From Voice Clinic to Operating Room: Are We Out of Tune?

Introduction: To determine the consistency and accuracy of preoperative diagnosis in the voice clinic with intraoperative diagnosis and to suggest a standardized laryngeal examination protocol in the UK that is supported by evidence-based findings.Method: From January 2011-September 2014, 164 patients were referred to the Multidisciplinary Team voice clinic and diagnosed with laryngeal pathology that required phonosurgery. The visualization (videostrobolaryngoscopy) in clinic was performed using either rigid laryngoscope or a video-naso-laryngoscope. Intraoperatively, laryngeal visualization and surgical procedure was conducted using Storz Aida HD system, 10-mm rigid laryngoscope 0° or 5-mm rigid laryngoscope 0°/30° and a Zeiss S7 microscope.Results: Of the 164 patients seen in the multidisciplinary voice clinic, 86 clinic diagnoses were confirmed intraoperatively (52.4%), 15 patients had the diagnosis confirmed intraoperatively with additional lesion found (9.1%). The clinic diagnosis changed intraoperatively in 63 cases (38.4%). 61 (37.2%) patients seen in the voice clinic were diagnosed with cyst, in 39.3% the diagnosis was confirmed intraoperatively with 5 cases (8.2%) having an additional diagnosis. Twenty (12.2%) patients were diagnosed with polyps, with 80% confirmation intraoperatively; 3 patients (10%) had an additional diagnosis.Conclusion: Videolaryngostroboscopy imaging of the larynx provides an outpatient tool for accurately diagnosing more than 50% of laryngeal pathologies when interpreted by multidisciplinary voice clinicians. However direct laryngeal examination under general anesthesia remains the gold standard when obtaining accurate diagnoses of laryngeal pathology. Patients diagnosed with nonorganic voice disorders should be considered for direct laryngoscopy under general anesthetic should they fail to respond to conservative management.     

Vocal fold exposure in phonosurgery

A difficult laryngeal exposure is made easier by placement of the patient's head and neck into the Boyce-Jackson “sniffing position” and then flexing them further if necessary, by selection of a laryngoscope appropriate to the patient and to the triangular glottic shape, by placement of the laryngoscope along the path of least resistance, by use of a true suspension device in order to apply the force for laryngoscopy towards the larynx and away from the teeth and gums, and by allowing time for the force to work. With these techniques, an easy exposure is made almost perfect. The true vocal folds are exposed from vocal process to anterior commissure without the need for external pressure, the endotracheal tube remains out of sight between the arytenoids, and there is no risk to the teeth, gums, and cervical spine.     

The potential role of ultrasound in differentiating solid and cystic swellings of the true vocal fold

This study was designed to investigate the potential role of ultrasound in the diagnosis of cysts of the true vocal fold. Materials and Methods: Grayscale ultrasound of the larynx was carried out in 29 patients with a swelling of the true vocal fold and dysphonia. The findings were then compared with those at subsequent microlaryngoscopy, in the majority of cases. Results and Conclusions: Whereas preoperative laryngeal ultrasound correctly predicted the surgical findings of a cystic lesion in only 5 of 11 cases, it correctly identified that no cyst was present in 15 of 16 instances when this had been queried. This study suggests that ultrasound may have some role in investigation of unilateral vocal fold pathology, but that further fine-tuning of the technique may be necessary.     

Functional reinnervation of vocal folds after selective laryngeal adductor denervation-reinnervation surgery for spasmodic dysphonia

Selective laryngeal adductor denervation-reinnervation surgery (SLAD-R) offers a viable surgical alternative for patients with adductor spasmodic dysphonia refractory to botulinum toxin injections. SLAD-R selectively denervates the symptomatic thyroarytenoid muscle by dividing the distal adductor branch of the recurrent laryngeal nerve (RLN), and preventing reinnervation, by the proximal RLN and maintaining vocal fold bulk and tone by reinnervating the distal RLN with the ansa cervicalis. We present a patient who had previously undergone successful SLAD-R but presented 10 years postoperatively with a new regional dystonia involving his strap muscles translocated to his reinnervated larynx by his previous ansa-RLN neurorraphy. The patient's symptomatic vocal fold adduction resolved completely on division of the ansa-RLN neurorraphy confirming successful selective functional reinnervation of vocal fold adductors by the ansa cervicalis.     

Animal model for training and improvement of the surgical skills in endolaryngeal microsurgery

Animal models for training of surgical skills were widely used for a long time in the education of medical practitioners. It is recognized, however, that endolaryngeal microsurgery requires highly refined skills to handle the delicate structures of the vocal folds under the microscope. The availability of fresh human laryngeal specimens is markedly restricted by legal and hygienic issues. The aim of this work was to report on the design of a feasible and effective model to provide the much needed skills in an animal laryngeal model that is as close as possible to the human vocal fold structure. In the initial phase of the research, three animal larynges were studied: porcine/pig, bovine/calf, and ovine/sheep larynges. The pig/porcine larynx was chosen for this experimental training model because it closely resembled the human laryngeal/glottal configurations. A study was carried out on 10 porcine/pig larynges to assess the dimensions of the glottis and study the histology of the layered structure of the vocal fold. The study was pursued to confirm the resemblance of this animal specimen to the human vocal fold. A wooden box with a black finished interior was prepared with an acrylic bed at its floor. This bed allows placement of the porcine/pig larynx. The design of the box allows the endoscopic exposure of the porcine/pig larynx through a rubber diaphragm. The darkness and confinement of the box, apart from the light of the endoscope, approximates the situation in live endoscopy. The operating microscope is then used to expose the glottis. Routine fine microlaryngeal instruments were used for training in the prescribed skills.     

New Visualization Technique with a Three-Dimensional Video-Assisted Stereoendoscopic System: Application of the BVHIS Display Method During Endolaryngeal Surgery

A three-dimensional video-assisted stereoendoscopic system (3D video system) developed by the Shinko Optical Company, Ltd. (Tokyo, Japan), and referred to as the binocular vision by horizontal image shifting display method (BVHIS display method), has been developed to digitally process ordinary video signals obtained with a video camera connected to a direct videolaryngoscope. The three-dimensional video system provides the surgeon with stereoendoscopic video images and enhances the ability of the surgeon to perform delicate endoscopic procedures. The three-dimensional video-assisted stereoendoscopic laryngosurgical procedure and its underlying principles are described in this paper. A total of 12 patients with laryngeal lesions causing dysphonia underwent three-dimensional video-assisted stereoendoscopic laryngosurgery. Although the video image obtained with the BVHIS display method is only pseudo-three-dimensional, this method enables the surgeon to perceive both depth perception and realism. We describe a surgical procedure using this new visualizing technique and the underlying principles of the technique. Preoperative and postoperative evaluations of the patients' vocal functions are also described. This system is a useful tool for the treatment of laryngeal lesions causing dysphonia.     

Mechanical and dynamic aspects of voice production as related to voice therapy and phonosurgery

Laryngeal framework surgery can change the position and tensionof the vocal folds safely without direct surgical intervention in the vocal fold proper. Some 23 years of experience with phonosurgery have proved its usefulness in treating dysphonia related to unilateral vocal fold paralysis, vocal fold atrophy, and pitch-related dysphonias. Meanwhile, much information about the mechanism of voice production has been obtained through intraoperative findings of voice and fiberscopic examination of the larynx . Based on such knowledge together with information obtained through model experiments, the human vocal organ was reconsidered mainly from the mechanical view point, and the roles of voice therapy and singing pedagogy were discussed in relation to phonosurgery. The vocal organ may not be an ideal musical organ and is rather vulnerable, but its potential is enormous.     

Combination thyroplasty and the "twisted larynx:" combined type IV and type I thyroplasty for superior laryngeal nerve weakness.

Vocal cord medialization through Isshiki type I thyroplasty is part of the standard approach for patients with unilateral vocal cord immobility secondary to recurrent laryngeal nerve paralysis. However, several other modalities have been used to treat the symptomatic "twisted" larynx caused by unilateral superior laryngeal nerve weakness. The Isshiki type IV thyroplasty (cricothyroid approximation) specifically addresses cricothyroid muscle weakness, but, canine studies at the Mayo Clinic demonstrated a trend toward decreased acoustic power and sound intensity with simulated cricothyroid activity. Thus it is reasoned that addition of an ipsilateral type I thyroplasty should help compensate for this power loss. Using videostroboscopic and acoustic analysis, 9 patients with unilateral superor laryngeal nerve weakness were treated with combination type IV and type I thyroplasty. Subjective dysphonia and objective visual and acoustic measurements revealed postoperative improvement in most patients. The combination type IV and type I thyroplasty is recommended for surgical treatment of patients with superior laryngeal nerve weakness, because it addresses cricothyroid muscle weakness without compromising vocal power.     

Combination thyroplasty and the “twisted larynx:” combined type IV and type I thyroplasty for superior laryngeal nerve weakness

Vocal cord medialization through Isshiki type I thyroplasty is part of the standard approach for patients with unilateral vocal cord immobility secondary to recurrent laryngeal nerve paralysis. However, several other modalities have been used to treat the symptomatic “twisted” larynx caused by unilateral superior laryngeal nerve weakness. The Isshiki type IV thyroplasty (cricothyroid approximation) specifically addresses cricothyroid muscle weakness, but, canine studies at the Mayo Clinic demonstrated a trend toward decreased acoustic power and sound intensity with simulated cricothyroid activity. Thus it is reasoned that addition of an ipsilateral type I thyroplasty should help compensate for this power loss.Using videostroboscopic and acoustic analysis, 9 patients with unilateral superor laryngeal nerve weakness were treated with combination type IV and type I thyroplasty. Subjective dysphonia and objective visual and acoustic measurements revealed postoperative improvement in most patients. The combination type IV and type I thyroplasty is recommended for surgical treatment of patients with superior laryngeal nerve weakness, because it addresses cricothyroid muscle weakness without compromising vocal power.     

Physiological aspects of a vocal exercise

The physiological aim of vocal exercises is mostly understood in intuitive terms only. This article presents an attempt to document the phonatory behavior induced by a vocal exercise. An elevated vertical position of the larynx is frequently associated with hyperfunctional phonatory habits, presumably because it induces an exaggerated vocal fold adduction. Using the multichannel electroglottograph (MEGG), the laryngeal position was determined in a group of subjects who performed a voice exercise that contained extremely prolonged versions of the consonant /b:/. This exercise is used by the coauthor (N.E.) as part of a standard vocal exercise program. Two of the seven subjects were dysphonic phonastenic patients, and the rest were normal trained or untrained persons. Different attempts to calibrate the MEGG confirmed a linear relationship with larynx height, provided electrode positioning was correct. The results showed that the exercise induced substantial vertical displacements of the larynx. Comparison with larynx height during voicing of other consonants showed that the /b/, in particular, tended to lower the larynx.     

The Value of Laryngeal Electromyography in the Evaluation of Laryngeal Motion Abnormalities

SUMMARY: Laryngeal electromyography (EMG) functions routinely as a prognostic tool in the evaluation of vocal fold paralysis, as a guide for therapeutic injections into the laryngeal muscles, and more recently as an assessment tool in the evaluation of vocal fold paresis. This study investigates the clinical utility of laryngeal EMG as a diagnostic aid in the evaluation of movement disorders of the larynx in patients complaining of dysphonia. A retrospective chart review of all laryngeal EMGs performed at a tertiary laryngology referral center over a 13-month period was performed. All laryngeal EMGs were performed to evaluate laryngeal motion abnormalities in dysphonic patients. Thirty-seven laryngeal EMGs were completed during this study period. Analysis of the data revealed that the medical treatment plan changed as a result of findings on laryngeal EMG in 10/37 patients (27.0%); laryngeal EMG guided and/or confirmed the course of treatment in 12/37 patients (32.4%) and did not change the treatment plan in 15/37 patients (40.5%). Laryngeal EMG is a useful diagnostic tool that, in this study, contributed significantly to and helped guide the evaluation and management of motion disorders in the larynx of dysphonic patients.     

Nonlinear behavior of vocal fold vibration: The role of coupling between the vocal folds

Coupling between the vocal folds is one of the nonlinear mechanisms allowing regulation and synchronization of mucosal vibration. The purpose of this study was to establish that modulations such as diplophonia and abnormalities observed in vocal signals that may be observed in some cases of laryngeal pathology can be considered as nonlinear behavior due to the persistence of some physical interaction (coupling). An experimental model using excised porcine larynx was designed to create tension asymmetry between the vocal folds and to obtain vocal signals with modulations. Signals were analyzed by spectral analysis and the phase portrait method. Results were compared with computer-generated synthetic signals corresponding to nonlinear combinations of sinusoid signals. Under these conditions, evidence of nonlinear behavior was detected in 85% of experimental signals. These findings were interpreted as a demonstration of vocal fold interaction. Based on these findings, the authors conclude that (1) coupling must be taken into account in physical models of laryngeal physiology, and that (2) methods of nonlinear dynamics may be used for objective voice analysis.     

A physiological and acoustic study on voiced bilabial fricative /β:/ as a vocal exercise

The voiced bilabial fricative /β:/ has been used as a vocal exercise. The present study investigated the effects of the exercise on voice production and voice source. This study compared vowel phonation on the syllable /a:p/ with the production of the exercise and vowel phonation before and immediately after the exercise. The methods were (a) dual-channel electroglottography, from which the vertical laryngeal position was derived, (b) electromyography using surface electrodes, and (c) inverse filtering of the acoustic signal to obtain an estimate of the voice source. In the production of /β:/ as compared with vowel phonation in most of the cases, the vertical laryngeal position seemed to be higher, the muscular activity of the larynx lower, and the slope of the voice source spectrum steeper. In vowel phonation after the exercise, the muscular activity seemed to be lower in most cases, although the voice source remained unchanged. This seems to indicate improved vocal economy.     

Standardized laryngeal videostroboscopic rating: Differences between untrained and trained male and female subjects, and effects of varying sound intensity, fundamental frequency, and age

To determine the influence of the factors gender, vocal training, sound intensity, pitch, and aging on vocal function, videolaryngostroboscopic images of 214 subjects, subdivided according to gender and status of vocal training, were evaluated by three judges with standardized rating scales, comprising aspects of laryngeal appearance (larynx/pharynx ratio; epiglottal shape; asymmetry arytenoid region; compensatory adjustments; thickness, width, length, and elasticity of vocal folds) and glottal functioning (amplitudes of excursion; duration, percentage, and type of vocal fold closure; phase differences; location of glottal chink). The video registrations were made while the subjects performed a set of phonatory tasks, comprising the utterance of the vowel /i/ at three levels of both fundamental frequency and sound intensity. Analysis of the rating scales showed generally sufficient agreement among judges. With the exception of more frequently observed complete closure and lateral phase differences of vocal fold excursions in trained subjects, no further differences were established between untrained and trained subjects. With an α level of p = 0.005, men differed from women with respect to laryngeal appearance (larynx/pharynx ratio, compensatory adjustments, and the presence of omega and deviant-shaped epiglottises), and their vocal folds were rated thicker in the vertical dimension, smaller in the lateral dimension, longer, and more tense, with smaller amplitudes of excursion during vibration. Glottal closure in male subjects was rated more complete, but briefer in duration. Significant effects of the factors pitch, sound intensity, and age on vocal fold appearance and glottal functioning were ascertained. Awareness of the influence of these factors, as well as the factor gender, on the rated scales is essential for an adequate evaluation of laryngostroboscopic images.     

Nonlinear dynamics of the voice: Signal analysis and biomechanical modeling

Irregularities in voiced speech are often observed as a consequence of vocal fold lesions, paralyses, and other pathological conditions. Many of these instabilities are related to the intrinsic nonlinearities in the vibrations of the vocal folds. In this paper, bifurcations in voice signals are analyzed using narrow-band spectrograms. We study sustained phonation of patients with laryngeal paralysis and data from an excised larynx experiment. These spectrograms are compared with computer simulations of an asymmetric 2-mass model of the vocal folds. (c) 1995 American Institute of Physics.     

Laryngeal Mechanisms During Human 4-kHz Vocalization Studied With CT, Videostroboscopy, and Color Doppler Imaging

The objective of this study was to investigate the underlying laryngeal mechanisms during the specific human 4-kHz vocalization. The laryngeal configuration during this vocalization was measured using high-resolution computerized tomographic scan and videostrobolaryngoscopy. The color Doppler imaging (CDI) of medical ultrasound was used to detect the vibrations of glottal and supraglottal mucosa. During the 4-kHz vocalization, the ventricular folds were adducted in the shape of a bimodal chink and the vocal folds were shaped as a "V" with an opening at the posterior glottis. In the coronal view, the laryngeal ventricles had collapsed and a divergent shaped conduit was observed at the posterior portion of the larynx. The surface mucosa vibration detected by CDI was noted over the bilateral ventricular folds and aryepiglottic folds. The vibration displacement was estimated to be on the order of 0.1mm. This vibration amplitude was too small to be detected in videostrobolaryngoscopy. The laryngeal configuration and CDI data suggested a diffuser jet with periodic vorticity bursts in the larynx producing 4 kHz voice.     

Pressure-flow relationships during phonation in the canine larynx

Measurements of air pressure and flow were made using an in vivo canine model of the larynx. Subglottic pressures at varying flow rates were taken during phonation induced by laryngeal nerve stimulation. Results showed that during constant vocal fold stiffness, subglottic pressure rose slightly with increased air flow. The larynx in the in vivo canine model exhibited a flow-dependent decrease in laryngeal airway resistance. Increasing flow rate was associated with an increase in frequency of phonation and open quotient, as measured glottographically. Results from this experiment were compared with a theoretical two-mass model of the larynx and other theoretical models of phonation. The influence of aerodynamic forces on glottal vibration is explained by increased lateral excursion of the vocal folds during the open interval and shortening of the closed interval during the glottal cycle.     

The effect of topical anesthesia on vocal fold motion

The objective of this study was to determine if topical anesthesia to the larynx and pharynx affects vocal fold motion during dynamic voice evaluation with transnasal flexible endoscopy. Transnasal dynamic laryngeal examinations of 10 patients with no voice complaints were evaluated by five blinded fellowship-trained laryngologists. Each patient was examined before and after application of topical anesthetic. Reviewers rated briskness of right and left vocal fold movement and longitudinal tension on a visual analogue scale. Statistical comparisons were made between individual subject scores before and after anesthetic application. Inter-rater reliability was also assessed. No statistical difference was observed between subject scores before and after anesthetic application. Average intraclass correlation coefficients were 0.643 and 0.591 for pre- and postanesthesia scores, respectively. Application of topical anesthesia to the larynx and pharynx does not affect vocal fold motion.     

Arytenoid Cartilage Dislocation: A 20-year Experience

SUMMARY: Arytenoid cartilage dislocation is an infrequently diagnosed cause of vocal fold immobility. Seventy-four cases have been reported in the literature to date. Intubation is the most common origin, followed by external laryngeal trauma. Decreased volume and breathiness are the most common presenting symptoms. We report on 63 patients with arytenoid cartilage dislocation treated by the senior author (RTS) since 1983. Significantly more posterior than anterior dislocations were represented. Although reestablishing joint mobility is difficult, endoscopic reduction should be considered to align the heights of the vocal processes. This process may result in significant voice improvement even long after the dislocation. Strobovideolaryngoscopy, laryngeal electromyography, and laryngeal computed tomography (CT) imaging are helpful in the evaluation of patients with vocal fold immobility to help distinguish arytenoid cartilage dislocation from vocal fold paralysis. Familiarity with signs and symptoms of arytenoid cartilage dislocation and current treatment techniques improves the chances for optimal therapeutic results.     

Effects of vagal nerve stimulation on laryngeal function

Functional electrical stimulation is a developing methodology that shows significant potential in the management of peripheral neuromuscular deficits. Potential applications in the head and neck area, including control of bilateral vocal fold paralysis and spasmodic dysphonia, have recently been explored. Despite promising early results, very little is known about the mechanisms of action or the long-term effects of electrical stimulation on human laryngeal function. Recent development of implantable vagal nerve stimulators as a method to control intractable seizures in individuals who have not responded to medication provides a unique opportunity to study its effect on the normal human larynx. Laryngeal and vocal function testing was studied on five individuals who had undergone vagal nerve stimulator implants for intractable seizures. Consistent abduction/adduction of the left vocal fold was achieved at 20 and 40 Hz, respectively. Higher levels of electrical stimulation produced hemispasm of the larynx. Results were consistent with studies in the literature of recurrent laryngeal nerve stimulation in animal and human models. The vagus nerve provides relatively easy access for implantation of electrodes to provide electrical stimulation to the muscles of the larynx. Vagal nerve stimulation may prove efficacious in the treatment of movement disorders of the larynx; further study is needed.