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Cellular and Molecular Life Sciences :... Oct 2020The larynx and vocal folds sit at the crossroad between digestive and respiratory tracts and fulfill multiple functions related to breathing, protection and phonation.... (Review)
Review
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.
Topics: Animals; Cell Differentiation; Humans; Laryngeal Diseases; Larynx; Mesenchymal Stem Cells; SOXB1 Transcription Factors; Signal Transduction; Thyroid Nuclear Factor 1; Vocal Cords
PubMed: 32253462
DOI: 10.1007/s00018-020-03506-x -
Orphanet Journal of Rare Diseases Dec 2011A laryngo-tracheo-esophageal cleft (LC) is a congenital malformation characterized by an abnormal, posterior, sagittal communication between the larynx and the pharynx,... (Review)
Review
A laryngo-tracheo-esophageal cleft (LC) is a congenital malformation characterized by an abnormal, posterior, sagittal communication between the larynx and the pharynx, possibly extending downward between the trachea and the esophagus. The estimated annual incidence of LC is 1/10,000 to 1/20,000 live births, accounting for 0.2% to 1.5% of congenital malformations of the larynx. These incidence rates may however be underestimated due to difficulty in diagnosing minor forms and a high mortality rate in severe forms. A slightly higher incidence has been reported in boys than in girls. No specific geographic distribution has been found. Depending on the severity of the malformation, patients may present with stridor, hoarse cry, swallowing difficulties, aspirations, cough, dyspnea and cyanosis through to early respiratory distress. Five types of laryngo-tracheo-esophageal cleft have been described based on the downward extension of the cleft, which typically correlates with the severity of symptoms: Type 0 laryngo-tracheo-esophageal cleft to Type 4 laryngo-tracheo-esophageal cleft. LC is often associated with other congenital abnormalities/anomalies (16% to 68%), mainly involving the gastro-intestinal tract, which include laryngomalacia, tracheo-bronchial dyskinesia, tracheo-bronchomalacia (mostly in types 3 and 4), and gastro-esophageal reflux disease (GERD). The syndromes most frequently associated with an LC are Opitz/BBB syndrome, Pallister Hall syndrome, VACTERL/VATER association, and CHARGE syndrome. Laryngeal clefts result from failure of fusion of the posterior cricoid lamina and abnormal development of the tracheo-esophageal septum. The causes of the embryological developmental anomalies leading to LC are not known but are thought to be multifactorial. LC appears to be mostly sporadic although some familial cases with suspected autosomal dominant transmission have been reported. The age of diagnosis depends mainly on the severity of the clinical symptoms and therefore on the extent of the LC. Diagnosis is made either based on clinical manifestations or on investigations, such as endoscopy, X-ray, CT scan, performed for other conditions. Differential diagnoses include tracheo-bronchial fistula, gastro-esophageal reflux disease and neurological swallowing disorders, as well as laryngomalacia and laryngeal palsy. Prenatal diagnosis of LC has never been reported, although associated anomalies may be detected on fetal ultrasonography. Once the cleft is diagnosed, it is essential to determine its length to orient the management and treatment approach. Management involves maintenance of satisfactory ventilation, prevention of secondary pulmonary complications as a result of repeated aspirations, and adequate feeding. Endotracheal intubation may be required for respiratory distress in severe cases. Treatment requires endoscopic or external surgery to close the cleft. Surgery should be performed as early as possible to avoid complications related to aspiration and gastric reflux, except in type 0 and type 1 cases in which conservative measures must first be attempted. The prognosis is variable depending on the severity of the LC and associated malformations. Early diagnosis and appropriate treatment and management help to reduce mortality and morbidity.
Topics: Abnormalities, Multiple; Animals; Child; Child, Preschool; Congenital Abnormalities; Endoscopy; Esophagus; Female; Humans; Infant; Infant, Newborn; Larynx; Male; Prognosis; Rats; Trachea
PubMed: 22151899
DOI: 10.1186/1750-1172-6-81 -
HNO Sep 2021Significant and new impulses regarding the treatment concept for outpatient phonosurgery on unsedated patients are currently coming from various Anglo-American authors.... (Review)
Review
Significant and new impulses regarding the treatment concept for outpatient phonosurgery on unsedated patients are currently coming from various Anglo-American authors. These "office-based procedures" have been propagated as an alternative to many conventional surgical interventions under anesthesia. The main reason for this remarkable development is the use of new endoscopic techniques in combination with photoangiolytic laser (KTP and blue laser), which allow safe and efficient phonosurgical procedures. Patient acceptance is high since outpatient procedures are considered to have a lower surgical risk. Despite the widespread euphoria, there is a lack of studies evaluating the medical decision criteria and safety management of office-based laryngeal surgery.
Topics: Ambulatory Surgical Procedures; Humans; Laryngeal Diseases; Laryngoplasty; Laryngoscopy; Larynx; Laser Therapy
PubMed: 34195859
DOI: 10.1007/s00106-021-01081-6 -
Journal of Voice : Official Journal of... Jan 2020The larynx is a complex organ which has a role in a variety of functions such as phonation, breathing, and swallowing. To research these functions, it is widely accepted... (Review)
Review
The larynx is a complex organ which has a role in a variety of functions such as phonation, breathing, and swallowing. To research these functions, it is widely accepted that in vivo studies provide more anatomically and physiologically relevant findings. However, invasive procedures are generally needed to measure variables such a subglottal pressure, vocal fold tension and stiffness, and cricothyroid muscle stretch. Performing studies using excised larynges is a useful technique which makes it possible to not only measure phonation parameters but control them as well. Early studies using excised larynges mainly focused on controlling specific parameters and mathematical modeling simulations. The use of these studies has helped further research in laryngeal anatomy, imaging techniques, as well as aerodynamic, acoustic, and biomechanical properties. Here, we describe the progress of this research over the past 5 years. The number of accepted animal models has increased and ideas from excised larynx studies are starting to be applied to treatment methods for laryngeal disorders. These experiments are only valid for an excised situation and must continue to be combined with animal experimentation and clinical observations.
Topics: Animals; Biomechanical Phenomena; Computer Simulation; Humans; Laryngectomy; Larynx; Models, Animal; Models, Theoretical; Phonation
PubMed: 30262190
DOI: 10.1016/j.jvoice.2018.07.023 -
Journal of Clinical Laboratory Analysis Feb 2021Tissue engineering has been a topic of extensive research in recent years and has been applied to the regeneration and restoration of many organs including the larynx.... (Review)
Review
OBJECTIVE
Tissue engineering has been a topic of extensive research in recent years and has been applied to the regeneration and restoration of many organs including the larynx. Currently, research investigating tissue engineering of the larynx is either ongoing or in the preclinical trial stage.
METHODS
A literature search was performed on the Advanced search field of PubMed using the keywords: "(laryncheal tissue engineering) AND (cartilage regeneration OR scaffolds OR stem cells OR biomolecules)." After applying the selection criteria, 65 articles were included in the study.
RESULTS
The present review focuses on the rapidly expanding field of tissue-engineered larynx, which aims to provide stem cell-based scaffolds combined with biological active factors such as growth factors for larynx reconstruction and regeneration. The trend in recent studies is to use new techniques for scaffold construction, such as 3D printing, are developed. All of these strategies have been instrumental in guiding optimization of the tissue-engineered larynx, leading to a level of clinical induction beyond the in vivo animal experimental phase.
CONCLUSIONS
This review summarizes the current progress and outlines the necessary basic components of regenerative laryngeal medicine in preclinical fields. Finally, it considers the design of scaffolds, support of growth factors, and cell therapies toward potential clinical application.
Topics: Animals; Humans; Larynx; Printing, Three-Dimensional; Tissue Engineering; Tissue Scaffolds
PubMed: 33320365
DOI: 10.1002/jcla.23646 -
Journal of Anatomy Sep 2020The synchronization of flight mechanics with respiration and echolocation call emission by bats, while economizing these behaviors, presumably puts compressive loads on...
The synchronization of flight mechanics with respiration and echolocation call emission by bats, while economizing these behaviors, presumably puts compressive loads on the cartilaginous rings that hold open the respiratory tract. Previous work has shown that during postnatal development of Artibeus jamaicensis (Phyllostomidae), the onset of adult echolocation call emission rate coincides with calcification of the larynx, and the development of flight coincides with tracheal ring calcification. In the present study, I assessed the level of reinforcement of the respiratory system in 13 bat species representing six families that use stereotypical modes of echolocation (i.e. duty cycle % and intensity). Using computed tomography, the degree of mineralization or ossification of the tracheal rings, cricoid, thyroid and arytenoid cartilages were determined for non-echolocators, tongue clicking, low-duty cycle low-intensity, low-duty cycle high-intensity, and high-duty cycle high-intensity echolocating bats. While all bats had evidence of cervical tracheal ring mineralization, about half the species had evidence of thoracic tracheal ring calcification. Larger bats (Phyllostomus hastatus and Pterpodidae sp.) exhibited more extensive tracheal ring mineralization, suggesting an underlying cause independent of laryngeal echolocation. Within most of the laryngeally echolocating species, the degree of mineralization or ossification of the larynx was dependent on the mode of echolocation system used. Low-duty cycle low-intensity bats had extensively mineralized cricoids, and zero to very minor mineralization of the thyroids and arytenoids. Low-duty cycle high-intensity bats had extensively mineralized cricoids, and patches of thyroid and arytenoid mineralization. The high-duty cycle high-intensity rhinolophids and hipposiderid had extensively ossified cricoids, large patches of ossification on the thyroids, and heavily ossified arytenoids. The high-duty cycle high-intensity echolocator, Pteronotus parnellii, had mineralization patterns and laryngeal morphology very similar to the other low-duty cycle high-intensity mormoopid species, perhaps suggesting relatively recent evolution of high-duty cycle echolocation in P. parnellii compared with the Old World high-duty cycle echolocators (Rhinolophidae and Hipposideridae). All laryngeal echolocators exhibited mineralized or ossified lateral expansions of the cricoid for articulation with the inferior horn of the thyroid, these were most prominent in the high-duty cycle high-intensity rhinolophids and hipposiderid, and least prominent in the low-duty cycle low-intensity echolocators. The non-laryngeal echolocators had extensively ossified cricoid and thyroid cartilages, and no evidence of mineralization/ossification of the arytenoids or lateral expansions of the cricoid. While the non-echolocators had extensive ossification of the larynx, it was inconsistent with that seen in the laryngeal echolocators.
Topics: Animals; Biological Evolution; Chiroptera; Echolocation; Flight, Animal; Larynx; Trachea
PubMed: 32319086
DOI: 10.1111/joa.13204 -
PloS One 2023In this study, 23 subjects produced cyclic transitions between rounded vowels and unrounded vowels as in /o-i-o-i-o-…/ at two specific speaking rates. Rounded vowels...
In this study, 23 subjects produced cyclic transitions between rounded vowels and unrounded vowels as in /o-i-o-i-o-…/ at two specific speaking rates. Rounded vowels are typically produced with a lower larynx position than unrounded vowels. This contrast in vertical larynx position was further amplified by producing the unrounded vowels with a higher pitch than the rounded vowels. The vertical larynx movements of each subject were measured by means of object tracking in laryngeal ultrasound videos. The results indicate that larynx lowering was on average 26% faster than larynx raising, and that this velocity difference was more pronounced in woman than in men. Possible reasons for this are discussed with a focus on specific biomechanical properties. The results can help to interpret vertical larynx movements with regard to underlying neural control and aerodynamic conditions, and to improve movement models for articulatory speech synthesis.
Topics: Male; Female; Humans; Speech; Phonetics; Larynx; Movement; Videotape Recording
PubMed: 36795744
DOI: 10.1371/journal.pone.0281877 -
European Archives of... Jun 2024To discuss the different swallowing improvement surgeries that address one or more dysfunctional pharyngolaryngeal structures causing dysphagia. These surgeries reduce... (Review)
Review
PURPOSE
To discuss the different swallowing improvement surgeries that address one or more dysfunctional pharyngolaryngeal structures causing dysphagia. These surgeries reduce the risk of aspiration without sacrificing vocal function.
METHODS
We searched the PubMed database and used Google Scholar search engine to find studies discussing the different swallowing improvement surgeries. A manual search of references in selected articles and reviews was done as well. No chronologic limitation was set for the studies; however, only articles written in English and Japanese were considered. Due to the nature of this article, no particular inclusion or exclusion criteria were set when searching for studies to be used as references; however, all relevant studies were reviewed and agreed upon by the authors for inclusion in this review article.
RESULTS/DISCUSSION
Surgeries to improve swallowing function can be categorized into those that reinforce nasopharyngeal closure or pharyngeal contraction, improve laryngeal elevation or pharyngoesophageal segment opening, and those that improve vocal fold closure to protect the airway during swallowing. They are an effective alternative treatment that may significantly improve these patients' quality of life. Swallowing rehabilitation with the altered pharyngolaryngeal structures is required post-operatively to significantly improve patients' dysphagia.
CONCLUSIONS
Surgeries to improve swallowing function address specific dysfunctional sites involved in the swallowing mechanism. Choosing the most appropriate surgery for each patient requires knowledge of the pathophysiology for their dysphagia and detailed pre-operative work-up.
Topics: Humans; Deglutition Disorders; Deglutition; Otorhinolaryngologic Surgical Procedures; Pharynx; Larynx
PubMed: 38265461
DOI: 10.1007/s00405-024-08452-z -
European Journal of Radiology Jan 2014External laryngeal trauma is a rare but potentially life-threatening situation in the acutely injured patient. Trauma mechanism and magnitude, maximum focus of the... (Review)
Review
External laryngeal trauma is a rare but potentially life-threatening situation in the acutely injured patient. Trauma mechanism and magnitude, maximum focus of the applied force, and patient related factors, such as age and ossification of the laryngeal cartilages influence the spectrum of observed injuries. Their correct diagnosis and prompt management are paramount in order to avoid patient death or long-term impairment of breathing, swallowing and speaking. The current review provides a comprehensive approach to the radiologic interpretation of imaging studies performed in patients with suspected laryngeal injury. It describes the key anatomic structures that are relevant in laryngeal trauma and discusses the clinical role of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the acute emergency situation. The added value of two-dimensional multiplanar reconstructions (2D MPR), three-dimensional volume rendering (3D VR) and virtual endoscopy (VE) for the non-invasive evaluation of laryngeal injuries and for treatment planning is discussed. The clinical presentation, biomechanics of injury, diagnostic pitfalls and pearls, common and uncommon findings are reviewed with emphasis of fracture patterns, involvement of laryngeal joints, intra- and extralaryngeal soft tissue injuries, and complications seen in the acute emergency situation. The radiologic appearance of common and less common long-term sequelae, as well as treatment options are equally addressed.
Topics: Aged; Humans; Larynx; Magnetic Resonance Imaging; Male; Neck Injuries; Soft Tissue Injuries; Tomography, X-Ray Computed; Wounds, Nonpenetrating; Wounds, Penetrating
PubMed: 24238937
DOI: 10.1016/j.ejrad.2013.10.021 -
Proceedings of the National Academy of... Oct 2018In its most basic conception, a novelty is simply something new. However, when many previously proposed evolutionary novelties have been illuminated by genetic,... (Review)
Review
In its most basic conception, a novelty is simply something new. However, when many previously proposed evolutionary novelties have been illuminated by genetic, developmental, and fossil data, they have refined and narrowed our concept of biological "newness." For example, they show that these novelties can occur at one or multiple levels of biological organization. Here, we review the identity of structures in the avian vocal organ, the syrinx, and bring together developmental data on airway patterning, structural data from across tetrapods, and mathematical modeling to assess what is novel. In contrast with laryngeal cartilages that support vocal folds in other vertebrates, we find no evidence that individual cartilage rings anchoring vocal folds in the syrinx have homology with any specific elements in outgroups. Further, unlike all other vertebrate vocal organs, the syrinx is not derived from a known valve precursor, and its origin involves a transition from an evolutionary "spandrel" in the respiratory tract, the site where the trachea meets the bronchi, to a target for novel selective regimes. We find that the syrinx falls into an unusual category of novel structures: those having significant functional overlap with the structures they replace. The syrinx, along with other evolutionary novelties in sensory and signaling modalities, may more commonly involve structural changes that contribute to or modify an existing function rather than those that enable new functions.
Topics: Animals; Biological Evolution; Birds; Fossils; Larynx; Phylogeny; Respiratory System; Trachea; Vocal Cords; Vocalization, Animal
PubMed: 30249637
DOI: 10.1073/pnas.1804586115