External laryngotracheal trauma: a case series and an algorithmic management strategy.

OBJECTIVES: External laryngotracheal trauma (ELT), blunt or penetrating, is a rare but potentially life-threatening injury. Immediate care in the emergency department can be challenging because it requires managing a potentially unstable airway and may have associated vascular injuries with massive bleeding. Here, we look at the details of injury, treatment measures, and outcomes in patients following ELT. METHODS: We retrospectively analyzed 22 patients treated at our center for ELT from January 2005 up to December 2021 with varying grades of injury. We looked at their status at presentation, management strategy and functional status. RESULTS: In our report, we include 18 men and 4 women having varying Schaefer injury grades. Eight patients had tracheostomy at presentation and eight had vocal fold immobility. Two patients were treated endoscopically, 12 had open surgery and 8 received no treatment. Of the patients undergoing open surgery, thyroid cartilage fracture was seen in 9 patients, thyroid plus cricoid fracture and cricotracheal separation were seen in 3 patients each. All patients were safely decannulated and spontaneous recovery of vocal cord palsy was seen in some patients. CONCLUSION: The success of managing ELT relies on fast decision-making, correct patient evaluation, securing the airway and maintaining the hemodynamic stability. Early surgical intervention must be aimed at optimally treating the larygotracheal injuries to prevent long-term disastrous consequences.

Autophagy protects against vocal fold injury-induced fibrosis.

Vocal fold scar formation due to vocal fold injury (VFI) is a common cause of surgery or trauma-induced voice disorders. Severe scar formation can lead to reduced voice quality or even be life-threatening. Here, we investigated the role of autophagy in VFI, focusing on fibrosis as a consequence of autophagy in inducing VFI. A VFI model was constructed in rats by dissecting the lamina propria tissue from the thyroarytenoid muscle. Real-time PCR and Western blot were used to analyze expressions of autophagy markers, including Beclin1 and Atg7, in VFI. Tgfb1 and Col1a1 were assessed to determine the correlation of fibrosis with VFI progression and autophagy levels. Rat vocal fold fibroblasts were also treated with TGF-ß1 or rapamycin, which activates and suppresses autophagy respectively, to explore how autophagy regulates fibrosis in VFI. Initially, we observed that autophagy was downregulated in vocal fold mucosa after VFI in rats. This was particularly evident by the time-dependent downregulation of Beclin1 and Atg7 following VFI. Concurrently, levels of Tgfb1 and Col1a1 also surged, hinting at elevated fibrosis levels. Furthermore, our experiments with TGF-ß1 stimulation revealed that it inhibited autophagy in rat vocal fold fibroblasts. Interestingly, when we introduced rapamycin, this effect was reversed. Our data suggest that autophagy is a suppressor of VFI by alleviating fibrosis, making targeting autophagy a potential therapeutic route in VFI.NEW & NOTEWORTHY The study has demonstrated that autophagy is a suppressor of VFI by alleviating fibrosis, making autophagy a potential therapeutic target in VFI.

Screening for Vocal Fold Movement Impairment in Children Undergoing Esophageal and Airway Surgery.

INTRODUCTION: Children undergoing cervical and/or thoracic operations are at risk for recurrent laryngeal nerve injury, resulting in vocal fold movement impairment (VFMI). Screening for VFMI is often reserved for symptomatic patients. OBJECTIVE: Identify the prevalence of VFMI in screened preoperative patients prior to an at-risk operation to evaluate the value of screening all patients at-risk for VFMI, regardless of symptoms. METHODS: A single center, retrospective review of all patients undergoing a preoperative flexible nasolaryngoscopy between 2017 and 2021, examining the presence of VFMI and associated symptoms. RESULTS: We evaluated 297 patients with a median (IQR) age of 18 (7.8, 56.3) months and a weight of 11.3 (7.8, 17.7) kilograms. Most had a history of esophageal atresia (EA, 60%), and a prior at-risk cervical or thoracic operation (73%). Overall, 72 (24%) patients presented with VFMI (51% left, 26% right, and 22% bilateral). Of patients with VFMI, 47% did not exhibit the classic symptoms (stridor, dysphonia, and aspiration) of VFMI. Dysphonia was the most prevalent classic VFMI symptom, yet only present in 18 (25%) patients. Patients presenting with a history of at-risk surgery (OR 2.3, 95%CI 1.1, 4.8, p = 0.03), presence of a tracheostomy (OR 3.1, 95%CI 1.0, 10.0, p = 0.04), or presence of a surgical feeding tube (OR 3.1, 95%CI 1.6, 6.2, p = 0.001) were more likely to present with VFMI. CONCLUSION: Routine screening for VFMI should be considered in all at-risk patients, regardless of symptoms or prior operations, particularly in those with a history of an at-risk surgery, presence of tracheostomy, or a surgical feeding tube. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:3564-3570, 2023.

Improving Timeliness of Vocal Fold Mechanical Injury Screening Following Norwood or Arch Reconstruction: A Quality Improvement Initiative at a Single Center.

Vocal fold (VF) immobility is a common complication after pediatric cardiothoracic surgeries involving the aortic arch and conotruncal region. Nasolaryngoscopy is considered the standard for diagnosis but is invasive and requires expertise and special resources. VF ultrasound (VF US) is an efficient, non-invasive alternative for VF evaluation in the post-cardiac surgical setting. Our aim was to improve screening rates for vocal fold motion impairment (VFMI) by implementing VF US in a group of pre-identified high-risk patients after index cardiac surgeries using Quality Improvement (QI) methodology. The QI project included formation of a widely representative stakeholder team, collaborative development of a screening protocol for the cohort of patients in our tertiary center. Baseline data were derived by retrospective review of screening and incidence of VFMI in a similar post-surgical cohort in 2 years prior to this intervention. We implemented an US screening algorithm with multidisciplinary care coordination. We evaluated feeding practices and length of stay (LOS) related to our screening interventions and documented follow up practices. Screening for VFMI by ultrasound increased from 59 to 92% after implementation of the VF screening protocol. Additionally, time between extubation and VF US decreased from 7.7 to 2.3 days. The positive predictive value of VF US was 96%. Patients with VFMI had a longer LOS and greater dependence on tube feeds at discharge after index surgery. We successfully implemented an ultrasound-based screening protocol for VFMI and demonstrated improved screening, timeliness and high positive predictive value of ultrasound.

Scarless Healing of Injured Vocal Folds Using an Injectable Hyaluronic Acid-Waterborne Polyurethane Hybrid Hydrogel to Tune Inflammation and Collagen Deposition.

Vocal fold (VF) scarring results from injury to the unique layered structure and is one of the main reasons for long-lasting dysphonia. A minimally invasive procedure with injectable hydrogels is a promising method for therapy. However, current surgical techniques or standard injectable fillers do not yield satisfactory outcomes. In this work, an injectable hybrid hydrogel consisting of oxide hyaluronic acid and hydrazide-modified waterborne polyurethane emulsion was injected precisely into the injury site and cross-linked in situ by a dynamic hydrazone bond. The prepared hydrogel displays excellent injectability and self-healing ability, showing favorable biocompatibility and biodegradability to facilitate endogenous newborn cell migration and growth for tissue regeneration. With the aim of evaluating the antifibrosis and regeneration capacity of the hybrid hydrogel in the VF scarring model, the morphology and vibration characteristics of VFs, inflammatory response, and healing status were collected. The hybrid hydrogel can decrease the inflammation and increase the ratio of collagen III/collagen I to heal damaged scar-free tissue. Fascinatingly, the mucosal wave oscillations of healing VF by injecting the hybrid hydrogel were vibrated like the normal VF, achieving functional restoration. This work highlights the utility of hybrid hydrogels consisting of synthetic biodegradable waterborne polyurethane emulsions and natural hyaluronic acid as promising biomaterials for scarless healing of damaged VFs.

Vocal fold injury models in rats: a literature review on techniques and methodology.

This study reviewed the current literature on technical aspects regarding controlled vocal fold injuries in the rat model. Data from PubMed, Embase, and Scopus database for English language literature was collected to identify methodological steps leading to a controlled surgical injury of the rat vocal fold. Inclusion criteria: full disclosure of anesthesia protocol, positioning of the rat for surgery, vocal fold visualization method, instrumentation for vocal fold injury, vocal fold injury type. Articles with partial contribution were evaluated and separately included due to the limited number of original methodologies. 724 articles were screened, and eleven articles were included in the analysis. Anesthesia: ketamine hydrochloride and xylazine hydrochloride varied in dose from 45 mg/kg and 4.5 mg/kg to 100 mg/kg and 10 mg/kg. Visualization: The preferred method was the 1.9 mm, 25-30 degree endoscopes. The widest diameter endoscope used was 2.7 mm with a 0 or 30 degree angle of view. Instruments for lesion induction range from 18 to 31G needles, microscissors, micro forceps to potassium titanyl phosphate, and blue light lasers. Injury types: vocal fold stripping was the main injury type, followed by vocal fold scarring and charring. One article describes scaffold implantation with injury to the superior aspect of the vocal fold. Rats are good candidates for in vivo larynx and vocal folds research. A more standardized approach should be considered regarding the type of vocal fold injury to ease data comparison.

Experimental model for controlled endoscopic subepithelial vocal fold injury in rats.

PURPOSE: To present a detailed, reproducible, cost-efficient surgical model for controlled subepithelial endoscopic vocal fold injury in the rat model. METHODS: Six male Sprague Dawley rats were enrolled in the experiment. The left vocal folds were used to carry out the injury model, and the right vocal fold served as control. After deep sedation, the rats were placed on a custom operating platform. The vocal fold injury by subepithelial stripping was carried out using custom-made microsurgical instruments under endoscopic guidance. Data were analyzed for procedural time and post-procedural pain. Microcomputed tomography (micro-CT) scan and histologic images were obtained to assess the length, area, and depth of injury to the vocal fold. RESULTS: The mean procedural time was 112 s. The mean control vocal fold length was 0.96 ± 0.04 mm. The mean vocal fold injury length was 0.53 ± 0.04 mm. The mean vocal fold surface was 0.18 ± 0.01 mm2 with a mean lesion area of 0.05 ± 0.00 mm2. Mean vocal fold injury depth was 375.4 ± 42.8 µm. The lesion length to vocal fold length ratio was 0.55 ± 0.03, as well as lesion area to vocal fold surface area was 0.29 ± 0.02. CONCLUSIONS: Our described experimental vocal fold injury model in rats is found to be fast, safe, cost-efficient, and reproducible with a rapid learning curve.

Inpatient Type 1 Thyroplasty Versus Injection Laryngoplasty for Vocal Fold Movement Impairment After Extent type I and II Aortic Repair.

IMPORTANCE: Vocal fold motion impairment (VFMI) due to neuronal injury is a known complication following thoracic aortic repair that can impair pulmonary toilet function and post-operative recovery. OBJECTIVE: To demonstrate clinical outcomes of patients undergoing inpatient vocal fold medialization for VFMI after aortic surgery. DESIGN: A 15-year retrospective chart review (2005-2019) of 259 patients with postoperative VFMI after thoracic aortic surgery registry was conducted. Data included demographics, surgery characteristics, laryngology exam, and postoperative clinical outcomes. Medialization procedures consisted of type 1 thyroplasty and injection laryngoplasty. SETTING: Tertiary care hospital. PARTICIPANTS: Two hundred and fifty-nine patients (median age 61, 71% male) with VFMI post-thoracic aortic repair met inclusion criteria; inpatient vocal fold medialization was performed for 203 (78%) patients. One hundred and twenty-six. (49%) received type 1 thyroplasty and 77 (30%) received injection laryngoplasty procedures at a median 7 days (IQR 5-8 days) from extubation. MAIN OUTCOMES: Primary study outcome measurements consisted of median LOS, median ICU LOS, complications intra- and postoperatively, and pulmonary complications (post-medialization bronchoscopies, pneumonia, tracheostomy, etc.). RESULTS: Post-medialization bronchoscopy rates were significantly lower in the medialization (n = 11) versus the non-medialization group (n = 8) (5% vs 14%, P = .02) and significantly higher in the injection laryngoplasty group (n = 77) versus thyroplasty group (n = 126) (10% vs 2%, P = .02). Further analysis revealed no significant difference in overall LOS and pulmonary complications between the techniques. CONCLUSION: Inpatient thyroplasty and injection laryngoplasty are both effective vocal fold medialization techniques after extent I and II aortic repair. Thyroplasty may have a small pulmonary toilet advantage, as measured by need for post-medialization bronchoscopy, compared to injection laryngoplasty.

Experimental model for controlled endoscopic subepithelial vocal fold injury in rats

Purpose: To present a detailed, reproducible, cost-efficient surgical model for controlled subepithelial endoscopic vocal fold injury in the rat model. Methods: Six male Sprague Dawley rats were enrolled in the experiment. The left vocal folds were used to carry out the injury model, and the right vocal fold served as control. After deep sedation, the rats were placed on a custom operating platform. The vocal fold injury by subepithelial stripping was carried out using custom-made microsurgical instruments under endoscopic guidance. Data were analyzed for procedural time and post-procedural pain. Microcomputed tomography (micro-CT) scan and histologic images were obtained to assess the length, area, and depth of injury to the vocal fold. Results: The mean procedural time was 112 s. The mean control vocal fold length was 0.96 ± 0.04 mm. The mean vocal fold injury length was 0.53 ± 0.04 mm. The mean vocal fold surface was 0.18 ± 0.01 mm2 with a mean lesion area of 0.05 ± 0.00 mm2. Mean vocal fold injury depth was 375.4 ± 42.8 µm. The lesion length to vocal fold length ratio was 0.55 ± 0.03, as well as lesion area to vocal fold surface area was 0.29 ± 0.02. Conclusions: Our described experimental vocal fold injury model in rats is found to be fast, safe, cost-efficient, and reproducible with a rapid learning curve.

Manejo de la patología congénita y adquirida de la vía aérea en el neonato por parte de un comité multidisciplinar en un centro terciario / Management of congenital and acquired airway pathologies in newborns by a cross-disciplinary committee at a third level hospital

Introducción: La exploración de vía aérea mediante broncoscopiaflexible/rígida en el neonato ha demostrado utilidad en el estridor persistente, extubaciones fallidas o para valorar complicaciones tras cirugíacardiaca. En nuestro hospital estas exploraciones son practicadas porun neumólogo, neonatólogo, otorrinolaringólogo y cirujano pediátricodel Comité de Vía Aérea Pediátrica, formado en 2014. Objetivo: Analizar las exploraciones de vía aérea practicadas aneonatos durante su estancia en Neonatología/Unidad de CuidadosIntensivos Neonatales desde la constitución del Comité de Vía Aérea.Materiales. Estudio retrospectivo de exploraciones de vía aéreapracticadas a neonatos en el periodo 2015-2019. Se recogen datosclínicos y demográficos, número de exploraciones, indicación, hallazgos y complicaciones. Se presentan las medias con su desviaciónestándar. Se consideró un resultado estadísticamente significativocuando p < 0,05. Resultados: Se analizaron 92 exploraciones de vía aérea en 51pacientes (género femenino: 54,9%). El 51% de los pacientes fueronprematuros. La extubación fallida y la persistencia de sintomatologíarespiratoria tras una extubación satisfactoria fueron las indicacionesmás frecuentes (35,3%). La estratificación por edad gestacional o porpeso al nacimiento no se asociaba a un mayor riesgo de presentar ha-llazgos patológicos en la exploración. El hallazgo más frecuente fue laparálisis de cuerda vocal (n = 14; 27,5%). En 10 pacientes (19,6%) nose encontraron hallazgos patológicos. Conclusión: La exploración de la vía aérea es útil en pacientes conestridor postextubación y para identificar parálisis de cuerda vocal trasextubación fallida. Además, permite el diagnóstico y tratamiento depatologías congénitas de la vía aérea.(AU)

Introduction: Neonatal airway examination through flexible/rigid bronchoscopy has proved to be useful in the presence of persis-tent stridor and extubation failure, as well as to assess complicationsfollowing cardiac surgery. At our institution, these examinations arecarried out by a pulmonologist, a neonatologist, an otorhinolaryngolo-gist, and a pediatric surgeon from the pediatric airway committee,established in 2014. Objective: To analyze the airway examinations performed in neo-nates during their stay at the neonatology/neonatal intensive care unitsince the airway committee was established.Materials and methods. A retrospective study of the airway ex-aminations conducted in neonates from 2015 to 2019 was carried out.Clinical and demographic data, number of examinations, indications,findings, and complications were collected. Results are presented asmean and standard deviation. Statistical significance was establishedat p < 0.05. Results: 92 airway examinations were analyzed in 51 patients(54.9% of whom were female). 51% of the patients were premature.Extubation failure and persistent respiratory symptoms followingsuccessful extubation were the most frequent indications for airwayexamination (35.3%). Stratification by gestational age or weight atbirth was not associated with an increased risk of pathological findingsat examination (p > 0.05). The most frequent finding was vocal cordparalysis (n = 14; 27.5%). In 10 patients (19.6%), no pathologicalfindings were observed. Conclusion: Airway examination is useful in patients with stridorto identify vocal cord paralysis following extubation failure. It alsoallows congenital airway pathologies to be diagnosed and treated. Thenumber of examinations with no pathological findings was similar tothat reported in international series.(AU)

Intubation-Related Laryngeal Deficiency and Vocal Fold Immobility in Pediatric Premature Patients.

OBJECTIVES/HYPOTHESIS: We report a posterior laryngeal rating system and measures of voice disability in pediatric patients undergoing phonosurgery for vocal fold paralysis. Posterior glottic deficiency may account for persistent voice disability. STUDY DESIGN: Retrospective Study. METHODS: Retrospective analyses of 66 subjects with primary unilateral vocal fold paralysis were reviewed for the status of posterior glottis and voice disability (Pediatric Voice Handicap Index [pVHI]). Gestation age (GA), weight, and medical/surgical history were reviewed. The width, length, and depth of the larynx were analyzed to create a reproducible rating scale. RESULTS: Mean GA was 29 weeks, with an intubation history for all subjects, with 90% having a left vocal fold immobility. Cardiac surgery was performed in 92% of subjects. A progressive rating (type 0-3) Benjamin Defect Severity Scale (BDSS) was developed to rate the absence or presence of a posterior abnormality. BDSS-2 and BDSS-3 subjects were more likely to have low birth weight. Extremely preterm GA was more likely to be associated with BDSS-1 (mild) or BDSS-2. History of multiple and prolonged intubations were seen more frequently in BDSS-2 or BDSS-3. Post-op pVHI reduced an average of 15 points for BDSS-0 to BDSS-2, but only 3 points for BDSS-3. Post-op pVHI matched normal values for preintervention dysphonic children. CONCLUSIONS: The presence of a persistent breathy voice after intervention for unilateral vocal fold immobility is potentially associated with posterior glottic defects. Low birth weight with multiple/prolonged intubation is more likely to be present with higher-grade BDs, whereas low GA is more likely to be associated with BDSS-1 to BDSS-2. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:2550-2557, 2021.

Patterns of Recurrence of Phonotraumatic Vocal Fold Lesions Suggest Distinct Mechanisms of Injury.

OBJECTIVES/HYPOTHESIS: To examine patterns of recurrence of benign phonotraumatic vocal fold lesions over time for insights into pathophysiology. STUDY DESIGN: Case series with mathematical modeling. METHODS: Medical records and stroboscopic exams of adults who underwent microlaryngoscopic resection of phonotraumatic vocal fold lesions over a 13-year period were reviewed for time to recurrence after surgery. Uniform and log-normal probability distributions were fitted to the time to recurrence curves for vocal fold polyps, midfold masses, and pseudocysts. Model fits were compared using the Akaike information criterion corrected, a standard measure of the goodness of fit. Stochastic simulations were used to verify that the mechanistic hypotheses were concordant with the selected probability distributions and empiric data. RESULTS: Of 567 patients who underwent microlaryngoscopic resection, 65 had a recurrence (16 polyps, 14 midfold masses, and 35 pseudocysts). Midfold mass and pseudocyst recurrences were predominantly seen in younger women. Polyps were best fit by a uniform distribution rather than log-normal, whereas midfold masses and pseudocysts were better fit by log-normal rather than uniform. Stochastic simulations suggest that polyps recur sporadically according to a paroxysmal-developmental model, whereas midfold mass and pseudocyst recurrences follow a force-multiplication, damage-accumulation process. CONCLUSIONS: Vocal fold polyps are acute lesions evenly distributed by age and gender that recur uniformly over time, suggesting they arise from sudden tissue reactions to phonotraumatic stress. Pseudocysts and midfold fibrous masses are chronic lesions predominantly found in young women that recur with log-normal distribution over time, suggesting gradual damage accumulation in larynges predisposed to enhanced phonotrauma. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:2523-2529, 2021.

Prospective Evaluation of Safety of Singing on Steroids: Testing the Truth of Received Wisdom.

OBJECTIVES/HYPOTHESIS: Performing while on steroids is widely considered to increase risk of vocal injury. This study aims to determine incidence and type of injury, and changes in performers' voices after treatment of vocal fold edema (VFE) with glucocorticoids. STUDY DESIGN: Prospective Cohort. METHODS: Fifty-five performers (34 female; 21 male) treated for acute VFE with short-course oral glucocorticoids were prospectively evaluated pre- and post-treatment. Subjects underwent videostroboscopy, acoustic/aerodynamic assessment, and functional assessment with the Singing Voice Handicap Index-10 (SVHI-10) and Evaluation of the Ability to Sing Easily (EASE). Blinded reviewers rated videostroboscopic examinations and performed audio-perceptual assessment. Chi-square tests and Wilcoxon signed rank tests were applied for analyses of treatment changes. RESULTS: Following glucocorticoid treatment, two instances of vocal fold hemorrhage (3.6%) and three instances of glottic thrush (5.5%) were observed. These resolved without consequence. Mucosal wave dynamics and edema improved. Nearly all subjects completed scheduled performances, and significant improvement was noted on the EASE, reflecting improved function after treatment. These were further supported by statistically significant improvements in CAPE-V and some acoustic and aerodynamic outcomes (semitone pitch range for females, airflow measures for males). CONCLUSIONS: Oral glucocorticoids appear to be generally safe for performers presenting with acute VFE. The incidence of adverse effects, specifically hemorrhage and thrush, was low and the effects transient. Vocal fold examination should be considered obligatory before prescribing glucorticoids to working performers. A treatment strategy for acute VF edema incorporating glucocorticoids when appropriate appears to result in significant improvements in measures of glottal function including videostroboscopic appearance, subject perception, and auditory perception. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:2298-2304, 2021.

Nerve Injury During Ultrasound-Guided Thyroid Biopsy-A First Reported Complication of Permanent Vocal Fold Paralysis.

Needle biopsy is a well-established component in the evaluation of thyroid nodules. The biopsy is usually performed with an ultrasound guidance and consists of either fine-needle aspiration or core needle biopsy. Although these terms are often used interchangeably, their difference is important. To our knowledge, we discuss the first reported case of biopsy-proven laryngeal nerve injury and permanent vocal fold paralysis following ultrasound-guided core biopsy of the thyroid. We advocate this complication be discussed as part of the consent process.

Operative Management of Vocal Fold Avulsion Following Pediatric Laryngotracheal Separation.

Laryngotracheal disruption in children is rare but life-threatening, and endolaryngeal injuries may go overlooked. We present the case of a 10-year-old boy who sustained near-complete laryngotracheal separation, multiple laryngeal fractures, and arytenoid and vocal fold avulsion following blunt cervical trauma. These injuries were not identified radiographically and only became apparent intraoperatively. Following surgical repair, the patient was successfully decannulated, eating a normal diet, and had a serviceable speaking voice within 2 months. In children, the diagnosis of severe endolaryngeal injuries may be elusive and therefore require high degree of clinical suspicion. Surgical success requires accurate diagnosis and prompt intervention.

Polymeric Microspheres Containing Human Vocal Fold Fibroblasts for Vocal Fold Regeneration.

OBJECTIVE: Most acellular injectable biomaterials for vocal fold (VF) wound treatment have limited regenerative potential due to their fast enzymatic degradation and limited recruitment of native cells postinjection. The injection of cells as therapeutic treatment often results in apoptosis due to stresses within the needle and the immune response of the host. Degradable microspheres may improve treatment effectiveness by increasing cell residence time, shielding cells during injection, and offering early protection against the immune system response. The objective of the present study was to investigate the potential of human VF fibroblasts encapsulated in polymeric microspheres as an injectable therapeutic treatment in vitro. METHODS: Alginate, alginate-poly-L-lysine, and alginate-chitosan microspheres were fabricated using electrospraying and characterized in terms of biocompatibility, swelling, and mechanical properties as well as cytokine production. RESULTS: Alginate microspheres were found to have the most desirable properties for VF regeneration. They were resistant to mechanical challenges. They were found to have a stiffness similar to that reported for native VF-lamina propria. They were found to be biocompatible and increased the proliferation of fibroblasts. Human VF fibroblasts encapsulated in alginate microspheres induced the production of interleukin (IL)-8 and IL-4 at 24 hours. CONCLUSION: The alginate microspheres fabricated in this study were found to offer potential advantages, as cell delivery tool. This study highlights the importance of combining biomaterials and cells to expedite the wound-healing process through cytokine production. Future work is aimed to further analysis of the wound-healing properties the microspheres. LEVEL OF EVIDENCE: NA Laryngoscope, 131:1828-1834, 2021.

Characterizing Vocal Fold Injury Recovery in a Rabbit Model With Three-Dimensional Virtual Histology.

OBJECTIVES/HYPOTHESIS: In animal studies of vocal fold scarring and treatment, imaging-based evaluation is most often conducted by tissue slicing and histological staining. Given variation in anatomy, injury type, severity, and sacrifice timepoints, planar histological sections provide limited spatiotemporal details of tissue repair. Three-dimensional (3D) virtual histology may provide additional contextual spatial information, enhancing objective interpretation. The study's aim was to evaluate the suitability of magnetic resonance imaging (MRI), microscale computed tomography (CT), and nonlinear laser-scanning microscopy (NM) as virtual histology approaches for rabbit studies of vocal fold scarring. METHODS: A unilateral injury was created using microcup forceps in the left vocal fold of three New Zealand White rabbits. Animals were sacrificed at 3, 10, and 39 days postinjury. ex vivo imaging of excised larynges was performed with MRI, CT, and NM modalities. RESULTS: The MRI modality allowed visualization of injury location and morphological internal features with 100-µm spatial resolution. The CT modality provided a view of the injury defect surface with 12-µm spatial resolution. The NM modality with optical clearing resolved second-harmonic generation signal of collagen fibers and two-photon autofluorescence in vocal fold lamina propria, muscle, and surrounding cartilage structures at submicrometer spatial scales. CONCLUSIONS: Features of vocal fold injury and wound healing were observed with MRI, CT, and NM. The MRI and CT modalities provided contextual spatial information and dissection guidance, whereas NM resolved extracellular matrix structure. The results serve as a proof of concept to motivate incorporation of 3D virtual histology techniques in future vocal fold injury animal studies. LEVEL OF EVIDENCE: NA Laryngoscope, 131:1578-1587, 2021.

Safety of Outpatient Type 1 Thyroplasty.

OBJECTIVE: Type 1 thyroplasty is an established procedure for the treatment of vocal fold paralysis to improve voice and swallowing outcomes. At our institution, we commonly perform this procedure on an outpatient basis in medically stable patients. With this study, we assess the safety of outpatient thyroplasty by examining complication and readmission rates, need for revision surgery, and predictors of these outcome measures. METHODS: We performed a retrospective review of patients undergoing outpatient type 1 thyroplasty for vocal fold paralysis between 2013 and 2018 at our institution. We documented the etiology of paralysis, comorbidities, and demographic data. Our primary outcome measures were complications, need for readmission, and need for revision surgery. RESULTS: During the study period, 160 patients met our inclusion criteria. Mean age at time of surgery was 62.1 ± 13.9 years; there were 82 (51%) males and 78 (49%) females. Nine (5.6%) patients experienced major complications after surgery and 7 (4.4%) patients required unplanned readmission. Mean time to complication was 6.9 ± 9.7 days. There were no instances of postoperative airway compromise requiring intervention. There were no mortalities. Of those who underwent primary surgery, 22 (14%) patients required revision surgery. CONCLUSION: Given that complications tend to occur in a delayed fashion rather than in the acute postoperative period, same-day discharge seems reasonable as compared to overnight observation in medically stable patients undergoing type 1 thyroplasty. LEVEL OF EVIDENCE: IV.

Inflammatory complications of vocal fold injection with hyaluronic acid: a multiinstitutional study

Background/aim: This study aimed to assess the inflammatory adverse reactions of vocal fold injection laryngoplasty with hyaluronic acid. Materials and methods: This study was a retrospective chart review of patients who underwent vocal fold injection augmentation with HA injection from January 2005 to September 2016 in nine different institutions. Demographic data, indication for injection, injection techniques, types of injection material, settings of procedure, and complications were reviewed. The types of complication, onset time, and management of complications were also noted. Results: In all, 467 patients were identified. The majority of patients had been injected under general anesthesia (n = 382, 84.7%). For injection material, two different types of hyaluronic acid were used: hyaluronic acid alone or hyaluronic acid with dextranomer. Complications occurred in nine patients (1.9%). The majority of complications were inflammatory reactions (n = 7, 1.47%). Main symptoms were dysphonia and/or dyspnea with an onset of 0 h to 3 weeks after the hyaluronic acid injection. Three patients were hospitalized, one of which was also intubated and observed in the intensive care unit for 24 h. Systemic steroids and antibiotics were the main medical treatment in the majority of cases. There was no statistical difference in complication rates between patients who received hyaluronic acid and those who received hyaluronic acid with dextranomer (P = 0.220). Conclusion: Hyaluronic acid can be considered as a safe substance for the injection of vocal folds with a low risk of inflammatory reaction.