Familial congenital bilateral vocal fold paralysis: a novel gene translocation

Active and Passive Bioimplants for Vocal Fold Paralysis

Vocal fold paralysis is one of the diseases that particularly affect quality of life. While unilateral paralysis leads to glottis closure insufficiency and hoarseness, bilateral paralysis compromises respiration and limits the exercise tolerance. Bioimplants have been used to treat persistent paralysis for over 100 years. The spectrum ranges from autologous tissue transfer and resorbable or permanent injection materials to composite thyroplasty implants and active electrical implants for neurostimulation of the larynx. If bioimplants are used in accordance with the recommendations, the quality of life of affected patients can be significantly improved today.

Sensory Innervation of the Larynx and the Search for Mucosal Mechanoreceptors

Purpose The larynx is a uniquely situated organ, juxtaposed between the gastrointestinal and respiratory tracts, and endures considerable immunological challenges while providing reflexogenic responses via putative mucosal mechanoreceptor afferents. Laryngeal afferents mediate precise monitoring of sensory events by relay to the internal branch of the superior laryngeal nerve (iSLN). Exposure to a variety of stimuli (e.g., mechanical, chemical, thermal) at the mucosa-airway interface has likely evolved a diverse array of specialized sensory afferents for rapid laryngeal control. Accordingly, mucosal mechanoreceptors in demarcated laryngeal territories have been hypothesized as primary sources of sensory input. The purpose of this article is to provide a tutorial on current evidence for laryngeal afferent receptors in mucosa, the role of mechano-gated ion channels within airway epithelia and mechanisms for mechanoreceptors implicated in laryngeal health and disease. Method An overview was conducted on the distribution and identity of iSLN-mediated afferent receptors in the larynx, with specific focus on mechanoreceptors and their functional roles in airway mucosa. Results/Conclusions Laryngeal somatosensation at the cell and molecular level is still largely unexplored. This tutorial consolidates various animal and human researches, with translational emphasis provided for the importance of mucosal mechanoreceptors to normal and abnormal laryngeal function. Information presented in this tutorial has relevance to both clinical and research arenas. Improved understanding of iSLN innervation and corresponding mechanotransduction events will help shed light upon a variety of pathological reflex responses, including persistent cough, dysphonia, and laryngospasm.

A Review of Treatment of Bilateral Vocal Fold Movement Impairment

Purpose of Review

Bilateral vocal fold immobility is a challenging life-threatening problem involving multiple treatment options and nuanced clinical decision making. We aim to provide relevant background on the etiology, diagnosis, and management of bilateral vocal fold movement impairment (BVFMI).

Recent Findings

Over the last 20 years, the management of bilateral vocal fold immobility has advanced significantly with the addition of multiple endoscopic approaches as well as procedures with the goal of returning dynamic function to the larynx, among them: selective reinnervation. Chemodenervation has also demonstrated promising results as a temporizing procedure in appropriately selected patients with BVFMI.

Summary

Tracheostomy remains the mainstay of emergent treatment for airway obstruction secondary to bilateral vocal fold immobility. However, recent advances in endoscopic approaches allow for avoidance of tracheostomy in many patients. Developments in dynamic procedures with the aim of restoring laryngeal function allow for adequate airway management while maintaining voice quality and limiting aspiration risk.

Mechanisms of larynx and vocal fold development and pathogenesis

The larynx and vocal folds sit at the crossroad between digestive and respiratory tracts and fulfill multiple functions related to breathing, protection and phonation. They develop at the head and trunk interface through a sequence of morphogenetic events that require precise temporo-spatial coordination. We are beginning to understand some of the molecular and cellular mechanisms that underlie critical processes such as specification of the laryngeal field, epithelial lamina formation and recanalization as well as the development and differentiation of mesenchymal cell populations. Nevertheless, many gaps remain in our knowledge, the filling of which is essential for understanding congenital laryngeal disorders and the evaluation and treatment approaches in human patients. This review highlights recent advances in our understanding of the laryngeal embryogenesis. Proposed genes and signaling pathways that are critical for the laryngeal development have a potential to be harnessed in the field of regenerative medicine.

Surgical Management of Bilateral Vocal Fold Paralysis in Children: A Systematic Review and Meta-analysis

OBJECTIVES

To examine and compare the outcomes of various types of glottic widening surgery (GWS) for initial management of bilateral vocal fold paralysis (BVFP) in children, the outcomes of different GWS procedures in children who underwent initial tracheostomy, and the rate of decannulation in children who underwent tracheostomy alone versus tracheostomy followed by GWS.

DATA SOURCES

PubMed, Web of Science, Cochrane Library, and Embase were searched following the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses) on September 9, 2019, with no date restriction.

REVIEW METHODS

Articles focusing on GWS or tracheostomy for initial management of BVFP were included. Articles describing patients who received no surgical intervention for BVFP were excluded.

RESULTS

A total of 5989 articles were reviewed: 67 articles met inclusion criteria, and 240 patients were incorporated into the analysis. Patients who underwent primary GWS had an eventual tracheostomy rate of 6.0% (5/83). There were no statistically significant differences in the rate of tracheostomy, reoperation, or mortality among cricoid split, suture lateralization, and cordectomy/cordotomy. Patients who underwent primary tracheostomy failed to achieve decannulation in 36.9% (58/157) of cases. Decannulation was more likely in tracheostomized children who received GWS than those who did not (odds ratio, 6.336; P < .0001).

CONCLUSIONS

Most children who undergo primary GWS for BVFP avoid tracheostomy or reoperation. These data demonstrated no differences in surgical outcomes among the most common types of GWS for BVFP. For children who receive a tracheostomy as their first intervention for BVFP, GWS is associated with a significantly improved rate of decannulation.

Isolated neonatal bilateral vocal cord paralysis revealing a unilateral medullary defect: a case report

Background

Congenital bilateral vocal cord paralysis is a rare occurrence. Approximately half the cases are associated with a major comorbidity, usually neurological, neuromuscular or malformative.

Case presentation

In a male newborn, respiratory distress syndrome and stridor were observed immediately following birth. The cause was bilateral vocal cord paralysis in the adducted position. Neuroradiological investigation revealed a unilateral discontinuity between the upper pons and the right medulla oblongata. Hypoplasia of the right posterior hemiarches of C1-C2 and the right exo-occipital bone was observed, as was a small clivus. MR angiography showed the absence of the distal right vertebral artery, with hypoplasia and parietal irregularities of the proximal segments. Respiratory autonomy was not obtained despite endoscopic laser cordotomy, corticosteroid therapy and nasal continuous positive airway pressure. The infant died at the age of 4 weeks after treatment was limited to comfort care.

Conclusions

A medullary lesion is an exceptional cause of congenital bilateral vocal cord paralysis. The strictly unilateral neurological and vascular defect and the absence of associated intracranial or extracranial malformation make this clinical case unique and suggest a disruptive mechanism. This case also highlights the help provided by advanced neuroimaging techniques, i.e. fibre tracking using diffusion tensor imaging, in the decision-making process.

Familial impairment of vocal cord mobility in childhood with clubfoot

We report on a family with three siblings, male and female, affected by congenital bilateral limitation of vocal cord abduction, with the additional finding of clubfeet in two. The paternal family history suggests an autosomal dominant inheritance. The siblings and father also have mild craniofacial features, which may be an expression of variability or may be unrelated. The association between congenital vocal cord paralysis and clubfeet has been reported with additional major features or in the context of Charcot-Marie-Tooth disease. However, the two in isolation have only been reported in one other family previously. Genomic analyses of the family, including chromosomal microarray and exome sequencing, showed neither a likely pathogenic variant in a known disease gene nor a compelling candidate gene variant. We propose that the association of these two findings constitutes a novel recognizable phenotype, for which a genetic cause remains undetermined.

Neonatal Stridor in Familial Congenital Laryngeal Paralysis (Plott Syndrome): A Case Study in an Omani Family

Stridor presenting soon after birth due to bilateral abductor vocal cord paralysis (VCP) is rare. We report a family with bilateral VCP affecting four male members in two generations and hence suggesting X-linked recessive inheritance. Severe stridor in the neonatal period requires meticulous airway evaluation, and tracheostomy in 35-70% cases. The current trend is towards conservative management and tracheostomy is avoided unless respiratory distress is severe or life-threatening. Neonatal VCP can be an isolated finding, or it can be familial with or without syndromic features. There are very few reports of non-syndromic familial cases. Unlike the cases reported previously, none of our patients required prolonged intubation or tracheostomy suggesting an excellent prognosis in such cases. This is the first case study of congenital familial non-syndromic VCP reported from the Middle East.