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Liu K, Ge P, Sheng X, Jiang J, Qin H. Survival in Vivo Canine Phonation Model Without Stimulation. Ann Otol Rhinol Laryngol 2018; 127:178-184. [PMID: 29298508 DOI: 10.1177/0003489417751473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES We describe a survival nonstimulated in vivo canine phonation model using distending laryngoscope, cramp frame, and constant humidified glottal airflow to elicit phonation. METHODS Five beagle dogs were involved in this study. One cuffed endotracheal tube was placed below the glottis through the tracheotomy and delivered humidified airflow to the glottis. Arytenoids approximation was maintained using a clamp under the distending laryngoscope. Acoustic and aerodynamic parameters were measured using synchronous signal collection system and analysis software. Vocal oscillation also was examined using stroboscope laryngeal imaging. RESULTS For the nonstimulated in vivo phonation animal, the sound intensity and fundamental frequency were 78.3 ± 6.8 dB and 127.6 ± 29.2 Hz in the first experiment and 82.9 ± 6.6 dB and 175.2 ± 4.4 Hz 4 weeks later. The aerodynamic analysis revealed the mean subglottal phonation threshold pressure (PTP) and phonation threshold flow (PTF) were 8.5 ± 4.0 cmH20 and 683.0 ± 356.4 mL/s in the first experiment and 16.1 ± 8.6 cmH20 and 384.8.0 ± 230.6 mL/s in the second experiment 4 weeks later. Stroboscope image revealed sustained vocal vibration during great airflow delivery to glottis in the phonation animal model. CONCLUSIONS We developed a survival nonstimulated in vivo phonation canine model that allows the study of long-term animal phonation study as its own control.
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Affiliation(s)
- Kena Liu
- 1 Department of Laryngopharynx Head & Neck Maxillofacial Surgery, Guangdong General Hospital and Guangdong Academy of Medical Sciences, School of Medicine, South China University Technology, Guangzhou City, PR China
| | - Pingjiang Ge
- 1 Department of Laryngopharynx Head & Neck Maxillofacial Surgery, Guangdong General Hospital and Guangdong Academy of Medical Sciences, School of Medicine, South China University Technology, Guangzhou City, PR China.,2 Southern Medical University, Guangzhou City, PR China
| | - Xiaoli Sheng
- 1 Department of Laryngopharynx Head & Neck Maxillofacial Surgery, Guangdong General Hospital and Guangdong Academy of Medical Sciences, School of Medicine, South China University Technology, Guangzhou City, PR China
| | - Jie Jiang
- 1 Department of Laryngopharynx Head & Neck Maxillofacial Surgery, Guangdong General Hospital and Guangdong Academy of Medical Sciences, School of Medicine, South China University Technology, Guangzhou City, PR China
| | - Huabiao Qin
- 3 School of Electronic and Information Engineering, South China University Technology, Guangzhou City, PR China
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2
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Wu CW, Randolph GW, Lu IC, Chang PY, Chen YT, Hun PC, Lin YC, Dionigi G, Chiang FY. Intraoperative neural monitoring in thyroid surgery: lessons learned from animal studies. Gland Surg 2016; 5:473-480. [PMID: 27867861 PMCID: PMC5106378 DOI: 10.21037/gs.2016.09.06] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 09/09/2016] [Indexed: 12/31/2022]
Abstract
Recurrent laryngeal nerve (RLN) injury remains a significant morbidity associated with thyroid and parathyroid surgery. In the past decade, surgeons have increasingly used intraoperative neural monitoring (IONM) as an adjunct technique for localizing and identifying the RLN, detecting RLN injury, and predicting the outcome of vocal cord function. In recent years, many animal studies have investigated common pitfalls and new applications of IONM. For example, the use of IONM technology in animal models has proven valuable in studies of the electrophysiology of RLN injury. The advent of animal studies has substantially improved understanding of IONM technology. Lessons learned from animal studies have immediate clinical applications in establishing reliable strategies for preventing intraoperative RLN injury. This article gives an overview of the research progress on IONM-relevant animal models.
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Affiliation(s)
- Che-Wei Wu
- Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Gregory W. Randolph
- Division of Thyroid and Parathyroid Endocrine Surgery, Department of Laryngology and Otology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, USA
| | - I-Cheng Lu
- Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Pi-Ying Chang
- Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Ting Chen
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Pao-Chu Hun
- Laboratory Animal Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Chu Lin
- Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Gianlorenzo Dionigi
- 1 Division of Surgery, Research Center for Endocrine Surgery, Department of Surgical Sciences and Human Morphology, University of Insubria (Como-Varese), Varese, Italy
| | - Feng-Yu Chiang
- Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
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3
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Howard NS, Mendelsohn AH, Berke GS. Development of the ex vivo laryngeal model of phonation. Laryngoscope 2015; 125:1414-9. [DOI: 10.1002/lary.25149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/13/2014] [Accepted: 12/12/2014] [Indexed: 11/09/2022]
Affiliation(s)
- N. Scott Howard
- Division of Otolaryngology-Head and Neck Surgery; San Antonio Military Medical Center; San Antonio Texas
| | - Abie H. Mendelsohn
- Department of Head & Neck Surgery; David Geffen School of Medicine at the University of California-Los Angeles; Los Angeles California
| | - Gerald S. Berke
- Department of Head & Neck Surgery; David Geffen School of Medicine at the University of California-Los Angeles; Los Angeles California
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Awan SN, Novaleski CK, Rousseau B. Nonlinear analyses of elicited modal, raised, and pressed rabbit phonation. J Voice 2014; 28:538-47. [PMID: 24836360 DOI: 10.1016/j.jvoice.2014.01.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 01/28/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVES/HYPOTHESIS The purpose of this study was to use nonlinear dynamic analysis methods such as phase space portraits and correlation dimension (D2) as well as descriptive spectrographic analyses to characterize acoustic signals produced during evoked rabbit phonation. METHODS Seventeen New Zealand white breeder rabbits were used to perform the study. A Grass S-88 stimulator (SA Instrumentation, Encinitas, CA) and constant current isolation unit (Grass Telefactor, model PSIU6; West Warwick, RI) were used to provide electrical stimulation to laryngeal musculature, and transglottal airflow rate and stimulation current (mA) were manipulated to elicit modal, raised intensity, and pressed phonations. Central 1 second portions of the most stable portion of the acoustic waveform for modal, raised intensity, and pressed phonations were edited and then analyzed via phase space portraits, Poincaré sections, and the estimation of the D2. In an attempt to limit the effects of the highly variable and nonstationary characteristics of some of the signals being analyzed, D2 analysis was also performed on the most stable central 200-millisecond portion of the acoustic waveform. Descriptive analysis of each phonation was also conducted using sound spectrograms. RESULTS Results showed that the complexity of phonation and the subsequent acoustic waveform is increased as transglottal airflow rate and degree of glottal adduction are manipulated in the evoked rabbit phonation model. In particular, phonatory complexity, as quantified via D2 analyses and demonstrated via spectrographic characteristics, increases from "modal" (ie, phonation elicited at just above the phonation threshold pressure) to raised intensity (phonation elicited by increasing transglottal airflow rate) to pressed (phonation elicited by increasing the stimulation current delivered to the larynx). Variations in a single dynamic dimension (airflow rate or adductory force) resulted in significantly increased productions of nonlinear phenomenon, including bifurcations from periodicity to regions of subharmonic content, fundamental frequency, and harmonic jumps, and evidence of periodicity within aperiodic regions ("chaos"). CONCLUSIONS The evoked rabbit phonation model described in this study allows for the elicitation of various types of phonations under controlled conditions and, therefore, has the potential to provide insight regarding important variables that may elicit examples of nonlinear phenomena such as subharmonics and deterministic chaos.
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Affiliation(s)
- Shaheen N Awan
- Department of Audiology and Speech Pathology, Bloomsburg University of Pennsylvania, Bloomsburg, Pennsylvania.
| | - Carolyn K Novaleski
- Department of Hearing and Speech Sciences, Vanderbilt University, Nashville, Tennessee
| | - Bernard Rousseau
- Department of Otolaryngology, Hearing and Speech Sciences, and Mechanical Engineering, Vanderbilt University School of Medicine, Nashville, Tennessee
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5
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Titze IR. Bi-stable vocal fold adduction: a mechanism of modal-falsetto register shifts and mixed registration. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2014; 135:2091-101. [PMID: 25235006 PMCID: PMC4167751 DOI: 10.1121/1.4868355] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The origin of vocal registers has generally been attributed to differential activation of cricothyroid and thyroarytenoid muscles in the larynx. Register shifts, however, have also been shown to be affected by glottal pressures exerted on vocal fold surfaces, which can change with loudness, pitch, and vowel. Here it is shown computationally and with empirical data that intraglottal pressures can change abruptly when glottal adductory geometry is changed relatively smoothly from convergent to divergent. An intermediate shape between large convergence and large divergence, namely, a nearly rectangular glottal shape with almost parallel vocal fold surfaces, is associated with mixed registration. It can be less stable than either of the highly angular shapes unless transglottal pressure is reduced and upper stiffness of vocal fold tissues is balanced with lower stiffness. This intermediate state of adduction is desirable because it leads to a low phonation threshold pressure with moderate vocal fold collision. Achieving mixed registration consistently across wide ranges of F0, lung pressure, and vocal tract shapes appears to be a balancing act of coordinating laryngeal muscle activation with vocal tract pressures. Surprisingly, a large transglottal pressure is not facilitative in this process, exacerbating the bi-stable condition and the associated register contrast.
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Affiliation(s)
- Ingo R Titze
- National Center for Voice and Speech, 136 South Main Street, Suite 320, Salt Lake City, Utah 84101
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6
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Döllinger M, Kobler J, Berry DA, Mehta DD, Luegmair G, Bohr C. Experiments on Analysing Voice Production: Excised (Human, Animal) and In Vivo (Animal) Approaches. Curr Bioinform 2011; 6:286-304. [PMID: 26581597 DOI: 10.2174/157489311796904673] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experiments on human and on animal excised specimens as well as in vivo animal preparations are so far the most realistic approaches to simulate the in vivo process of human phonation. These experiments do not have the disadvantage of limited space within the neck and enable studies of the actual organ necessary for phonation, i.e., the larynx. The studies additionally allow the analysis of flow, vocal fold dynamics, and resulting acoustics in relation to well-defined laryngeal alterations. PURPOSE OF REVIEW This paper provides an overview of the applications and usefulness of excised (human/animal) specimen and in vivo animal experiments in voice research. These experiments have enabled visualization and analysis of dehydration effects, vocal fold scarring, bifurcation and chaotic vibrations, three-dimensional vibrations, aerodynamic effects, and mucosal wave propagation along the medial surface. Quantitative data will be shown to give an overview of measured laryngeal parameter values. As yet, a full understanding of all existing interactions in voice production has not been achieved, and thus, where possible, we try to indicate areas needing further study. RECENT FINDINGS A further motivation behind this review is to highlight recent findings and technologies related to the study of vocal fold dynamics and its applications. For example, studies of interactions between vocal tract airflow and generation of acoustics have recently shown that airflow superior to the glottis is governed by not only vocal fold dynamics but also by subglottal and supraglottal structures. In addition, promising new methods to investigate kinematics and dynamics have been reported recently, including dynamic optical coherence tomography, X-ray stroboscopy and three-dimensional reconstruction with laser projection systems. Finally, we touch on the relevance of vocal fold dynamics to clinical laryngology and to clinically-oriented research.
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Affiliation(s)
- Michael Döllinger
- University Hospital Erlangen, Medical School, Laboratory for Computational Medicine, Department for Phoniatrics and Pediatric Audiology, Bohlenplatz 21, 91054 Erlangen, Germany
| | - James Kobler
- Center for Laryngeal Surgery and Voice Rehabilitation, Massachusetts General Hospital, 620 Thier Building, 55 Fruit Street, Boston, Massachusetts 02114, USA
| | - David A Berry
- The Laryngeal Dynamics Laboratory, Division of Head & Neck Surgery, UCLA School of Medicine, 31-24 Rehab Center, 1000 Veteran Ave., Los Angeles, CA, 90095-1794, USA
| | - Daryush D Mehta
- Center for Laryngeal Surgery and Voice Rehabilitation, Massachusetts General Hospital, One Bowdoin Square, 11 Floor, Boston, Massachusetts 02114, USA
| | - Georg Luegmair
- University Hospital Erlangen, Medical School, Laboratory for Computational Medicine, Department for Phoniatrics and Pediatric Audiology, Bohlenplatz 21, 91054 Erlangen, Germany
| | - Christopher Bohr
- University Hospital Erlangen, Medical School, ENT-Hospital, Waldstrasse 1, 91054 Erlangen, Germany
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7
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Alipour F, Jaiswal S. Phonatory characteristics of excised pig, sheep, and cow larynges. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 123:4572-81. [PMID: 18537405 PMCID: PMC2468220 DOI: 10.1121/1.2908289] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The purpose of this study was to examine the phonatory characteristics of pig, sheep, and cow excised larynges and to find out which of these animal species is the best model for human phonation. Excised pig, sheep, and cow larynges were prepared and mounted over a tapered tube on the excised bench that supplied pressurized, heated, and humidified air in a manner similar to that for excised canine models. Each excised larynx was subjected to a series of pressure-flow experiments with adduction as major control parameter. The subglottal pressure, electroglottograph (EGG), mean flow rate, audio signal, and sound pressure level were recorded during each experiment. EGG signal was used to extract the fundamental frequency. It was found that pressure-frequency relations were nonlinear for these species with large rate of frequency changes for the pig. The average oscillation frequencies for these species were 220+/-57 Hz for the pig, 102+/-33 Hz for the sheep, and 73+/-10 Hz for the cow. The average phonation threshold pressure for the pig was 7.4+/-2.0 cm H(2)O, 6.9+/-2.9 cm H(2)O for the sheep, and 4.4+/-2.3 cm H(2)O for the cow.
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Affiliation(s)
- Fariborz Alipour
- Department of Speech Pathology and Audiology, The University of Iowa, Iowa City, Iowa 52242, USA.
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8
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Abstract
Phase measures with simultaneously recorded electroglottography (EGG) and photoglottography (PGG) signals have been studied in canine models and found to be sensitive to the effect of recurrent laryngeal nerve (RLN) paralysis on vocal fold vibration. This study examined the usefulness of this type of measure in clinical application. The combined glottographic signals were obtained from 5 men with a diagnosis of unilateral RLN paralysis and 5 age-matched controls. In the patient group, EGG waveforms were found to have a consistent phase delay in relation to PGG. A measure of the overall glottographic phase difference (GPD) was found to significantly distinguish the control group (mean GPD = 0.2371 ms) from the patient group (mean GPD = -0.2765 ms). A validity analysis performed on 19 subjects with or without unilateral RLN paralysis confirmed that the GPD test had a relatively high efficiency (91.7%) in detecting unilateral RLN paralysis in the male population.
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Affiliation(s)
- J Jiang
- Department of Otolaryngology-Head and Neck Surgery, Northwestern University School of Medicine, Chicago, Illinois 60611-3008, USA
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9
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Abstract
Experimental induced phonation in the dog has been used in short-term studies by several investigators and has proved quite useful in laryngeal research. In this study a long-term canine phonation model is described that uses permanently implanted electrodes on the superior and recurrent laryngeal nerves. A serial induced phonation model has not been previously reported and is needed for laryngeal research in which voice results are a primary end point. Inexpensive, reliable, nontoxic electrodes were designed and fabricated. The laryngeal nerves were found to be quite susceptible to injury, necessitating a series of changes in electrode design. Electrode durability and laryngeal nerve viability improved with each design modification; the final design gave a recurrent laryngeal nerve viability rate of 100% at 6 weeks, 83% at 9 weeks, and 73% at 12 weeks. Induced phonation was successfully produced on a repeated basis by stimulating the recurrent laryngeal nerves while passing air through the larynx, in 22 (95.6%) of 23 animals. Stimulation of the superior laryngeal nerves increased vocal fold length and tension but was not required for phonation. Technical aspects of chronic implantation and stimulation of the laryngeal nerves are discussed. The development and successful long-term implantation of electrodes on the laryngeal nerves and their use in repeated induced phonation have not been reported previously.
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Affiliation(s)
- R C Paniello
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Paniello RC, Dahm JD. Reversibility of medialization laryngoplasty. An experimental study. Ann Otol Rhinol Laryngol 1997; 106:902-8. [PMID: 9373079 DOI: 10.1177/000348949710601104] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Medialization laryngoplasty has become a routine procedure for cases of unilateral vocal fold paralysis. In certain clinical situations, it may become desirable to reverse the procedure and remove the implant. This process was studied experimentally in eight dogs in a chronic model of induced canine phonation. A silicone polymer implant was inserted to medialize one normal vocal fold for a period of 1 month, after which it was removed. Motion of the cricoarytenoid (CA) joint and induced phonation were studied weekly while the implant was in place, and for another month following implant removal. Significant abnormalities were found even with this relatively short period of implantation. With the implant in place, impairment of CA joint mobility was found in seven of the eight dogs, precluding phonation. A dense fibrous capsule rapidly developed around the implant, making its removal technically difficult. Following implant removal, a gradual return to normal function was found in only three of the eight dogs. One of the animals had evidence of neural injury, while four had intact neural function but impaired mobility or fixation of the CA joint. Medialization laryngoplasty should not be considered a reversible procedure. The clinical implications of these findings are discussed.
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Affiliation(s)
- R C Paniello
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, and the Veterans Administration Medical Center, St. Louis, Missouri, USA
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11
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Abstract
The time courses of vocal fold elongation and contraction have been measured as a function of intrinsic laryngeal muscle activity. The superior and recurrent laryngeal nerves of anesthetized canines were stimulated supramaximally (on-off in all combinations) while the vocal folds were surgically exposed and illuminated for conventional and higher speed (300 frames per second) video recording. Microsutures were placed on various points on the vocal folds to measure elongation and contraction. Vocal fold strain, defined as elongation divided by rest length, ranged from -17% to +45%. The typical time constant for exponential increase or decrease in strain was about 30 ms. This reflects primarily the intrinsic muscle activation times rather than a passive (inertial or viscoelastic) response of cricothyroid joint rotation or translation.
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Affiliation(s)
- I R Titze
- National Center for Voice and Speech, University of Iowa, Iowa City 52242, USA
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12
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Verneuil A, Kreiman J, Kevorkian K, Gerratt BR, Berke GS. Effects of driving pressure and recurrent laryngeal nerve stimulation on glottic vibration in a constant pressure model. Otolaryngol Head Neck Surg 1996; 115:15-23. [PMID: 8758624 DOI: 10.1016/s0194-5998(96)70130-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Glottic phonatory parameters have been studied in constant flow models; however, the lung-thorax system is better viewed as a constant pressure source. Adjusting the driving pressure and recurrent laryngeal nerve stimulation as independent variables, rather than as dependent variables, may provide a more physiologic understanding of laryngeal function and glottic parameters, including subglottic pressure, airflow, fundamental frequency, and glottic area. In three dogs subglottic pressure and airflow were measured in two separate conditions: with constant recurrent laryngeal nerve stimulation and varying driving pressure, and with constant driving pressure and varying recurrent laryngeal nerve stimulation. Videostroboscopic measures on four dogs assessed glottic areas with constant recurrent laryngeal nerve stimulation at different driving pressures. With constant recurrent laryngeal nerve stimulation, increasing driving pressure had no effect on glottic areas, whereas subglottic pressure, fundamental frequency, and airflow increased significantly. However, changes in subglottic pressure were minimal in comparison with changes in driving pressure. At constant driving pressure, increasing recurrent laryngeal nerve stimulation increased subglottic pressure and fundamental frequency and decreased airflow. These findings suggest that during phonation subglottic pressure is primarily dependent on recurrent laryngeal nerve stimulation and laryngeal muscular contraction, but not on lung driving pressure.
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Affiliation(s)
- A Verneuil
- Division of Head and Neck Surgery, UCLA School of Medicine, Los Angeles, CA 90095-1794, USA
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13
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Nasri S, Namazie A, Ye M, Kreiman J, Gerratt BR, Berke GS. Characteristics of an in vivo canine model of phonation with a constant air pressure source. Laryngoscope 1996; 106:745-51. [PMID: 8656961 DOI: 10.1097/00005537-199606000-00015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Many previous studies of laryngeal biomechanics using in vivo models have employed a constant air How source. Several authors have recently suggested that the lung-thorax system functions as a constant pressure source during phonation. This study describes an in vivo canine system designed to maintain a constant peak subglottic pressure (Psub) using a pressure-controlling mechanism. Increasing levels of recurrent laryngeal nerve (RLN) stimulation resulted in a significant rise in resistance followed by a plateau. For a given Psub, flow decreased significantly and precipitously with increasing stimulation and then quickly plateaued. Vocal intensity increased with increasing RLN stimulation until a peak was reached. After this peak, intensity dropped until a plateau was reached, corresponding to the flow minimum. At a given Psub, increasing levels of RLN stimulation resulted in a normal distribution of vocal efficiencies.
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Affiliation(s)
- S Nasri
- Division of Head and Neck Surgery, Stanford University Medical Center (S.N.), Stanford, Calif
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14
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Nasri S, Namazie A, Kreiman J, Sercarz JA, Gerratt BR, Berke GS. A pressure-regulated model of normal and pathologic phonation. Otolaryngol Head Neck Surg 1994; 111:807-15. [PMID: 7991263 DOI: 10.1177/019459989411100618] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Recent evidence suggests that the lung-thorax system functions as a constant pressure source during phonation. However, previous animal models used a constant flow source. This article describes an in vivo canine model that maintains a constant subglottic pressure during phonation to more closely simulate the pulmonary system. At any given subglottic pressure, increasing levels of recurrent laryngeal nerve stimulation resulted in a significant rise in resistance followed by a plateau. Increasing levels of superior laryngeal nerve stimulation, however, produced no significant change in glottal resistance. Three experimental conditions were studied: normal, unilateral recurrent laryngeal nerve paralysis, and paralysis followed by arytenoid adduction. In normal canines, maximal vocal efficiency values were the highest, indicating the best match between pressure and resistance. The vocal efficiency values were significantly lower in recurrent laryngeal nerve paralysis, indicating pressure-resistance mis-match. Arytenoid adduction increased the maximal vocal efficiency values and decreased the mismatch observed in the paralyzed state. These findings may provide insight into an understanding of normal and pathologic laryngeal behavior.
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Affiliation(s)
- S Nasri
- Division of Head and Neck Surgery, University of California, Los Angeles School of Medicine 90024-1624
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15
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Nasri S, Beizai P, Sercarz JA, Kreiman J, Graves MC, Berke GS. Function of the interarytenoid muscle in a canine laryngeal model. Ann Otol Rhinol Laryngol 1994; 103:975-82. [PMID: 7993010 DOI: 10.1177/000348949410301208] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The interarytenoid (IA) muscle has rarely been studied in the living larynx. In this work, the role of the IA muscle in phonation was studied in three dogs by means of an in vivo phonation model. The isolated action of the IA muscle was studied by sectioning and stimulating its nerve branch. As IA activity increased, subglottic pressure increased significantly until a plateau was reached. In the absence of superior laryngeal nerve stimulation, the fundamental frequency rose with increasing IA activity. In the presence of superior laryngeal nerve stimulation, however, no significant change in fundamental frequency was observed with increasing IA activity. Measurement of adductory force demonstrated that the IA muscle adducts primarily the posterior vocal fold. In this canine model, phonation was not possible without IA stimulation, owing to a large posterior glottic chink.
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Affiliation(s)
- S Nasri
- Division of Head and Neck Surgery, UCLA School of Medicine 90024-1624
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16
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Green DC, Berke GS, Graves MC. A functional evaluation of ansa cervicalis nerve transfer for unilateral vocal cord paralysis: future directions for laryngeal reinnervation. Otolaryngol Head Neck Surg 1991; 104:453-66. [PMID: 1903856 DOI: 10.1177/019459989110400406] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
There are a variety of methods for treating unilateral vocal cord paralysis, but to date there are few objective studies that evaluate the functional results of nerve transfer from the ansa cervicalis. Six dogs underwent unilateral recurrent laryngeal nerve section with immediate reanastamosis to the sternothyroid branch of the ansa cervicalis. After 5 to 6 months, measurements of vocal efficiency and acoustic parameters, videolaryngoscopy, videostroboscopy, and evoked electromyography were performed. Identical measurements were made in eight control dogs during normal electrically induced phonation and a simulated unilateral recurrent laryngeal nerve paralysis. Histologic analysis of both vocalis muscles, recurrent laryngeal nerves, ansa cervicalis, and the ansa-recurrent laryngeal nerve anastamosis site was performed. Evidence of reinnervation was found in all of the animals that underwent nerve transfer. The vocal efficiency and acoustic quality after ansa cervicalis nerve transfer were dependent on the degree of electrical stimulation from the transferred nerve to the reinnervated cord during phonation. In the absence of electrical stimulation to the nerve transfer, physiologic vocal cord motion could not be elicited from the reinnervated cord.
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Affiliation(s)
- D C Green
- Division of Head and Neck Surgery, UCLA School of Medicine
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