Vocal Fold Impact Stress Analysis

Vocal fold impact stress (force/area) has been implicated as a factor possibly contributing to the formation of nodules and polyps. The force of impact of a moving body is related to its acceleration. Since the mass of the folds is relatively constant, one expects impact force to be directly proportional to acceleration. A measure that reflects the relative displacement of the vocal folds is photoglottography (PGG). The velocity and acceleration of the folds are easily obtained by calculating the first and second derivatives of the PGG displacement waveform. This study, therefore, compared the second derivative of the PGG signal with simultaneously measured impact stress in an excised canine larynx model. Glottal transillumination (PGG) was measured with a subglottic transducer. A miniature force transducer placed in the midline between the vocal folds measured impact stress at the midglottal position. For nine different larynges, there was a positive and linear relationship between the second derivative of PGG and impact stress. The statistically significant results support the hypothesis that the second derivative of PGG m ay provide a use fulnoninvasive way to estimate relative vocal fold impact stress.     

Biochemical Markers Associated With Acute Vocal Fold Wound Healing: A Rabbit Model

This study seeks to determine the ability of enzyme-linked immunosorbent assays (ELISAs) of vocal fold secretions to detect and describe the acute tissue response to injury in a rabbit vocal fold model. Vocal fold secretions were collected before the induction of a unilateral surgical injury to the vocal fold and at 6 timepoints after injury (1, 5, 7, 10, 14, and 21 days). Secretions were then subjected to ELISAs to assess concentrations of interleukin-1 beta (IL-1beta) and prostaglandin-E2 (PGE-2). The results indicate that ELISAs may be useful in documenting fluctuations in these markers associated with the wound healing process in the rabbit model. The temporal expression of both IL-1beta and PGE-2 was consistent with their proposed roles in the wound healing cascade in other systems, pointing to the potential that surface secretions may be at least partial indicators of wound healing events within the tissue.     

Vocal Improvement After Voice Therapy in Unilateral Vocal Fold Paralysis

Unilateral vocal fold paralysis (UVFP) is associated with changes in acoustic and aerodynamic voice measurements and can have a significant impact on a patient's quality of life. Few objective data regarding the efficacy of voice therapy for UVFP exist. The aim of this study was to retrospectively analyze voice modifications in a group of patients with UVFP before and after voice therapy. Forty patients with UVFP of different etiology were included in the study. Each subject had voice therapy with an experienced speech/language pathologist twice a week; the mean number of sessions was 12.6. A multidimensional assessment protocol was used; it included videoendoscopy, the maximum phonation time (MPT), the GIRBAS scale, spectrograms and a perturbation analysis, and the Voice Handicap Index (VHI). Pre- and posttreatment data were compared by means of the Wilcoxon and Student's t tests. A complete glottal closure was seen in 8 patients before voice therapy and in 14 afterward. Mean MPT increased significantly. In the perceptual assessment, the difference was significant for five out of six parameters. A significant improvement was found on spectrographic analysis; as for perturbation analysis, the differences in jitter, shimmer, and noise-to-harmonic ratio values were significant. VHI values showed a clear and significant improvement. A significant improvement of voice quality and quality of life after voice therapy is an often reached and reasonable goal in patients with UVFP.     

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.     

Outcomes of Intubation-induced Vocal Fold Motion Impairment

ObjectiveVocal fold motion impairment (VFMI) is a potential consequence of intubation. Studies describing the natural course of this complication are largely case reports. This study aims to evaluate outcomes for a cohort of patients who endured varying degrees of vocal fold immobility or hypomobility post-intubation.Study DesignRetrospective chart review.MethodsUpon excluding known causes of VFMI, such as surgeries and tumors involving the head and neck, VFMI cases (ICD-9 diagnosis code 478.3) were identified from 2008 to 2014 at a regional healthcare institution. A total of 2,387 were identified and of those, 25 were intubation-induced VFMI cases. This cohort was then examined for notable features.ResultsWith a mean prolonged intubation duration of 6.55 days, 68% of cases resulted in left unilateral, 8% right unilateral, and 24% bilateral VFMI. Overall, 80% of patients experienced a recovery outcome (voice improvement or restoration of vocal fold mobility). Median recovery time was 4.31 months (mean, 6.51 months; range, 19-715 days). In cases of unilateral VFMI, 95% of cases had a recovery outcome. In cases of bilateral VFMI, 33% of cases had a recovery outcome. Additionally, bilateral cases showed a statistically significant association with an approximately 36-fold lower odds of recovery than unilateral cases (odds ratio, 0.0278; 95% confidence interval, 0.0020-0.3868; P value, 0.0077).ConclusionsIntubation-induced VFMI is rare. In this cohort, most cases resulted from prolonged intubation. While spontaneous recovery was the most common outcome, full remission was not guaranteed in every case. A sizable proportion of cases revealed bilateral motion impairment which was less likely to resolve. Our results are informative for tracheostomy decision-making and differential diagnoses for post-intubation laryngeal symptomatology.     

Fibronectin: An Interesting Vocal Fold Protein

A great deal of information is accruing regarding the function of the extracellular matrix. Once thought to be simply a structural entity to surround cells, it is now known to do much more. Fibronectin in particular has received specific attention. Fibronectin is a ubiquitous glycoprotein found most abundantly in the extracellular matrix of regenerating, healing, and embryonic tissue. Vast evidence supports the fact that fibronectin participates in many diverse functions throughout the body that are relevant to vocal fold biology. This article introduces the structure of fibronectin and its isoforms and provides an introduction to some of the many functions it plays. It also reviews the evidence about fibronectin's place in vocal folds and vocal fold pathology. It discusses fibronectin's presence in vocal nodules, vocal polyps, vocal scarring, and Reinke's edema, and reviews the data on its role in mucosal wave impairment. Lastly, it discusses preliminary microarray data that show gene expression for fibronectin to be upregulated in true vocal folds when compared to false vocal folds.