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Pesticides and Chronic Diseases
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
This patient's history was significant. His problem began in 1976 when he met a motor vehicle accident and suffered a pharyngeal injury. Thereafter, between 1976 and 1978, he had many upper respiratory and pharyngeal infections and was told that his immune system was destroyed. He also had voice problems in the form of dysphonia. This patient had a history of asthma as an infant; he also had a tonsillectomy in 1957 and a myelogram in 1975. For a long period of time, he had been sensitive to sulfa drugs. His family history was negative for neurological disease, but positive for organic heart disease and cancer.
Injection Materials for the Larynx
Published in Gilson Khang, Handbook of Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine, 2017
Dong Wook Kim, Seong Keun Kwon
After the occurrence of VFP, voice quality is largely determined by the muscle tone and position of the affected vocal fold, and by each patient’s unique laryngeal compensatory strategy. An atrophic and poorly compensated VFP typically presents with a breathy, weak voice due to air escape. The position of the denervated vocal fold is an especially important factor in the decision to perform medialization laryngoplasty (Fig. 15.1).2,6,7,8 In cases of VFP in which the affected vocal fold is in a far lateral position, open medialization including thyroplasty and arytenoid adduction procedures are usually performed. However, when the affected vocal fold is in a median or paramedian position, there may be a good indication for injection laryngoplasty. Denervation atrophy of the laryngeal muscles progresses over time after RLN injury or resection, and is characterized by diminished volume and tone of the laryngeal muscular structures, which causes a breathy dysphonia.19,20,21 In some animal studies, denervation atrophy progressed until 3 months after RLN resection, and was followed by recovery of the atrophied muscle until at least 9 months.22,23 However, in the clinical setting in humans, clinicians usually report a longer period of progressive muscular atrophy in VFP patients, and even shrinkage of the SLP in severe cases. The shrinkage of the SLP is characterized by alterations in the organization and distribution of the components of extracellular matrix (ECM) such as a loss of HA. These histological changes in the viscoelastic properties of the vocal fold mucosa are associated with stiffening that leads to a dysphonic, often breathy and barely sustainable voice, and can severely impact a patient’s quality of life.24,25 Nonetheless, even after nerve transection, reinnervation of the affected laryngeal musculature occasionally occurs. The source of this reinnervation is not known, but it may include regenerated fibers from the transected RLN, the superior laryngeal nerve (SLN), cervical autonomic nerves, and nerve branches innervating the pharyngeal constrictors. Unfortunately, although reinnervation can prevent muscle atrophy, it usually does not restore useful movement to the vocal fold because of synkinesis,26 which is the phenomenon that results from nonselective innervation of adductor and abductor muscles. During synkinesis, muscles that perform opposite functions contract simultaneously, causing immobility or hypomobility of the vocal fold. In these cases, a medialization procedure such as injection laryngoplasty should be performed.
Numerical analysis and comparison of flow fields in normal larynx and larynx with unilateral vocal fold paralysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Amirhossein Bagheri Sarvestani, Ebrahim Goshtasbi Rad, Kamyar Iravani
Dysphonia, the medical term for disorders of the voice, has either organic or functional causes due to the impairment of any one of the vocal organs (Oren et al. 2016). However, typically it is caused by some kind of interruption of the ability of the vocal folds to vibrate normally during exhalation and phonation (Little et al. 2011). Unilateral vocal fold paralysis (UVFP) is a major cause of dysphonia and with a large number of causes being attributed to this malfunction and changing trends in etiology from place-to-place and over time, it is of utmost importance to arrive at a correct diagnosis to plan further management and also a proper treatment (Yamauchi et al. 2016). The objective of this research is (a) to investigate and compare flow field in a normal larynx and a larynx subjected to unilateral vocal fold paralysis and (b) to analyze the effects of bringing the ill vocal fold closer to healthy one on flow physics. These contributions allow us to gain some new insights into the pathological study of diseased larynx in the hope of getting closer to improve treatment methods.