Vocal Process Avulsion

Vocal process avulsion is a rare complication of intubation or external laryngeal trauma that can cause significant dysphonia. The vocal process develops independently from the body of the arytenoid cartilage, which results in a fusion plane that is vulnerable to trauma. The findings of vocal process avulsion may be subtle, and the relationship of the vocal process to the body of the arytenoid cartilage must be examined closely. Stroboscopy is critical in the evaluation. We describe three cases of vocal process avulsion encountered by the senior author (R.T.S.) over the last 5 years and discuss our approaches to evaluation and treatment. All cases were repaired endoscopically. However, we used three different techniques. These include chemical tenotomy with botulinum toxin, closed reduction with fat injection, and open reduction via cordotomy.     

Video-Assisted Rigid Endoscopic Laryngosurgery: Application to Cases with Difficult Laryngeal Exposure

In some cases of microlaryngosurgery, laryngeal exposure with a direct laryngoscope is difficult because of a variety of reasons. In such cases, we now use a long rigid endoscope inserted into the side tube of the direct laryngoscope together with a video system. The lesion can be removed while the phonosurgeon observes the magnified images of the larynx on the video monitor. We describe the surgical procedure together with the preoperative and postoperative evaluation of vocal function in 13 patients with benign laryngeal lesions. A good surgical and vocal outcome was achieved in all cases. The method appeared to be useful for treating dysphonia in patients in whom it was difficult to expose the larynx with a direct laryngoscope.     

Laryngeal airway resistance in teacherswith vocal fatigue: A preliminary study

A noninvasive pressure-flow technique was used to compare laryngealairway resistances in nine female classroom teachers with symptoms of vocal fatigue and seven teachers without symptoms of vocal fatigue. Data were collected two times per day on the Monday, Wednesday, and Friday of a typical work-week. No significant between-group differences were found, but two within-group differences were notable. Airflow in the fatigued subjects decreased across the sampling period (p = .0009). In the controls, air pressure increased across the sampling period (p = .021). These findings suggest that both groups may have reacted to vocal demands during the week by employing two different strategies to maintain habitual laryngeal airway resistance: laryngeal adjustments alone or laryngeal adjustments plus increased respiratory drive. The first strategy, employed by the fatigued subjects, may have been less efficient, thereby provoking conditions associated with their vocal fatigue.     

Vocal Evaluation in Teachers With or Without Symptoms

The aim of this study was to perform voice evaluation in teachers with and without vocal symptoms, identifying etiologic factors of dysphonia, voice symptoms, vocal qualities, and laryngeal lesions. Eighty teachers were divided into two groups: GI (without or sporadic symptoms, 40) and GII (with frequent vocal symptoms, 40). They answered a specific questionnaire, and were subject to a perceptual vocal assessment (maximum phonation time, glottal attack, resonance, coordination of breathing and voicing, pitch, and loudness), GIRBAS scale, and to videolaryngoscopy. Females were predominant in both groups, and the age range was from 36 to 50 years. Elementary teachers predominated, working in classes with 31-40 students. Voice symptoms and alterations in the perceptual vocal analysis and in the GIRBAS scale were more frequent in GII. In 46 teachers (GI-16; GII-30), videolaryngoscopy exams were abnormal with the vocal nodules being the most frequent lesions. These results indicate that a teacher's voice is compromised, and requires more attention including control of environmental factors and associated diseases, preventive vocal hygiene, periodic laryngeal examinations, and access to adequate specialist treatment.     

Minifenestration Type I Thyroplasty Using an Expanded Polytetrafluoroethylene Implant

Several methods have been used to treat laryngeal incompetence, but no ideal technique has been identified. This paper describes a clinical experience with minifenestration type I thyroplasty using a new device made of expanded polytetrafluoroethylene (ePTFE). The device, a thin ribbon of ePTFE, is inserted through a 4-mm fenestration to produce vocal fold medialization. At our center, 26 of these devices have been implanted in the past 3 years. Good or satisfactory results were achieved in 96% of cases. Advantages of this technique include easy insertion of the implant, nominal cost and biocompatibility of the ePTFE device, ready availability of all instruments required for the procedure, and elimination of the need to perform arytenoid adduction.     

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.     

Effects of laryngeal endoscopy on the vocal performanceof young adult females with normal voices

This study investigated changes in maximum phonation time andacoustic and perceptual measures of voice following topical anesthesia and laryngeal endoscopy with the flexible endoscope. Forty-four females, aged 18–33 years and with normal voices, performed four vocal tasks: (a) 3-second /i/ prolongation, (b) maximum phonation time on /i/, (c) stepwise scale-singing, and (d) reading a standard passage. Subjects performed these tasks prior to anesthesia, after anesthesia, and again during laryngeal endoscopy. Voice samples were analyzed for jitter, shimmer, harmonic-to-noise ratio, speaking fundamental frequency, maximum phonational frequency range, maximum phonation time, harshness, and breathiness. Results demonstrated significant reductions in maximum phonational frequency range following anesthesia and, during laryngeal endoscopy, reductions in maximum phonation time and increases in speaking fundamental frequency, minimum fundamental frequency on scale-singing, and breathiness. Clinicians using laryngeal endoscopy for evaluation and management of vocal dysfunction should, therefore, consider the possible effects of these procedures on vocal functioning.     

Vocal Fold Paralysis Following Radiotherapy for Nasopharyngeal Carcinoma: Laryngeal Electromyography Findings

Laryngeal electromyography was used to study the pattern of neurological injury in three patients with unilateral vocal fold paralysis following radiotherapy for nasopharyngeal carcinoma. The thyroarytenoid and cricothyroid muscles were assessed to give an indication of recurrent and superior laryngeal nerve function. Two patients demonstrated both recurrent and superior laryngeal neuropathy suggesting injury at the skull base. The other patient had only recurrent laryngeal neuropathy indicating more distal involvement. Subclinical neuropathic changes were seen in two cases on the side contralateral to the vocal fold paralysis. These patients may be at increased risk of developing bilateral vocal fold paralysis and potentially life-threatening airway obstruction. Long-term follow-up is recommended for such patients, especially if medialization thyroplasty is being considered. This is the first report describing the use of electromyography to determine the pattern of nerve injury in patients with vocal fold paralysis following head and neck radiotherapy.     

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.     

Videokymography: High-speed line scanning of vocal fold vibration

A digital technique for high-speed visualization of vibration, called videokymography, was developed and applied to the vocal folds. The system uses a modified video camera able to work in two modes: high-speed (nearly 8,000 images/s) and standard (50 images/s in CCIR norm). In the high-speed mode, the camera selects one active horizontal line (transverse to the glottis) from the whole laryngeal image. The successive line images are presented in real time on a commercial TV monitor, filling each video frame from top to bottom. The system makes it possible to observe left-right asymmetries, open quotient, propagation of mucosal waves, movement of the upper and, in the closing phase, the lower margins of the vocal folds, etc. The technique is suitable for further processing and quantification of recorded vibration.     

Strobophotoglottographic transillumination as a method for the analysis of vocal fold vibration patterns

The purpose of this exploratory study was to determine if laryngeal transillumination in combination with stroboscopy (strobophotoglottography; SPGG) is useful for (1) the visualization of vocal fold vibration (VFV) opening patterns, (2) the localization of initial vocal fold opening in horizontal glottal thirds (anterior, midmembranous, and posterior), (3) determination of the temporal correspondence of the so-called electroglottography (EGG)-knee and initial vocal fold separation, and, finally, (4) automatized quantitative measurements of glottal area function within endoscopic images. With stroboscopic transillumination, initial inferior vocal fold separation was detectable during the "closed" phase, where the vocal folds were still closed in the upper portion and therefore initial inferior vocal fold separation could not be visualized with usual laryngoscopy techniques. In the horizontal plane within similar fundamental frequencies in modal voice registers in two male subjects, localization of initial glottal opening depended on the voice types used (soft, normal, or pressed phonation). We found zipperlike posterior-to-anterior openings, initial midmembranous openings, initial anterior openings, as well as simultaneous initial opening of all three portions in the two healthy male adults examined. This technique proved to add temporal and spatial information to vocal fold opening patterns and extends our examination techniques to the very beginning of vocal fold opening at the inferior portion. Simultaneous electroglottogram tracking and comparison with bidirectionally illuminated stroboscopic images revealed a time-locked correspondence of the EGG-knee with the aforementioned initial inferior vocal fold separation. Bidirectional illumination combined with digital color extraction techniques allowed for image separation of subglottally and supraglottally illuminated structures. This facilitated vocal fold contour detection and automatized image processing, for example, for determination of glottal area function, and is considered to be a further step to objective automatized quantitative measurements within endoscopic images.     

Phonation thresholds as a function of laryngeal size in a two-mass model of the vocal folds

This letter analyzes the oscillation onset-offset conditions of the vocal folds as a function of laryngeal size. A version of the two-mass model of the vocal folds is used, coupled to a two-tube approximation of the vocal tract in configuration for the vowel /a/. The standard male configurations of the laryngeal and vocal tract models are used as reference, and their dimensions are scaled using a single factor. Simulations of the vocal fold oscillation and oral output are produced for varying values of the scaling factor. The results show that the oscillation threshold conditions become more restricted for smaller laryngeal sizes, such as those appropriate for females and children.     

Acoustic roles of the laryngeal cavity in vocal tract resonance

The acoustic effects of the laryngeal cavity on the vocal tract resonance were investigated by using vocal tract area functions for the five Japanese vowels obtained from an adult male speaker. Transfer functions were examined with the laryngeal cavity eliminated from the whole vocal tract, volume velocity distribution patterns were calculated, and susceptance matching analysis was performed between the laryngeal cavity and the vocal tract excluding the laryngeal cavity (vocal tract proper). It was revealed that the laryngeal cavity generates one of the formants of the vocal tract, which is the fourth in the present study. At this formant, the resonance of the laryngeal cavity (the 1/4 wavelength resonance) induces the open-tube resonance of the vocal tract proper (the 3/2 wavelength resonance). At the other formants, on the other hand, the vocal tract proper acts as a closed tube, because the laryngeal cavity has only a small contribution to generating these formants and the effective closed end of the whole vocal tract is the junction between the laryngeal cavity and the vocal tract proper.     

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.     

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.     

Electrophysiologic monitoring of the recurrent laryngeal nerves may not predict bilateral vocal fold immobility after thyroid surgery

Two cases of bilateral vocal fold immobility (VFI) after identification and preservation of the recurrent laryngeal nerves (RLNs) required tracheotomy until vocal fold recovery. The first patient underwent thyroid surgery without preoperative or postoperative evaluation of the vocal folds, administration of postoperative intravenous steroids, or electrophysiologic monitoring of the RLNs, whereas the second patient underwent a thyroid procedure in which all of the aforementioned were executed. Preoperative and postoperative clinical evaluation of the RLNs is strongly suggested in patients undergoing thyroid surgery, especially revision surgery. Patients potentially undergoing total thyroidectomy should be counseled about the remote chance of airway obstruction and should be properly selected for this operation. Subclinical stretching of the RLNs or ischemia from the endotracheal tube cuff can result in unilateral VFI, and rarely bilateral VFI, requiring reintubation, tracheotomy, or vocal fold lateralization. Electrophysiologic monitoring may not always predict bilateral VFI.     

Analysis of Vocal-fold Vibrations from High-Speed Laryngeal Images Using a Hilbert Transform-Based Methodology

This paper presents a Hilbert transform-based approach to analyze vocal fold vibrations in human subjects exhibiting normal and abnormal voice productions. This new approach is applied to the analysis of glottal area waveform (GAW) and is capable of providing useful information on the vocal fold vibration. The GAW is extracted from high-speed laryngeal images by delineating the glottal edge for each image frame. An analytic signal is generated through the Hilbert transform of the GAW, which yields a recognizable pattern of the vocal fold vibration in the analytic phase plane. The vibratory pattern is comprehensive and can be correlated with specific voice conditions. Quantitative measures of the glottal perturbation are introduced using the analytic amplitude and instantaneous frequency obtained from the analysis. Examples of clinical voice recordings are used to evaluate and test the effectiveness of this approach in providing qualitative representation and quantitative characteristics of vocal fold vibratory behavior. The results demonstrate the potential of using this new analytical tool incorporated with the high-speed laryngeal imaging modality for clinical voice assessment.     

Vocal violence in actors: An investigation into its acoustic consequences and the effects of hygienic laryngeal release training

Acoustic analysis techniques were used to investigate the short-term consequences of vocally violent behavior, and to compare voice production before and after training in hygienic laryngeal release (HLR) techniques. Twenty-seven actors ranging in age from 17 to 48 years were audiorecorded before and after multiple productions of 4 vocally violent behaviors: grunting, groaning, sobbing, and shouting. After training in HLR techniques, the experimental protocol was repeated. Audiorecordings of vowels (produced at 3 pitch levels: modal F0, minimum F0, maximum F0) before and after vocal violence, and before and after HLR training, were analyzed using the Multidimensional Voice Program (4305, Kay Elemetrics Corp, Lincoln Park, NJ). After vocal violence, no consistent acoustic changes were detected for voice generated at modal and minimum F0; however, significant increases in both fundamental frequency range and maximum F0 were observed. After training in HLR techniques, acoustic measures sensitive to pitch and amplitude perturbation, and non-harmonic noise, improved across pitch levels. The results also indicated that vocal training does defend the laryngeal system from undesirable changes related to vocally violent maneuvers that might surface at the extremes of an actor's pitch range. Because the HLR technique used in this investigation was multimodal, interesting questions are raised regarding which aspect of training is primarily responsible for the observed effects. Further study is required to identify such factors.     

Vocal Process Avulsion

Vocal process avulsion is a rare condition in which laryngeal trauma causes a separation of the vocal process from the body of the arytenoid cartilage. Typically symptoms are dysphonia and shortness of breath during phonation. Strobovideolaryngoscopy, laryngeal electromyography, and laryngeal computed tomography are helpful in establishing this important and sometimes elusive diagnosis. Several treatment modalities have been reported with varying success. We report four new cases, review four cases reported previously by the senior author, and suggest approaches to diagnosis and optimal treatment of vocal process avulsion.     

Subglottic Jet Ventilation for Suspension Microlaryngoscopy

High-frequency subglottic jet ventilation was used in 142 consecutive adults with grade I airways treated with suspension microlaryngoscopy. All cases were managed by the senior anesthesiologist (AP) and the large majority by the senior surgeon (JR), between 2000 and 2002. The laser was used in 30% of cases. There were few complications, none serious, associated with this technique in this series. The subglottic catheter never proved impossible to insert and only needed to be replaced by the supraglottic catheter in two patients because of limitation of visualization of the posterior glottis. The technique was used in a wide variety of surgical pathology from benign hyperfunction-related laryngeal pathology through paralytic vocal fold conditions through papilloma. Advantages and disadvantages over traditional intubation techniques and supraglottic jet ventilation are reviewed, including such issues as ease of intubation/ventilation, surgical exposure/control, maintenance of O2 and CO2 levels, and use in the limited/borderline airway.