Outpatient transoral laser vaporization of anterior glottic webs and keel placement: Risks of airway compromise

Management of acquired anterior glottic webs involves resection of the web with reconstitution of a linear vocal fold edge and anterior commissure. Traditional procedures such as transcervical midline thyrotomy (with tracheostomy) and keel placement have been used for patients with extensive scar formation and airway compromise. However, in selected patients with more limited scarring and minimal-to-no airway compromise, a transoral endoscopic approach may be a viable option. In three patients, transoral laser vaporization followed by transoral keel placement and outpatient removal resulted in a vocal quality that perceptually improved without any evidence of respiratory compromise postoperatively.     

Vocal fold vibration of the canine larynx: Observation from an infraglottic view

The authors studied the vibratory action of the canine vocal fold from the tracheal side utilizing high-speed cinematography. Five excised canine larynges were used, and the lower surface of the vocal fold of three of them were marked with India ink as a tracer of a specific point on the vocal fold. A mucosal prominence, called the mucosal upheaval, appeared between the anterior commissure and the vocal process. Vibration was not seen below the mucosal upheaval. The mucosal wave started to move medially from just above the mucosal upheaval. The mucosal wave then became the free edge (lower lip) and collided with that of the other side at the midline. After collision, the lower lip moved upward to become the upper lip. At the same time, a part of the lower lip reflected laterally. The mucosal wave of the next cycle started from just above the mucosal upheaval during an opening phase. The mucosal upheaval vibrated with a low amplitude and with an earlier phase than the other portion of the vocal fold. The increase in tension of the vocal fold did not change the basic vibratory pattern of the mucosal upheaval, the mucosal wave, or the free edge. However, analysis of the mark before and after the increase in tension revealed that the mucosal upheaval occurred more medially or above when the vocal fold tension increased.     

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.     

Sarcoidosis Presenting as Bilateral Vocal Fold Paralysis

Sarcoidosis with cranial polyneuritis and mediastinal granulomatous compression as a cause of unilateral left vocal fold paralysis has been reported infrequently. No case of sarcoidosis causing bilateral vocal fold paralysis in the abducted position has been reported in the Otolaryngology/Voice literature. Vocal fold function can be impacted in sarcoidosis by direct laryngeal involvement or by neural pathways. In the patient described in this case, sarcoid cranial polyneuritis coupled with bilateral paratracheal and mediastinal adenopathy resulted in bilateral vocal fold paralysis. This patient had a dramatic response to treatment with steroids. Sarcoidosis should be included in the differential diagnosis of unilateral or bilateral vocal fold paralysis.     

Endoscopic microsuture repair of vocal fold defects

The presence of a nonvibratory segment of vocal folds after microlaryngeal surgery is often a cause of poor voice result. The etiology of a nonvibratory segment is due to full thickness epithelial defect followed by secondary wound closure and scar contracture. To reduce scar contracture and nonvibratory segment of the vocal folds, primary repair with a 6-0 chromic endo-knot suture technique was used to close defects and approximate microflaps of the vocal folds. This was done in 18 patients with epithelial defects after resection of benign vocal fold lesions. The pathologic findings included severe polypoid degeneration (n = 7), fusiform laryngeal polyps (n = 5), sulcus vocalis (n = 2), cyst (n = 2), and keratosis (n = 2). Voice was improved in all patients after surgery. Comparison of vocal fold vibration before and after surgery showed improvements in configuration, amplitude, and mucosal wave. Vocal folds that were sutured all had good vibratory characteristics; none had a nonvibrating segment at the site of suture placement. Voice and healing after microsuture technique were near normal by Day 10 and return of mucosal wave was often complete by Day 14. Endoscopic microsuture closure of microflaps of the vocal folds edge is safe and affords the surgeon an opportunity for primary repair with improved functional result.     

The shear modulus of the human vocal fold in a transverse direction

The aim of this study was to measure the shear modulus of the vocal fold in a human hemilarynx, such that the data can be related to direction of applied stress and anatomical context. Dynamic spring rate data were collected using a modified linear skin rheometer using human hemilarynges, and converted to estimated shear modulus via application of a simple shear model. The measurement probe was attached to the epithelial layer of the vocal fold cover using suction. A sinusoidal force of 3g was applied to the epithelium, and the resultant displacement logged at a rate of 1kHz. Force measurement accuracy was 20microg and position measurement accuracy was 4microm. The force was applied in a transverse direction at the midmembranous point between the vocal process and the anterior commissure. The shear modulus of the three female vocal folds ranged from 814 to 1232Pa. The shear modulus of the three male vocal folds ranged from 1021 to 1796Pa. These data demonstrate that it is possible to obtain estimates for the shear modulus of the vocal fold while preserving anatomical context. The modulus values reported here are higher than those reported using parallel plate rheometry. This is to be expected as the tissue is attached to surrounding structures, and is under natural tension.     

The biomechanics of the medialization laryngoplasty(thyroplasty type 1) in an ex vivo canine model

The biomechanics of medialization laryngoplasty are not well understood. An excised canine larynx model was used to test the effects of various sized silicon implants. The vocal fold length, position, and tension were measured. Medialization laryngoplasty did not affect vocal fold length. At the mid-membranous vocal fold, larger shims resulted in greater medialization and tension. Medialization laryngoplasty neither medialized nor stiffened the vocal process to resist lateralizing forces. We conclude that medialization laryngoplasty provides bulk and support for defects of the membranous region of the vocal fold, but does not appear to close a posterior glottal gap. The selection of a surgical procedure to treat glottal incompetence should take into account the unique biomechanical properties of the anterior (membranous vocal folds) and posterior (cartilaginous portion) glottis.     

Soft tissue response in the rabbit larynx following implantation of Lactosorb (PLA/PGA copolymer) prosthesis for medialization laryngoplasty

This project is designed to provide initial data regarding the use of polylactic acid/polyglycolic acid (PLA/PGA) copolymer ("LactoSorb" [Walter Lorenz Corp]), an alloplastic, resorbable material, as a prosthesis in an animal model of vocal fold medialization. Fifteen New Zealand white rabbits were utilized for left medialization laryngoplasty with LactoSorb implants after undergoing left recurrent laryngeal nerve section. At 1, 3, 6, and 9 months, the rabbits were sacrificed and their larynges were evaluated both grossly and histologically for tissue response to, and resorption characteristics of the implant, tissue cellularity, maintenance of vocal fold medialization, and airway patency. Additionally, 4 rabbits were used as controls, implanted with silicone rubber medialization implants, and sacrificed at 9 months for comparison. One rabbit underwent no surgery and was likewise used as a control. Grossly, no airway obstruction was noted, and no extrusions of the implants occurred. The LactoSorb implant maintained medialization in each group of sacrificed rabbits. Histologic findings revealed a very discrete, fibrous capsule around the implant in the 1- and 3-month rabbits, and the LactoSorb was still grossly visible. At 6 months, the thin fibrous capsule partially remained; at 9 months, the capsule was no longer evident, and the implant was no longer grossly visible. Endoscopic findings at the time of sacrifice in those rabbits implanted with silicone rubber included grossly patent airways with maintenance of medialization. In the rabbits implanted with silicone rubber, the histologic findings are similar to those described elsewhere. LactoSorb, because of its intermittent resorption rate, could offer an ideal alternative to currently utilized temporary, or resorbable, materials, and as such will hopefully prove an invaluable tool in the laryngologist's treatment planning and surgical repair of the patient with a paralyzed vocal fold.     

Predicted Singers' Vocal Fold Lengths and Voice Classification—A Study of X-Ray Morphological Measures

Students admitted to the solo singing education at the University of Music Dresden, Germany have been submitted to a detailed physical examination of a variety of factors with relevance to voice function since 1959. In the years 1959–1991, this scheme of examinations included X-ray profiles of the singers' vocal tracts. This material of 132 X-rays of voice professionals was used to investigate different laryngeal morphological measures and their relation to vocal fold length. Further, the study aimed to investigate if there are consistent anatomical differences between singers of different voice classifications. The study design used was a retrospective analysis. Vocal fold length could be measured in 29 of these singer subjects directly. These data showed a strong correlation with the anterior-posterior diameter of the subglottis and the trachea as well as with the distance from the anterior contour of the thyroid cartilage to the anterior contour of the spine. These relations were used in an attempt to predict the 132 singers' vocal fold lengths. The results revealed a clear covariation between predicted vocal fold length and voice classification. Anterior-posterior subglottic-tracheal diameter yielded mean vocal fold lengths of 14.9, 16.0, 16.6, 18.4, 19.5, and 20.9 mm for sopranos, mezzo-sopranos, altos, tenors, baritones, and basses, respectively. The data support the assumption that there are consistent anatomical laryngeal differences between singers of different voice classifications, which are of relevance to pitch range and timbre of the voice.     

Reflux and vocal disorders in singers with bulimia

Dysphonia associated with bulimia has been described in the literature associated with vocal fold edema and polypoid changes. Laryngopharyngeal reflux (LPR) has been documented to cause reflux vocal fold pathology including edema and polypoid changes. We studied eight singers with bulimia and documented vocal fold pathology, including edema, posterior commissure hypertrophy, ventricular obliteration, and telangiectasia. Reflux was demonstrated in all eight. The results of this study showed that LPR may be a contributing factor to vocal disorders in singers with bulimia.     

The frequency of hard glottal attacks in patients with muscle tension dysphonia, unilateral benign masses and bilateral benign masses

Hard or abrupt glottal attack (HGA) is one of the vocal behaviors often associated with benign lesion of the vocal folds. This study was designed to determine whether the frequency of HGA was different in hyperfunctional voice patients with and without vocal fold masses. One hundred and forty-seven subjects were studied. All subjects received a complete otolaryngological evaluation including strobovideolaryngoscopy, objective voice measures, and evaluation by a speech-language pathologist. Thirty-two patients were diagnosed with muscle tension dysphonia (19 male, 13 female) without vocal fold masses. Fifty-seven patients were diagnosed with unilateral vocal fold masses (29 male, 28 female), most of which were cysts. Fifty-eight patients were diagnosed with bilateral vocal fold masses (13 male, 45 female). Of the 45 females with bilateral vocal fold masses. 26 had a vocal cyst and reactive nodule and 19 had bilateral vocal fold nodules. The control group was balanced and matched based on sex and on percentage of singers and nonsingers. It consisted of 49 subjects with no vocal fold pathology (20 male, 29 female). The group was composed of professional speakers, singers, and nonprofessional speakers. All voice disordered groups demonstrated higher frequencies of HGA than the control group. Differences were found between the male and female subjects in this study. No differences were found between the various disorders. Differences were also found between the subgroups of bilateral masses, where the bilateral nodules group presented a higher frequency of HGA than the cyst and contralateral reactive nodule.     

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.     

A preliminary study of particle velocity during phonation in an in vivo canine model

The particle velocity across the glottis was measured with simultaneous electroglottography, photoglottography, and subglottic pressure in an in vivo canine model of phonation. A constant temperature anemometer measured flow velocity at five midline anterior to posterior glottal positions. Tracheal input air flow was varied in five steps from 175 to 500 cc/s, while vocal fold approximation was achieved by constant electrical stimulation of the laryngeal nerves. For all levels of air flow, a decreasing peak velocity gradient was observed from the anterior commissure to the arytenoids. Time-varying features of the flow velocity are discussed in relation to glottal vibratory events and aerodynamics.     

Pitch-raising surgery in male-to-female transsexuals

Several surgical methods for pitch raising have been described such as cricothyroid approximation, anterior commissure advancement, scarification, and injection of triamcinolone into the vocal folds. These procedures have different disadvantages and risks. A new method for pitch raising via endolaryngeal shortening of the vocal folds is presented. Long-term results of the first 10 patients are presented. In 1 person, who smoked immediately after surgery, coughed, and did not observe voice rest, there was a dehiscent suture. In 9 transsexuals after surgery the voice range was reduced for the lower frequencies, and a permanent 9.2-semitone increase of the mean, spontaneous fundamental frequency was obtained.     

Laryngeal injuries after short-versus long-term intubation

Forty-five patients were seen over a 5-year period with laryngeal injuries following endotracheal intubation (ETI). The mean duration of ETI was 5.6 days (2 hours to 37 days). Patients intubated for less than 24 hours were most likely to present with a vocal fold immobility or an anterior glottic web. Long-term intubation was associated with the development of subglottic stenoses and granulomas. Patients with vocal fold immobility were seen more often after ETI for surgical reasons and had a significantly higher incidence of previous intubation and tobacco usage. Subglottic stenoses were seen in younger patients intubated for medical reasons and associated with nasogastric tubes and longer periods of intubation.     

Analysis of spasmodic dysphonia by aerodynamic and laryngostroboscopic measurements

Sequential assessment of laryngeal function using laryngostroboscopy and phonatory air flow assessment was carried out in 18 patients with spasmodic dysphonia (SD). Comparison was made between findings in patients before treatment (n = 18), after unilateral recurrent nerve block by lidocaine (n = 6), after bilateral injections of botulinum toxin (Botox) (n = 13), and prior to Botox reinjection (n = 3). Unilateral nerve block resulted in higher mean phonatory airflows than after bilateral Botox injections. Both unilateral nerve block and Botox injections increased fluctuant or alternating flow source (AC); however, unilateral nerve block resulted in more unmodulated airflow leakage. Phonation time on a single breath was longer than with Botox injection. Bilateral Botox injections resulted in better glottal closure, fewer instances of vocal fold level differences, and, better vocal fold vibrations with phase symmetry, as determined by laryngostroboscopy. Partial bilateral denervation using Botox resulted in laryngeal function, which appeared to be intermediate between that of tightly squeezed pretreatment status and a breathy voice with incomplete adduction after unilateral nerve block. Of all treatments assessed, bilateral partial denervation by Botox appeared to be the most physiologic in restoring normal vocal fold vibratory function and airflow.     

Quantitative assessment of voice quality following laser surgery for reinke''s edema

Although laser surgery has been widely advocated for use in the treatment of vocal fold papilloma because it does not incur bleeding, it has been questioned for use in treating Reinke's edema due to the possibility of heat dispersion to normal surrounding tissue and of scarring. We present a series of 8 cases in which laser surgery was the method of treatment for bilateral Reinke's edema. In each case, voice therapy was selected as the initial treatment; laser surgery was performed following voice therapy. Prior to and following surgery, videostroboscopic examinations were performed on the subjects. Only 4 subjects were available for assessment at the 1-month postoperative period. From the audio track of the videotape, the speaking fundamental frequency, perturbation measures for the vowel /i/, and noise-to-harmonic ratio of a completely voiced sentence were obtained. From the videostroboscopic recordings, the symmetry of the vocal folds, the presence or absence of the mucosal wave and the glottic closure pattern, prior to and after surgery, were judged independently by 3 examiners. The fundamental frequencies approximated the normal male and female ranges for those subjects seen 1 month after surgery. In addition, the noise-to-harmonic ratio and the relative average perturbation improved. Stroboscopy revealed irregularities in the symmetry of vocal folds, mucosal wave, and glottic closure 1 month after surgery.     

Permanent medialization of the paralyzed vocal fold utilizing botulinum toxin and Gelfoam

The clinical picture of a paralyzed vocal fold often has the same appearance as a subluxated arytenoid, with anterior and medial displacement of the arytenoid and a foreshortened and lax vocal fold. Previous work by the authors has shown that a subluxated arytenoid may be permanently repositioned by reduction and selective injection of the intrinsic laryngeal musculature with botulinum toxin. The injection changes the forces within the larynx, allowing the arytenoid to be brought back to proper position on the cricoid cartilage. This concept has been extended to the paralyzed vocal fold. It has been noted that even a clinically paralyzed vocal fold has voluntary motor units that may still act on the arytenoid through residual action from the interarytenoid and synkinesis. These forces are significant enough to manipulate the arytenoid and, thus, the vocal fold, into its correct, adducted position. In this paper, the arytenoid is mobilized to free any fibrosis. The thyroarytenoid and lateral cricoarytenoid muscles are then injected to prevent any forward synkinetic pull on the arytenoid. Next, a Gelfoam injection medializes the vocal fold to create glottic closure. This rebalancing sufficiently positions the arytenoid, so that valvular function is permanently restored. In the ten patients studied for over 1 year, there was a 90% success rate as measured by videostroboscopy, phonation time, and V-RQOL analysis. There were no untoward complications. All the materials used are nonpermanent. The procedure does not limit other techniques from being performed at a later time.     

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.     

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.