Morphologic ultrastructure of anchoring fibers in normal vocal fold basement membrane zone

Reinke's Edema: New Insights into Voice Analysis, a Retrospective Study

PURPOSE

Reinke's edema (RE) is a pathological condition involving increased volume of the vocal folds and resulting in significant impact on speech, fundamental frequency, and vocal range. Literature reports few studies which analyze vocal features according to the severity of RE. The aims of this study were to investigate the aerodynamics, acoustic characteristics, and sound spectrograms of a group of RE patients and to assess whether there was any correlation with their endoscopic grading.

METHODS

A total of 98 patients were included in the study, 49 patients with RE and 49 healthy volunteers (HV). Multidimensional Voice Program was used to perform objective voice assessment. Maximum phonation time (MPT) and Voice Handicap Index (VHI) questionnaire were collected. The spectrograms of the vowel /a/ and of the word /aiuole/, which contains the five Italian vowels, of each patient were analyzed according to the classification of Yanaghiara modified by Ricci Maccarini and De Colle. Laryngological assessment was used to record vocal folds morphology according to Yonekawa's classification. Univariate analysis was used to compare group outcomes. Bivariate analysis was used to compare endoscopic grading and voice analysis results.

RESULTS

Univariate analysis of the HV and RE groups revealed statistically significant differences (P < 0.05) for the following parameters: jitter%, shimmer%, harmonic-to-noise ratio (NHR), voice turbulence index (VTI), MPT, VHI except for soft phonation index. Spearman's rank correlation showed a positive correlation between vocal parameters such as jitter%, shimmer%, NHR, VTI, and RE gradings. A negative correlation was found between MPT and RE gradings. Bivariate analysis indicated a strong positive correlation between RE grading and the spectrogram classification performed both with the vowel / a / (Rho 0.86; P = 0.0001) and with the word / aiuole / (Rho 0.81; P = 0.0001).

CONCLUSION

The present study demonstrates that patients with RE have different voice characteristics compared to HV. In particular, the voice analysis highlighted acoustic parameters that correlated to differing degrees of RE. In addition, spectrogram analysis should be considered for acoustic assessments before and after medical and surgical therapy and also in forensic medicine.

The role of platelet-rich plasma in microlaryngeal surgery: a randomised, controlled trial

Objective

Platelet-rich plasma has gained interest over the two last decades, mainly because of its role in regenerative medicine. This work aimed to assess the role of intra-operative local application of platelet-rich plasma gel in the improvement of quality of voice after microlaryngeal surgery.

Method

This was a prospective comparative study that included 40 patients undergoing microlaryngeal surgery for benign vocal fold lesions. There were two groups divided equally into study group A and control group B. The assessment of voice was performed by videostroboscopy and acoustic analysis pre-operatively and at two weeks and one and three months post-operatively.

Results

The data demonstrated that all the stroboscopic and acoustic parameters showed significant improvement in both groups. Group A showed significant improvement regarding acoustic parameters at the third post-operative follow up when compared with group B.

Conclusion

Platelet-rich plasma has a beneficial effect on voice quality following microlaryngeal surgery based in particular on acoustic parameters.

[Molecular laryngology : A new chapter in the understanding of laryngeal diseases]

BACKGROUND

Despite considerable advances in laryngological research, there is still a plethora of (benign) vocal fold pathologies that cannot be treated causally. This is due to the limited accessibility and sensitive microarchitecture of the vocal folds, which cannot be investigated at a cellular level. Consequently, current pathophysiological knowledge is frequently based on macroscopic findings. The impact of interventions is mainly evaluated endoscopically or via indirect diagnostic methods.

OBJECTIVE

The aim of this article is to discuss state-of-the-art biotechnological methods used in laryngological research, illustrated by practical examples.

RESULTS

In recent years, animal and in vitro experiments have significantly contributed to a continuous expansion of knowledge in this field, particularly regarding vocal fold inflammation and scar formation. Vocal fold fibroblasts, the most important cellular component of the lamina propria, can be accredited a central role in these processes.

CONCLUSION

Our knowledge regarding macroanatomy and macropathophysiology of several pathologies has increased considerably in recent years. In vitro trials have shown, e.g., that vocal fold fibroblasts in an inflammatory setting secrete less profibrotic and proinflammatory cytokines when exposed to vibration. Early vocal exercises after surgical interventions on the vocal folds may therefore promote better wound healing and consequently improved phonation. Research in molecular laryngology should create a solid basis of knowledge for subsequent clinical studies.

Evaluation of the Human Vocal Fold Lamina Propria Development Using Optical Coherence Tomography

OBJECTIVES/HYPOTHESIS

Identifying distinctive features of the vocal fold (VF) during development could have significant clinical implications for treating voice disorders. This study investigates the structural organization of the VF microanatomy across gender and age groups using optical coherence tomography (OCT).

STUDY DESIGN

Prospective clinical trial.

MATERIALS AND METHODS

In vivo OCT images were acquired from 97 patients (58 males and 39 females) aged between 6 weeks and 27 years. All patients showed no signs of vocal fold pathology on endoscopy. Morphological features were extracted from OCT images and statistically compared between age groups. This study was performed at Massachusetts Eye and Ear between 2017 and 2019.

RESULTS

All OCT acquisitions show a stratified microanatomy across age groups, even in newborns suggesting the presence of a superficial lamina propria (SLP) at birth. Furthermore, the optical scattering in the VF lamina propria changes according to age, suggesting subepithelial maturation. Although the epithelium thickness was relatively constant across age groups, the SLP showed a significant linear relationship between age and thickness (P = .016). Furthermore, a significant difference (P = .002) in SLP thickness was found between young adult males and females. The overall thickness of the entire mucosa did not change significantly with age.

CONCLUSION

OCT is a noninvasive imaging modality capable of providing quantitative morphological features to describe the VF development. A stratified structure can be observed in OCT from newborns to young adults. Further investigations could combine OCT, acoustic measurements, and molecular sensitive techniques to provide a complete interpretation of the VF development.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:E2558-E2565, 2021.

Quantitative evaluation of the human vocal fold extracellular matrix using multiphoton microscopy and optical coherence tomography

Identifying distinct normal extracellular matrix (ECM) features from pathology is of the upmost clinical importance for laryngeal diagnostics and therapy. Despite remarkable histological contributions, our understanding of the vocal fold (VF) physiology remains murky. The emerging field of non-invasive 3D optical imaging may be well-suited to unravel the complexity of the VF microanatomy. This study focused on characterizing the entire VF ECM in length and depth with optical imaging. A quantitative morphometric evaluation of the human vocal fold lamina propria using two-photon excitation fluorescence (TPEF), second harmonic generation (SHG), and optical coherence tomography (OCT) was investigated. Fibrillar morphological features, such as fiber diameter, orientation, anisotropy, waviness and second-order statistics features were evaluated and compared according to their spatial distribution. The evidence acquired in this study suggests that the VF ECM is not a strict discrete three-layer structure as traditionally described but instead a continuous assembly of different fibrillar arrangement anchored by predominant collagen transitions zones. We demonstrated that the ECM composition is distinct and markedly thinned in the anterior one-third of itself, which may play a role in the development of some laryngeal diseases. We further examined and extracted the relationship between OCT and multiphoton imaging, promoting correspondences that could lead to accurate 3D mapping of the VF architecture in real-time during phonosurgeries. As miniaturization of optical probes is consistently improving, a clinical translation of OCT imaging and multiphoton imaging, with valuable qualitative and quantitative features, may have significant implications for treating voice disorders.

Epithelium of the human vocal fold as a vibrating tissue

OBJECTIVES

The human adult vocal fold mucosa, especially, superficial layer of the lamina propria (Reinke's space) has attracted notice as an important vibrating structure. However, fine structures of the stratified squamous epithelium of the human adult vocal fold, which is another histological component of the mucosa, remain enigmatic.

METHODS

Three normal human adult vocal folds and epiglottises and three newborn vocal folds were investigated. Observations using transmission electron microscopy and light microscopy including immunohistochemistry were performed.

RESULTS

The most obvious feature of the epithelium of the human adult vocal folds was that the intercellular spaces between adjacent epithelial cells were large (984 ± 186 nm) compared with the stratified squamous epithelium of the human adult epiglottis and the human newborn vocal fold. Even though intercellular spaces between adjacent epithelial cells of the human adult vocal fold were large, desmosomes at the junctions of two adjacent epithelial cells made firm intercellular adhesion. Tonofilaments composed of the bundles of intermediate filaments anchored to the desmosomes. Desmosomes formed a continuous cytoskeletal network throughout the epithelial cells and epithelium of the human adult vocal fold. In addition, a great deal of E-cadherin (adhesive glycoprotein) was present between epithelial cells especially the lower half of the stratified squamous epithelium of the human adult vocal fold.

CONCLUSIONS

From the functional morphological point of view, stratified squamous epithelium of the human adult vocal fold seems to form a structural framework of tensile strength with pliability suitable structure for vibration.

Longitudinal Voice Outcomes Following Serial Potassium Titanyl Phosphate Laser Procedures for Recurrent Respiratory Papillomatosis

OBJECTIVE

Repeated surgical interventions are usually required to control recurrent respiratory papillomatosis (RRP), but at considerable risk of worsened postoperative voice quality. Potassium titanyl phosphate (KTP) laser has been reported to effectively manage RRP; however, voice quality after repeated procedures has not been investigated.

METHODS

This study recruited 16 patients with RRP treated using KTP laser between 2013 and 2019. KTP laser procedures were performed under general anesthesia via direct suspension laryngoscope or under local anesthesia via flexible endoscope, depending on the need for pathological proof, patient tolerance, and lesion size and location. Disease control was investigated by videolaryngostroboscopy. Voice outcome was evaluated using a 10-item voice handicap index (VHI-10), acoustic and perceptual analyzes.

RESULTS

We reviewed the medical records of 11 male and 5 female patients with RRP (age range: 23-73 years). Five patients received KTP laser once, six patients received it 2 to 5 times, and five patients received 6 to 15 procedures. Median VHI-10 decreased from 28.3 to 12.0 points after the initial procedure and were maintained at 10.1 to 11.0 points following subsequent procedures (P < .01, generalized estimating equation). Acoustic and perceptual analysis of voice quality also revealed significant improvements (P < .01), which remained stable even after 6 to 10 KTP laser procedures. Minor adverse events included slight fibrotic change of vocal folds and glottic web, but these did not significantly alter postoperative voice quality.

CONCLUSION

This longitudinal follow-up study revealed that serial KTP laser procedures can effectively control RRP while preserving phonatory function and maintaining adequate voice quality.

LEVEL OF EVIDENCE

4.

High Radiofrequency Surgery and Chromoendoscopy: A Novel Surgical Technique for the Treatment of Respiratory Papillomatosis

Recurrent Respiratory Papillomatosis is a highly recurrent and residual disease. The use of indigo-carmine chromoendoscopy increases the early detection of nonvisible disease and reduces the possibility of leaving residual lesions. The best chances of papillomatosis being eradicated depend upon a surgical shallow epitheliolysis approach applied to patients who have never been surgically damaged before. We developed a novel surgical technique based upon the use of a time controlled High Radiofrequency (HRF) energy output. We applied a three-step bloodless HRF-surgical technique, that is, epitheliolysis, angiolysis and peeling without the aid of adjunct therapies. It acts according to differences in the water density of the tissues. We use it to remove the epithelial viral reservoir thus preserving subepithelial layers. For this purpose, we designed and manufactured a custom-made HRF electrodes set for office and O.R. use. From 2005 to 2018, 39 patients (100%) with recurrent respiratory papillomatosis participated in the present prospective work. Twenty-five (64,10%) achieved complete postsurgical remission, 6 (15,38%) were lost to follow up, and 8 (20,51%) present partial remissions. Thirty-six patients had laryngeal papillomatosis. Follow-up was possible in 30 of the 36 patients with laryngeal papillomatosis with a success remission rate of 83,33% (25 of 30). Eleven of those 36 (30,55%) entered this study without previous surgical treatment and 9 of 11 (81,81%) were cured. Indigo-carmine chromoendoscopy, a visualization solution for papillomatosis detection, together with a bloodless HRF-surgical technique proved to be effective tools to eradicate papillomatosis. Voice restoration to normal or near normal levels was achieved in all patients.

Pathophysiology of Fibrosis in the Vocal Fold: Current Research, Future Treatment Strategies, and Obstacles to Restoring Vocal Fold Pliability

Communication by voice depends on symmetrical vibrations within the vocal folds (VFs) and is indispensable for various occupations. VF scarring is one of the main reasons for permanent dysphonia and results from injury to the unique layered structure of the VFs. The increased collagen and decreased hyaluronic acid within VF scars lead to a loss of pliability of the VFs and significantly decreases their capacity to vibrate. As there is currently no definitive treatment for VF scarring, regenerative medicine and tissue engineering have become increasingly important research areas within otolaryngology. Several recent reviews have described the problem of VF scarring and various possible solutions, including tissue engineered cells and tissues, biomaterial implants, stem cells, growth factors, anti-inflammatory cytokines antifibrotic agents. Despite considerable research progress, these technical advances have not been established as routine clinical procedures. This review focuses on emerging techniques for restoring VF pliability using various approaches. We discuss our studies on interactions among adipose-derived stem/stromal cells, antifibrotic agents, and VF fibroblasts using an in vitro model. We also identify some obstacles to advances in research.

585-NM Pulsed Dye Laser Treatment of Glottal Dysplasia

Management of glottal dysplasia can be difficult and often results in a suboptimal treatment outcome. The surgeon and patient must cooperatively balance decisions regarding the effects of possible malignancy, vocal dysfunction, and recurrences leading to multiple use of general anesthetics. A pilot study was done in 57 cases (36 patients and 97 vocal folds) without complication to evaluate the effectiveness of a 585-nm pulsed dye laser (PDL; 450-μs pulse width, 19 to 76-J/cm2 fluence, 1- to 2-mm spot size) in the treatment of vocal fold keratosis. Forty of the 57 cases had bilateral treatment. Phonomicrosurgical resection was done in 35 of the 57 cases after PDL treatment. Of this group, 10 cases were found to have hyperplasia, 21 dysplasia, 4 carcinoma in situ, and 1 carcinoma. One patient had phonomicrosurgical resection before PDL treatment. In 21 of the 57 cases, the disease was irradiated without resection (4 unilateral lesions and 17 bilateral lesions). Approximately 80% of the patients in this series had a greater than 70% reduction in the size of the lesion with the use of the PDL irrespective of whether they underwent resection. Clinical observation revealed no new anterior commissure web formation despite bilateral anterior commissure treatment in 28 of the 57 cases. The PDL enhanced the epithelial excision by improving hemostasis and by creating an optimal dissection plane between the basement membrane and the underlying superficial lamina propria. In this initial trial, the PDL provided relatively safe and effective treatment for glottal dysplasia. Analysis of patterns of recurrence will require longer follow-up.

Phonatory function after prolonged voice use in Brazilian woman

OBJECTIVES

To evaluate the behavior of the phonatory function and the perceived strain in Brazilian young women, before and after a test of prolonged voice use test, for a period of one continuous hour.

METHODS

Twenty young women without laryngeal disorders participated in the study and were submitted to vocal acoustic analysis (MDVP-Advanced, CSL-Kay Pentax®), perceptual voice assessment, carried out by five judges, and the measurement of speech-strain level using a visual analog scale before and after a prolonged use of the voice, from the reading of a standardized text for one hour in usual vocal intensity and frequency, without breaks for hydration or vocal rest. The description and comparison between the variables and the appropriate statistical analysis were carried out.

RESULTS

The acoustic parameters of fundamental (f0) and low frequency (Flo) of the emission increased after 1 hour of voice use, while the values for the amplitude tremor intensity index (Atri), amplitude variation (vAm), noise-to-harmonic ratio (NHR), and soft phonation index (SPI) were reduced after the prolonged voice use test. The judges agreed with the decrease in the overall level of dysphonia (kappa=0.66), roughness (kappa=0.59), and vocal breathiness (kappa=0.73); increased phonatory stability (kappa=0.64); vocal projection (kappa=0.48); pitch (kappa=0.74); and loudness (kappa=0.65). The phonatory strain increased significantly after the test (p=0.003).

CONCLUSION

One hour of prolonged voice use seems to favor laryngeal adaptation and increased adductor muscle activity to maintain vocal efficiency. However, the self-perception of vocal strain is evident and can be understood as a sign of muscle fatigue caused by continuous use.

Treatment of Hemorrhagic Vocal Polyps by Pulsed Dye Laser-Assisted Laryngomicrosurgery

Objective. Conventional surgical techniques of laryngomicrosurgery (LMS) on hemorrhagic vocal polyps are often difficult due to obscuration of the surgical field by inadvertent bleeding from the lesion, and there are often significant amounts of mucosal epithelium loss. Here, we introduce our surgical technique using pulsed dye laser (PDL), which can effectively resect the polyp with vocal fold mucosa preservation. Methods. Patients who were diagnosed with hemorrhagic vocal polyp and who were surgically managed using PDL from March 2013 to October 2014 were retrospectively reviewed. Preoperative and postoperative clinical outcomes and surgical findings were evaluated. Results. A total of 39 patients were treated with PDL-assisted enucleation LMS. The average age was 43.7 years (range 20–73), and there were 20 males and 19 females (17 professional voice users). In all cases, the hemorrhagic polyp was successfully enucleated after application of PDL, thereby preserving the overlying epithelium. Postoperative voice outcomes were favorable with clear preservation of the vocal fold mucosal wave. Conclusion. PDL-assisted enucleation LMS for the treatment of hemorrhagic vocal polyps can be a safe and effective surgical technique. It can be considered a promising treatment option for hemorrhagic vocal polyps.

The unsolved chapter of vocal fold scars and how tissue engineering could help us solve the problem

Vocal fold scarring is a relatively small field in scar research with prerequisites found nowhere else. The deterioration of the delicate tri-layered micro-structure of the epithelium of the vocal folds leads to impaired vibration characteristics resulting in a permanent hoarse and breathy voice. Tissue engineering approaches could help to restore the pre-injury status. Despite a considerable progress in this field during the last years, routine clinical applications are not available so far. One reason might be that vocal fold fibroblasts, as the responsible cell type for fibrogenesis, have very particular properties that are only poorly characterized. Moreover, in vivo trials are costly and time consuming and a representative in vitro model does not exist so far. These particular circumstances lead to innovative in vitro strategies and concepts such as macro-molecular crowding that can also be applied in adjacent fields.

[The electron microscopic study of tumour-like structures on the vocal cords]

We have undertaken the electron microscopic investigation into peculiarities of six tumour-like structures on the vocal cords. The study has demonstrated changes in the number and distribution patterns of intercellular junctions, keratin and tonofilament contents in epithelial cells, basal membrane structure, and composition of the basic substance in lamina propria. All the examined tumour-like structures contained bacteria an two of them had viral particles in vacuoles of fibroblasts. Moreover, the bacteria were found on the surface of epithelium, between epithelial cells and in the basic substance in lamina propria. Cytoplasm of epithelial cells and fibroblasts not infrequently contained bacteria in the phase of division.

Vocal fold epithelial barrier in health and injury: a research review

PURPOSE

Vocal fold epithelium is composed of layers of individual epithelial cells joined by junctional complexes constituting a unique interface with the external environment. This barrier provides structural stability to the vocal folds and protects underlying connective tissue from injury while being nearly continuously exposed to potentially hazardous insults, including environmental or systemic-based irritants such as pollutants and reflux, surgical procedures, and vibratory trauma. Small disruptions in the epithelial barrier may have a large impact on susceptibility to injury and overall vocal health. The purpose of this article is to provide a broad-based review of current knowledge of the vocal fold epithelial barrier.

METHOD

A comprehensive review of the literature was conducted. Details of the structure of the vocal fold epithelial barrier are presented and evaluated in the context of function in injury and pathology. The importance of the epithelial-associated vocal fold mucus barrier is also introduced.

RESULTS/CONCLUSIONS

Information presented in this review is valuable for clinicians and researchers as it highlights the importance of this understudied portion of the vocal folds to overall vocal health and disease. Prevention and treatment of injury to the epithelial barrier is a significant area awaiting further investigation.

Clinical diagnosis and histological analysis of vocal nodules and polyps

Recent studies emphasize the importance of the clinical-histology correlation in laryngeal pathologies.

Objective

To compare the ENT diagnosis with the pathology diagnosis one of 132 surgical specimens, from 119 patients with vocal nodules and polyps.

Method

Retrospective study. We investigated the paraffin blocks corresponding to the lesions of the operated patients. We made new histology cross-sections, totaling 396 new slides, divided into three groups: hematoxylin and eosin, Gomori trichrome and PAS. We analyzed the following histological parameters: epithelium, lamina propria, basement membrane, vascular changes. We compared the laryngological and pathological diagnoses, and we did the statistical analysis, checking the predominant histological aspects in each lesion.

Results

There was an agreement between the clinical and pathological diagnoses in 123 (93.18%) of 132 lesions analyzed (42.42% nodules and 50.76% polyps). In the histological parameters we found: epithelial changes such as nodules hyperplasia (82.14%) and polyp atrophy (31.34%). Lamina propria: edema in polyps (71.43%), fibrosis in the nodules (57.14%). Basement membrane: thickened nodules (100%), thin/no change in polyps (100%). There was a predominance of vascular changes in the polyps.

Conclusion

We found a high correlation between the ENT diagnosis and the pathology report. Histopathologically, the nodules presented with predominantly epithelial changes, lamina propria and basement membrane fibrosis, while the polyps by changes strictly on the lamina propria and vascular aspects.

Vocal fold scars: current concepts and future directions. Consensus report of the Phonosurgery Committee of the European Laryngological Society

Scarring of the vocal folds leads to a deterioration of the highly complex micro-structure with consecutively impaired vibratory pattern and glottic insufficiency. The resulting dysphonia is predominantly characterized by a reduced vocal capacity. Despite the considerable progress in understanding of the underlying pathophysiology, the treatment of scarred vocal folds is still an unresolved chapter in laryngology and phonosurgery. Essential for a successful treatment is an individual, multi-dimensional concept that comprises the whole armamentarium of surgical and non-surgical (i.p. voice therapy) modalities. An ideal approach would be to soften the scar, because the reduced pliability and consequently the increased vibratory rigidity impede the easiness of vibration. The chosen phonosurgical method is determined by the main clinical feature: Medialization techniques for the treatment of glottic gap, or epithelium freeing techniques for improvement of vibration characteristics often combined with injection augmentation or implantation. In severe cases, buccal mucosa grafting can be an option. New developments, include treatment with anxiolytic lasers, laser technology with ultrafine excision/ablation properties avoiding coagulation (Picosecond infrared laser, PIRL), or techniques of tissue engineering. However, despite the promising results by in vitro experiments, animal studies and first clinical trials, the step into clinical routine application has yet to be taken.

Current Understanding and Future Directions for Vocal Fold Mechanobiology

The vocal folds, which are located in the larynx, are the main organ of voice production for human communication. The vocal folds are under continuous biomechanical stress similar to other mechanically active organs, such as the heart, lungs, tendons and muscles. During speech and singing, the vocal folds oscillate at frequencies ranging from 20 Hz to 3 kHz with amplitudes of a few millimeters. The biomechanical stress associated with accumulated phonation is believed to alter vocal fold cell activity and tissue structure in many ways. Excessive phonatory stress can damage tissue structure and induce a cell-mediated inflammatory response, resulting in a pathological vocal fold lesion. On the other hand, phonatory stress is one major factor in the maturation of the vocal folds into a specialized tri-layer structure. One specific form of vocal fold oscillation, which involves low impact and large amplitude excursion, is prescribed therapeutically for patients with mild vocal fold injuries. Although biomechanical forces affect vocal fold physiology and pathology, there is little understanding of how mechanical forces regulate these processes at the cellular and molecular level. Research into vocal fold mechanobiology has burgeoned over the past several years. Vocal fold bioreactors are being developed in several laboratories to provide a biomimic environment that allows the systematic manipulation of physical and biological factors on the cells of interest in vitro. Computer models have been used to simulate the integrated response of cells and proteins as a function of phonation stress. The purpose of this paper is to review current research on the mechanobiology of the vocal folds as it relates to growth, pathogenesis and treatment as well as to propose specific research directions that will advance our understanding of this subject.

[Vocal fold scars: pathogenesis, diagnosis, therapy]

Scarring of the vocal folds leads to a deterioration of the highly complex microstructure with consecutively impaired vibratory pattern and glottic insufficiency. The resulting dysphonia is predominantly characterized by a reduced vocal capacity. Despite considerable progress in the understanding of the underlying pathophysiology, treatment of scarred vocal folds is still an unresolved chapter in laryngology and phonosurgery. Decisive for successful treatment is an individual, multidimensional concept that comprises the whole armamentarium of surgical and nonsurgical (e.g. voice therapy) modalities. The chosen phonosurgical method is determined by the main clinical feature: medialization techniques for treatment of glottic insufficiency, or epithelium-freeing techniques for improvement of vibration characteristics often combined with injection augmentation or implantation. In severe cases, buccal mucosa grafting can be an option. New developments include treatment with angiolytic lasers [pulse dye laser, PDL; potassium titanyl phosphate (KTP) laser], or techniques of tissue engineering. However, despite promising results with in vitro experiments, animal studies and first clinical trials, application in clinical routine has not yet been achieved.

Developing a porcine model for study of vocal fold scar

The porcine larynx is very similar in size and structure to that of humans, and wound healing in pigs is very similar to that of humans. However, the pig is not often used in vocal fold scar research because it is difficult to view the vocal folds endoscopically. To further assess the pig as a model for studying vocal scar, we compared the plane of surgical dissection in the mucosa of four porcine vocal folds with that in eight human cadaver larynges. The plane of dissection was quite similar in porcine and human larynges, occurring within the loose layer of the superficial lamina propria. We also compared healing of porcine vocal folds after elevation and replacement of an epithelial flap versus excision of epithelium, leaving an open wound. After 6 weeks, larynges were harvested for histologic examination. There was no significant difference between the mucosa of the normal vocal fold and that of the healed microflap. However, after healing of epithelial excision, there was a depressed scar, with average lamina propria thickness of 302 μm versus 864 μm for the normal fold (P<0.05). Finally, to document that the mucosal wave can be evaluated in the porcine larynx, we developed a preparation that removes the false vocal folds, to allow ex vivo phonation. Experimentally created scar in the porcine larynx is a favorable model for the study of vocal fold healing and for assessment of treatments for vocal fold scar.

Study of the influence of psychological factors in the etiology of vocal nodules in women

OBJECTIVE

The role placed by certain psychological factors such as stress and personality on the development of vocal nodules has not yet been established. The aim of this case-control type study is to analyze the relationship between these psychological factors and the presence of vocal nodules while also considering the professional and social aspects of the subjects suffering from this pathology.

METHODS

The case group is made up of 50 patients diagnosed with vocal nodules and with at least 6 months of evolution. The control group is made up of 50 patients diagnosed with nasal respiratory insufficiency. All the patients were examined by laryngeal stroboscopy. For the personality study, the perceived stress, and the voice use, the Minnesota Multiphasic Personality Inventory-2, Levenstein Perceived Stress Questionnaire, and Goldman Voice Use Survey were used, respectively.

RESULTS

The subjects with vocal nodules presented a mean perceived stress score of 0.41±0.09, which was higher than that of the control group (0.35±0.06), the differences observed being statistically significant (P<0.001). In the personality study (MMPI-2), the only scale that was associated with the presence of the vocal nodules was that of psychomotor acceleration. The mean score obtained for the scale was 51.64±8.25 in the vocal nodule group and 45.02±0.06 in the control group (P<0.001). In the analysis of voice use, the subjects with vocal nodules scored 9.31±1.36, which was significantly higher than the score of the control group (8.07±1.24; P<0.001). In addition, other variables were associated with the presence of vocal nodules, such as being young and working in professions considered to be of vocal risk.

CONCLUSIONS

Perceived stress and personality features of hyperactivity and impulsivity are independent factors related to vocal nodules.

Cross-sample validation provides enhanced proteome coverage in rat vocal fold mucosa

The vocal fold mucosa is a biomechanically unique tissue comprised of a densely cellular epithelium, superficial to an extracellular matrix (ECM)-rich lamina propria. Such ECM-rich tissues are challenging to analyze using proteomic assays, primarily due to extensive crosslinking and glycosylation of the majority of high M_r ECM proteins. In this study, we implemented an LC-MS/MS-based strategy to characterize the rat vocal fold mucosa proteome. Our sample preparation protocol successfully solubilized both proteins and certain high M_r glycoconjugates and resulted in the identification of hundreds of mucosal proteins. A straightforward approach to the treatment of protein identifications attributed to single peptide hits allowed the retention of potentially important low abundance identifications (validated by a cross-sample match and de novo interpretation of relevant spectra) while still eliminating potentially spurious identifications (global single peptide hits with no cross-sample match). The resulting vocal fold mucosa proteome was characterized by a wide range of cellular and extracellular proteins spanning 12 functional categories.

Biocompatibility of a synthetic extracellular matrix on immortalized vocal fold fibroblasts in 3-D culture

In order to promote wound repair and induce tissue regeneration, an engineered hyaluronan (HA) hydrogel - Carbylan GSX, which contains di(thiopropionyl) bishydrazide-modified hyaluronic acid, di(thiopropionyl) bishydrazide-modified gelatin and polyethylene glycol diacrylate - has been developed for extracellular matrix (ECM) defects of the superficial and middle layers of the lamina propria. The purpose of this study was to evaluate the biocompatibility of Carbylan GSX in a previously established immortalized human vocal fold fibroblast (hVFF) cell line prior to human clinical trials. Immortalized hVFF proliferation, viability, apoptosis and transcript analysis for both ECM constituents and inflammatory markers were measured for two-dimensional and three-dimensional (3-D) culture conditions. There were no significant differences in morphology, cell marker protein expression, proliferation, viability and apoptosis of hVFF cultured with Carbylan GSX compared to Matrigel, a commercial 3-D control, after 1 week. Gene expression levels for fibromodulin, transforming growth factor-beta1 and tumor necrosis factor-alpha were similar between Carbylan GSX and Matrigel. Fibronectin, hyaluronidase 1 and cyclooxygenase II expression levels were induced by Carbylan GSX, whereas interleukins 6 and 8, Col I and hyaluronic acid synthase 3 expression levels were decreased by Carbylan GSX. This investigation demonstrates that Carbylan GSX may serve as a natural biomaterial for tissue-engineering of human vocal folds.

Morphological and extracellular matrix changes following vocal fold injury in mice

Mouse experimental models are commonly utilized tools in biomedical research but remain underrepresented in vocal fold biology, presumably due to the small size of the larynx and limited description of the anatomical, cellular and extracellular composition of the vocal folds. In this study, we provide a whole-mount serial section-based histological description of vocal fold morphology of wild-type FVB strain mice, alongside a histological and immunohistochemical (IHC)-based quantitative analysis of extracellular matrix (ECM) alteration 1, 7, 14, 28, 42 and 56 days following unilateral vocal fold injury. IHC was specific for procollagen type I, collagen type I, collagen type III, collagen type IV, elastin, decorin, fibronectin and hyaluronic acid binding protein 2. The histological description confirmed the presence of a laryngeal alar structural complex in the mouse, which appears to be a morphological feature unique to rodents. The lamina propria appeared uniform without evidence of a distinct layer structure as has been reported in larger animals and humans. Time-dependent alterations in vocal fold morphology, ECM organization and ECM protein/glycoconjugate abundance were observed in injured vocal folds compared to control. The presence of a mature scar was observed between 28 and 42 days postinjury. Morphological and ECM changes following vocal fold injury in the mouse were generally consistent with those reported in other animal models, particularly the rat, although wound repair in the mouse appears to occur at a faster rate.

Copyright © 2010 S. Karger AG, Basel

Vocal fold nodules: morphological and immunohistochemical investigations

The objective of this study was to investigate the morphological and immunohistochemical characteristics of vocal fold nodules. The study design was prospective and retrospective. For the histological study, we reviewed 15 slides from the surgical cases of vocal fold nodules, in which we analyzed epithelium, basal membrane (bm), and lamina propria. For the transmission and scanning electron microscopy (TEM, SEM) studies, five new cases on vocal fold nodules were included. Immunohistochemistry study was carried out in the 15 specimens, using antifibronectin, antilaminin, and anticollagen IV antibodies. The main histological alterations were epithelial hyperplasia (73.33%), basement membrane thickening (86.66%), edema, and fibrosis (93.33%). SEM--reduction in mucous lacing and increase in the desquamating cells, without epithelial erosion. TEM--hyperplasia of the epithelium, enlargement of the intercellular junctions, which was filled by fluid, subepithelial thickening of the lamina reticularis, and break points in the basal membrane. Immunohistochemistry--we identified greater immunoexpression of fibronectin on the basal membrane, on the lamina propria, and around the vessels. Antilaminin and anticollagen IV antibodies showed higher pigmentation on the endothelium of the vessels than that on the basal membrane. In vocal fold nodules, combined assessment using light microscopy, electron microscopy, and immunohistochemistry can reveal important morphological details useful in characterizing these lesions.

Liquid accumulation in vibrating vocal fold tissue: a simplified model based on a fluid-saturated porous solid theory

The human vocal fold is treated as a continuous, transversally isotropic, porous solid saturated with liquid. A set of mathematical equations, based on the theory of fluid-saturated porous solids, is developed to formulate the vibration of the vocal fold tissue. As the fluid-saturated porous tissue model degenerates to the continuous elastic tissue model when the relative movement of liquid in the porous tissue is ignored, it can be considered a more general description of vocal fold tissue than the continuous, elastic model. Using the fluid-saturated porous tissue model, the vibration of a bunch of one-dimensional fibers in the vocal fold is analytically solved based on the small-amplitude assumption. It is found that the vibration of the tissue will lead to the accumulation of excess liquid in the midmembranous vocal fold. The degree of liquid accumulation is positively proportional to the vibratory amplitude and frequency. The correspondence between the liquid distribution predicted by the porous tissue theory and the location of vocal nodules observed in clinical practice, provides theoretical evidence for the liquid accumulation hypothesis of vocal nodule formation (Jiang, Ph.D., dissertation, 1991, University of Iowa).

Office-based laryngeal laser surgery with local anesthesia

PURPOSE OF REVIEW

Office-based laryngeal laser surgery was created recently and is emerging as a reliable and practical method of treating a number of laryngeal lesions. This style of minimally invasive surgery is becoming increasingly popular in the United States and abroad.

RECENT FINDINGS

Fiber-based lasers and distal-chip flexible endoscopy have facilitated a new style of surgery. Epithelial diseases such as dysplasia and papillomatosis are well suited for treatment. Although the initial angiolytic laser used was a 585-nm pulsed-dye laser, the 532-nm pulsed-potassium-titanyl-phosphate laser has been demonstrated to be more effective. The 2013-nm Thulium laser shows promise as an office-based laser that simulates the properties of the carbon dioxide laser.

SUMMARY

Evolving technologies to enhance laryngoscopic imaging and lasers along with socioeconomic forces should lead to increasing numbers of laryngeal procedures being performed in the office with local anesthesia.

April 16th: The World Voice Day

Although the voice is used as an everyday basis of speech, most people realize its importance only when a voice problem arises. Increasing public awareness of the importance of the voice and alertness to voice problems are the main goals of the World Voice Day, which is celebrated yearly on April 16th. The event started as a national initiative in Brazil in 1999 and quickly spread internationally. The article provides a brief history of the World Voice Day, together with basic background information.

Ultrastructural evaluation of 585-nm pulsed-dye laser-treated glottal dysplasia

OBJECTIVE/HYPOTHESIS

To describe the ultrastructural changes occurring within pulsed-dye laser (PDL)-treated glottal tissues.

STUDY DESIGN

Prospective.

METHODS

Nine patients presenting with glottal dysplasia requiring biopsy to rule out microinvasive carcinoma were enrolled in this prospective study. At least two samples were obtained in each case: one from a PDL-treated area and another from a non-PDL-treated area (obtained from a nonphonatory region as an internal control). In some cases, a third sample was obtained from the junction between PDL- and non-PDL-treated areas. All samples were examined with light microscopy (H and E stain) and transmission electron microscopy. Observations were made of morphological changes within the epithelium, epithelial/ superficial lamina propria (SLP) junction, and the lamina propria of tissues treated with the PDL. Eight of nine patients were followed for a period of 9-25 months (mean, 18 months) with two recurrences that were retreated with awake-PDL and followed for an additional 8.3 and 9.5 months without recurrence. Vocal fold appearance returned to normal within 3-4 weeks posttreatment.

RESULTS

Intraepithelial desmosome junctions were preferentially destroyed, and regional blood vessels were coagulated. The PDL consistently caused a separation of epithelial cells away from the basement membrane.

CONCLUSIONS

The PDL allowed for both a surgical and a nonsurgical multimodality method for treatment of precancerous lesions with minimal effects on the SLP.

Neto J, Pontes P. Diferenciação histopatológica e imunoistoquímica das alterações epiteliais no nódulo vocal em relação aos pólipos e ao edema de laringe

OBJETIVO: Avaliar, por meio de técnicas histológicas e imunoistoquímicas, o epitélio nos nódulos vocais em relação aos pólipos, ao edema de laringe e às pregas vocais sem lesões macroscópicas. FORMA DE ESTUDO: Clínico retrospectivo. MATERIAL E MÉTODO: Por meio de levantamento de prontuário, foram identificados vinte e seis pacientes com lesões laríngeas inflamatórias (nódulos, pólipos e edema de laringe), que haviam sido submetidos à cirurgia. Pregas vocais sem alterações macroscópicas foram obtidas a partir de autópsia de cadáveres. Para análise do epitélio, foram realizadas colorações pela técnica da hematoxilina-eosina e do ácido periódico de Schiff e técnicas de imunoistoquímica com anticorpos dirigidos contra laminina e colágeno IV. A leitura das lâminas foi realizada por meio de microscopia óptica. RESULTADOS: Houve maior imunoexpressão de laminina e colágeno IV nos nódulos quando comparados aos pólipos (p=0,034 e p=0, 036, respectivamente), assim como quando comparados às pregas vocais sem lesões macroscópicas (p=0,019 e p=0, 021, respectivamente). Nódulos tendem a apresentar maior espessura da membrana basal, quando utilizamos coloração pela técnica do PAS, em relação aos pólipos (p=0,102). O edema de laringe não se diferenciou das demais nas técnicas utilizadas (p> 0,10). CONCLUSÕES: O Nódulo Vocal diferencia-se dos pólipos, nas três técnicas utilizadas para detecção da membrana basal (PAS, laminina, colágeno IV), e das pregas vocais sem lesões macroscópicas em duas das técnicas utilizadas (laminina e colágeno IV). Edema de laringe não se diferencia das demais lesões, nem de pregas vocais sem lesões macroscópicas, quando utilizadas as técnicas anteriormente descritas, para estudo da membrana basal.

Ultrastructural study of muscle in vocal fold: postmortem damage observations

Various authors have published results related to the ultrastructure of vocal folds in specific areas proceeding from human cadavers. Nevertheless, starting from the premise that a fundamental principle of sampling and the samples should be a true representative of the whole, the authors decided to examine vocal folds from human cadavers and compare them to normal vocal folds from the guinea pig (Cavia porcellus). The findings of these authors demonstrated clearly that the conclusion of Rhodin (1954) is correct, that a biological sample must be preserved immediately after blood circulation ceases, and that the intermediary time between biopsy and fixation cannot be more than 3 minutes. Cells fixed a few hours after death appeared disaggregated, and many of their endocellular components were profoundly altered. The results obtained by the authors suggests that ultrastructural studies with cadaverous material may lead to serious risks or doubts about the accuracy of the results and consequently result in dubious interpretations.

Comparison of human fibroblast ECM-related gene expression on elastic three-dimensional substrates relative to two-dimensional films of the same material

Three-dimensional elastic substrates were fabricated from a commercially available polyurethane with an internal porosity of approximately 70% and elastic modulus of 27.4+/-2.76 KPa and examined for suitability in vocal fold tissue engineering. Using immunohistochemistry, biomechanical testing, and RT-PCR; we examined human fibroblast viability, distribution and extracellular matrix related gene expression within substrates for periods up to 4 weeks. We found that cells were capable of colonizing the entire volume of a 5mm wide x 3mm deep x 20mm long substrate at high viability. Histological cross-sections showed extensive extracellular matrix deposited around the cells and throughout the pore structure of the substrates, which consisted of fibronectin and type I collagen. Cell seeded substrates displayed a significantly higher elastic modulus than unseeded controls similar to native tissue. The transfer of cell growth from two-dimensional to three-dimensional culture resulted in changes in ECM-related gene expression consistent with decreasing cell migration and increasing tissue formation. We found that fibroblasts cultured in three-dimensional substrates expressed significantly higher levels of mRNA for elastin and fibromodulin, while expressing significantly lower levels of mRNA for MMP-1 and hyaluronidase relative to two-dimensional substrates of the same material. The results suggest that three-dimensionally porous, Tecoflex-derived elastic biomaterials may be suitable substrates for engineering vocal fold tissue.

Speaking fundamental frequency in monozygotic and dizygotic twins

The speaking fundamental frequency (SFF) and the intraindividual variation of the SFF during the reading of a Dutch standard text were measured in 30 female monozygotic twins (MT) and 30 dizygotic twins (DT), aged 15-29 years. A control group was created that consisted of 30 nonrelated paired individuals of equal age. Studying the intrapair correlation coefficients it seemed that the SFF was similar to a greater degree in MT and to a lesser degree in DT, while there was no correlation at all in nonrelated peers. These results are compatible with a genetic basis for the SFF. On the other hand, the intraindividual variation of the SFF was highly similar in MT and in DT (but not in nonrelated peers), so that for this parameter it was not possible to discern the influences of genetic disposition and shared environment.

A quantitative output-cost ratio in voice production

A quantitative output-cost ratio (OCR) is proposed for objective use in voice production and is defined as the ratio of the acoustic output intensity to the collision intensity of the vocal folds. Measurement of the OCR is demonstrated in a laboratory experiment using 5 excised larynges and a transducer designed for use on human subjects. Data were gathered at constant fundamental frequency (150 Hz). Subglottal pressure was varied from 1.0 to 1.6 kPa, and glottal width at the vocal processes was varied from a pressed condition to a 2-mm gap. The OCR was plotted as a function of glottal width. With no vocal tract, the excised larynx experiments yielded a broad maxima in the OCR curves, across all subglottal pressure conditions, at about 0.6 mm. Computer simulations indicate that sharper maxima may occur when the influence of the vocal tract is taken into account. The potential clinical utility of the OCR is discussed for treatment of a wide range of voice disorders, including those involving both hyper- and hypoadduction.

Medical and surgical treatment of pediatric dysphonia

The production of sound for communication is the last of the prime functions of the larynx, yet it is its most salient feature. Pediatric dysphonia may be caused by a variety of general causes. These causes may be classified as infectious, anatomic, congenital, inflammatory, neoplastic, neurologic, and iatrogenic. When a child presents with hoarseness, a complete assessment is necessary. Fine points during the history and physical may help distinguish between those pathologic conditions found in these general categories.

Cellular physiology of the vocal folds

This article discusses cellular architecture and physiology relevant to phonation biology. The mucociliary blanket and its role in external vocal fold lubrication are presented. The epithelium, basement membrane zone, and lamina propria all have specific roles in oscillating tissue. Three cell types, fibroblast, myofibroblast, and macrophage, maintain important and unique roles. Protein turnover in the lamina propria is important, and slowing matrix turnover may be a leading factor in creating some of the characteristics associated with vocal senescence. Lastly, aspects of cellular health and cellular pathology are discussed.

Influence of phonation on basement membrane zone recovery after phonomicrosurgery: a canine model

The process of wound healing at the basement membrane zone of the vocal folds after phonomicrosurgery was investigated. The influence of phonation and the implied optimal period of voice rest were considered. Phonomicrosurgery was performed on both vocal folds of 20 adult dogs. In 10 dogs, the left recurrent laryngeal nerve was simultaneously resected to simulate iatrogenic voice rest; the remaining 10 dogs were allowed to phonate normally. The healing process of the vocal folds of each group was observed at 1, 2, 4, 8, and 12 weeks after surgery with immunohistochemical staining and transmission electron microscopy. In the voice rest group, the basement membrane was completely re-formed in 2 weeks, and the "cover" appeared completely rearranged by 8 weeks. The results of the phonation group were characterized by a delayed healing process and basement membrane changes. These results suggest that voice rest of at least 2 weeks after surgery may be beneficial and that vocal hygiene should be maintained for as long as 8 weeks.

Biomechanical and histologic observations of vocal fold fibrous proteins

This article discusses the molecular composition of the vocal fold and the relationship of fibrous molecules to the biomechanical and physiological performance of the tissue. The components of the extracellular matrix may be divided into fibrous proteins and interstitial proteins. The fibrous proteins, consisting of collagens and elastins, are the focus of this report. Elastin concentration varies by tissue depth in the vocal folds. Variation of elastin by age is reported, but some controversy exists. The biomechanical terms of stress and strain (and stress-strain curves of human vocal folds) are related to the fibrous proteins of the vocal folds. The fibrous proteins, their role in stress, and their effect on the dynamic range of vocal pitch are presented.

Correspondence of electroglottographic closed quotient to vocal fold impact stress in excised canine larynges

The purpose of this study was to explore the possible use of the electroglottographic closed quotient (EGG CQ) as a noninvasive estimate of vocal fold impact stress (SI). Two excised canine larynges were used. Each larynx was mounted and vocal fold oscillation was induced using a humidified air source. Twenty-seven experimental trials were conducted for each larynx. Trials involved variations in vocal process gap, vocal fold elongation, and subglottic pressure. Simultaneous measures were made of vocal fold SI at the midpoint of the membranous vocal folds, and EGG CQ (dimensionless ratio). The results indicated that when threshold and saturation effects were excluded, the SI and the CQ were strongly related (linear correlation r = .83 and .96 for the two individual larynges, and .81 for the combined data). Within the region of linear relation, an increase of.15 in the CQ corresponded to about 1 kPa increase in SI for the combined data. Discussion focuses on possible clinical implications and the likely reasons for threshold and saturation phenomena.