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Canadian Journal of Anaesthesia =... Oct 2003To review recent findings concerning neuromuscular blockade and monitoring at the larynx, the diaphragm, and the corrugator supercilii muscle. (Review)
Review
PURPOSE
To review recent findings concerning neuromuscular blockade and monitoring at the larynx, the diaphragm, and the corrugator supercilii muscle.
SOURCE
This narrative review is based on recent publications.
PRINCIPAL FINDINGS
Neuromuscular blockade at the larynx and the diaphragm is less intense than at the adductor pollicis muscle; the onset and offset of neuromuscular blockade is more rapid. The corrugator supercilii muscle reflects better the time course of neuromuscular blockade of the larynx than the adductor pollicis muscle, is better suited to monitor the onset of neuromuscular blockade for intubation, and should give a better reflection of the time course and degree of neuromuscular blockade of the larynx or the diaphragm. Recovery of neuromuscular function at the end of any procedure is best reflected at the adductor pollicis muscle where neuromuscular transmission is last restored. Clinical monitoring of the larynx or the diaphragm is still limited by the absence of a simple method. Acceleromyography of the corrugator supercilii muscle is prone to artifacts that do not occur during monitoring of the adductor pollicis muscle. Phonomyography, a new method of monitoring that is currently being tested, is based on the phenomenon that muscle contraction creates low-frequency sound waves, which can be detected using special microphones to quantify neuromuscular blockade. This method seems promising because it can be easily used on all muscles of interest.
CONCLUSION
Research during the last 15 years has greatly enhanced our knowledge about how muscles react differently to muscle relaxants and has enabled us to achieve better surgical conditions with safer use of muscle relaxants. Interesting technologies have been developed to reliably monitor neuromuscular blockade at the larynx and the diaphragm, but are currently restricted to research settings. Our increased understanding should help us in ongoing efforts to develop the "ideal" muscle relaxant and the "ideal" method of neuromuscular monitoring.
Topics: Diaphragm; Humans; Laryngeal Muscles; Larynx; Monitoring, Intraoperative; Neuromuscular Blockade
PubMed: 14525816
DOI: 10.1007/BF03019373 -
Advances in Oto-rhino-laryngology 2020Visual diagnosis of laryngeal neurologic impairments is not only possible but is perhaps the most accurate method for evaluating the neurologic status of the upper... (Review)
Review
Visual diagnosis of laryngeal neurologic impairments is not only possible but is perhaps the most accurate method for evaluating the neurologic status of the upper airway. Precise assessments may lead to appropriate treatment without an EMG study. Principles of the neurolaryngology examination include: (1) each muscle has a single action; (2) that action can be elicited and to some degree isolated and visualized; (3) each muscle has an appropriate time to contract; (4) that timing can be compared to the opposite side; (5) inappropriate timing represents reinnervation; (6) inappropriate degree of motion represents reinnervation; (7) patients naturally compensate for any loss; (8) removing compensation during an exam reveals pathology. Some of the visual diagnostic findings available to the astute endoscopic examiner are (1) paralysis, (2) paresis, (3) synkinesis, (4) fixation, (5) tremor, (6) spasm, and (7) reinnervation.
Topics: Electromyography; Endoscopy; Humans; Laryngeal Diseases; Laryngeal Muscles; Nervous System Diseases
PubMed: 33166977
DOI: 10.1159/000456679 -
Acta Oto-laryngologica May 1993It is apparent that voice disorders frequently labelled "functional" are associated with laryngeal muscle misuse. This use of the word "functional" is, however,... (Review)
Review
It is apparent that voice disorders frequently labelled "functional" are associated with laryngeal muscle misuse. This use of the word "functional" is, however, intrinsically ambiguous, and so we propose an alternative term based on descriptive features of dysfunction: "muscle misuse voice disorders". Persistent phonation with an abnormal laryngeal posture can lead to organic changes such as nodules or polyps, particularly in females with posterior glottic chink. We hypothesized that the chink was related to an overall increase in laryngeal muscle tension, and more directly due to inadequate relaxation of the posterior crico-arytenoid muscle during phonation. We employed the term "muscular tension dysphonia" (MTD) to note this condition, but it may be that the term "laryngeal isometric" is superior since there are other misuses of the larynx that obviously are manifestations of abnormalities of muscular tension. With this in mind we have evolved a new classification based on the laryngeal isometric, glottic and supraglottic lateral contraction states, antero-posterior contraction states, conversion aphonia, psychogenic bowing, and adolescent transitional dysphonia.
Topics: Female; Humans; Isometric Contraction; Laryngeal Muscles; Male; Muscular Diseases; Phonation; Vocal Cords; Voice Disorders
PubMed: 8517149
DOI: 10.3109/00016489309135839 -
The Journal of the Acoustical Society... Aug 2021Using a continuum model based on magnetic resonance imaging of a canine larynx, parametric simulations of the vocal fold vibration during phonation were conducted with...
Using a continuum model based on magnetic resonance imaging of a canine larynx, parametric simulations of the vocal fold vibration during phonation were conducted with the cricothyroid muscle (CT) and the thyroarytenoid muscle (TA) independently activated from zero to full activation. The fundamental frequency (f) first increased and then experienced a downward jump as TA activity gradually increased under moderate to high CT activation. Proper orthogonal decomposition analysis revealed that the vocal fold vibrations were dominated by two modes representing a lateral motion and rotational motion, respectively, and the f drop was associated with a switch on the order of the two modes. In another parametric set where only the vocalis was active, f increased monotonically with both TA and CT activity and the mode switch did not occur. The results suggested that the active stress in the TA, which causes large stress differences between the body and cover, is essential for the occurrence of the rotational mode and mode switch. Relatively greater TA activity tends to promote the rotational mode, while relatively greater CT activity tends to promote the lateral mode. The results also suggested that the vibration modes affected f by affecting the contribution of the TA stress to the effective stiffness. The switch in the dominant mode caused the non-monotonic change of f.
Topics: Animals; Dogs; Laryngeal Muscles; Larynx; Phonation; Vibration; Vocal Cords
PubMed: 34470336
DOI: 10.1121/10.0005883 -
Journal of Clinical Neurophysiology :... Aug 2015Needle electromyography is an important tool in the diagnosis of neuromuscular diseases and has also been applied successfully in the evaluation of the vocal cord... (Review)
Review
Needle electromyography is an important tool in the diagnosis of neuromuscular diseases and has also been applied successfully in the evaluation of the vocal cord paralysis. Laryngeal electromyography, initially described by Weddell, is used to determine the cause of vocal cord paralysis and to differentiate organic from nonorganic causes of speech disorders. This test allows the diagnosis of lower motor neuron and nerve paralysis as well as myopathies. Laryngeal electromyography also helps to determine the prognosis of paralysis caused by traumatic injury of the laryngeal nerves and is used for guidance during botulinum toxin injection in spasmodic dysphonias. Single fiber electromyography is used to diagnose abnormalities of neuromuscular transmission and is applied in the study the architecture of the motor unit in muscles. This article reviews the techniques of laryngeal muscles single fiber electromyography, provides limited informative data, and discusses its potential value in the evaluation of patients with dysphonia.
Topics: Adult; Electromyography; Female; Humans; Laryngeal Diseases; Laryngeal Muscles; Male; Muscle Fibers, Skeletal; Young Adult
PubMed: 26241239
DOI: 10.1097/WNP.0000000000000176 -
Clinical Otolaryngology and Allied... Jun 1990One hundred and thirty-four hemilarynges were examined for the presence of the ceratocricoid muscle. This muscle arises from the cricoid cartilage, below the posterior...
One hundred and thirty-four hemilarynges were examined for the presence of the ceratocricoid muscle. This muscle arises from the cricoid cartilage, below the posterior cricoarytenoid muscle, and inserts onto the posterior aspect of the inferior horn of the thyroid cartilage. A prevalence of 6.3% was found. The anatomy, relations and innervation of the muscle are discussed.
Topics: Adult; Aged; Aged, 80 and over; Cricoid Cartilage; Female; Humans; Laryngeal Cartilages; Laryngeal Muscles; Larynx; Male; Middle Aged; Muscles; Thyroid Cartilage
PubMed: 2394026
DOI: 10.1111/j.1365-2273.1990.tb00783.x -
The Annals of Otology, Rhinology, and... May 2008This study was performed to investigate the muscle-nerve-muscle reinnervation technique in the larynx, in which a nerve conduit implanted into an innervated muscle... (Comparative Study)
Comparative Study
OBJECTIVES
This study was performed to investigate the muscle-nerve-muscle reinnervation technique in the larynx, in which a nerve conduit implanted into an innervated muscle conducts axonal sprouting into a denervated muscle while maintaining function of the donor muscle.
METHODS
In this study, the muscle-nerve-muscle technique was used to direct superior laryngeal nerve axons to reinnervate intrinsic laryngeal muscles by implanting the recurrent laryngeal nerve stump into the cricothyroid muscle in 8 dogs. In 4 of the dogs, the recurrent laryngeal nerve trunk to the adductor muscles was divided so that all axonal sprouting was directed to the posterior cricoarytenoid muscle. Six-month electromyography data were obtained from 6 of the 8 dogs.
RESULTS
All 6 dogs showed evidence of successful reinnervation of the thyroarytenoid or posterior cricoarytenoid muscles with action potentials that corresponded to spontaneous respiratory efforts, while the donor cricothyroid muscles retained their phasic contraction. These responses were obliterated when the recurrent laryngeal nerve conduit was divided. Histologic examination of the intrinsic laryngeal muscles demonstrated successful reinnervation.
CONCLUSIONS
The results confirm that intrinsic laryngeal muscles may be successfully reinnervated by the superior laryngeal nerve with the muscle-nerve-muscle technique, without sacrifice of function of the cricothyroid muscle. This method offers an alternative source of appropriately firing axons for laryngeal reinnervation procedures.
Topics: Animals; Disease Models, Animal; Dogs; Electromyography; Female; Laryngeal Muscles; Laryngoscopy; Muscle Contraction; Plastic Surgery Procedures; Recurrent Laryngeal Nerve; Treatment Outcome; Vocal Cord Paralysis; Vocal Cords
PubMed: 18564536
DOI: 10.1177/000348940811700509 -
Otolaryngologic Clinics of North America Nov 1988The larynx serves three basic functions in humans. In order of functional priority they are protective, respiratory, and phonatory. This article discusses these three... (Review)
Review
The larynx serves three basic functions in humans. In order of functional priority they are protective, respiratory, and phonatory. This article discusses these three roles in terms of phylogeny, developmental anatomy, and neuromuscular reflex activity.
Topics: Animals; Deglutition; Glottis; Humans; Laryngeal Cartilages; Laryngeal Muscles; Laryngeal Nerves; Muscles; Phonation; Respiration
PubMed: 3054715
DOI: No ID Found -
International Anesthesiology Clinics 1990
Review
Topics: Humans; Laryngeal Muscles; Larynx
PubMed: 2185987
DOI: 10.1097/00004311-199002820-00006 -
Anesthesia and Analgesia May 2012
Topics: Female; Humans; Laryngeal Muscles; Palpation
PubMed: 22523407
DOI: 10.1213/ANE.0b013e31823a84ef