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Larynx
Kinds of Larynx Terms modified by Larynx Selected AbstractsOnset and Offset Phonation Threshold Flow in Excised Canine Larynges,THE LARYNGOSCOPE, Issue 7 2008Michael F. Regner Abstract Objectives/Hypothesis: In this study, we examined the hypothesis that the minimum flow required for phonation onset, the onset phonation threshold flow (PTF), is greater than the minimum flow to sustain phonation, the offset PTF. We also explored the hypothesis that the ratio of these two (PTF offset divided by PTF onset) falls within [0.707, 1.0]. Study Design: This was a methodology study to measure onset and offset PTFs in 10 excised canine larynges; their ratio (PTF offset divided by PTF onset) was predicted to fall in a specific domain. Methods: The onset and offset PTF and phonation threshold pressure (PTP) values were observed using 10 excised canine larynges mounted on a bench apparatus. The subglottal flow was increased until phonation was observed, and then decreased until phonation ceased; airflow and pressure measurements at critical conditions of phonation were observed as the PTF and PTP. Larynges with elongated vocal folds were then tested to observe PTF and determine if the hypothesis was observed in pathologic-like larynges. Results: The offset PTF was always less than the onset PTF (P , .0001) and 80.0% of the observed onset-offset PTF ratios were bound by [0.707, 1.0]. Conclusions: PTF onset or offset could be a useful diagnostic parameter of the voice, particularly when used in conjunction with PTP to describe laryngeal resistance and aerodynamic power. Further exploration of the relationship between onset and offset PTF values could augment clinical diagnostic ability and advance current theories on the physics of phonation. [source] Helicobacter pylori Colonization in the Larynges of Patients With Hoarseness,,THE LARYNGOSCOPE, Issue 3 2008Tuan-Jen Fang MD Abstract Objectives: Vocal nodules and polyps are two common noninfectious causes of hoarseness. Patients with persistent hoarseness often require microscopic laryngeal surgery to excise mass lesions of the larynx despite extensive voice resting and modification of voice use behavior. Helicobacter pylorihas recently been reported to present in the upper aerodigestive tract. This study applies the rapid urease test to determine the colonization of Helicobacter pylori in surgical specimens of patients with vocal nodules and polyps. Methods: In this prospective study, 53 consecutive patients with vocal nodules (n = 20) or vocal polyps (n = 33) were investigated from November 2004 to July 2005. Microscopic laryngeal surgery was performed in all cases. Tissue specimens harvested from the larynx were analyzed using the rapid urease test. Results: The study population consisted of 33 females and 20 males with a mean age of 43.1 ± 9.9 years. Thirteen (24.5%) of the 53 patients revealed Helicobacter pylori colonization, and all were histopathologically diagnosed with vocal polyps. The difference in incidence of Helicobacter pylori colonization between vocal nodules and vocal polyps was statistically significant (0% [0/20] vs. 39.4% [13/33], P = .001). Conclusions:Helicobacter pylori often colonizes in the larynxes of patients with vocal polyps. These results indicate the involvement of Helicobacter pylori in vocal polyps. However, the presence of Helicobacter pylori as an etiologic factor in vocal polyps remains inconclusive. [source] Aerodynamics of the Human Larynx During Vocal Fold Vibration,THE LARYNGOSCOPE, Issue 12 2005Randall L. Plant MD Abstract Objectives: The goal of this study was to comprehensively analyze the influence of aerodynamics on laryngeal function. Three specific aspects were considered: 1) a multidimensional comparison of the interaction of subglottic pressure, sound intensity, and fundamental frequency; 2) examination of instantaneous changes in subglottic pressure during each glottic cycle; and 3) determination of the threshold subglottic pressure for vocal fold vibration and its dependence on other aerodynamic factors. Study Design: Prospective study with six healthy individuals without history of voice disorders. Methods: The subjects vocalized the vowel sound /i/ with a variety of different intensities, pitch, and sound intensity. Subglottic air pressure, fundamental frequency, sound intensity, and the electroglottography signal were simultaneously measured. Results: Linear relationships were seen in all subjects between subglottic air pressure and sound intensity, although there were large variations in the slopes of these relationships. Rapid variations in subglottic pressure during each glottic cycle were detected, corresponding to the opening of the vocal folds with each individual vibration. Threshold pressures for vocal fold vibration were dependent primarily on sound intensity and fundamental frequency and tended to be higher at vibration onset than at offset. Conclusion: The larynx responded in a predictable pattern to general aerodynamic forces, but there was tremendous variability in its specific behavior. Fundamental frequency and sound intensity tended to increase with subglottic air pressure, but that relationship was not seen consistently in all subjects. The relationship between subglottic air pressure and sound intensity was usually linear, unlike the exponential relationship seen in previous studies. Subglottic pressure was noted to undergo rapid change with each glottic cycle in some, but not all, subjects and was most strongly affected by average subglottic pressure. Phonation threshold air pressure was influenced by the sound intensity and, to a smaller extent, by the fundamental frequency of the voiced sound. [source] A Study of Moderately Differentiated Neuroendocrine Carcinomas of the Larynx and an Examination of Non-Neoplastic Larynx Tissue for Neuroendocrine CellsTHE LARYNGOSCOPE, Issue 7 2004Jin-Haeng Chung MD Abstract Objectives/Hypothesis: To determine the most appropriate terminology for neuroendocrine carcinomas (NEC) of the larynx, successive clinicopathologic studies are encouraged. The typical location and immunophenotype of laryngeal NEC raise a question of whether any precursor cells exist. Study Design: Six patients with laryngeal NEC were analyzed. Another 20 laryngectomy specimens were examined for the presence of non-neoplastic neuroendocrine cells. Methods: Tumor morphology and patient outcome were determined, and tumor tissue underwent immunohistochemical examination to identify cytokeratin, neuroendocrine markers (chromogranin, synaptophysin, CD56, calcitonin), S-100 protein, and p53 protein. A neuroendocrine marker study was also performed on non-neoplastic regions of another 20 laryngectomy specimens to identify any neuroendocrine cells. Results: Laryngeal NEC, all submucosal, exhibited various morphology with or without histologic evidences of neuroendocrine differentiation. The tumors showed frequent (67%) calcitonin expression, calcitonin secretion in one case, and common (50%) p53 over-expression. Three patients died within 3 years. In the non-neoplastic larynx specimens, Kulchitsky cell-like bipolar neuroendocrine cells were identified in the basal and middle layer of the respiratory epithelium of the ventricle and subglottis but none in the submucosal layer of the supraglottic region. The neuroendocrine cells did not express calcitonin. Conclusions: Moderately differentiated or large-cell NEC is a more favored term than atypical carcinoid until more refined classifications for upper respiratory tract NEC are agreed on. Despite the confirmed presence of neuroendocrine cells in the respiratory epithelium of the larynx, the origin of laryngeal NEC remains unknown. p53 mutation might be one of the major molecular steps in the pathogenesis of laryngeal NEC. [source] Paratracheal Lymph Node Involvement in Advanced Cancer of the Larynx, Hypopharynx, and Cervical EsophagusTHE LARYNGOSCOPE, Issue 9 2003Conrad V. Timon MD, FRCSI Abstract Objectives/Hypothesis The presence of nodal metastatic disease in head and neck cancer is the foremost prognostic factor. Although neck dissection is the surgical gold standard for the treatment of cervical lymphatic spread, the paratracheal nodal group is not routinely included in the dissection. The study determined the nodal yield, presence of metastases, and prognostic importance of paratracheal nodes in patients with advanced carcinoma of the upper aerodigestive tract. Study Design Prospective histological and survival analysis. Methods Over a 4-year period (October 1994,June 1998), consecutive patients undergoing laryngectomy with or without pharyngectomy or cervical esophagectomy underwent paratracheal node dissection on a prospective basis. Nodal tissue was examined for the presence of metastases. Statistical comparison of survival probability was determined by use of log-rank/,2 test. Results Fifty patients have been included in the study to date, with a minimal follow-up of 3 years. The average number of paratracheal nodes dissected was three per side (range, 1,5). Thirteen (26%) patients demonstrated histological evidence of paratracheal nodal metastases (larynx, 20%; postcricoid/cervical esophageal region, 43%). Five patients (10%) had positive paratracheal nodes alone in a histologically negative cervical neck dissection. The majority of positive paratracheal nodes were less than 1 cm in diameter and appeared negative preoperatively. The absence of positive paratracheal nodes may have a survival benefit. Conclusion The study highlighted the propensity of advanced carcinoma of the upper aerodigestive tract to involve the paratracheal nodes. This area should be routinely dissected in the surgical management of these tumors. [source] Surgical Closure of the Larynx for Intractable Aspiration: Surgical Technique Using Closure of the Posterior GlottisTHE LARYNGOSCOPE, Issue 1 2003Kiminori Sato MD No abstract is available for this article. [source] Age-Related Mitochondrial DNA Mutations in the Human LarynxTHE LARYNGOSCOPE, Issue 12 2000Jose M. Manaligod MD Abstract Objective To determine whether age-related mitochondrial DNA mutations occur in the human larynx. Study Design Genetic study of cadaveric larynx specimens. Methods Vocal fold mucosa, thyroarytenoid muscle, and cricoarytenoid joint tissue were harvested from 13 fresh postmortem larynges (age range, 2 d,82 y). DNA was extracted from each sample, and the polymerase chain reaction (PCR) was used to amplify a target DNA sequence resulting from the common age-associated, 4977,base-pair (bp) mitochondrial DNA deletion. PCR products were visualized by agarose gel electrophoresis. Automated sequencing determined the sequence of identified PCR products. Subjects Thirteen cadaveric larynges were obtained through the University of Kentucky Medical Center (Lexington, KY). Specimens from patients with a history of head and neck cancer, previous laryngeal trauma, or surgery were excluded. Results Strongly positive bands were identified in samples from three individuals. Weaker bands were seen in samples from four other samples. No band was noted from the two pediatric larynges. Different band patterns were seen among the three different tissue sites in the larynges with positive PCR products, but no consistent pattern was seen. Sequencing of the identified PCR products from selected samples confirmed that they were products of the age-associated, 4977-bp mitochondrial DNA deletion. Conclusions An age-associated mitochondrial DNA deletion was detected in several postmortem human larynges. Its presence seemed to increase in appearance with age. In the larynges in which the deletion occurred, there were individual regional differences in the occurrence of the deletion, but no consistent pattern was noted across all individuals who carried the deletion. [source] Surgery of the Larynx, Trachea, Esophagus and Neck.ANZ JOURNAL OF SURGERY, Issue 8 2003Christopher J. O'Brien MS, FRACS No abstract is available for this article. [source] Effect of magnitude and direction of force on laryngeal abduction: Implications for the nerve-muscle pedicle graft techniqueEQUINE VETERINARY JOURNAL, Issue 4 2009P. CRAMP Summary Reasons for performing study: The nerve-muscle pedicle graft technique is a treatment for recurrent laryngeal neuropathy (RLN), but the optimal placement of the pedicles within the cricoarytenoideus dorsalis (CAD) muscle is unknown. Hypothesis: The magnitude and direction of force placed on the muscular process of the left arytenoid cartilage affects the magnitude of laryngeal abduction. Methods: Five larynges were harvested from cadavers. Using increments of 0.98 N, a dead-weight force generator applied a force of 0,14.7 N for 1 min each to the left muscular process at 0, 10, 20, 30, 40, 50, 60 and 70° angles. The rima glottis was photographed digitally 1 min after each force had been applied. Distances between biomarkers (Lines 1,4) and right to left angle quotient (RLQ) were used to assess the degree of left arytenoid abduction. Results: Increasing force from 0,14.7 N progressively and significantly increased the length of all lines and RLQ, indicating abduction. Furthermore, there was a significant interaction between force and angles. Applying forces of 7.84 N or greater (Lines 2,4 and RLQ) or 11.76 N or greater (Line 1) at angles 0, 10, 20 and 30° resulted in significantly greater abduction than applying the same forces at 40, 50, 60 and 70°. Angles of 0,30° correspond with the direction of pull exerted by the lateral compartment of the CAD muscle. Conclusion: In RLN, nerve-muscle pedicle grafts should be placed preferentially in the lateral rather than in the medial compartment of the CAD muscle. Potential relevance: The information presented can be used to assist surgeons in the planning and application of the nerve-muscle pedicle graft procedure. [source] Intra-articular stabilisation of the equine cricoarytenoid jointEQUINE VETERINARY JOURNAL, Issue 6 2008J. CHEETHAM Summary Reasons for performing study: The success of laryngoplasty is limited by abduction loss in the early post operative period. Objective: To determine the efficacy of polymethylmethacrylate (PMMA) in stabilising the cricoarytenoid joint (CAJ) and reducing the force on the laryngoplasty suture. Hypothesis: Injection into the cricoarytenoid joint resists the forces produced by physiological laryngeal air flows and pressures thereby reducing the force experienced by the laryngoplasty suture. Methods: Ten cadaver larynges were collected at necropsy and PMMA was injected into one CAJ at selected random. Each larynx was subjected to physiological conditions with with constant (static) or cycling (dynamic) flow. The specimens were tested sequentially in each of 4 conditions: 1) bilateral full abduction (Control 1); 2) transection of the suture on the side without PMMA; 3) bilateral abduction achieved by replacing the suture (Control 2); and 4) cutting the suture on the PMMA side. Tracheal pressure and flow and pressure in the flow chamber were recorded using pressure and flow transducers. The strain experienced by each suture during bilateral abduction (Controls 1 and 2) was measured. Statistical comparison of the 4 conditions was performed using a mixed effect model with Tukey's post hoc test for multiple comparisons. The strain gauge data were analysed by paired comparison of the regression slopes. Results: In the static and dynamic states, tracheal pressure increased and tracheal flow decreased when the suture on the non-cement side was cut (P<0.05). There was no significant difference in any outcome measure between PMMA injected into the CAJ and bilaterally abducted specimens (Controls 1 and 2) for either condition. The rate of increase in strain with increasing translaryngeal pressure was significantly less on the suture with PMMA placed in the CAJ (P = 0.03). Conclusions: These data provide strong evidence that injecting PMMA into the CAJ resists the collapsing effect of physiological airflows and pressures in vitro and reduces the force experienced by the laryngoplasty suture during maximal abduction. Potential relevance: Augmentation of prosthetic laryngoplasty with this technique may reduce arytenoid abduction loss in the early post operative period. [source] Distribution of mucins and antimicrobial substances lysozyme and lactoferrin in the laryngeal subglottic regionJOURNAL OF ANATOMY, Issue 4 2008Hannes Kutta Abstract The subglottic region of the larynx is of high clinical relevance with regard to infections and malignancies. Little is known about the distribution of mucins and antimicrobial substances in this area. In this study, we have investigated the mucin distribution in the normal subglottis of the larynx. Moreover, we analysed the expression of lysozyme and lactoferrin in this area. Therefore, the subglottic region of 34 larynges was investigated immunohistochemically with different antibodies to mucins and antimicrobial substances. The epithelium reacted positive with antibodies to mucins MUC1 (34/34), 5AC (26/34), 5B (10/34), 7 (8/34), 8 (10/34) and 16 (19/34); submucosal glands were positive to mucins MUC1 (34/34), 5B (10/34), 7 (8/34), and 16 (19/34); high columnar epithelial cells and serous parts of subepithelial seromucous glands were also positive for lysozyme (34/34) and lactoferrin (34/34). The results show that human subglottic epithelium and subepithelial submucosal glands produce a broad spectrum of mucins that is almost comparable with that in other areas of the respiratory tract. We hypothesize that the mucin diversity of the subglottis has an impact on positive functional consequences during vocal production and antimicrobial defence. This antimicrobial defence is supported by synthesis and secretion of antimicrobial substances such as lysozyme and lactoferrin. Moreover, knowledge of the observed distribution pattern of mucins in the subglottis can be a useful tool for a classification of subglottic laryngeal carcinomas. [source] Nordic rattle: the hoarse vocalization and the inflatable laryngeal air sac of reindeer (Rangifer tarandus)JOURNAL OF ANATOMY, Issue 2 2007Roland Frey Abstract Laryngeal air sacs have evolved convergently in diverse mammalian lineages including insectivores, bats, rodents, pinnipeds, ungulates and primates, but their precise function has remained elusive. Among cervids, the vocal tract of reindeer has evolved an unpaired inflatable ventrorostral laryngeal air sac. This air sac is not present at birth but emerges during ontogenetic development. It protrudes from the laryngeal vestibulum via a short duct between the epiglottis and the thyroid cartilage. In the female the growth of the air sac stops at the age of 2,3 years, whereas in males it continues to grow up to the age of about 6 years, leading to a pronounced sexual dimorphism of the air sac. In adult females it is of moderate size (about 100 cm3), whereas in adult males it is large (3000,4000 cm3) and becomes asymmetric extending either to the left or to the right side of the neck. In both adult females and males the ventral air sac walls touch the integument. In the adult male the air sac is laterally covered by the mandibular portion of the sternocephalic muscle and the skin. Both sexes of reindeer have a double stylohyoid muscle and a thyroepiglottic muscle. Possibly these muscles assist in inflation of the air sac. Head-and-neck specimens were subjected to macroscopic anatomical dissection, computer tomographic analysis and skeletonization. In addition, isolated larynges were studied for comparison. Acoustic recordings were made during an autumn round-up of semi-domestic reindeer in Finland and in a small zoo herd. Male reindeer adopt a specific posture when emitting their serial hoarse rutting calls. Head and neck are kept low and the throat region is extended. In the ventral neck region, roughly corresponding to the position of the large air sac, there is a mane of longer hairs. Neck swelling and mane spreading during vocalization may act as an optical signal to other males and females. The air sac, as a side branch of the vocal tract, can be considered as an additional acoustic filter. Individual acoustic recognition may have been the primary function in the evolution of a size-variable air sac, and this function is retained in mother,young communication. In males sexual selection seems to have favoured a considerable size increase of the air sac and a switch to call series instead of single calls. Vocalization became restricted to the rutting period serving the attraction of females. We propose two possibilities for the acoustic function of the air sac in vocalization that do not exclude each other. The first assumes a coupling between air sac and the environment, resulting in an acoustic output that is a combination of the vocal tract resonance frequencies emitted via mouth and nostrils and the resonance frequencies of the air sac transmitted via the neck skin. The second assumes a weak coupling so that resonance frequencies of the air sac are lost to surrounding tissues by dissipation. In this case the resonance frequencies of the air sac solely influence the signal that is further filtered by the remaining vocal tract. According to our results one acoustic effect of the air sac in adult reindeer might be to mask formants of the vocal tract proper. In other cervid species, however, formants of rutting calls convey essential information on the quality of the sender, related to its potential reproductive success, to conspecifics. Further studies are required to solve this inconsistency. [source] Arctic roars , laryngeal anatomy and vocalization of the muskox (Ovibos moschatus Zimmermann, 1780, Bovidae)JOURNAL OF ZOOLOGY, Issue 4 2006R. Frey Abstract The impressive roaring of adult male muskoxen most often occurs during rutting contests. Roaring in adult females is primarily relevant to mother,infant communication. Loud roars are produced by taking up a specific roaring posture. Acoustic recordings were made in a small herd of zoo muskoxen during three successive rutting seasons. Earlier recordings of a different herd were used for comparison. Head-and-neck specimens were subjected to vascular injection, macroscopic anatomical dissection, computer tomographic analysis and skeletonization. Isolated preserved larynges of young animals were dissected for ontogenetic comparison. Despite a pronounced sexual dimorphism of head mass, larynx size is almost identical in adult male and female muskoxen, as is the fundamental frequency of their roars. Remarkably, the larynges of both sexes of muskoxen are provided with an unpaired ventrorostral ventricle. Probably, this ventricle is inflated during the initial phase of a roar. The ventricle may have two functions: to increase the amplitude of roaring and to darken the timbre of the roars by acting as an additional resonance space. The vocal fold of adult female and young individuals has a sharp rostral edge and a vocal ligament is still present. During male ontogeny the vocal ligament becomes transformed into a large fat pad extending into the wall of the laryngeal vestibulum. Accordingly, the glottic region in the adult male lacks any sharp edges of the mucosa. In both sexes the thyroarytenoid muscle is divided into three portions. A single roar may comprise phases of different sound volume. The roars of both muskox sexes are characterized by a pulsed structure. We suggest that two oscillating systems are involved in the production of roars: one comprising only the medial portion of the vocal fold and one including its lateral portion. [source] Three-dimensional arytenoid movement induced by vocal fold injections,THE LARYNGOSCOPE, Issue 8 2010Ted Mau MD Abstract Objectives/Hypothesis: To quantitatively characterize arytenoid movement induced by vocal fold injection augmentation in an excised larynx model. Study Design: Laboratory and computational. Methods: Vocal folds of human cadaveric larynges were injected with calcium hydroxylapatite. High-resolution computed tomography scans were obtained before and after injection. Densities corresponding to the arytenoid and cricoid cartilages were extracted and processed with custom MATLAB routines to generate selective three-dimensional reconstructions of the larynx. Pre- and postinjection positions of the arytenoid were compared. Results: Vocal fold injections resulted in predominantly small-magnitude medial rotation and medial translation of the arytenoid. Movements in other directions as would be expected in physiologic adduction were not observed. Conclusions: Vocal fold injection augmentation induced passive movement of the arytenoid that has not been described previously. This movement does not reproduce the trajectory of physiologic adduction. This finding has implications for the treatment of unilateral vocal fold paralysis without arytenoid repositioning maneuvers. Laryngoscope, 2010 [source] Imaging of the Calf Vocal Fold With High-Frequency Ultrasound,THE LARYNGOSCOPE, Issue 10 2008Conor J. Walsh MSME Abstract Objectives/Hypothesis: High-frequency ultrasound imaging offers the potential for assisting in the diagnosis and treatment of vocal fold pathology if it allows aspects of vocal fold microstructure to be visualized noninvasively. The objective of this study was to assess the ability of high-frequency ultrasound to image vocal fold anatomy and injected biomaterials. Study Design: The vocal folds of two excised calf larynges were imaged ex vivo and compared with corresponding histological sections. Methods: High-frequency ultrasound imaging was performed under saline submersion using 40 and 50 MHz transducers, and corresponding cryostat cross-sections were stained with H&E, Trichome, and Verhoeff's Van Gieson stains. Results: The epithelial surface, lamina propria, and underlying muscle were easily identified with the high-frequency ultrasound as verified with histological sections representing each imaged region. The arytenoid cartilage vocal process can also be clearly distinguished from the surrounding tissue, as can the full extent of injected biomaterials within the superficial lamina propria. Useful ultrasound resolution was obtained to depths of at least 10 mm within the tissue with the 40 MHz transducer. Conclusions: This preliminary study demonstrates the capability of high-frequency ultrasound to image the layered anatomy of the calf vocal fold and to discern materials injected into the superficial lamina propria, indicating that this technology holds a strong potential for use in phonosurgery. [source] Optimization of Autologous Muscle Stem Cell Survival in the Denervated Hemilarynx,THE LARYNGOSCOPE, Issue 7 2008Stacey L. Halum MD Abstract Objective: Current treatments for vocal fold paralysis are suboptimal in that they fail to restore dynamic function. Autologous muscle stem cell (MSC) therapy is a promising potential therapy for vocal fold paralysis in that it can attenuate denervation-induced muscle atrophy and provide a vehicle for delivery of neurotrophic factors, thereby potentially selectively guiding reinnervation. The goal of this project was to characterize optimal conditions for injected autologous MSC survival in the thyroarytenoid (TA) muscle following recurrent laryngeal nerve (RLN) injury by local administration of adjuvant factors. Study Design: Animal experiment. Methods: Unilateral RLN transection and sternocleidomastoid muscle (,1 g) biopsies were performed in 20 male Wistar rats. One month later, 106 autologous MSCs labeled via retroviral-enhanced green fluorescent protein (EGFP) transduction were injected into the denervated hemilarynx of each animal with one of four adjuvant therapies: cardiotoxin [(CTX) 10,5 M], insulin-like growth factor-1 [(IGF- 1) 100 ,g/mL], ciliary neurotrophic factor [(CNTF) 50 ,g/mL], or saline. Animals were euthanized 1 month later and larynges harvested, sectioned, and analyzed for MSC survival. Results: All specimens demonstrate extensive MSC survival, with fusion of the MSCs with the denervated myofibers. Based on mean fluorescent intensity of the laryngeal specimens, IGF-1 and CNTF had the greatest positive influence on MSC survival. Myofiber diameters demonstrated myofiber atrophy to be inversely related to MSC survival, with the least atrophy in the groups having the greatest MSC survival. Conclusions: Autologous MSC therapy may be a future treatment for vocal fold paralysis. These findings support a model whereby MSCs genetically engineered to secrete CNTF and/or IGF-1 may not only promote neural regeneration, but also enhance MSC survival in an autocrine fashion. [source] Onset and Offset Phonation Threshold Flow in Excised Canine Larynges,THE LARYNGOSCOPE, Issue 7 2008Michael F. Regner Abstract Objectives/Hypothesis: In this study, we examined the hypothesis that the minimum flow required for phonation onset, the onset phonation threshold flow (PTF), is greater than the minimum flow to sustain phonation, the offset PTF. We also explored the hypothesis that the ratio of these two (PTF offset divided by PTF onset) falls within [0.707, 1.0]. Study Design: This was a methodology study to measure onset and offset PTFs in 10 excised canine larynges; their ratio (PTF offset divided by PTF onset) was predicted to fall in a specific domain. Methods: The onset and offset PTF and phonation threshold pressure (PTP) values were observed using 10 excised canine larynges mounted on a bench apparatus. The subglottal flow was increased until phonation was observed, and then decreased until phonation ceased; airflow and pressure measurements at critical conditions of phonation were observed as the PTF and PTP. Larynges with elongated vocal folds were then tested to observe PTF and determine if the hypothesis was observed in pathologic-like larynges. Results: The offset PTF was always less than the onset PTF (P , .0001) and 80.0% of the observed onset-offset PTF ratios were bound by [0.707, 1.0]. Conclusions: PTF onset or offset could be a useful diagnostic parameter of the voice, particularly when used in conjunction with PTP to describe laryngeal resistance and aerodynamic power. Further exploration of the relationship between onset and offset PTF values could augment clinical diagnostic ability and advance current theories on the physics of phonation. [source] Collagen Fiber and Versican Distribution Within the Lamina Propria of Fetal Vocal Folds,THE LARYNGOSCOPE, Issue 2 2008Rogerio Borghi Buhler MD Abstract Objectives: To analyze the presence and distribution of collagen fibers and versican in human vocal fold lamina propria of fetal larynges. Study Design: Cross sectional analysis of cadaveric vocal folds of human fetuses. Methods: Seven fetal larynges obtained from 28- to 36-week-old fetuses were analyzed with the Picrosirius-polarization method, immunohistochemistry, and image analysis. Results: Collagen fibers within the lamina propria exhibited a monolaminar distribution pattern and spatial arrangement in "wicker basket." Versican distribution was larger in the superficial and intermediate layers when compared to the deep layer. Conclusion: Our findings suggest that collagen and versican distribution and arrangement within the lamina propria in the developing fetus are important for vocalization at birth. [source] Viscoelastic and Histologic Properties in Scarred Rabbit Vocal Folds After Mesenchymal Stem Cell Injection,THE LARYNGOSCOPE, Issue 7 2006S Hertegård MD Abstract Objective/Hypothesis: The aim of this study was to analyze the short-term viscoelastic and histologic properties of scarred rabbit vocal folds after injection of human mesenchymal stem cells (MSC) as well as the degree of MSC survival. Because MSCs are antiinflammatory and regenerate mesenchymal tissues, can MSC injection reduce vocal fold scarring after injury? Study Design: Twelve vocal folds from 10 New Zealand rabbits were scarred by a localized resection and injected with human MSC or saline. Eight vocal folds were left as controls. Material and Methods: After 4 weeks, 10 larynges were stained for histology and evaluation of the lamina propria thickness. Collagen type I content was analyzed from six rabbits. MSC survival was analyzed by fluorescent in situ hybridization staining from three rabbits. Viscoelasticity for 10 vocal folds was analyzed in a parallel-plate rheometer. Results: The rheometry on fresh-frozen samples showed decreased dynamic viscosity and lower elastic modulus (P < .01) in the scarred samples injected with MSC as compared with the untreated scarred group. Normal controls had lower dynamic viscosity and elastic modulus as compared with the scarred untreated and treated vocal folds (P < .01). Histologic analysis showed a higher content of collagen type 1 in the scarred samples as compared with the normal vocal folds and with the scarred folds treated with MSC. MSCs remained in all samples analyzed. Conclusions: The treated scarred vocal folds showed persistent MSC. Injection of scarred rabbit vocal folds with MSC rendered improved viscoelastic parameters and less signs of scarring expressed as collagen content in comparison to the untreated scarred vocal folds. [source] Three-dimensional reconstruction of immunolabeled neuromuscular junctions in the human thyroarytenoid muscleTHE LARYNGOSCOPE, Issue 11 2003Andrew D. Sheppert MD Abstract Objectives/Hypothesis: The objective was to reveal the location of the neuromuscular junctions in a three-dimensional reconstruction of the human thyroarytenoid muscle within the true vocal fold. Study Design: Immunohistochemical analysis of serially sectioned human true vocal folds was performed, followed by reconstruction in three dimensions using computer imaging software. Methods: Six fresh human larynges from autopsy were harvested, fixed in formalin, and embedded in paraffin. Eight vocal cords were studied from these six larynges. Five-micron serial sections were collected throughout the entire vocal cord in an axial plane at 500-,m intervals. Immunohistochemical analysis was performed with anti-synaptophysin antibody. A computer-controlled imaging and reconstruction system was used to create a three-dimensional reconstruction from the serial sections and to represent the location of the clustered band of neuromuscular junctions within each true vocal fold. The vocal cord was divided into equal thirds from anterior to posterior for statistical analysis. Results: The most neuromuscular junctions (74%) we're located in the middle third, and the least (7%) were found in the anterior third. The difference in anterior-to-posterior distribution was statistically significant in all eight specimens by ,2 analysis (P < .001). Conclusion: The distribution of neuromuscular junctions is not random within the human thyroarytenoid muscle. Because neuromuscular junctions are most highly concentrated in a band within the mid belly of the muscle, botulinum toxin type A (Botox) injection in patients with spasmodic dysphonia should be targeted to this region. [source] Delivery of an Adenoviral Vector to the Crushed Recurrent Laryngeal Nerve,THE LARYNGOSCOPE, Issue 6 2003Adam Rubin MD Abstract Objectives Objectives were to create a model of recurrent laryngeal nerve injury for testing the efficacy of potential therapeutic viral gene therapy vectors and to demonstrate that remote injection of a viral vector does not cause significant additional neuronal injury. Study Design Animal model. Methods Rats were randomly assigned to three groups of 10 animals each. In group I, the recurrent laryngeal nerve was crushed. In group II, the nerve was crushed and then injected with an adenoviral vector containing no transgene. In group III, the nerve was identified but was not crushed. Rats were killed at 1 week, and their larynges and brainstems were cryosectioned in 15-,m sections. Laryngeal cryosections were processed for acetylcholine histochemical analysis (motor endplates) followed by neurofilament immunoperoxidase (nerve fibers). Percentage of nerve,endplate contact was determined and compared between groups. Fluorescent in situ hybridization was performed on brainstem sections from rats in group II to confirm the presence of virus. Results No significant difference in percentage of nerve,endplate contact exists between the two crushed-nerve groups (groups I and II) (P = .88). The difference between both crushed-nerve groups and the group with noncrushed nerves (group III) was highly significant (P <.0001). The presence of virus was confirmed in group II rats. Conclusions Crush provides a significant measurable injury to the recurrent laryngeal nerve and may be used as a model to explore therapeutic interventions for nerve injury. The remote injection of viral vector did not cause significant additional neuronal injury. Remote delivery of viral vectors to the central nervous system holds promise in the treatment of recurrent laryngeal nerve injury and central nervous system diseases. [source] Homologous Collagen Substances for Vocal Fold AugmentationTHE LARYNGOSCOPE, Issue 5 2001Mark S. Courey MD Abstract Objectives/Hypothesis Dysphonia resulting from failure of glottic closure during voicing is a difficult clinical problem. Recently developed homologous collagen compounds may be beneficial in treating this problem. The objectives of this thesis are to: 1) evaluate the potential site(s) of collagen graft placement in the human vocal fold, quantify the amount of graft material that can be injected into these sites, and determine how these sites are accessed by the currently available surgical tools for injection; 2) determine the effects of the superficial vocal fold implant on laryngeal vibratory patterns and characterize how the implant affects the forces required to bring vocal folds into an adducted position for vibration; and 3) evaluate the host response to two different forms of cadaveric collagen. Study Design Prospective laboratory. Methods Three separate experiments were undertaken: 1) Eight cadaver larynges were injected with collagen compounds through a 27-gauge needle. The amount of substance required to medialize the vocal fold and potential positions for graft placement were evaluated. 2) Six cadaver larynges were mounted on a stabilizing stand while airflow, vocal fold length, adduction forces, and abduction forces on the vocal folds were manipulated. Vibratory patterns before and after the injection of the vocal folds with solubilized collagen were assessed. 3) A nude mouse model was used to study the host response to two different exogenous collagen compounds. Results Solubilized collagen compounds could be injected reliably into the superficial layer of the lamina propria (SLLP), medial portion of the thyroarytenoid muscle, or lateral portion of the thyroarytenoid muscle. When injected superficially, significantly less material was required to displace the medial edge of the vocal fold to midline (P = .0001). When graft material was placed into the medial portion of the thyroarytenoid (TA) muscle, the forces required to bring the vocal fold into a position suitable for vibration were significantly reduced (P = .0106) and the vibratory patterns of the vocal folds were not impaired. Both AlloDerm® and Dermalogen® solubilized preparations of human dermal tissue were well tolerated in the nude-mouse model. Minimal inflammatory reaction occurred. Small amounts of graft material were identified histologically at the end of the 6-month study period. The graft material appeared organized and had been infiltrated with fibroblasts of host origin. Conclusions Homologous collagen compounds can be reliably injected into the cadaveric human larynx. When the substances are injected into the medial portion of the TA muscle, immediately deep to the vocal ligament, they decrease the force of contraction needed to bring the vocal folds into a position adequate for phonation and have minimal affect on the vibratory patterns. These forms of homologous collagen are well tolerated. A small amount persists over a 6-month interval. These materials warrant further clinical trials in human subjects. [source] Fascia Augmentation of the Vocal Fold: Graft Yield in the Canine and Preliminary Clinical Experience,THE LARYNGOSCOPE, Issue 5 2001Sanford G. Duke MD Abstract Introduction Glottal insufficiency resulting from vocal fold bowing, hypomobility, or scar is frequently treated by injection augmentation. Injection augmentation with fat, collagen, gel foam, polytef, and recently, fascia lata has been previously reported. Variable graft yield and poor host-tissue tolerance have motivated the continued search for an ideal graft substance. Study Design A prospective trial of autologous fascia augmentation of the vocal cord in the human and in an animal model. Methods Autologous fascia injection augmentation (AFIA) was evaluated in 8 canines and 40 patients at our institution between 1998 and 2000. The animal study compared graft yield from AFIA with autologous fat yield. The outcome measure was graft yield calculated from histological examination of larynges 12 weeks after injection augmentation. Clinical trial outcome measures included symptom surveys, acoustical voice analyses, and subjective voice assessments. Mean follow-up was 9 months. Results In the canine larynx, the mean graft yield for AFIA was 33% (range, 5%,84%) compared with autologous lipoinjection (47%; range, 7%,96%;P = .57). Subjective improvement in vocal quality was reported by 95% of patients (38 of 40) after AFIA. Preoperative and postoperative voice analysis data were obtained from 26 patients. Subjective voice rating demonstrated a significant improvement after AFIA (P <.0001). Acoustical parameters of jitter, shimmer, noise-to-harmonic ratio, phonatory range, and degree unvoiced improved significantly (P <.05) in all patients after fascia augmentation. Conclusions Based on the animal study, we concluded that graft yields are excellent but variable for AFIA. The result is similar in variability and overall yield to autologous lipoinjection. Subjective and objective analyses of voice outcomes after AFIA are universally improved. Fascia appears to be an excellent alternative to lipoinjection in properly selected cases of glottic insufficiency. [source] Age-Related Mitochondrial DNA Mutations in the Human LarynxTHE LARYNGOSCOPE, Issue 12 2000Jose M. Manaligod MD Abstract Objective To determine whether age-related mitochondrial DNA mutations occur in the human larynx. Study Design Genetic study of cadaveric larynx specimens. Methods Vocal fold mucosa, thyroarytenoid muscle, and cricoarytenoid joint tissue were harvested from 13 fresh postmortem larynges (age range, 2 d,82 y). DNA was extracted from each sample, and the polymerase chain reaction (PCR) was used to amplify a target DNA sequence resulting from the common age-associated, 4977,base-pair (bp) mitochondrial DNA deletion. PCR products were visualized by agarose gel electrophoresis. Automated sequencing determined the sequence of identified PCR products. Subjects Thirteen cadaveric larynges were obtained through the University of Kentucky Medical Center (Lexington, KY). Specimens from patients with a history of head and neck cancer, previous laryngeal trauma, or surgery were excluded. Results Strongly positive bands were identified in samples from three individuals. Weaker bands were seen in samples from four other samples. No band was noted from the two pediatric larynges. Different band patterns were seen among the three different tissue sites in the larynges with positive PCR products, but no consistent pattern was seen. Sequencing of the identified PCR products from selected samples confirmed that they were products of the age-associated, 4977-bp mitochondrial DNA deletion. Conclusions An age-associated mitochondrial DNA deletion was detected in several postmortem human larynges. Its presence seemed to increase in appearance with age. In the larynges in which the deletion occurred, there were individual regional differences in the occurrence of the deletion, but no consistent pattern was noted across all individuals who carried the deletion. [source] Comparative Histology and Vibration of the Vocal Folds: Implications for Experimental Studies in Microlaryngeal Surgery ,THE LARYNGOSCOPE, Issue 5 2000C. Gaelyn Garrett MD Abstract Objectives/Hypothesis To determine the most suitable animal model for experimental studies on vocal fold surgery and function by a histological comparison of the microflap surgical plane and laryngeal videostroboscopy (LVS) in different species of animals. A second goal was to determine how the layered vocal fold structure in humans and three different animal species affects surgical dissection within the lamina propria. Study Design Prospective laboratory. Methods Three larynges each from dogs, monkeys, and pigs were compared with three ex vivo human larynges. Microflap surgery was performed on one vocal fold from each larynx. Both the operated and nonoperated vocal folds were examined histologically using stains specific for elastin, mature collagen, and ground substance. Based on the histological results, LVS was performed on two dogs and two pigs after first performing a tracheotomy for ventilation and airflow through the glottis. Arytenoid adduction sutures were placed to facilitate vocal fold adduction. Results The distributions of the collagen and elastin fibers were found to differ among the species with concentrations varying within species. Unlike the human vocal fold, which has a higher elastin concentration in the deeper layers of the lamina propria, both the pig and the dog had a thin band of elastin concentrated just deep to the basement membrane zone in the superficial layer. Just deep to this thin band, the collagen and the elastin were less concentrated. The monkey vocal fold had a very thin mucosal layer with less elastin throughout the mucosa. The microflap dissections in each of the dog, pig, and human vocal folds were similar, being located within that portion of the superficial lamina propria where the elastin and mature collagen are less concentrated. The microflap plane in the monkey vocal fold was more deeply located near the vocalis fibers. Despite the differences in elastin concentration, the microflap plane in both the dog and the pig was found to be similar to that in humans. The dog anatomy was much more suitable for microsuspension laryngoscopy and stroboscopic examination. The dog vocal folds vibrated in a similar fashion to human vocal folds with mucosal waves and vertical phase differences, features not seen in the pig vocal folds. Conclusions Based on both the histological and stroboscopic results, the dog was believed to be a more suitable animal model for studies on vocal fold surgery, acknowledging that no animal's laryngeal anatomy is identical to that of the human. The dog LVS model presented allows for longitudinal laryngeal studies requiring repeated examinations at multiple time periods with histological correlation applied at sacrifice. [source] Topography and interactions of the arytenoid and cricoid articular facets: Implications for vocal process positional shiftsCLINICAL ANATOMY, Issue 3 2004Kenneth X. Probst Abstract Using new computer applications and digital technologies, we provide a rigorous description and realistic illustrations of the arytenoid-on-the cricoid rotations. We also provide the articular facet topography and interactions that underlay those rotations and the concomitant vocal process positional shifts. The thyroid cartilage and all soft tissues were removed from three excised, preserved, normal, adult human larynges without disturbing the crico-arytenoid (CA) articular capsule. Three CA assemblies were thus prepared and used to digitize arytenoid rotations and vocal process positional shifts, and, after disarticulation, also the surface contour of the arytenoid and cricoid facets, and the cricoid lumen margin. The digitized data served to computer generate 2D and 3D graphic visualizations of the vocal process positional shifts, of the topography of the facets, and of the facet motion sequences that show that the anteroposteriorly concave arytenoid facet slides and conjunctly rotates on the anteroposteriorly convex cricoid facet. Visual details of all graphic representations and facet motion sequences were essentially identical across the three assemblies. Then, based on the computer generated data obtained from the largest of the CA assemblies, 3D, realistic, and hand-drawn images were made that illustrate the directions in which the arytenoids can rotate and the vocal processes concomitantly shift positions. Results indicate that when the arytenoids rotate by sliding from anterior to posterior on the cricoid facets about a primary axis of motion aligned from medial, posterior, and superior, to lateral, anterior, and inferior, their vocal processes shift positions along a plane obliquely oriented from anterior and medial, to posterior and lateral, and from inferior and medial, to superior and lateral. Clin. Anat. 17:206,213, 2004. © 2004 Wiley-Liss, Inc. [source] Visco-elastic changes of vocal fold mucosa related to high and low relative air humidityCLINICAL OTOLARYNGOLOGY, Issue 4 2000R.J.B. Hemler Objective. To study the effects of high and low relative air humidity (RH) on the visco-elastic properties of the vocal fold cover. Materials and methods. The vocal fold mucosa of sheep larynges was microdissected. The mucosal specimens were attached on one side to an oscillator and on the other side to a force transducer. A sinusoidal oscillation (stress) was applied to the specimen and the transduced force (strain) was recorded in two different conditions of a continuous passing airflow: either dry air (RH = 0%) or humid air (RH = 100%). Of the recorded stress and strain curves the gain and phase-shift between the curves were computed and from these parameters stiffness and viscosity were calculated. In both air conditions the deep surface of the specimen was in contact with a saline bath. Results. Stiffness and viscosity both increased significantly more in dry air than in humid air. This increased stiffness and viscosity returned to baseline values after rehydration. Conclusion. We conclude that these findings indicate that changes in the RH of the airflow passing over the vocal cords influences the visco-elastic properties of the vocal cord cover. [source] Mechanisms of genioglossus responses to inspiratory resistive load in rabbitsACTA PHYSIOLOGICA, Issue 3 2002N. P. ALEKSANDROVA ABSTRACT The purpose of the present study has been to determine whether pharyngeal dilator muscles participate in inspiratory load compensatory responses and if so, to elucidate role of upper airway mechanoreceptors in these responses. The experiments were performed on anaesthetized rabbits. Each animal was tested in three ways by the imposition of inspiratory resistive load: (1) at upper airways via face mask, (2) at the tracheostomic cannula placed below larynx (all upper airway receptors were `bypassed') and (3) at the mouth after the section of the hypoglossus nerves (motor denervation of genioglossus muscle). The inspiratory load applied to the upper airways evoked significant increases in integrated genioglossus activity (to 129 ± 14.7% of control) and its inspiratory duration (to 113 ± 5% of control) already within the first loaded breath (P < 0.05). The increases in the inspiratory activity of musculius genioglossus were relatively greater than the simultaneous increases in the activity of the diaphragm. Motor denervation of the pharynx dilator muscles (including m. genioglossus) increased airway resistance to 184 ± 19% of control (P < 0.05) and induced obstructive alterations in the breathing pattern during unloaded breathing: decrease in maximal inspiratory flow (,13%) and increase in the level of negative oesophageal pressure (+14%) and the peak diaphragm activity (+6%). After nervi hypoglossus sections additional increases in motor and pressure outputs were required in order to maintain unaltered ventilation at the same degree of loading as before denervation. The results indicate that the pharyngeal dilator muscles have a role in compensation of added inspiratory load. Activation of these muscles facilitate the load compensating function of `pump' muscles by decreasing airway resistance. Tracheostomy did not reduce the genioglossus response to inspiratory loading, ruling out any role for upper airways receptors in the genioglossus response to inspiratory load compensations. [source] Genetic disruption of CYP26B1 severely affects development of neural crest derived head structures, but does not compromise hindbrain patterningDEVELOPMENTAL DYNAMICS, Issue 3 2009Glenn Maclean Abstract Cyp26b1 encodes a cytochrome-P450 enzyme that catabolizes retinoic acid (RA), a vitamin A derived signaling molecule. We have examined Cyp26b1,/, mice and report that mutants exhibit numerous abnormalities in cranial neural crest cell derived tissues. At embryonic day (E) 18.5 Cyp26b1,/, animals exhibit a truncated mandible, abnormal tooth buds, reduced ossification of calvaria, and are missing structures of the maxilla and nasal process. Some of these abnormalities may be due to defects in formation of Meckel's cartilage, which is truncated with an unfused distal region at E14.5 in mutant animals. Despite the severe malformations, we did not detect any abnormalities in rhombomere segmentation, or in patterning and migration of anterior hindbrain derived neural crest cells. Abnormal migration of neural crest cells toward the posterior branchial arches was observed, which may underlie defects in larynx and hyoid development. These data suggest different periods of sensitivity of anterior and posterior hindbrain neural crest derivatives to elevated levels of RA in the absence of CYP26B1. Developmental Dynamics 238:732,745, 2009. © 2009 Wiley-Liss, Inc. [source] Morphology and histology of the larynx of the common toad Rhinella arenarum (Hensel, 1867) (Anura, Bufonidae)ACTA ZOOLOGICA, Issue 4 2009Gladys N. Hermida Abstract The structure of the larynx of the toad Rhinella arenarum was exhaustively studied. The laryngeal skeleton consists of three bilaterally symmetrical cartilages: the cricoid and two arytenoids. Internally, each half-larynx has an anterior and a posterior chamber. The first chamber is delimited by the epithelium covering the arytenoid cartilage and the anterior membrane. The latter consists of fibro-elastic tissue and contains blood capillaries that, judging by their location and distribution, might serve to maintain vocal cord turgidity. At the level of the cricoid cartilage, two structures are reported here for the first time: the posterodorsal and the anteroventral processes. Both processes are associated with the insertion of the posterior membrane. A cartilaginous rod is located at the free margin of the posterior membrane. This rod appears to support the membrane when the air flows. The distal portion of the larynx communicates with the proximal region of the lung. The epithelium of the laryngeal mucosa contains ciliated cells, goblet cells, secretory cells with short microvilli and neuroendocrine cells immunopositive to PGP 9.5. The results obtained in this study provide new information about the internal organization of the larynx in anurans, which could serve as additional morphological characters for phylogenetic relationships. [source] | |||||||||||||||||||||||||||||||||||||