome of subglottic mucosal tissue between patients with iSGS and controls, and between tracheal and subglottic tissue within patients. METHODS: RNA sequencing was conducted on biopsied mucosal samples collected from subglottic and tracheal (in-patient control) regions in iSGS patients, and from subglottis in controls. The gene expression differences were validated on a protein level by (1) staining the tissue samples obtained from a second cohort of patients and controls; and (2) in vitro functional assays using primary subglottic epithelial cells from both iSGS patients and healthy donors. RESULTS: We found 7 upregulated genes in the subglottic region of iSGS patients relative to both the tracheal mucosa and subglottic region of controls. A gene ontology enrichment analysis found that the epithelial cell differentiation and cornification pathways are significant, involving specifically 3 of the genes: involucrin (IVL), small proline rich protein 1B (SPRR1B), and keratin 16 (KRT16). Involvement of these pathways suggests squamous metaplasia of the epithelium. Histological analyses of epithelium in subglottic mucosal biopsies revealed squamous metaplasia in 41% of the samples from iSGS patients and in 25% from controls. Immunohistochemical evaluation of the samples presented with squamous epithelium revealed increased expression of the protein encoded by SPRR1B, hyperproliferative basal cells, shedding of apical layers, and accompanying lesions in iSGS compared to CTRL. Cultured primary subglottic epithelial cells from iSGS patients had higher proliferation rates compared to healthy donors and squamous metaplastic differentiation formed thinner epithelia with increased expression proteins encoded by INV, SPRR1B, and KRT16, suggesting intrinsic dysfunction of basal cells in iSGS. CONCLUSIONS: Abnormal squamous differentiation of epithelial cells may contribute to the pathogenesis of iSGS. Patients having metaplastic epithelial phenotype may be sensitive to drugs that reverse it to a normal phenotype.

The impact of digital inequities on laryngeal cancer disparities in the US.

OBJECTIVES: To develop and implement a novel, comprehensive tool, the Digital Inequity Index (DII), that quantifiably measures modern-technology access in the US to assess the impact of digital inequity on laryngeal cancer (LC) care nationwide. METHODS: DII was calculated based on 17 census-tract level variables derived from the American Community Survey and Federal Communications Commission. Variables were categorized as infrastructure-access (i.e., electronic device ownership, type of broadband, internet provider availability, income-broadband subscription ratio) or sociodemographic (i.e., education, income, disability status), ranked and then averaged into a composite score. 22,850 patients from 2008 to 2017 in SEER were assessed for regression trends in long-term follow-up, survival, prognosis, and treatment across increasing overall digital inequity, as measured by the DII. This methodology allows for us to assess the independent contribution of digital inequity adjusted for socioeconomic confounders. RESULTS: With increasing overall digital inequity, length of long-term follow-up (p < 0.001) and survival (p = 0.025) decreased. Compared to LC patients with low DII, high DII was associated with increased odds of advanced preliminary staging (OR 1.06; 95 % CI 1.03-1.08), treatment with chemotherapy (OR 1.06; 95 % CI 1.04-1.08), and radiation therapy (OR 1.02; 95 % CI 1.00-1.04), as well as decreased odds of surgical resection (OR 0.96; 95 % CI 0.94-97). CONCLUSIONS: Digital inequities are associated with detrimental trends in LC patient outcomes in the US, allowing discourse for targeted means of alleviating disparities while contextualizing national sociodemographic trends of the impact of online access on informed care.

Analgesia in Transcutaneous Laryngeal Botulinum Toxin Injections: A Randomized Crossover Trial.

OBJECTIVES: There is an absence of data in the literature regarding methods to improve the patient experience during the performance of awake in-office laryngeal injections. This study sought to evaluate whether the use of local anesthetic or a vibrating instrument decreased overall pain experienced by patients with laryngeal dystonia, frequently referred to as spasmodic dysphonia (SD), undergoing transcervical botulinum toxin injections. METHODS: This was an unblinded, prospective randomized control trial with a crossover design where each patient received transcutaneous transcricothyroid injection of botulinum toxin with alternating use of no anesthesia, local anesthesia (2% lidocaine in 1:100,000 epinephrine), and vibrating instrument in three consecutive laryngeal injections to treat adductor SD. Patients were randomized to the order they received these treatments. Patients measured pain on a 0-10 visual analogue scale (VAS) and selected their preferred technique after receiving all three analgesic modalities. RESULTS: Thirty-two patients completed the study. There was no statistically significant difference in pain between the three analgesic techniques (p = 0.38). The most preferred analgesic technique was the vibrating wand (44% (14/32)). Lidocaine was the second most preferred (37% (12/32)) and 19% (6/32) of patients preferred nothing. When combining the wand and nothing groups, 63% of patients preferred one of these two methods (95% exact CI: 44%-79%). CONCLUSION: There was no statistically significant difference in median pain experienced by patients during laryngeal botulinum toxin injection between these different analgesic modalities. More than half of the patients selected a preference for a technique that did not include lidocaine. This data supports individualization of analgesia during transcutaneous laryngeal injections. LEVEL OF EVIDENCE: 2 Laryngoscope, 134:2277-2281, 2024.

Factors Associated With Otolaryngologists Performing Tracheotomy.

Importance: Tracheotomies are frequently performed by nonotolaryngology services. The factors that determine which specialty performs the procedure are not defined in the literature but may be influenced by tracheotomy approach (open vs percutaneous) and other clinicodemographic factors. Objective: To evaluate demographic and clinical characteristics associated with tracheotomies performed by otolaryngologists compared with other specialists and to differentiate those factors from factors associated with use of open vs percutaneous tracheotomy. Design, Setting, and Participants: This multicenter, retrospective cohort study included patients aged 18 years or older who underwent a tracheotomy for cardiopulmonary failure at 1 of 8 US academic institutions between January 1, 2013, and December 31, 2016. Data were analyzed from September 2022 to July 2023. Exposure: Tracheotomy. Main Outcomes and Measures: The primary outcome was factors associated with an otolaryngologist performing tracheotomy. The secondary outcome was factors associated with use of the open tracheotomy technique. Results: A total of 2929 patients (mean [SD] age, 57.2 [17.2] years; 1751 [59.8%] male) who received a tracheotomy for cardiopulmonary failure (652 [22.3%] performed by otolaryngologists and 2277 [77.7%] by another service) were analyzed. Although 1664 of all tracheotomies (56.8%) were performed by an open approach, only 602 open tracheotomies (36.2%) were performed by otolaryngologists. Most tracheotomies performed by otolaryngologists (602 of 652 [92.3%]) used the open technique. Multivariable regression analysis revealed that self-reported Black race (odds ratio [OR], 1.89; 95% CI, 1.52-2.35), history of neck surgery (OR, 2.71; 95% CI, 2.06-3.57), antiplatelet and/or anticoagulation therapy (OR, 1.74; 95% CI, 1.29-2.36), and morbid obesity (OR, 1.54; 95% CI, 1.24-1.92) were associated with greater odds of an otolaryngologist performing tracheotomy. In contrast, history of neck surgery (OR, 1.36; 95% CI, 0.96-1.92), antiplatelet and/or anticoagulation therapy (OR, 0.80; 95% CI, 0.56-1.14), and morbid obesity (OR, 0.94; 95% CI, 0.74-1.19) were not associated with undergoing open tracheotomy when performed by any service, and Black race (OR, 0.56; 95% CI, 0.44-0.71) was associated with lesser odds of an open approach being used. Age-adjusted Charlson Comorbidity Index score greater than 4 was associated with greater odds of both an otolaryngologist performing tracheotomy (OR, 1.26; 95% CI, 1.03-1.53) and use of the open tracheotomy technique (OR, 1.48, 95% CI, 1.21-1.82). Conclusions and Relevance: In this study, otolaryngologists were significantly more likely than other specialists to perform a tracheotomy for patients with history of neck surgery, morbid obesity, and ongoing anticoagulation therapy. These findings suggest that patients undergoing tracheotomy performed by an otolaryngologist are more likely to present with complex and challenging clinical characteristics.

Significance of age and sex in botulinum neurotoxin dosing for adductor spasmodic dysphonia.

Objectives: This study aims to analyze the impact of age and sex on botulinum neurotoxin (BoNT-A) dosing and outcomes in adductor spasmodic dysphonia (AdSD). Methods: A database review of all spasmodic dysphonia patients treated with BoNT from 1989 to 2018 at the Mayo Clinic in Arizona was performed. Only patients who had received ≥4 injections of BoNT-A for AdSD were included. Patients were divided into two cohorts to analyze age, with an age of first treatment cutoff of 60 years. Patients were divided into male and female cohorts to analyze sex. Results: The final analysis included 398 patients. The mean dose of BoNT-A per treatment was significantly higher in the younger cohort (4.4 vs. 3.9 units, p = 0.048). The mean maximal benefit was similar (72% vs. 70%, p = 0.48); however, the mean length of benefit was significantly shorter in younger patients (3.0 vs. 3.6 months, p < 0.01). The mean BoNT-A dose was significantly higher in the female cohort (4.2 vs. 3.6 units, p = 0.02). The mean maximal benefit was similar (69% vs. 75%, p = 0.58), as was the mean length of benefit (3.2 vs. 3.5 months, p = 0.11). Conclusions: This study suggests that age and sex influence BoNT-A dosing and outcomes in AdSD.

Interim Results of a Phase 1/2 Open-Label Study of INO-3107 for HPV-6 and/or HPV-11-Associated Recurrent Respiratory Papillomatosis.

OBJECTIVE: To evaluate the safety, immunogenicity, and efficacy of INO-3107, a DNA immunotherapy designed to elicit targeted T-cell responses against human papillomavirus (HPV) types 6 and 11, in adult patients with recurrent respiratory papillomatosis (RRP; NCT04398433). METHODS: Eligible patients required ≥2 surgical interventions for RRP in the year preceding dosing. INO-3107 was administered by intramuscular (IM) injection followed by electroporation (EP) on weeks 0, 3, 6, and 9. Patients underwent surgical debulking within 14 days prior to first dose, with office laryngoscopy and staging at screening and weeks 6, 11, 26, and 52. Primary endpoint was safety and tolerability, as assessed by treatment-emergent adverse events (TEAEs). Secondary endpoints included frequency of surgical interventions post-INO-3107 and cellular immune responses. RESULTS: An initial cohort of 21 patients was enrolled between October 2020 and August 2021. Fifteen (71.4%) patients had ≥1 TEAE; 11 (52.4%) were Grade 1, and 3 (14.3%) were Grade 3 (none treatment related). The most frequently reported TEAE was injection site or procedural pain (n = 8; 38.1%). Sixteen (76.2%) patients had fewer surgical interventions in the year following INO-3107 administration, with a median decrease of 3 interventions versus the preceding year. The RRP severity score, modified by Pransky, showed improvement from baseline to week 52. INO-3107 induced durable cellular responses against HPV-6 and HPV-11, with an increase in activated CD4 and CD8 T cells and CD8 cells with lytic potential. CONCLUSION: The data suggest that INO-3107 administered by IM/EP is tolerable and immunogenic and provides clinical benefit to adults with RRP. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:3087-3093, 2023.

Comparative Treatment Outcomes for Idiopathic Subglottic Stenosis: 5-Year Update.

The North American Airway Collaborative (NoAAC) previously published a 3-year multi-institutional prospective cohort study showing variation in treatment effectiveness between 3 primary surgical techniques for idiopathic subglottic stenosis (iSGS). In this report, we update these findings to include 5 years of data evaluating treatment effectiveness. Patients in the NoAAC cohort were re-enrolled for 2 additional years and followed using the prespecified published protocol. Consistent with prior data, prospective observation of 487 iSGS patients for 5 years showed treatment effectiveness differed by modality. Cricotracheal resection maintained the lowest rate of recurrent operation (5%), followed by endoscopic resection with adjuvant medical therapy (30%) and endoscopic dilation (50%). These data support the initial observations and continue to provide value to providers and patients navigating longitudinal decision-making. Level of evidence: 2-prospective cohort study.

Outcomes of KTP Laser Ablation in Glottic Neoplasms: A Systematic Review and Meta-Analysis.

OBJECTIVES: To evaluate the safety and clinical effectiveness of transoral laser microsurgery (TLM) with potassium-titanyl-phosphate (KTP) laser ablation for glottic neoplasms. DATA SOURCE: MEDLINE via PubMed, SCOPUS, Web of Science, and Cochrane Library. REVIEW METHODS: A systematic review and meta-analysis of studies assessing the safety and efficacy of KTP laser therapy in patients with early-stage glottic neoplasms. RESULTS: Eight studies were included. After an average follow-up of 3.3 years, the overall survival and disease-free survival for patients who underwent KTP were 90.7% (95% CI 85%-96.5%) and 98.5% (95% CI 97.3%-99.8%), respectively. In the single-arm meta-analysis, the pooled estimate of recurrence was 7.7% (95% CI 3.4%-12%). The overall voice handicap index (VHI) estimate attributed to KTP in the single-arm meta-analysis was 6.76 (95% CI [3.05, 10.48]) and 5.21 (95% CI [2.86, 7.56]) within 6 months and after a one-year follow-up, respectively. CONCLUSION: KTP laser ablation is a safe and effective method for treating patients with early glottic neoplasms. Laryngoscope, 133:1806-1814, 2023.

Is Continued Perioperative Antithrombotic Therapy Safe When Performing Open Tracheostomy?

OBJECTIVES: To date, there are no specific guidelines on antithrombotic therapy (ATT) management, which includes both anticoagulation and antiplatelet medications, for open tracheostomy. The objective of this study was to evaluate whether the use of perioperative antithrombotic medication during open tracheostomy influences the incidence of perioperative or postoperative complications. METHODS: A retrospective review was conducted of all patients who underwent open tracheostomies at a tertiary care medical center from January 2015 to December 2019. Charts were reviewed for demographics, comorbidities, indication for tracheostomy, ATT use, operative details, and complications. RESULTS: A total of 217 tracheostomies were evaluated for this study, of which 148 (68.2%) were not on ATT and 69 (31.8%) were on ATT during surgery. No significant difference was observed based on ATT status in perioperative bleeding (P = .983), postoperative bleeding (P = .24), or median days to decannulation (P = .5986). ATT patients were 2.67 times more likely to experience 30-day mortality than those non-ATT patients (P = .035). There was only one death due to hemorrhage in the ATT group. This was unrelated to the tracheostomy. This compares to 2 hemorrhage-related deaths in those not on ATT. CONCLUSION: There was no significant difference in perioperative or postoperative bleeding based on ATT use. Patients on ATT were significantly more likely to experience 30-day mortality, however only one death was due to hemorrhage in the ATT group and was unrelated to tracheostomy. Therefore, continued perioperative ATT use appears to be safe when performing open tracheostomy. LEVEL OF EVIDENCE: 4.

A Heterotopic Mouse Model for Studying Laryngeal Transplantation.

Laryngeal heterotopic transplantation, although a technically challenging procedure, offers more scientific analysis and cost benefits compared to other animal models. Although first described by Shipchandler et al. in 2009, this technique is not widely used, possibly due to the difficulties in learning the microsurgical technique and time required to master it. This paper describes the surgical steps in detail, as well as potential pitfalls to avoid, in order to encourage effective use of this technique. In this model, the bilateral carotid arteries of the donor larynx are anastomosed to the recipient carotid artery and external jugular vein, allowing for blood flow through the graft. Blood flow can be confirmed intraoperatively by the visualization of blood filling in the graft bilateral carotid arteries, reddening of the thyroid glands of the graft, and bleeding from micro vessels in the graft. The crucial elements for success include delicate preservation of the graft vessels, making the correct size arteriotomy and venotomy, and using the appropriate number of sutures on the arterial-arterial and arterial-venous anastomoses to secure vessels without leakage and prevent occlusion. Anyone can become proficient in this model with sufficient training and perform the procedure in approximately 3 h. If performed successfully, this model allows for immunologic studies to be performed with ease and at low cost.

Radiation-Induced Laryngeal Mucous Membrane Pemphigoid.

OBJECTIVES: Bullous pemphigoid has previously been linked to radiotherapy, but here we report the first case of MMP suspected to be a consequence of RT. METHODS: The patient described is an 85-year-old male who underwent RT to treat squamous cell carcinoma of the palatine tonsil. Shortly after therapy, the patient developed blisters with worsening dyspnea and dysphonia. RESULTS: This patient was successfully treated with a combination of oral immunosuppressants and surgical intervention. CONCLUSION: This incident underscores that not all episodes of mucosal ulceration following radiation are a result of mucositis and MMP should be considered in the differential. LEVEL OF EVIDENCE: Level 4.

Clinicodemographic Predictors of Tracheotomy Tube Size and Decannulation: A Multiinstitutional Retrospective Cohort Study on Tracheotomy.

OBJECTIVE: We aimed to discern clinico-demographic predictors of large (≥8) tracheostomy tube size placement, and, secondarily, to assess the effect of large tracheostomy tube size and other parameters on odds of decannulation before hospital discharge. SUMMARY OF BACKGROUND DATA: Factors determining choice of tracheostomy tube size are not well-characterized in the current literature, despite evidence linking large tracheostomy tube size with posttracheotomy tracheal stenosis. The effect of tracheostomy tube size on timing of decannulation is also unknown, an important consideration given reported associations between endotracheal tube size and probability of failed extubation. METHODS: We collected information pertaining to patients who underwent tracheotomy at 1 of 10 U.S. health care institutions between 2010 and 2019. Tracheostomy tube size was dichotomized (≥8 and <8). Multivariable logistic regression models were fit to identify predictors of (1) large tracheostomy tube size, and (2) decannulation before hospital discharge. RESULTS: The study included 5307 patients, including 2797 (52.7%) in the large tracheostomy cohort. Patient height (odds ratio [OR] = 1.060 per inch; 95% confidence interval [CI] 1.041-1.070) and obesity (1.37; 95% CI 1.1891.579) were associated with greater odds of large tracheostomy tube; otolaryngology performing the tracheotomy was associated with significantly lower odds of large tracheostomy tube (OR = 0.155; 95% CI 0.131-0.184). Large tracheostomy tube size (OR = 1.036; 95% CI 0.885-1.213) did not affect odds of decannulation. CONCLUSIONS: Obesity was linked with increased likelihood of large tracheostomy tube size, independent of patient height. Probability of decannulation before hospital discharge is influenced by multiple patient-centric factors, but not by size of tracheostomy tube.

Trilayered Hydrogel Scaffold for Vocal Fold Tissue Engineering.

The lamina propria within the vocal fold (VF) is a complex multilayered tissue that increases in stiffness from the superficial to deep layer, where this characteristic is crucial for VF sound production. Tissue-engineered scaffolds designed for VF repair must mimic the biophysical nature of the native vocal fold and promote cell viability, cell spreading, and vibration with air flow. In this study, we present a unique trilayered, partially degradable hydrogel scaffold that mimics the multilayered structure of the VF lamina propria. Using thiol-norbornene photochemistry, trilayered hydrogel scaffolds were fabricated via layer-by-layer stacking with increasing polymer concentration from the top to middle to deep layer. Mechanical analysis confirmed that hydrogel modulus increased with increasing polymer concentration. Partially degradable hydrogels promoted high cell viability and cell spreading in three dimensions as assessed via live/dead and cytoskeleton staining, respectively. Importantly, partially degradable hydrogels maintained some degree of the three dimensional polymer network following protease exposure, while still enabling encapsulated cells to remodel their local environment via protease secretion. Finally, the trilayered hydrogel scaffold successfully vibrated and produced sound in proof-of-concept air flow studies. This work represents a critical first step toward the design of a multilayered, hydrogel scaffold for vocal fold tissue engineering.

Anxiety and Depression in Patients With Idiopathic Subglottic Stenosis.

OBJECTIVES: To characterize the presence and severity of anxiety and depression in patients with symptomatic idiopathic subglottic stenosis (ISGS). To determine the relationship between dyspnea severity and anxiety and depression symptom severity. METHODS: Patients diagnosed with idiopathic subglottic stenosis and treated at Mayo Clinic Florida or Mayo Clinic Arizona retrospectively completed the PROMIS Depression, PROMIS Anxiety, PROMIS Dyspnea Functional Limitations, and Dyspnea Index questionnaires. Patients with dyspnea and without idiopathic subglottic stenosis were also asked to complete the questionnaires as a control group. RESULTS: This explorative retrospective study includes 44 control patients and 46 ISGS patients. Unadjusted and adjusted group comparisons found no statistically significant difference in dyspnea index, depression, anxiety, nor dyspnea functional limitation scores. Relationships between dyspnea severity and anxiety and depression severity were significant and persistent in both groups. Anxiety and depression were positively correlated (r = 0.66). Dyspnea severity positively correlate with both anxiety and depression (anxiety r = 0.49, depression r = 0.32). CONCLUSIONS: Patients with symptomatic idiopathic subglottic stenosis are not at an increased risk of having anxiety and depression when compared to other dyspneic patients. As dyspnea severity worsens, patients are more likely to experience anxiety and depression. These findings support the prior literature and suggest the presence of dyspnea may warrant appropriate psychological screening and treatment to optimize dyspneic patients' quality of life and symptom improvement.

Regenerating airway epithelium using fibrous biomimetic basement membranes.

There are reciprocal interactions between epithelial cells and underlying basement membrane. The resemblance of biomaterials to native basement membrane is thus critical for their success when used to regenerate epithelium-containing organs. Particularly, the use of nanofibers and the incorporation of basement membrane proteins may mimic both biophysical and biochemical properties of basement membrane, respectively. Herein we tested how electrospun polycaprolactone/heparin fibers with and without adsorbed laminin and collagen IV proteins affect epithelial cell functions. We found that airway epithelial cells attached, migrated, and proliferated on all scaffolds but protein-functionalized fibers promoted higher attachment, quicker migration, and increased proliferation. Fibers were then integrated on polyethylene scaffolds and cultured at an air-liquid interface. The detection of secretory and ciliated cell markers was higher in cells on polyethylene with fibers. These findings demonstrate that electrospun fibers incite beneficial epithelial cell responses and can be used in the fabrication of bioengineered functional epithelia.

Prognostic and Treatment Differences Between T1a and T1b Glottic Cancer.

OBJECTIVES: This study was designed to evaluate significant differences in treatment and survival outcomes between patients with T1a and T1b glottic cancer. METHODS: Patients within the SEER Research Plus, 18 Registries dataset who were diagnosed with Stage I T1a or T1b cancer of the glottis between 2004 and 2015 were included in this study. Data prior to 2004 could not be included, as the SEER database did not distinguish between T1a and T1b glottic cancer until that year. RESULTS: The 5-year disease-specific survival for T1a patients was significantly better than that of patients diagnosed with T1b glottic cancer. Age and year of diagnosis were also independent factors that impacted mortality. More patients who were diagnosed with T1b glottic cancer underwent external beam radiation than those diagnosed with T1a glottic cancer. CONCLUSION: Our data shows that there are several independent factors effecting mortality including T classification, age at time of diagnosis, and year of diagnosis. T1a glottic cancers also show a significantly better prognosis compared with T1b. T1b glottic cancers are much more likely to be treated with primary radiotherapy compared with surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:2187-2193, 2022.

Human amniotic epithelial cell transplantation improves scar remodeling in a rabbit model of acute vocal fold injury: a pilot study.

OBJECTIVE: To gain insight into the molecular mechanisms underlying the early stages of vocal fold extracellular matrix (ECM) remodeling after a mid-membranous injury resulting from the use of human amniotic epithelial cells (hAEC), as a novel regenerative medicine cell-based therapy. METHODS: Vocal folds of six female, New Zealand White rabbits were bilaterally injured. Three rabbits had immediate bilateral direct injection of 1 × 106 hAEC in 100 µl of saline solution (hAEC) and three with 100 µl of saline solution (controls, CTR). Rabbits were euthanized 6 weeks after injury. Proteomic analyses (in-gel trypsin protein digestion, LC-MS/MS, protein identification using Proteome Discoverer and the Uniprot Oryctolagus cuniculus (Rabbit) proteome) and histological analyses were performed. RESULTS: hAEC treatment significantly increased the expression of ECM proteins, elastin microfibril interface-located protein 1 (EMILIN-1) and myocilin that are primarily involved in elastogenesis of blood vessels and granulation tissue. A reactome pathway analysis showed increased activity of the anchoring fibril formation by collagen I and laminin, providing mechanical stability and activation of cell signaling pathways regulating cell function. hAEC increased the abundance of keratin 1 indicating accelerated induction of the differentiation programming of the basal epithelial cells and, thereby, improved barrier function. Lastly, upregulation of Rab GDP dissociation inhibitor indicates that hAEC activate the vesicle endocytic and exocytic pathways, supporting the exosome-mediated activation of cell-matrix and cell-to-cell interactions. CONCLUSIONS: This pilot study suggests that injection of hAEC into an injured rabbit vocal fold favorably alters ECM composition creating a microenvironment that accelerates differentiation of regenerated epithelium and promotes stabilization of new blood vessels indicative of accelerated and improved repair.

A Tissue Engineered Construct for Laryngeal Regeneration: A Proof-of-Concept Device Design Study.

OBJECTIVES/HYPOTHESIS: Develop a patient-specific tissue engineered construct for laryngeal reconstruction following a partial laryngectomy. STUDY DESIGN: Bench and animal research. METHODS: A construct made from a porous polyethylene scaffold shaped in a canine-specific configuration and seeded with autologous canine adipose-derived stem cells in fibrin glue was implanted in a canine following a partial laryngectomy. After 1 year, the construct was first evaluated in vivo with high-speed imaging and acoustic-aerodynamic measures. It was then explanted and evaluated histologically. RESULTS: The canine study at 1 year revealed the construct provided voicing (barking) with acoustic and aerodynamic measures within normal ranges. The canine was able to eat and breathe normally without long-term support. The construct was integrated with epithelialization of all areas except the medial portion of the vocal fold structure. No anti-infective agents were needed after the standard perioperative medications were completed. CONCLUSION: This study provided a successful first step toward developing a patient-specific composite construct for patients undergoing partial laryngectomies. LEVEL OF EVIDENCE: NA Laryngoscope, 132:S1-S11, 2022.

High Speed Video Observations of Vocal Fold Kinematics While Playing a Clarinet.

INTRODUCTION: In this pilot study, flexible high-speed video (HSV) technology with synchronized audio is used to visualize vocal fold behavior in a wind instrumentalist. Specifically, this study aims to contribute to describing the vocal fold behavior of a professional clarinet musician playing varying tones and melodies. METHOD: Vocal folds of a healthy 26-year-old professional clarinet musician were recorded utilizing a HSV camera coupled to a flexible endoscope, which allowed the synchronous recording of audio with vocal fold movement at the onset, playing, and offset of playing. Two raters experienced with analyzing vocal folds described vocal fold motion of each sample. Samples were processed through a software model to determine the vocal fold movement relative to their position at rest. Digital kymograms (DKGs) were additionally obtained to visualize vocal fold micromovements throughout each sample. RESULTS: At the onset of playing, the raters observed the vocal folds moving to a paramedian position. Vocal fold adduction varied according to the task performed and ranged from 58% to 77% of the original resting glottis width. The calculated changes in glottis width and DKGs were consistent with the descriptions by the raters. CONCLUSION: This study demonstrates the utility of flexible HSV in observing vocal fold motion before, during, and after events other than sustained phonation. The incomplete adducted vocal fold postures observed while playing the clarinet not only differ from phonation but also differ depending on task. These various postures may contribute to voice fatigue in wind instrumentalists or to various disorders experienced during their careers.