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Otolaryngology--head and Neck Surgery :... Jan 2014Traditionally, otologists have aimed to produce a clean, dry, safe ear with the best possible hearing result. More recently, "less invasively" has been added to this... (Review)
Review
Traditionally, otologists have aimed to produce a clean, dry, safe ear with the best possible hearing result. More recently, "less invasively" has been added to this list of goals. The development of small-diameter, high-quality rigid endoscopes and high-definition video systems has made totally endoscopic, transcanal surgery a reality in adult otology and a possibility in pediatric otology. This article reviews the anatomy of the pediatric middle ear and its surrounding airspaces and structures based on the work of dozens of researchers over the past 50 years. It will focus on the developmental changes in ear anatomy from birth through the first decade, when structure and function change most rapidly. Understanding the limits and possibilities afforded by new endoscopic technologies, the pediatric otologist can strive for results matching or exceeding those achieved by more invasive surgical approaches.
Topics: Child; Child, Preschool; Ear Canal; Ear Ossicles; Ear, Middle; Endoscopy; Eustachian Tube; Humans; Infant; Infant, Newborn; Tympanic Membrane
PubMed: 24154745
DOI: 10.1177/0194599813509589 -
Hearing Research Feb 2021The erroneous idea that mammalian three-ossicle middle ears are superior to single-ossicle ones has influenced thinking about prostheses. Evolutionary facts and...
The erroneous idea that mammalian three-ossicle middle ears are superior to single-ossicle ones has influenced thinking about prostheses. Evolutionary facts and measurements indicate that single-ossicle ears are equivalent and more flexible, supporting - in spite of new technological reconstruction techniques - their continued use as prostheses.
Topics: Animals; Ear Ossicles; Ear, Middle; Prostheses and Implants
PubMed: 33310566
DOI: 10.1016/j.heares.2020.108144 -
Otolaryngology--head and Neck Surgery :... Apr 2017Objective In this report, we review the recent literature (ie, past 4 years) to identify advances in our understanding of the middle ear-mastoid-eustachian tube system.... (Review)
Review
Objective In this report, we review the recent literature (ie, past 4 years) to identify advances in our understanding of the middle ear-mastoid-eustachian tube system. We use this review to determine whether the short-term goals elaborated in the last report were achieved, and we propose updated goals to guide future otitis media research. Data Sources PubMed, Web of Science, Medline. Review Methods The panel topic was subdivided, and each contributor performed a literature search within the given time frame. The keywords searched included middle ear, eustachian tube, and mastoid for their intersection with anatomy, physiology, pathophysiology, and pathology. Preliminary reports from each panel member were consolidated and discussed when the panel met on June 11, 2015. At that meeting, the progress was evaluated and new short-term goals proposed. Conclusions Progress was made on 13 of the 20 short-term goals proposed in 2011. Significant advances were made in the characterization of middle ear gas exchange pathways, modeling eustachian tube function, and preliminary testing of treatments for eustachian tube dysfunction. Implications for Practice In the future, imaging technologies should be developed to noninvasively assess middle ear/eustachian tube structure and physiology with respect to their role in otitis media pathogenesis. The new data derived from these structure/function experiments should be integrated into computational models that can then be used to develop specific hypotheses concerning otitis media pathogenesis and persistence. Finally, rigorous studies on medical or surgical treatments for eustachian tube dysfunction should be undertaken.
Topics: Animals; Congresses as Topic; Ear, Middle; Eustachian Tube; Humans; Mastoid; Models, Animal
PubMed: 28372527
DOI: 10.1177/0194599816647959 -
PloS One 2021As the resolution of 3D printing techniques improves, the possibility of individualized, 3-ossicle constructions adds a new dimension to middle ear prostheses. In order...
As the resolution of 3D printing techniques improves, the possibility of individualized, 3-ossicle constructions adds a new dimension to middle ear prostheses. In order to optimize these designs, it is essential to understand how the ossicles and ligaments work together to transmit sound, and thus how ligaments should be replicated in a middle ear reconstruction. The middle ear ligaments are thought to play a significant role in maintaining the position of the ossicles and constraining axis of rotation. Paradoxically, investigations of the role of ligaments to date have shown very little impact on middle ear sound transmission. We explored the role of the two attachments in the gerbil middle ear analogous to human ligaments, the posterior incudal ligament and the anterior mallear process, severing both attachments and measuring change in hearing sensitivity. The impact of severing the attachments on the position of the ossicular chain was visualized using synchrotron microtomography imaging of the middle ear. In contrast to previous studies, a threshold change on the order of 20 dB across a wide range of frequencies was found when both ligaments were severed. Concomitantly, a shift in position of the ossicles was observed from the x-ray imaging and 3D renderings of the ossicular chain. These findings contrast with previous studies, demonstrating that these ligaments play a significant role in the transmission of sound through the middle ear. It appears that both mallear and incudal ligaments must be severed in order to impair sound transmission. The results of this study have significance for middle ear reconstructive surgery and the design of 3D-printed three-ossicle biocompatible prostheses.
Topics: Acoustic Stimulation; Action Potentials; Animals; Auditory Threshold; Biocompatible Materials; Cochlea; Ear, Middle; Female; Gerbillinae; Lasers, Gas; Ligaments; Male; Ossicular Prosthesis; Printing, Three-Dimensional; X-Ray Microtomography
PubMed: 34428235
DOI: 10.1371/journal.pone.0255821 -
Journal of Anatomy Feb 2016Middle ear surgery is strongly influenced by anatomical and functional characteristics of the middle ear. The complex anatomy means a challenge for the otosurgeon who... (Review)
Review
Middle ear surgery is strongly influenced by anatomical and functional characteristics of the middle ear. The complex anatomy means a challenge for the otosurgeon who moves between preservation or improvement of highly important functions (hearing, balance, facial motion) and eradication of diseases. Of these, perforations of the tympanic membrane, chronic otitis media, tympanosclerosis and cholesteatoma are encountered most often in clinical practice. Modern techniques for reconstruction of the ossicular chain aim for best possible hearing improvement using delicate alloplastic titanium prostheses, but a number of prosthesis-unrelated factors work against this intent. Surgery is always individualized to the case and there is no one-fits-all strategy. Above all, both middle ear diseases and surgery can be associated with a number of complications; the most important ones being hearing deterioration or deafness, dizziness, facial palsy and life-threatening intracranial complications. To minimize risks, a solid knowledge of and respect for neurootologic structures is essential for an otosurgeon who must train him- or herself intensively on temporal bones before performing surgery on a patient.
Topics: Ear Diseases; Ear, Middle; Hearing Loss; Humans
PubMed: 26482007
DOI: 10.1111/joa.12389 -
Otolaryngologic Clinics of North America Dec 2006Many options are available to manage a patient who has atelectatic ears. Establishing normal middle ear ventilation and aeration is the cornerstone to successful control... (Review)
Review
Many options are available to manage a patient who has atelectatic ears. Establishing normal middle ear ventilation and aeration is the cornerstone to successful control of these ears. Often, medical management with nasal steroids and decongestants is all that is needed. If recurrent infections have weakened the tympanic membrane progressively, or the middle ear environment is so severe that medical management does not correct the problem, then surgical correction is often necessary. This article explores the pathogenesis of middle ear atelectasis and explains a classification system to help the clinician determine the best course of management.
Topics: Ear Diseases; Ear, Middle; Eustachian Tube; Humans; Tympanic Membrane
PubMed: 17097442
DOI: 10.1016/j.otc.2006.09.002 -
Hearing Research Jul 2013Results from developmental and phylogenetic studies have converged to facilitate insight into two important steps in vertebrate evolution: (1) the ontogenetic origin of... (Review)
Review
Results from developmental and phylogenetic studies have converged to facilitate insight into two important steps in vertebrate evolution: (1) the ontogenetic origin of articulating elements of the buccal skeleton, i.e., jaws, and (2) the later origins of middle ear impedance-matching systems that convey air-borne sound to the inner ear fluids. Middle ear ossicles and other skeletal elements of the viscerocranium (i.e., gill suspensory arches and jaw bones) share a common origin both phylogenetically and ontogenetically. The intention of this brief overview of middle-ear development is to emphasize the intimate connection between evolution and embryogenesis. Examples of developmental situations are discussed in which cells of different provenance, such as neural crest, mesoderm or endoderm, gather together and reciprocal interactions finally determine cell fate. Effects of targeted mutagenesis on middle ear development are described to illustrate how the alteration of molecularly-controlled morphogenetic programs led to phylogenetic modifications of skeletal development. Ontogenetic plasticity has enabled the diversification of jaw elements as well as middle ear structures during evolution. This article is part of a special issue entitled "MEMRO 2012".
Topics: Animals; Biological Evolution; Cell Lineage; Chickens; Ear Ossicles; Ear, Middle; Endoderm; Mesoderm; Mice; Neural Crest; Phylogeny; Species Specificity; Tympanic Membrane
PubMed: 23396272
DOI: 10.1016/j.heares.2013.01.019 -
The American Journal of Otology Mar 1997To review current concepts of the mechanical processes of the human middle ear, and to apply them to practical issues in clinical otology and tympanoplasty surgery. (Review)
Review
OBJECTIVE
To review current concepts of the mechanical processes of the human middle ear, and to apply them to practical issues in clinical otology and tympanoplasty surgery.
BACKGROUND
The wide range of conductive hearing losses associated with middle ear pathology and reconstruction cannot be adequately explained by simple models of middle ear function.
METHODS
Variables used to describe the system are sound pressure, volume velocity, and acoustic impedance. The relationship between specific middle ear structures and these variables is described such that inferences can be drawn regarding sound conduction in the normal, diseased, and reconstructed middle ear.
RESULTS AND CONCLUSIONS
Sound can be transmitted from the car canal to the cochlea via two mechanisms: the tympano-ossicular system (ossicular coupling) and direct acoustic stimulation of the oval and round windows (acoustic coupling). Acoustic coupling is negligibly small in normal ears, but can play a significant role in some diseased and reconstructed ears. In the normal ear, middle ear pressure gain (which is the result of ossicular coupling) is frequency-dependent and less than generally believed. The severity of conductive hearing loss due to middle-ear disease or after tympanoplasty surgery can be predicted by the degree to which ossicular coupling, acoustic coupling, and stapescochlear input impedance are altered. Hearing after type IV and V tympanoplasty is determined solely by acoustic coupling. The difference in magnitude between the oval- and round-window pressures is more important than the difference in phase in determining cochlear input. In tympanoplasty types I, II, and III, adequate middle-ear and round-window aeration is necessary and the tympanic membrane-ossicular configuration may be less crucial.
Topics: Acoustics; Cochlea; Ear Ossicles; Ear, Middle; Hearing Loss, Conductive; Humans; Ossicular Prosthesis; Otosclerosis; Severity of Illness Index; Tympanic Membrane Perforation; Tympanoplasty
PubMed: 9093668
DOI: No ID Found -
Acta Oto-laryngologica. Supplementum 1990The ventilation mechanism of the middle ear is very important as regards the pathogenesis of middle ear disease, but its mode of function is still obscure. Therefore, we...
The ventilation mechanism of the middle ear is very important as regards the pathogenesis of middle ear disease, but its mode of function is still obscure. Therefore, we tried to measure the ventilation and clearance of the middle ear using radio-isotope imaging techniques and 133Xe in order to gain a clearer picture of the ventilation mechanism. In normal Eustachian tube cases, approximately 10% of the initially insufflated gas immediately entered into the middle ear cavity and mastoid air cells. The gas introduced into the middle ear diminished at a rate of 8% of volume per hour in the normal resting state. Two hours after the first procedure, air was insufflated, and gas volume in the middle ear cavity immediately diminished by 30%. In stenotic tube cases, it proved difficult to insufflate the gas into the middle ear, however, its diminishing rate with the passage of time was slightly faster than in normal tube cases. From this data, it was evident that air could easily and quickly enter into even the periphery of the mastoid air cells by insufflation via the Eustachian tube, despite the fact that the middle ear and mastoid air cells form a closed cavity. In the resting state, moreover, the air in the middle ear was thought to be absorbed mainly into the middle ear mucosa at a regular rate. It was confirmed that the insufflation procedure as a therapy for tubal stenosis and OME is very useful for the ventilation of the middle ear.
Topics: Air; Constriction, Pathologic; Ear, Middle; Eustachian Tube; Humans; Radionuclide Imaging; Xenon Radioisotopes
PubMed: 2239243
DOI: 10.3109/00016489009124806 -
Journal of Anatomy Feb 2016Anatomists and zoologists who study middle ear morphology are often interested to know what the structure of an ear can reveal about the auditory acuity and hearing... (Review)
Review
Anatomists and zoologists who study middle ear morphology are often interested to know what the structure of an ear can reveal about the auditory acuity and hearing range of the animal in question. This paper represents an introduction to middle ear function targetted towards biological scientists with little experience in the field of auditory acoustics. Simple models of impedance matching are first described, based on the familiar concepts of the area and lever ratios of the middle ear. However, using the Mongolian gerbil Meriones unguiculatus as a test case, it is shown that the predictions made by such 'ideal transformer' models are generally not consistent with measurements derived from recent experimental studies. Electrical analogue models represent a better way to understand some of the complex, frequency-dependent responses of the middle ear: these have been used to model the effects of middle ear subcavities, and the possible function of the auditory ossicles as a transmission line. The concepts behind such models are explained here, again aimed at those with little background knowledge. Functional inferences based on middle ear anatomy are more likely to be valid at low frequencies. Acoustic impedance at low frequencies is dominated by compliance; expanded middle ear cavities, found in small desert mammals including gerbils, jerboas and the sengi Macroscelides, are expected to improve low-frequency sound transmission, as long as the ossicular system is not too stiff.
Topics: Acoustic Impedance Tests; Animals; Ear, Middle; Hearing; Mammals; Models, Biological
PubMed: 26100915
DOI: 10.1111/joa.12316