Voice rest after vocal fold polyp surgery: A Swedish register study of 588 patients.

Objective: To evaluate the impact of voice rest on patient-reported voice outcome 4 months after vocal fold polyp surgery. Methods: Preoperative information was collected about age, sex, and smoking habits and the voice handicap index-10 (VHI-10). Four months postoperatively, voice rest (total voice rest, spoke single words, and spoke normally), and pre and postoperative voice therapy were reported. This was correlated to voice satisfaction from a two-category subjective evaluation "satisfied/ not satisfied" and to VHI-10. Logistic regression models with relative risk for NOT being satisfied with voice after surgery were performed. Results: Data from 588 patients were available. The group "spoke normally" showed the highest degree of patient satisfaction (92%). Younger patients (<59 years) were more satisfied than older (90% vs. 81.5%). High age and low VHI-10 scores before surgery were statistically significant for negative voice outcome. Gender or voice rest type did not significantly affect outcome. The largest improvement in VHI-scores was in the group who spoke normally and least in the group who spoke single words. Conclusion: We found no significant difference in the two-category subjective voice outcome depending on voice rest. VHI-10 showed a statistically significant positive effect on self-evaluated voice outcome, with the largest improvement in the group with no voice rest. However, the clinical relevance of the VHI changes is unclear. The present study does not show any advantage of total voice rest as compared to relative voice rest or speaking freely. High age and low preoperative VHI scores were significant risk factors for worse voice outcome. Level of evidence: 4.

Treatment of vocal fold scarring with autologous bone marrow-derived human mesenchymal stromal cells-first phase I/II human clinical study: commentary to response.

We would like to thank for the interest for the article and comments in the response. We believe that cell therapy may offer a treatment for severe voice problems in patients with vocal fold scarring and MSC treatment is a valuable alternative.

Treatment of vocal fold scarring with autologous bone marrow-derived human mesenchymal stromal cells-first phase I/II human clinical study.

BACKGROUND: Vocal fold (VF) scarring, caused by surgery or inflammation, often results in severe voice problems or aphonia. Effective lasting treatment is lacking. Previous in vitro and in vivo animal studies reported positive effects on VF scar resolution with mesenchymal stromal cell (MSC) implantation. The principal aim of this study was to examine safety aspects and secondly treatment efficacy vocal fold function in patients with VF scarring and severe voice problems. METHODS: In this open-label phase I/II study, 16 patients were treated with surgical scar resection followed by injection of autologous MSCs (0.5-2 × 106 MSCs/patient). Patients were monitored 1 year for serious adverse events (SAE) or minor complications. Therapeutic efficacy on treated VFs was evaluated by measurement of VF vibrations using high-speed laryngoscopy (HSL) and phonation pressure threshold (PTP) for elasticity and VF function. Patients self-reported voice change using the Voice Handicap Index (VHI). RESULTS: No SAE or minor side effects were reported. Video ratings of VF vibrations and digitized analysis of HSL and PTP were significantly improved for 62-75% of the patients (depending on parameter). Two patients showed deteriorated VF vibrations, but improved PTP. VHI was significantly improved in 8 patients, with the remaining experiencing no significant change. CONCLUSIONS: The results indicate that local injection of autologous MSC into scarred VFs with severe voice problems may offer a safe and feasible therapeutic option. VF vibration and elasticity were improved in approximately two thirds of treated patients. This clinical study is registered in clinicaltrials.gov (ID: NCT01981330). Retrospective registration of first patient (20130511). https//: register.clinicaltrials.gov/.

Mesenchymal stromal cells modulate tissue repair responses within the injured vocal fold.

OBJECTIVES/HYPOTHESIS: This study aimed to determine whether local injection of human mesenchymal stromal cells (MSC) could modulate the early inflammatory response within injured vocal folds (VFs) to promote wound-healing processes. STUDY DESIGN: Experimental xenograft model. METHODS: VF injury was surgically induced by bilateral resection of the lamina propria of rabbits, and MSC were immediately injected into the injured area of both VFs. Animals were sacrificed on days 2, 4, and 24. Histological analyses were performed by hematoxylin and eosin, Masson's Trichrome, and elastin staining. Cell death was visualized by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and the M2 macrophage marker, CD163, detected by immunohistochemistry. Persistence of injected MSC was evaluated by fluorescent in situ hybridization (FISH). Quantitative polymerase chain reaction was performed on the contralateral VF. RESULTS: Histological examination at days 2 and 4 indicated that MSC were able to reduce tissue inflammation, with gene expression analysis confirming a significant reduction of proinflammatory markers, interleukin (IL)-1ß, and IL-8. FISH demonstrated low-level persistence of injected MSC at both time points, and TUNEL confirmed localized cell death at the injury site. Increased levels of CD163+ anti-inflammatory macrophages indicated a change in the immune milieu, supporting wound resolution. Evidence of a more organized collagen matrix suggests that MSC may enhance the production of a functional repair tissue after injury, despite their low-level persistence within the tissue. CONCLUSIONS: This study demonstrates that MSC are able to positively modulate the early wound-healing response through resolution of the inflammatory phase and promotion of tissue repair. LEVEL OF EVIDENCE: NA Laryngoscope, 130:E21-E29, 2020.

Hyaluronan Hydrogels for the Local Delivery of Mesenchymal Stromal Cells to the Injured Vocal Fold.

Mesenchymal stromal cells (MSCs) promote wound healing by expediting the inflammatory phase. Local injection of MSCs into injured vocal folds (VFs) is effective in animal models, suggesting suitability for clinical translation. Despite their therapeutic potential, MSCs do not persist within the VF. This study evaluates whether hyaluronan (HA) hydrogels offer a safe delivery vehicle for local injection of MSCs into VFs, and increase longevity of the cells within the injured tissue. MSCs ± HA hydrogel were exposed to interleukin (IL)1ß, IL8, and chemokine (C-C motif) ligand 4, and evaluated for mRNA expression of matrix remodeling genes and secretion of immunomodulatory/prohealing factors. Chemotaxis/invasion in response to inflammation was evaluated. A lapin model of VF injury evaluated in vivo effects of MSCs ± HA hydrogel on enhancing VF healing. Histological evaluation of inflammation, type I collagen expression, HA hydrogel resorption, and MSC persistence was evaluated at 3 and 25 days after injury. MSCs within HA hydrogel were responsive to their extracellular environment, upregulating immunomodulatory factors when exposed to inflammation. Despite delayed migration out of the gel in vitro, the MSCs did not persist longer within the injured tissue in vivo. MSCs ± HA hydrogel exerted equivalent dampening of inflammation in vivo. The gel was resorbed within 25 days and no edema was evident. HA hydrogels can be safely used in the delivery of MSCs to injured VFs, minimizing leakage of administered cells. MSCs within the HA hydrogel did not persist longer than those in suspension, but did exert comparable therapeutic effects.

Effects of Gender-confirming Pitch-raising Surgery in Transgender Women a Long-term Follow-up Study of Acoustic and Patient-reported Data.

OBJECTIVES: Transgender women often seek to feminize their voice so that it becomes congruent with their gender identity. Many receive voice therapy (VT) with good results. Some also need pitch-raising surgery. The purpose of this study was to investigate long-term effects and to compare outcomes between cricothyroid approximation (CTA) and glottoplasty (GP). METHODS: This study included retrospective data from 24 patients (35-67 years). Eleven patients had undergone CTA and 13 had undergone GP. Audio recordings were performed in a sound-treated booth and patients answered questionnaires before and after VT, post surgery, and at 1-year follow-up. Fundamental frequency (fo) measures were extracted from voice range profiles (VRPs) and speech range profiles (SRPs) and were compared with cisgender data. RESULTS: Minimum fo in VRP increased significantly only after CTA (95 to 123 Hz). Maximum fo in VRP was significantly lowered after GP (765 to 652 Hz), even more after CTA (677 to 475 Hz). Speaking mean fo increased significantly after VT and post surgery, and was thereafter stable (CTA 167 Hz, GP 169 Hz). The maximum fo in the SRP increased only after VT. The frequency ranges were strongly reduced after CTA. Patients were in general satisfied at follow-up and rated the GP outcomes more favorably than CTA. CONCLUSIONS: Both surgical methods have advantages and disadvantages. The very restricted speaking and physiological frequency ranges, which do not favor an optimal female voice, were mainly found after the irreversible CTA. Thus, CTA is no longer performed at our hospital, whereas surgical techniques based on GP are being developed further. We strongly recommend the use of VRPs to evaluate treatment effects.

Background Factors and Subjective Voice Symptoms in Patients with Acquired Vocal Fold Scarring and Sulcus Vocalis.

OBJECTIVE: Vocal fold scarring (VFS) and sulcus vocalis (SV) often result in severe and chronic voice disorders. This study compares subjective voice complaints as rated with the Voice Handicap Index and etiological factors for patients with VFS and SV. PATIENTS AND METHODS: Data were collected from the medical records at the Department of Otorhinolaryngology, Karolinska University Hospital, for 27 VFS patients and 27 SV patients. Descriptive background factors were compared between the groups and data were compared from the Swedish Voice Handicap Index (Sw-VHI) questionnaires. RESULTS: Previous laryngeal surgery/trauma was significantly more common for the patients with VFS. The SV group had significantly more persistent dysphonia since childhood. It was significantly more common to have a non-Germanic language origin among the SV patients. VFS and SV rated high for the total median Sw-VHI scores. The VFS group's total Sw-VHI and the three domain scores were significantly higher compared to the SV group. The physical domain showed a significantly higher score when compared to the functional and emotional domains in the SV cohort and when compared to the emotional domain in the VFS cohort. CONCLUSION: There are significant differences between the VFS group and SV group regarding etiological factors as well as the Sw-VHI. The degree and profile of VHI should be considered when selecting patients and evaluating the result of new treatments for this group of patients.

Freddie Mercury-acoustic analysis of speaking fundamental frequency, vibrato, and subharmonics.

Freddie Mercury was one of the twentieth century's best-known singers of commercial contemporary music. This study presents an acoustical analysis of his voice production and singing style, based on perceptual and quantitative analysis of publicly available sound recordings. Analysis of six interviews revealed a median speaking fundamental frequency of 117.3 Hz, which is typically found for a baritone voice. Analysis of voice tracks isolated from full band recordings suggested that the singing voice range was 37 semitones within the pitch range of F#2 (about 92.2 Hz) to G5 (about 784 Hz). Evidence for higher phonations up to a fundamental frequency of 1,347 Hz was not deemed reliable. Analysis of 240 sustained notes from 21 a-cappella recordings revealed a surprisingly high mean fundamental frequency modulation rate (vibrato) of 7.0 Hz, reaching the range of vocal tremor. Quantitative analysis utilizing a newly introduced parameter to assess the regularity of vocal vibrato corroborated its perceptually irregular nature, suggesting that vibrato (ir)regularity is a distinctive feature of the singing voice. Imitation of subharmonic phonation samples by a professional rock singer, documented by endoscopic high-speed video at 4,132 frames per second, revealed a 3:1 frequency locked vibratory pattern of vocal folds and ventricular folds.

Tissue engineering in the larynx and airway.

PURPOSE OF REVIEW: Tissue engineering is a rapidly expanding field in medicine and involves regeneration and restoration of many organs, including larynx and the airways. Currently, this is not included in routine practice; however, a number of clinical trials in humans are ongoing or starting. This review will cover publications during the past 2 years and the focus is on larynx and trachea. RECENT FINDINGS: Recent reports concern the development and investigations of cell therapies, including biological factors such as growth factors which promote healing of damage and increased vascular support of the tissue. A separate section concerns studies of stromal cells and stem cells in tissue engineering. Cell therapies and treatment with biological active factors are often combined with the development of scaffolds to support or reconstruct the soft tissue in the larynx or the cartilages in trachea or larynx. New techniques for scaffold construction, such as 3D printing, are developed. The trend in the recent publications is to combine these methods. SUMMARY: Recent advances in tissue engineering of the larynx and trachea include the development of cell therapies or treatment with biological active factors often in combination with scaffolds.

Magnetic Resonance Imaging of the Vocal Folds in Women With Congenital Adrenal Hyperplasia and Virilized Voices.

PURPOSE: Women with congenital adrenal hyperplasia (CAH) may develop a virilized voice due to late diagnosis or suboptimal suppression of adrenal androgens. Changes in the vocal folds due to virilization have not been studied in vivo. The purpose was to investigate if the thyroarytenoid (TA) muscle is affected by virilization and correlate findings to fundamental frequency (F0). METHOD: A case-control study using magnetic resonance imaging and voice recordings. Four women with CAH with virilized voices (26-40 years), and 5 female and 4 male controls participated. Measurements of cross-sectional TA muscle area, vocal fold length, vocal tract length, and acoustic analyses of F0 were performed. RESULTS: Women with CAH had larger cross-sectional TA muscle area than female control subjects and smaller than male controls. A significant negative correlation was found between TA muscle area and mean F0. The patients had a smaller physiological voice range than both female and male controls. CONCLUSION: Data from our small study suggest that a larger TA muscle area is strongly associated with a lower F0 and thus the anatomical explanation for a female virilized voice, suggesting an androgen effect on the vocal folds. The findings from the present study need to be confirmed in a larger study.

Stem cell approaches for vocal fold regeneration.

OBJECTIVES/HYPOTHESIS: Current interventions in the management of vocal fold (VF) dysfunction focus on conservative and surgical approaches. However, the complex structure and precise biomechanical properties of the human VF mean that these strategies have their limitations in clinical practice and in some cases offer inadequate levels of success. Regenerative medicine is an exciting development in this field and has the potential to further enhance VF recovery beyond conventional treatments. Our aim in this review is to discuss advances in the field of regenerative medicine; that is, advances in the process of replacing, engineering, or regenerating the VF through utilization of stem cells, with the intention of restoring normal VF structure and function. DATA SOURCES: English literature (1946-2015) review. METHODS: We conducted a systematic review of MEDLINE for cases and studies of VF tissue engineering utilizing stem cells. RESULTS: The three main approaches by which regenerative medicine is currently applied to VF regeneration include cell therapy, scaffold development, and utilization of growth factors. CONCLUSION: Exciting advances have been made in stem cell biology in recent years, including use of induced pluripotent stem cells. We expect such advances to be translated into the field in the forthcoming years. Laryngoscope, 126:1865-1870, 2016.

Stem Cell Therapy in Injured Vocal Folds: A Three-Month Xenograft Analysis of Human Embryonic Stem Cells.

We have previously shown that human embryonic stem cell (hESC) therapy to injured rabbit vocal folds (VFs) induces human tissue generation with regained VF vibratory capacity. The aims of this study were to test the sustainability of such effect and to what extent derivatives of the transplanted hESCs are propagated in the VFs. The VFs of 14 New Zealand rabbits were injured by a localized resection. HESCs were transplanted to 22 VFs which were analyzed for persistence of hESCs after six weeks and after three months. At three months, the VFs were also analyzed for viscoelasticity, measured as dynamic viscosity and elastic modulus, for the lamina propria (Lp) thickness and relative content of collagen type I. Three months after hESC cell therapy, the dynamic viscosity and elastic modulus of the hESC treated VFs were similar to normal controls and lower than untreated VFs (p ≤ 0.011). A normalized VF architecture, reduction in collagen type I, and Lp thickness were found compared with untreated VFs (p ≤ 0.031). At three months, no derivatives of hESCs were detected. HESCs transplanted to injured rabbit VFs restored the vibratory characteristics of the VFs, with maintained restored function for three months without remaining hESCs or derivatives.

Resonance tube phonation in water: High-speed imaging, electroglottographic and oral pressure observations of vocal fold vibrations--a pilot study.

Phonation into glass tubes ('resonance tubes'), keeping the free end of the tube in water, has been a frequently used voice therapy method in Finland and more recently also in other countries. The purpose of this exploratory study was to investigate what effects tube phonation with and without water has on the larynx. Two participants were included in the study. The methods used were high-speed imaging, electroglottographic observations of vocal fold vibrations, and measurements of oral pressure during tube phonation. Results showed that the fluctuation in the back pressure during tube phonation in water altered the vocal fold vibrations. In the high-speed imaging, effects were found in the open quotient and amplitude variation of the glottal opening. The open quotient increased with increasing water depth (from 2 cm to 6 cm). A modulation effect by the water bubbles on the vocal fold vibrations was seen both in the high-speed glottal area tracings and in the electroglottography signal. A second experiment revealed that the increased average oral pressure was largely determined by the water depth. The increased open quotient can possibly be explained by an increased abduction of the vocal folds and/or a reduced transglottal pressure. The back pressure of the bubbles also modulates glottal vibrations with a possible 'massage' effect on the vocal folds. This effect and the well-defined average pressure increase due to the known water depth are different from those of other methods using a semi-occluded vocal tract.

A portable high-speed camera system for vocal fold examinations.

AIM: In this article, we present a new portable low-cost system for high-speed examinations of the vocal folds. Analysis of glottal vibratory parameters from the high-speed recordings is compared with videostroboscopic recordings. METHODS AND RESULTS: The high-speed system is built around a Fastec 1 monochrome camera, which is used with newly developed software, High-Speed Studio (HSS). The HSS has options for video/image recording, contains a database, and has a set of analysis options. The Fastec/HSS system has been used clinically since 2011 in more than 2000 patient examinations and recordings. The Fastec 1 camera has sufficient time resolution (≥4000 frames/s) and light sensitivity (ISO 3200) to produce images for detailed analyses of parameters pertinent to vocal fold function. The camera can be used with both rigid and flexible endoscopes. The HSS software includes options for analyses of glottal vibrations, such as kymogram, phase asymmetry, glottal area variation, open and closed phase, and angle of vocal fold abduction. It can also be used for separate analysis of the left and vocal fold movements, including maximum speed during opening and closing, a parameter possibly related to vocal fold elasticity. A blinded analysis of 32 patients with various voice disorders examined with both the Fastec/HSS system and videostroboscopy showed that the high-speed recordings were significantly better for the analysis of glottal parameters (eg, mucosal wave and vibration asymmetry). CONCLUSIONS: The monochrome high-speed system can be used in daily clinical work within normal clinical time limits for patient examinations. A detailed analysis can be made of voice disorders and laryngeal pathology at a relatively low cost.

Injection of human mesenchymal stem cells improves healing of vocal folds after scar excision--a xenograft analysis.

OBJECTIVES: Using a xenograft model the aim was to analyze if injection of human mesenchymal stem cells (hMSC) into the rabbit vocal fold (VF), after excision of an established scar, can improve the functional healing of the VF. STUDY DESIGN: Prospective design with an experimental xenograft model. METHODS: The VFs of 12 New Zealand rabbits were injured by a bilateral localized resection. After 9 weeks the scar after the resection was excised and hMSC were injected into the VFs. After another 10 weeks 10 VFs were dissected and stained for histology. Lamina propria thickness and relative content of collagen type I were measured. Viscoelasticity of 14 VFs at phonatory frequencies was quantified by a simple-shear rheometer. The hMSC survival was determined using a human DNA specific reference probe, that is, FISH analysis. RESULTS: The viscoelastic measurements, that is, dynamic viscosity and elastic shear modulus for the hMSC-treated VFs, were found to be similar to those of normal controls and were significantly lower than those of untreated controls (P < .05). A significant reduction in lamina propria thickness was also shown for the hMSC treated VFs compared with the untreated VFs (P < .05). This histologic finding corresponded with the viscoelastic results. No hMSC survived 10 weeks after the injection. CONCLUSIONS: Human mesenchymal stem cells injected into the rabbit VF following the excision of a chronic scar, were found to enhance the functional healing of the VF with reduced lamina propria thickness and restored viscoelastic shear properties.

Injection of human mesenchymal stem cells improves healing of scarred vocal folds: analysis using a xenograft model.

OBJECTIVES/HYPOTHESIS: The aims were to analyze if improved histological and viscoelastic properties seen after injection of human mesenchymal stem cells (hMSCs) in scarred vocal folds (VFs) of rabbits are sustainable and if the injected hMSCs survive 3 months in the VFs. STUDY DESIGN: Experimental xenograft model. METHODS: Eighteen VFs of 11 New Zealand white rabbits were scarred by a bilateral localized resection. After 3 months the animals were sacrificed. Twelve VFs were dissected and stained for histology, lamina propria thickness, and relative collagen type I analyses. The hMSCs survival was analyzed using a human DNA-specific reference probe, that is, fluorescence in situ hybridization staining. Viscoelasticity, measured as the dynamic viscosity and elastic modulus, was analyzed in a parallel-plate rheometer for 10 VFs. RESULTS: The dynamic viscosity and elastic modulus of hMSC-treated VFs were similar to that of normal controls and significantly improved compared to untreated controls (P < .05). A reduction in lamina propria thickness and relative collagen type 1 content were also shown for the hMSC-treated VFs compared to the untreated VFs (P < .05). The histological pictures corresponded well to the viscoelastic results. No hMSCs survived. CONCLUSIONS: Human mesenchymal stem cells injected into a scarred vocal fold of rabbit enhance healing of the vocal fold with reduced lamina propria thickness and collagen type I content and restore the viscoelastic function.

Elasticity measurements in scarred rabbit vocal folds using air pulse stimulation.

This study aimed to compare vocal fold elasticity data from a new method for non-invasive analysis by stimulations of the mucosa with short air pulses. The depth of the mucosal deflections is measured with laser pulses by means of a special algorithm. Ten scarred New Zealand rabbit vocal folds and four normal rabbit folds were measured directly after sacrifice. The elastic data were compared to histological sections from the scarred vocal folds analysed by a pathologist. The results showed significantly lower elasticity (higher stiffness) values for the more scarred vocal folds as compared to samples with minor damage (P=0.03). It is concluded that the air pulse stimulation method is a promising tool for non-invasive quantification of vocal fold scarring.

Not just sound: supplementing the voice range profile with the singer's own perceptions of vocal challenges.

A commercial phonetograph was complemented with a response button, such that presses resulted in marked regions in the voice range profile (VRP). This study reports the VRP data of 16 healthy female professionally trained singers (7 mezzo-sopranos and 9 sopranos). Subjects pressed the button to indicate sensations of vocal instability or reduced control during phonation. Each press thereby marked potential areas of difficulty. A method is presented to quantify the consistency of button use for repeated tasks. The pattern of button presses was significantly consistent within subjects. As expected, the singers pressed at the extremes of VRP contours as well as at register transitions. These results and the potential of the method for the assessment of vocal problems of singers are discussed.