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.     

Repetitive Phonatory Tasks for Identifying Vocal Fold Paresis

Vocal fold paresis may be present in patients with voice complaints. Identification of paresis is important so that appropriate neurolaryngologic evaluation can be ordered and the appropriate treatment can be offered. Repetitive phonatory tasks (RPTs) fatigue patients vocally and may elicit signs of subtle paresis. In this study, four laryngologists independently reviewed the RPT portions of routine fiberoptic voice examinations of 100 patients in a blinded fashion. All patients had presented with voice complaints, were suspected of having a movement disorder of the larynx, and had been referred for laryngeal electromyography (LEMG). Predictions were compared with LEMG results and with predictions made at the time of each initial evaluation. Although RPTs are useful to laryngologists, predictions based on the entire examination are more accurate. LEMG can confirm clinical suspicions or identify paresis missed on fiberoptic laryngeal examination.     

Strobovideolaryngoscopic Findings in Singing Teachers

Professional voice users often present to otolaryngologists and laryngologists with specific voice complaints. The contributions of pathologic lesions to the patients' vocal complaints are not always clear on examination, and often, premorbid examinations of the larynx are not available for review. This study examines the incidence of laryngeal pathology among singing teachers. At a national convention of singing teachers, volunteers were recruited for a "free strobovideolaryngoscopic examination." All volunteers completed a detailed questionnaire of their vocal and medical history and underwent strobovideolaryngoscopic examination. Strobovideolaryngoscopic examinations were completed in 20 volunteers, 7 of whom had voice complaints and 13 of whom perceived their voices to be normal. Vocal fold masses were common among the asymptomatic singing teachers. Evidence of reflux laryngitis was a common finding among both symptomatic and asymptomatic singing teachers. Asymmetries in vocal fold hypomobility were more common among those with voice complaints than was the presence of vocal fold masses in the population studied.     

Current Understanding and Review of the Literature: Vocal Fold Scarring

Vocal fold scarring is the greatest cause of poor voice after vocal fold injury. Scarring causes a disruption of the viscoelastic layered structure of the lamina propria, an increase in stiffness of the vibratory structure, and glottic incompetence. Current treatments for this complex condition are inconsistent and often produce suboptimal results. Research investigating this condition has dramatically increased over the last several years. The literature has been directed toward understanding vocal fold scarring at the biological level and translating this to the clinical forum. We present an up-to-date, thorough, and scholarly review of the literature in vocal fold scarring since 1996.     

Vocal Fold Mucosal Tears: Maintaining a High Clinical Index of Suspicion

Vocal fold mucosal tears have been discussed in the literature rarely, although they are not uncommon clinically. Disruptions in the epithelium usually follow trauma that may result from voice abuse and/or misuse, coughing, and other causes. A high index of suspicion is necessary to avoid missing vocal fold mucosal tears, and strobovideolaryngoscopy is indispensable in making the diagnosis. A brief period of complete voice rest is the standard of care and appears to be helpful in avoiding adverse sequelae and advancing the healing process, but there are no scientific studies to confirm its efficacy. Mucosal tears may heal completely or may be followed by the development of vocal fold masses, scar, and permanent dysphonia.     

Determining the etiology of mild vocal fold hypomobility

The prevalence of mild vocal fold hypomobility is unknown. In a study by Heman-Ackah et al, vocal fold hypomobility in a population of singing teachers was found to be associated more frequently with vocal complaints than was the presence of vocal fold masses.¹ The etiology of mild vocal fold hypomobility has not been previously explored. In the present study, a retrospective chart review was performed of 134 patients who presented to a tertiary laryngology referral center over a 6-month period for evaluation of vocal complaints. Of the 134 patients, 61 (46%) were found to have mild vocal fold hypomobility previously undiagnosed by the referring otolaryngologist. Imaging studies and laboratory tests to evaluate for structural, metabolic, and infectious causes of the decreased mobility had been ordered. Forty-nine patients completed the work-up. Of these, 41 out of 49 (84%) were found to have imaging or laboratory findings that could explain the hypomobility. Thyroid abnormalities were found to be associated with vocal fold hypomobility in 21 out of 49 (43%) of those with a complete evaluation. Other causes of vocal fold hypomobility included idiopathic (8 of 49, 16%), viral neuritis (5 of 49, 10%), central nervous system abnormality (4 of 49, 8%), neural tumor (3 of 49, 6%), joint dysfunction (3 of 49, 6%), iatrogenic nerve injury (2 of 49, 4%), myopathy (2 of 49, 4%), and noniatrogenic traumatic nerve injury (1 of 49, 2%), This study shows that unilateral vocal fold hypomobility often is associated with a physiologic process, and a complete investigation to determine the etiology is warranted in all cases.     

Vocal Nodules and Laryngeal Morphology

Our purpose was to study the occurrence of vocal fold nodules under conditions of habitual vocal abuse associated with increased laryngeal muscle tension, to identify the existence of a relationship between vocal nodules and laryngeal morphology. We studied one group of 30 subjects with vocal nodules, 18 to 50 years old, who were compared with two control groups, one of females and one of males, consisting of 30 subjects each. The parameters evaluated were: type of vocal folds coaptation, glottic proportion (GP) and abduction angle (AA), obtained by videotelelaryngoscopy. In the nodules group, the larynges presented a mean value of GP similar to that of the female group, both of which were lower than the mean GP value of the male group. On the other hand, the mean AA was lower than the one in the female group, and closer to the one in the male group. We concluded that vocal nodules were present only in larynges with a predominantly young female morphology, with functional limitations of abduction.     

Cooperative Regulation of Vocal Fold Morphology and Stress by the Cricothyroid and Thyroarytenoid Muscles

Voice is produced by vibrations of vocal folds that consist of multiple layers. The portion of the vocal fold tissue that vibrates varies depending primarily on laryngeal muscle activity. The effective depth of tissue vibration should significantly influence the vibrational behavior of the tissue and resulting voice quality. However, thus far, the effect of the activation of individual muscles on the effective depth is not well understood. In this study, a three-dimensional finite element analysis is performed to investigate the effect of the activation of two major laryngeal muscles, the cricothyroid (CT) and thyroarytenoid (TA) muscles, on vocal fold morphology and stress distribution in the tissue. Because structures that bear less stress can easily be deformed and involved in vibration, information on the morphology and stress distribution may provide a useful estimate of the effective depth. The results of the analyses indicate that the two muscles perform distinct roles, which allow cooperative control of the morphology and stress. When the CT muscle is activated, the tip region of the vocal folds becomes thinner and curves upward, resulting in the elevation of the stress magnitude all over the tissue to a certain degree that depends on the stiffness of each layer. On the other hand, the TA muscle acts to suppress the morphological change and controls the stress magnitude in a position-dependent manner. Thus, the present analyses demonstrate quantitative relationships between the two muscles in their cooperative regulation of vocal fold morphology and stress.     

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.     

Vocal Fold Wound Healing: A Review for Clinicians

SUMMARY: The basic science of wound healing is largely omitted from the curriculum of many voice clinicians. This fact is relatively disheartening as most therapeutic manipulation in the realm of laryngology and voice disorders deals with injured tissue. Therefore, the selection of therapeutic tasks for persons with vocal injury should ideally be informed by basic science in wound healing. Recently, several investigators have initiated lines of research to determine the course of vocal fold wound healing and the potential role of therapeutic agents, including behavioral agents. The current review seeks to provide a foundation of basic wound healing science and present the most current data regarding the wound healing process in the vocal folds.