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The Laryngoscope Sep 2019To investigate the role of laryngopharyngeal reflux (LPR) in the development of benign lesions of the vocal folds (BLVF).
OBJECTIVES
To investigate the role of laryngopharyngeal reflux (LPR) in the development of benign lesions of the vocal folds (BLVF).
METHODS
PubMed, Cochrane Library, and Scopus were searched by three independent investigators for articles published between January 1990 and November 2018 providing substantial information about the role of LPR in the development of nodules, polyps, cysts, Reinke's edema, and sulcus vocalis. Inclusion, exclusion, diagnostic criteria and clinical outcome evaluation of included studies were analyzed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria.
RESULTS
Of the 155 relevant publications, 42 studies were included. Thirty-five were clinical studies and seven were experimental research studying the impact of reflux on vocal fold tissue. Only seven clinical studies utilized objective LPR diagnoses (pH monitoring), suggesting an association between LPR and the development of nodules, polyps, and Reinke's edema. These studies were characterized by a substantial heterogeneity due to discrepancies in inclusion/exclusion criteria, diagnostic methods, and clinical outcome evaluation. The few basic science studies on this topic support that LPR creates an environment that may predispose to BLVF through changes in defense mechanisms of the vocal folds, cell-to-cell dehiscence, inflammatory reaction of the vocal folds, and reaction to phonotrauma.
CONCLUSIONS
Caustic mucosal injury from LPR could cause increased susceptibility of the vocal fold mucosa to injury and subsequent formation of nodules, polyps, or Reinke's edema. However, the heterogeneity and the low number of high-quality studies limit the ability to draw definitive conclusions. Future clinical and experimental studies are needed to better identify the role of reflux in development of BLVF. Laryngoscope, 129:E329-E341, 2019.
Topics: Clinical Trials as Topic; Humans; Laryngeal Diseases; Laryngeal Edema; Laryngopharyngeal Reflux; Polyps; Prospective Studies; Retrospective Studies; Vocal Cords
PubMed: 30892725
DOI: 10.1002/lary.27932 -
Annals of Medicine 2023To compare CO laser resection and laryngeal microsurgery for vocal cord polyps and provide evidence for the optimal surgical method.
OBJECTIVE
To compare CO laser resection and laryngeal microsurgery for vocal cord polyps and provide evidence for the optimal surgical method.
METHODS
This was a retrospective cohort study that included 74 patients with vocal cord polyps who underwent either CO laser resection or laryngeal microsurgery in our hospital from August 2018 to December 2021. According to their preference, 77 patients were divided into two groups: a CO laser resection group ( = 35) and a laryngeal microsurgery group ( = 39). Patients were evaluated two days before surgery, and follow-ups were conducted one, two and four weeks after surgery. The voice handicap index (VHI-10) score, voice acoustic analysis results and electronic laryngoscopy results were collected for each patient, and the differences between the two groups were evaluated.
RESULTS
The basic demographic characteristics of the 74 patients were comparable, and all patients completed postoperative follow-up observations. A total of 30 (85.71%) patients in the CO laser resection group and 22 (56.41%) patients in the laryngeal microsurgery group were healed. The total effectiveness rate of the CO laser resection group (94.29%) was significantly higher than that of the laryngeal microsurgery group (82.05%), and the difference between the two groups was statistically significant ( = .037). Both surgical methods had a positive effect on reducing VHI-10 scores with the effect of CO laser resection being more obvious. The difference between the two groups in this regard was statistically significant ( < .001). The effects of each surgical method on the average fundamental frequency perturbation (jitter), amplitude perturbation (shimmer), maximum phonation time and dysphonia severity index were not statistically significant ( > .05).
CONCLUSION
CO laser resection and laryngeal microsurgery have similar effects on voice quality, but CO laser resection has higher clinical efficacy.
Topics: Humans; Microsurgery; Vocal Cords; Carbon Dioxide; Retrospective Studies; Laryngeal Diseases; Treatment Outcome; Lasers, Gas; Polyps
PubMed: 38010099
DOI: 10.1080/07853890.2023.2280228 -
Biomechanics and Modeling in... Aug 2023Neck muscles play important roles in various physiological tasks, including swallowing, head stabilization, and phonation. The mechanisms by which neck muscles influence...
Neck muscles play important roles in various physiological tasks, including swallowing, head stabilization, and phonation. The mechanisms by which neck muscles influence phonation are not well understood, with conflicting reports on the change in fundamental frequency for ostensibly the same neck muscle activation scenarios. In this work, we introduce a reduced-order muscle-controlled vocal fold model, comprising both intrinsic muscle control and extrinsic muscle effects. The model predicts that when the neck muscles pull the thyroid cartilage in the superior-anterior direction (with a sufficiently large anterior component), inferior direction, or inferior-anterior direction, tension in the vocal folds increases, leading to fundamental frequency rise during sustained phonation. On the other hand, pulling in the superior direction, superior-posterior direction, or inferior-posterior direction (with a sufficiently large posterior component) tends to decrease vocal fold tension and phonation fundamental frequency. Varying the pulling force location alters the posture and phonation biomechanics, depending on the force direction. These findings suggest potential roles of particular neck muscles in modulating phonation fundamental frequency, with implications for vocal hyperfunction.
Topics: Laryngeal Muscles; Phonation; Vocal Cords; Biomechanical Phenomena; Electric Stimulation
PubMed: 37169957
DOI: 10.1007/s10237-023-01724-3 -
The Laryngoscope Oct 2017A custom-designed probe was developed to measure vocal fold surface resistance in vivo. The purpose of this study was to demonstrate proof of concept of using vocal fold...
OBJECTIVES/HYPOTHESIS
A custom-designed probe was developed to measure vocal fold surface resistance in vivo. The purpose of this study was to demonstrate proof of concept of using vocal fold surface resistance as a proxy of functional tissue integrity after acute phonotrauma using an animal model.
STUDY DESIGN
Prospective animal study.
METHODS
New Zealand White breeder rabbits received 120 minutes of airflow without vocal fold approximation (control) or 120 minutes of raised intensity phonation (experimental). The probe was inserted via laryngoscope and placed on the left vocal fold under endoscopic visualization. Vocal fold surface resistance of the middle one-third of the vocal fold was measured after 0 (baseline), 60, and 120 minutes of phonation. After the phonation procedure, the larynx was harvested and prepared for transmission electron microscopy.
RESULTS
In the control group, vocal fold surface resistance values remained stable across time points. In the experimental group, surface resistance (X% ± Y% relative to baseline) was significantly decreased after 120 minutes of raised intensity phonation. This was associated with structural changes using transmission electron microscopy, which revealed damage to the vocal fold epithelium after phonotrauma, including disruption of the epithelium and basement membrane, dilated paracellular spaces, and alterations to epithelial microprojections. In contrast, control vocal fold specimens showed well-preserved stratified squamous epithelia.
CONCLUSIONS
These data demonstrate the feasibility of measuring vocal fold surface resistance in vivo as a means of evaluating functional vocal fold epithelial barrier integrity. Device prototypes are in development for additional testing, validation, and for clinical applications in laryngology.
LEVEL OF EVIDENCE
NA Laryngoscope, 127:E364-E370, 2017.
Topics: Animals; Disease Models, Animal; Dysphonia; Friction; Laryngeal Mucosa; Laryngoscopy; Microscopy, Electron, Transmission; Phonation; Prospective Studies; Rabbits; Vocal Cords
PubMed: 28573762
DOI: 10.1002/lary.26715 -
Methods in Molecular Biology (Clifton,... 2022Healthy vocal fold mucosa is composed of two major cell types, non-keratinized stratified squamous epithelium and vocal fold fibroblasts. Although dysfunction of the...
Healthy vocal fold mucosa is composed of two major cell types, non-keratinized stratified squamous epithelium and vocal fold fibroblasts. Although dysfunction of the epithelium may play a significant pathogenic role in vocal fold diseases, studies at the genetic and molecular level using primary epithelial cells or models of human vocal fold mucosa have been significantly limited by the availability of relevant tissue types, poor growth, and heterogeneity of primary vocal fold epithelial cells. Here, we describe in vitro developmental differentiation of human induced pluripotent stem cells into vocal fold basal epithelial progenitors that were reseeded on collagen-fibroblast constructs to induce stratification and generate a three-dimensional model of human vocal fold mucosa. The engineered vocal fold mucosa represents physiologically relevant and clinically useful model that can be used as a tool for disease modeling and testing of therapeutic approaches for the treatment of laryngeal and VF inflammation.
Topics: Cell Differentiation; Epithelial Cells; Humans; Induced Pluripotent Stem Cells; Laryngeal Mucosa; Vocal Cords
PubMed: 33959913
DOI: 10.1007/7651_2021_392 -
Journal of Voice : Official Journal of... Nov 2017Airway exposure to nanoparticles is common in occupational settings. Inhaled nanoparticles have toxic effects on respiratory tissue. Vocal folds are also at direct risk...
OBJECTIVES
Airway exposure to nanoparticles is common in occupational settings. Inhaled nanoparticles have toxic effects on respiratory tissue. Vocal folds are also at direct risk from inhaled nanoparticles. This study investigated the effects of single-walled carbon nanotubes (SWCNT), a type of nanoparticle, on vocal fold epithelium and fibroblasts. These cell types were selected for study as the epithelium is the outer layer of the vocal folds and fibroblasts are the most common cell type in connective tissue underlying the epithelium.
METHODS
Native porcine vocal fold epithelium and cultured human vocal fold fibroblasts were exposed to SWCNTs (100 ng/mL) and control (no SWCNT) in vitro. Epithelial and fibroblast viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Epithelial barrier integrity was assessed with transepithelial resistance and sodium fluorescein permeability. Epithelial tight junctional protein occludin expression was measured with Western blot. Gene expressions of the fibroblast-specific protein 1 (FSP-1), α-smooth muscle actin (α-SMA), and collagen III (Col-III) were assessed using quantitative polymerase chain reaction.
RESULTS
Transcriptional expression of genes encoding FSP-1 and Col-III was increased significantly following SWCNT exposure. There were no significant differences between control and SWCNT groups on any of the other measures.
CONCLUSIONS
SWCNT exposure induces vocal fold fibroblasts to a fibrotic phenotype. These data help us understand vocal fold defense mechanisms and lay the groundwork for studying the physiological effects of nanoparticle exposure in vivo.
Topics: Actins; Animals; Calcium-Binding Proteins; Cell Survival; Cells, Cultured; Collagen Type III; Electric Impedance; Epithelial Cells; Fibroblasts; Fibrosis; Humans; Nanotubes, Carbon; Occludin; Permeability; Respiratory Mucosa; Risk Assessment; S100 Calcium-Binding Protein A4; Sus scrofa; Time Factors; Vocal Cords
PubMed: 28438490
DOI: 10.1016/j.jvoice.2017.03.014 -
PloS One 2023Oblique orientation of vocal cord demands strict compliance, by technicians and clinicians, to the recommended parallel plane CT scan of larynx. Repercussions of...
Oblique orientation of vocal cord demands strict compliance, by technicians and clinicians, to the recommended parallel plane CT scan of larynx. Repercussions of non-compliance has never been investigated before. We aimed to observe influence of non-parallel vocal cord plane CT scan on qualitative and quantitative glottic parameters, keeping parallel plane CT as a standard for comparison. Simultaneous identification of potential suboptimal imaging sequelae as a result of unformatted CT plane was also identified. In this study we included 95 normal adult glottides and retrospectively analyzed their anatomy in two axial planes, non-parallel plane ① and parallel to vocal cord plane ②. Qualitative (shape, structures at glottic level) and quantitative (anterior commissure ACom, vocal cord width VCw, anteroposterior AP, transverse Tr, cross-sectional area CSA) glottic variables were recorded. Multivariate statistical analysis was used to predict pattern and their impact on glottic anatomy. Plane ① displayed supraglottic features in glottis; adipose (90.5%) and split thyroid laminae (70.6%). Other categorical variables: atypical shape, submental structures and multilevel vertebral crossing were also in majority. All glottic dimensions varied significantly between two planes with most in ACom (-5.8mm) and CSA (-15.0 mm2). In contrast, plane ② manifested higher VCw (>73%), Tr (66.3%), CSA (64.2%) and AP (44.2%) measurements. On correlation analysis, variation in ACom, CSA, Tr was positively associated with VC or plane obliquity (p<0.05). This variability was more in obese and short necked subjects. Change in one parameter also modified other significantly i.e., ACom versus AP and CSA versus Tr. Results indicated statistically significant change in subjective and objective anatomical parameters of glottis on non-application of appropriate CT larynx protocol for image analysis hence highlighting importance of image reformation.
Topics: Adult; Humans; Vocal Cords; Retrospective Studies; Glottis; Larynx; Tomography, X-Ray Computed; Laryngeal Neoplasms
PubMed: 37903145
DOI: 10.1371/journal.pone.0293659 -
Laryngo- Rhino- Otologie May 2022Vocal fold paralysis is one of the diseases that particularly affect quality of life. While unilateral paralysis leads to glottis closure insufficiency and hoarseness,...
Vocal fold paralysis is one of the diseases that particularly affect quality of life. While unilateral paralysis leads to glottis closure insufficiency and hoarseness, bilateral paralysis compromises respiration and limits the exercise tolerance. Bioimplants have been used to treat persistent paralysis for over 100 years. The spectrum ranges from autologous tissue transfer and resorbable or permanent injection materials to composite thyroplasty implants and active electrical implants for neurostimulation of the larynx. If bioimplants are used in accordance with the recommendations, the quality of life of affected patients can be significantly improved today.
Topics: Humans; Laryngoplasty; Larynx; Quality of Life; Vocal Cord Paralysis; Vocal Cords
PubMed: 35605617
DOI: 10.1055/a-1708-2881 -
Ear, Nose, & Throat Journal May 2021To investigate the value of diffusion tensor imaging (DTI) in the evaluation of vocal fold tissue microstructure after recurrent laryngeal nerve (RLN) injury.
OBJECTIVE
To investigate the value of diffusion tensor imaging (DTI) in the evaluation of vocal fold tissue microstructure after recurrent laryngeal nerve (RLN) injury.
METHODS
Six canines were divided into 2 groups: a unilateral vocal fold paralysis group (n = 4) and a control group (n 2). The RLN was cut in the unilateral vocal fold paralysis group, and no intervention was applied in the control group. After 4 months, the canines' larynges were removed and placed in a small animal magnetic resonance imaging (MRI) system (9.4T BioSpec MRI; Bruker, Germany). After scanning, the vocal folds were isolated, sectioned, and stained. The slides were then analyzed for the cross-sectional area and muscle fiber density through feature extraction technology. Pearson correlation analysis was performed on the DTI scan and histological section extraction results.
RESULTS
In the vocal fold muscle layer, the fractional anisotropy (FA) of the unilateral RLN injury group was higher than that of the control group, and the Tensor Trace was lower than that of the control group. This difference was statistically significant, < .05. In the lamina propria, the FA of the unilateral RLN injury group was lower than that of the control group, > .05, and the Tensor Trace was lower than that of the control group, < .05. The muscle fiber cross-sectional area of the RLN injury group was significantly smaller than the control group with statistical significance, < .05, and the density of muscle fibers was lower, < .05. The correlation coefficient between FA and the cross-sectional area was -0.838, = .002, and .726; = .017 between Tensor Trace and the cross-sectional area.
CONCLUSION
Diffusion tensor imaging is an effective method to assess the changes in the microstructure of atrophic vocal fold muscle tissue after RLN injury.
Topics: Animals; Anisotropy; Diffusion Tensor Imaging; Dogs; Humans; Laryngeal Muscles; Recurrent Laryngeal Nerve Injuries; Vocal Cord Paralysis; Vocal Cords
PubMed: 31550925
DOI: 10.1177/0145561319874721 -
The Laryngoscope Jul 2016To describe a nonstimulated in vivo rabbit phonation model using an Isshiki type IV thyroplasty and uninterrupted humidified glottal airflow to produce sustained audible...
OBJECTIVES/HYPOTHESIS
To describe a nonstimulated in vivo rabbit phonation model using an Isshiki type IV thyroplasty and uninterrupted humidified glottal airflow to produce sustained audible phonation.
STUDY DESIGN
Prospective animal study.
METHODS
Six New Zealand white breeder rabbits underwent a surgical procedure involving an Isshiki type IV thyroplasty and continuous airflow delivered to the glottis. Phonatory parameters were examined using high-speed laryngeal imaging and acoustic and aerodynamic analysis. Following the procedure, airflow was discontinued, and sutures remained in place to maintain the phonatory glottal configuration for microimaging using a 9.4 Tesla imaging system.
RESULTS
High-speed laryngeal imaging revealed sustained vocal fold oscillation throughout the experimental procedure. Analysis of acoustic signals revealed a mean vocal intensity of 61 dB and fundamental frequency of 590 Hz. Aerodynamic analysis revealed a mean airflow rate of 85.91 mL/s and subglottal pressure of 9 cm H2 O. Following the procedure, microimaging revealed that the in vivo phonatory glottal configuration was maintained, providing consistency between the experimental and postexperimental laryngeal geometry. The latter provides a significant milestone that is necessary for geometric reconstruction and to allow for validation of computational simulations against the in vivo rabbit preparation.
CONCLUSION
We demonstrate a nonstimulated in vivo phonation preparation using an Isshiki type IV thyroplasty and continuous humidified glottal airflow in a rabbit animal model. This preparation elicits sustained vocal fold vibration and phonatory measures that are consistent with our laboratory's prior work using direct neuromuscular stimulation for evoked phonation.
LEVEL OF EVIDENCE
N/A. Laryngoscope, 126:1589-1594, 2016.
Topics: Acoustics; Animals; Computer Simulation; Glottis; Laryngeal Muscles; Male; Models, Animal; Phonation; Pressure; Prospective Studies; Rabbits; Vibration; Vocal Cords
PubMed: 26971861
DOI: 10.1002/lary.25559