Effects of Superomedial Partial Arytenoidectomy on Incomplete Posterior Glottal Closure Caused by Arytenoid Positional Asymmetry in Excised Human Larynges.

OBJECTIVES: To analyze the effects that arytenoid positional asymmetry has on posterior glottic closure and to determine whether superomedial partial arytenoidectomy (SPA) can provide a benefit in cases of such asymmetry. METHODS: In this experimental study, we evaluated posterior glottic closure in 10 larynges freshly excised from human cadavers, measuring the distance between the vocal processes before and after artificially simulated positional asymmetry of the arytenoid cartilages. We then performed SPA, after which we again measured the distance between the vocal processes. RESULTS: In all of the larynges studied, the posterior glottic closure went from complete to incomplete after simulation of arytenoid positional asymmetry, the median distance observed between the vocal processes being 1.74mm (interquartile range 0.22). The SPA performed after arytenoid asymmetry caused the posterior glottic closure to return from incomplete to complete in all of the larynges studied. CONCLUSION: Our results suggest that arytenoid positional asymmetry impairs posterior glottic closure and that SPA improves posterior glottic closure in such cases of arytenoid asymmetry.

Excised human larynx in N-vinyl-2-pyrrolidone-embalmed cadavers can produce voiced sound by pliable vocal fold vibration.

Tissue-hardening effect and health-hazard issue of formaldehyde (FA) have long been a great disadvantage of this conventional fixative in anatomical research. We recently developed a FA-free embalming method for cadavers which utilizes N-vinyl-2-pyrrolidone (NVP) and enables assessment of motion kinetics by maintaining the softness of embalmed tissue. By assessing the feasibility of NVP-embalmed tissue to mimic vocalization, this study aimed to prove the potential of embalmed cadavers, which have previously been used only for the understanding of anatomical morphology, for the assessment of precise motion physiology in the human body. Ten cadavers embalmed in NVP (n = 6) and FA (n = 4) were incorporated in this study. Excised larynges underwent experimental phonation to mimic vocalization with fast and pliable vibration of vocal folds. High-speed digital imaging was utilized for the assessment of vocal fold vibration. Furthermore, acoustic analysis of the voiced sound, and reproducibility examination were also performed. Regular vocal fold vibrations successfully produced voiced sounds during experimental phonation using NVP-embalmed larynges. The vibratory frequency, vibration amplitude, and stretch rate of the vocal folds were comparable to those of living humans. Six months after the first experiment, the vocal parameters were reproduced, to suggest the long-term preservation potential of our NVP-embalming technique. On the other hand, neither voiced sound nor vocal fold vibration were observed in FA-embalmed larynges. This novel embalming technique could pioneer the next era to utilize embalmed cadavers for the examination of motion physiology in the human body.

Bipedicled Vocal Fold Mucosal Flap: An Experimental Study.

OBJECTIVE: To determine the dimensions of mucosal defects that can be covered by a bipedicled vocal fold mucosal flap. METHODS: We used 20 adults human larynges (10 of each gender) excised from cadavers, divided into 2 groups of 10 larynges (5 of each gender) each. In one group (the normal flap group), we created the largest possible bipedicled vocal fold mucosal flap and then quantified the dimensions of the largest defect that could be covered by displacing the flap medially. In the other group (the augmented flap group), the flap was augmented laterally with mucosa from the laryngeal ventricle and we determined whether the larger flap would effectively cover larger defects. RESULTS: The mean width of mucosal defect capable of being covered was 1.51 mm when the normal bipedicled flap was employed and was 1.67 mm when the augmented flap was applied. However, the difference was not statistically significant. We found that defect size correlated with vocal fold length, width and flap size in the normal flap group, whereas it correlated only with vocal fold length in the augmented flap group. The bipedicled flap is capable of covering larger defects in males. CONCLUSION: Enlargement of a bipedicled vocal fold mucosal flap with laryngeal ventricular mucosa does not necessarily translate to an increase in the size of defect that can be covered. On average, the flap should be 30% larger than the width of the defect. The statistical model for predicting the defect size based on the vocal fold length, vocal fold width, and flap size has excellent predictive quality when a normal flap is employed.

Source and Filter Acoustic Measures of Young, Middle-Aged and Elderly Adults for Application in Vowel Synthesis.

INTRODUCTION: The output sound has important changes throughout life due to anatomical and physiological modifications in the larynx and vocal tract. Understanding the young adult to the elderly speech acoustic characteristics may assist in the synthesis of representative voices of men and women of different age groups. OBJECTIVE: To obtain the fundamental frequency (f0), formant frequencies (F1, F2, F3, F4), and bandwidth (B1, B2, B3, B4) values extracted from the sustained vowel /a/ of young, middle-aged, and elderly adults who are Brazilian Portuguese speakers; to present the application of these parameters in vowel synthesis. STUDY DESIGN: Prospective study. METHODS: The acoustic analysis of tokens of the 162 sustained vowel /a/ produced by vocally healthy adults, men, and women, between 18 and 80 years old, was performed. The adults were divided into three groups: young adults (18 to 44 years old); middle-aged adults (45 to 59 years old) and, elderly adults (60 to 80 years old). The f0, F1, F2, F3, F4, B1, B2, B3, B4 were extracted from the audio signals. Their average values were applied to a source-filter mathematical model to perform vowel synthesis in each age group both men and woman. RESULTS: Young women had higher f0 than middle-aged and elderly women. Elderly women had lower F1 than middle-aged women. Young women had higher F2 than elderly women. For the men's output sound, the source-filter acoustic measures were statistically equivalent among the age groups. Average values of the f0, F1, F2, F3, F4, B1, and B2 were higher in women. The sound waves distance in signals, the position of formant frequencies and the dimension of the bandwidths visible in spectra of the synthesized sounds represent the average values extracted from the volunteers' emissions for the sustained vowel /a/ in Brazilian Portuguese. CONCLUSION: Sustained vowel /a/ produced by women presented different values of f0,F1 and F2 between age groups, which was not observed for men. In addition to the f0 and the formant frequencies, the bandwidths were also different between women and men. The synthetic vowels available represent the acoustic changes found for each sex as a function of age.

Bipedicled Vocal Fold Mucosal Flap Use in Phonomicrosurgery: Case Series.

OBJECTIVES: The objective of this study was to present a novel surgical technique involving the use of a "bipedicled vocal fold mucosal flap" to repair a mucosal defect and to evaluate the outcomes of patients in whom it was used. MATERIAL AND METHODS: This was a retrospective study of 6 clinical cases. All patients underwent surgery between November 2000 and July 2018, and all procedures were performed by the same surgeon. For the auditory-perceptual assessment, the Grade-Roughness-Breathiness-Asthenia-Strain hoarseness scale was used. We based the stroboscopic evaluation on the European Laryngological Society protocol, analyzing the parameters glottal closure, mucosal wave, and phase symmetry. RESULTS: Ages at the time of surgery ranged from 10 to 52 years, and all of the patients were male. Preexisting vocal fold lesions included polyps, cysts, a sulcus, and mucosal bridges. Among the stroboscopic parameters, only the mucosal wave differed significantly between the preoperative and postoperative periods (P = 0.046). There were also significant postoperative improvements in the overall grade of dysphonia (P = 0.025) and in the degree of breathiness (P = 0.025). CONCLUSIONS: The use of a bipedicled vocal fold mucosal flap appears to promote significant improvements in the mucosal wave and in voice quality. In the patients evaluated here, the technique was used without preoperative planning. However, it proved to be a safe and appropriate means of repairing mucosal defects in the vocal folds, with the potential to preserve rheological properties and promote healing with less chance of fibrosis.

Variant of the Technique for Laryngeal Microsurgery in Cases of Difficult Laryngoscopy

Abstract Introduction Low exposure of the larynx can make laryngeal microsurgery difficult or even impossible. The application of rigid and contact endoscopy enabled oblique and retrograde angled visualization, allowing transoperative staging with greater reach of the anatomical areas. However, there is difficulty or even impossibility of performing the surgical act, due to the incompatibility of the angled path with the straight surgical tools. Objective To demonstrate the efficiency of the variant of the technique for laryngeal microsurgery in cases of difficult laryngoscopy and to analyze the new surgical instruments specific to the endoscopic procedure. Methods This is a cross-sectional retrospective study, based on the analysis of 30 medical records of patients treated surgically at a philanthropic hospital in the state of Sergipe, Brazil, between the years of 2014 and 2015. Results The technical variant used 30- and 70-degree endoscopes that provided complete oblique view of the endolarynx. The association of angled instruments (forceps, suction pumps, retractors and scissors) enabled the execution of the surgical procedures. Conclusion The association of rigid endoscopy with angled instruments promoted full visualization of the surgical lesion and operative resolution. (AU)

Variant of the Technique for Laryngeal Microsurgery in Cases of Difficult Laryngoscopy.

Introduction Low exposure of the larynx can make laryngeal microsurgery difficult or even impossible. The application of rigid and contact endoscopy enabled oblique and retrograde angled visualization, allowing transoperative staging with greater reach of the anatomical areas. However, there is difficulty or even impossibility of performing the surgical act, due to the incompatibility of the angled path with the straight surgical tools. Objective To demonstrate the efficiency of the variant of the technique for laryngeal microsurgery in cases of difficult laryngoscopy and to analyze the new surgical instruments specific to the endoscopic procedure. Methods This is a cross-sectional retrospective study, based on the analysis of 30 medical records of patients treated surgically at a philanthropic hospital in the state of Sergipe, Brazil, between the years of 2014 and 2015. Results The technical variant used 30- and 70-degree endoscopes that provided complete oblique view of the endolarynx. The association of angled instruments (forceps, suction pumps, retractors and scissors) enabled the execution of the surgical procedures. Conclusion The association of rigid endoscopy with angled instruments promoted full visualization of the surgical lesion and operative resolution.

Fundamental Frequency in Excised Human Larynges after Anterior Glottic Web Formation of Various Extents.

OBJECTIVE: To determine the effect of vocal fold anterior web formation on fundamental frequency with a cadaveric excised larynx model. STUDY DESIGN: Experimental study with excised human larynges. SETTING: Academic tertiary care hospital. SUBJECTS AND METHODS: Sixteen freshly excised human larynges were evaluated with high-speed videoendoscopy and digital kymography during artificially produced vibration. Each larynx was assessed in 4 conditions: preoperative controls and after 25%, 33%, and 50% decreases in the vibratory portion of the vocal folds. The following parameters were evaluated: fundamental frequency, periodicity, vocal fold vibration amplitude, phase symmetry, and glottic closure. RESULTS: The mean fundamental frequencies were 208.87, 250.20, 292.37, and 342.67 Hz for preoperative controls and 25%, 33%, and 50% reductions in vibratory length of the vocal folds, respectively. Fundamental frequency increased with each increase in anterior glottic web extent, and the difference among the groups was statistically significant in absolute values in hertz and in semitone elevation. The mathematical models for estimating postoperative fundamental frequency had a statistically significant coefficient. The vibration of the vocal folds remained periodic in all larynges before and after the procedures. CONCLUSION: There was a significant and progressive increase in the fundamental frequency with each enlargement of anterior glottic web. Based on the control frequency, mathematical models could estimate the value of the fundamental frequency after the procedure.

The Influence of Auditory Feedback and Vocal Rehabilitation on Prelingual Hearing-Impaired Individuals Post Cochlear Implant.

OBJECTIVE: To verify changes in the perceptual and acoustic vocal parameters in prelingual hearing-impaired adults with cochlear implants after vocal rehabilitation. HYPOTHESIS: Auditory feedback restoration alone after cochlear implant is not enough for vocal adjustments. A targeted and specific voice therapy intervention is required. STUDY DESIGN: Prospective and pre-post repeated measures design. METHODS: Twenty literate adults with severe to profound prelingual bilateral sensorineural hearing loss participated in the study; individuals were implanted late and were fluent users of oral language. Ages ranged from 17 to 48 years. All individuals presented normal results in laryngoscopy, and hearing thresholds with the cochlear implant were over 40 dB HL. Individuals were randomly distributed into two groups: Group 1 (treatment group) and Group 2 (control group), both with ten patients each, five men and five women, matching mean age and hearing deprivation time before the cochlear implantation. Patients from Group 1 underwent a protocol of vocal therapy including 12 individual sessions with the same clinician. Group 2 only underwent vocal recordings. The vocal recordings occurred before and after the participation in the therapy protocol for Group 1 and after the same period, 3 months later, without any intervention, for Group 2. The recording sessions used the Consensus Auditory-Perceptual Evaluation of Voice protocol sentence reading and emission of sustained vowel /a/. Auditory-perceptual evaluation of voices was performed by three judges, and the acoustical analysis used the Praat program. RESULTS: Statistically significant reductions in the overall vocal degree, vocal instability, and degree of resonance change were observed after vocal rehabilitation in Group 1. Statistically, individuals from Group 1 did not differ in regard to the modification of acoustic parameters. Group 2 did not present significant changes in any of the analyzed parameters. CONCLUSIONS: The cochlear implanted adults submitted to vocal rehabilitation presented changes in the auditory-perceptual parameters, with reduction of the overall voice severity, vocal instability, and degree of resonance after vocal intervention. There were no changes in the acoustic parameters in the implanted prelingual hearing-impaired adult subjects.

Impact of Cricothyroid Muscle Contraction on Vocal Fold Vibration: Experimental Study with High-Speed Videoendoscopy.

OBJECTIVES: The aim of this study was to evaluate the effects of cricothyroid muscle contraction on vocal fold vibration, as evaluated with high-speed videoendoscopy, and to identify one or more aspects of vocal fold vibration that could be used as an irrefutable indicator of unilateral cricothyroid muscle paralysis. STUDY DESIGN: This was an experimental study employing excised human larynges. METHODS: Twenty freshly excised human larynges were evaluated during artificially produced vibration. Each larynx was assessed in three situations: bilateral cricothyroid muscle contraction, unilateral cricothyroid muscle contraction, and no contraction of either cricothyroid muscle. The following parameters were evaluated by high-speed videoendoscopy: fundamental frequency, periodicity, amplitude of vocal fold vibration, and phase symmetry between the vocal folds. RESULTS: Although neither unilateral nor bilateral cricothyroid muscle contraction altered the periodicity of vibration or the occurrence of phase asymmetry, there was a significant decrease in fundamental frequency in parallel with decreasing longitudinal tension. We also found an increase in vibration amplitude of right and left vocal folds, which were similar in terms of their behavior for this parameter in the various situations studied. CONCLUSION: Our results suggest that differences in vibration amplitude and phase symmetry between vocal folds are not reliable indicators of unilateral cricothyroid muscle paralysis.

High-speed Videolaryngoscopy: Quantitative Parameters of Glottal Area Waveforms and High-speed Kymography in Healthy Individuals.

OBJECTIVES: We conducted a study to obtain quantitative parameters of the vocal dynamic using high-speed videolaryngoscopy and to characterize the vocal fold vibration pattern of healthy individuals by analyzing glottal area waveforms and high-speed kymography. METHODS: Laryngeal images of 45 healthy individuals were captured using high-speed videolaryngoscopy. The open and speed quotients of the glottal area waveforms and high-speed kymography were obtained and statistically analyzed according to the gender of each individual. RESULTS: Glottal area waveforms revealed average values of 0.85 and 1.16 for open and speed quotients, respectively, for women, and 0.70 and 1.19 for men. Using high-speed kymography, quantitative parameters of open and speed quotients for women were 0.62 and 1.02, respectively, and for men were 0.57 and 1.12. By gender, a significant statistical difference emerged for open quotients obtained from both glottal area waveforms (P = 0.004) and high-speed kymography (P = 0.013). CONCLUSION: Obtained by using computational tools specifically for analyzing laryngeal images from high-speed videolaryngoscopy, quantitative parameters of glottal area waveforms and high-speed kymography in healthy individuals provide reference data and normality for future studies.

Surgical approach to the thyroarytenoid branch of the inferior laryngeal nerve through the thyroid cartilage.

PURPOSE: To describe the anatomical course of the intralaryngeal portion of the inferior laryngeal nerve (ILN) and to standardize the surgical access to its thyroarytenoid branch (TAb) through the thyroid cartilage. METHODS: Under surgical microscopy, 33 adult human excised larynges were dissected, to expose the intralaryngeal portion of ILN. The point of entry of TAb, ILN's terminal branch, in the thyroarytenoid (TA) muscle was determined and correlated with thyroid cartilage dimensions. RESULTS: After entering the larynx, the ILN consistently traveled between the thyroid cartilage and the lateral cricoarytenoid muscle in an anterior and slightly cranial course. The distance from the point of entry of the TAb in the TA muscle to the midline (TAb-H) and to the inferior border (TAb-V) of the thyroid cartilage differed according to gender. In females, mean distances of TAb-H and TAb-V were 20.5mm and 5.2mm and in males, 22.3mm and 5.9mm, respectively. CONCLUSION: The intralaryngeal course of the inferior laryngeal nerve presents low variability and measures from landmarks in the thyroid cartilage help to estimate the point of entry of thyroarytenoid branch in thyroarytenoid muscle.

Surgical approach to the thyroarytenoid branch of the inferior laryngeal nerve through the thyroid cartilage

ABSTRACT PURPOSE: To describe the anatomical course of the intralaryngeal portion of the inferior laryngeal nerve (ILN) and to standardize the surgical access to its thyroarytenoid branch (TAb) through the thyroid cartilage. METHODS: Under surgical microscopy, 33 adult human excised larynges were dissected, to expose the intralaryngeal portion of ILN. The point of entry of TAb, ILN's terminal branch, in the thyroarytenoid (TA) muscle was determined and correlated with thyroid cartilage dimensions. RESULTS: After entering the larynx, the ILN consistently traveled between the thyroid cartilage and the lateral cricoarytenoid muscle in an anterior and slightly cranial course. The distance from the point of entry of the TAb in the TA muscle to the midline (TAb-H) and to the inferior border (TAb-V) of the thyroid cartilage differed according to gender. In females, mean distances of TAb-H and TAb-V were 20.5mm and 5.2mm and in males, 22.3mm and 5.9mm, respectively. CONCLUSION: The intralaryngeal course of the inferior laryngeal nerve presents low variability and measures from landmarks in the thyroid cartilage help to estimate the point of entry of thyroarytenoid branch in thyroarytenoid muscle.

Effect of sugarcane biopolymer in vocal fold of rabbits. Comparative study with calcium hydroxyapatite.

PURPOSE: To compare the inflammatory reaction caused by the injection of a sugarcane biopolymer (SCB) into the vocal fold of rabbits with that caused by calcium hydroxyapatite (CaH). METHODS: CaH (Radiesse(r)) and SCB gel were injected respectively into the right and left vocal cords of thirty rabbits. The rabbits were distributed into two equal groups and sacrificed at three and twelve weeks after injection. We then evaluated the intensity of the inflammatory reaction, plus levels of neovascularization, fibrogenesis and inflammatory changes in the vocal mucosa. RESULTS: The vocal cords injected with CaH had a stronger inflammatory reaction by giant cells in both study periods. The SCB group had a more intense inflammatory involvement of polymorphonuclear cells three weeks after injection. SCB caused a higher level of neovascularization compared with CaH three weeks after the procedure. CONCLUSION: Whereas calcium hydroxyapatite triggers a more intense and lasting inflammatory reaction mediated by giant cells, sugarcane biopolymer causes a greater response from polymorphonuclear leukocytes, as well as higher levels of vneoascularization three weeks after injection.

Effect of sugarcane biopolymer in vocal fold of rabbits. Comparative study with calcium hydroxyapatite

PURPOSE: To compare the inflammatory reaction caused by the injection of a sugarcane biopolymer (SCB) into the vocal fold of rabbits with that caused by calcium hydroxyapatite (CaH). METHODS: CaH (Radiesse(r)) and SCB gel were injected respectively into the right and left vocal cords of thirty rabbits. The rabbits were distributed into two equal groups and sacrificed at three and twelve weeks after injection. We then evaluated the intensity of the inflammatory reaction, plus levels of neovascularization, fibrogenesis and inflammatory changes in the vocal mucosa. RESULTS: The vocal cords injected with CaH had a stronger inflammatory reaction by giant cells in both study periods. The SCB group had a more intense inflammatory involvement of polymorphonuclear cells three weeks after injection. SCB caused a higher level of neovascularization compared with CaH three weeks after the procedure. CONCLUSION: Whereas calcium hydroxyapatite triggers a more intense and lasting inflammatory reaction mediated by giant cells, sugarcane biopolymer causes a greater response from polymorphonuclear leukocytes, as well as higher levels of vneoascularization three weeks after injection. .

Improvement of Vocal Pathologies Diagnosis Using High-Speed Videolaryngoscopy

Introduction The study of the dynamic properties of vocal fold vibration is important for understanding the vocal production mechanism and the impact of organic and functional changes. The advent of high-speed videolaryngoscopy (HSV) has provided the possibility of seeing the real cycle of vocal fold vibration in detail through high sampling rate of successive frames and adequate spatial resolution. Objective To describe the technique, advantages, and limitations of using HSV and digital videokymography in the diagnosis of vocal pathologies. Methods We used HSV and digital videokymography to evaluate one normophonic individual and four patients with vocal fold pathologies (nodules, unilateral paralysis of the left vocal fold, intracordal cyst, and adductor spasmodic dysphonia). The vocal fold vibration parameters (glottic closure, vibrational symmetry, periodicity, mucosal wave, amplitude, and glottal cycle phases) were assessed. Results Differences in the vocal vibration parameters were observed and correlated with the pathophysiology. Conclusion HSV is the latest diagnostic tool in visual examination of vocal behavior and has considerable potential to refine our knowledge regarding the vocal fold vibration and voice production, as well as regarding the impact of pathologic conditions have on the mechanism of phonation...

Comparative analysis of vocal fold vibration using high-speed videoendoscopy and digital kymography.

OBJECTIVES: To compare high-speed videoendoscopy (HSV) and digital kymography (DKG) in the vocal fold vibration analysis of normophonic women with no vocal fold abnormalities. STUDY DESIGN: Prospective study comparing quantitative parameters extracted by HSV and DKG. METHODS: Eighteen normophonic women whose age ranged from 18 to 45 years participated in the study. The procedures comprised HSV and DKG of the medial line of the vocal folds. The parameters evaluated were fundamental frequency (F0), open quotient (OQ), and duration of vibration cycle phases (open phase, closed phase, opening phase, and closing phase). RESULTS: The F0 results of HSV and DKG were similar. However, significant differences were found in both duration of vibration cycle phases and OQ, indicating a longer open phase in the vocal fold vibration when this phase was measured by HSV. CONCLUSIONS: The results emphasize the need to set up different normative threshold values for both HSV and DKG.