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Clinical Radiology Aug 2014Active middle ear implants (AMEIs) have been available for a number of years and yet most radiologists have never heard of them. Some bear a striking resemblance to... (Review)
Review
Active middle ear implants (AMEIs) have been available for a number of years and yet most radiologists have never heard of them. Some bear a striking resemblance to cochlear implants whereas others are more similar to conventional hearing aids. The aims of this review are to provide an introduction as to the types of implants available, how they work and when they are indicated. Also, to highlight important pre-operative imaging features that can influence surgery and to consider the role of imaging in the post-operative setting. As patient choice increases, it becomes more likely that radiologists will encounter these devices in daily practice and knowledge of them may prove useful.
Topics: Ear, Middle; Hearing Loss; Humans; Labyrinth Diseases; Magnetic Resonance Imaging; Ossicular Prosthesis; Perioperative Care; Tomography, X-Ray Computed; United Kingdom
PubMed: 24780584
DOI: 10.1016/j.crad.2014.02.004 -
Finite element modelling of the human middle ear using synchrotron-radiation phase-contrast imaging.Computers in Biology and Medicine May 2023Finite element (FE) models of the middle ear often lack accurate geometry of soft tissue structures, such as the suspensory ligaments, as they can be difficult to...
Finite element (FE) models of the middle ear often lack accurate geometry of soft tissue structures, such as the suspensory ligaments, as they can be difficult to discern using conventional imaging modalities, such as computed tomography. Synchrotron-radiation phase-contrast imaging (SR-PCI) is a non-destructive imaging modality that has been shown to produce excellent visualization of soft tissue structures without the need for extensive sample preparation. The objectives of the investigation were to firstly use SR-PCI to create and evaluate a biomechanical FE model of the human middle ear that includes all soft tissue structures, and secondly, to investigate how modelling assumptions and simplifications of ligament representations affect the simulated biomechanical response of the FE model. The FE model included the suspensory ligaments, ossicular chain, tympanic membrane, the incudostapedial and incudomalleal joints, and the ear canal. Frequency responses obtained from the SR-PCI-based FE model agreed well with published laser doppler vibrometer measurements on cadaveric samples. Revised models with exclusion of the superior malleal ligament (SML), simplification of the SML, and modification of the stapedial annular ligament were studied, as these revised models represented modelling assumptions that have been made in literature.
Topics: Humans; Synchrotrons; Finite Element Analysis; Percutaneous Coronary Intervention; Ear, Middle; Stapes
PubMed: 36907036
DOI: 10.1016/j.compbiomed.2023.106747 -
Hearing Research Jul 2021The incudo-malleal joint (IMJ) in the human middle ear is a true diarthrodial joint and it has been known that the flexibility of this joint does not contribute to...
The incudo-malleal joint (IMJ) in the human middle ear is a true diarthrodial joint and it has been known that the flexibility of this joint does not contribute to better middle-ear sound transmission. Previous studies have proposed that a gliding motion between the malleus and the incus at this joint prevents the transmission of large displacements of the malleus to the incus and stapes and thus contributes to the protection of the inner ear as an immediate response against large static pressure changes. However, dynamic behavior of this joint under static pressure changes has not been fully revealed. In this study, effects of the flexibility of the IMJ on middle-ear sound transmission under static pressure difference between the middle-ear cavity and the environment were investigated. Experiments were performed in human cadaveric temporal bones with static pressures in the range of +/- 2 kPa being applied to the ear canal (relative to middle-ear cavity). Vibrational motions of the umbo and the stapes footplate center in response to acoustic stimulation (0.2-8 kHz) were measured using a 3D-Laser Doppler vibrometer for (1) the natural IMJ and (2) the IMJ with experimentally-reduced flexibility. With the natural condition of the IMJ, vibrations of the umbo and the stapes footplate center under static pressure loads were attenuated at low frequencies below the middle-ear resonance frequency as observed in previous studies. After the flexibility of the IMJ was reduced, additional attenuations of vibrational motion were observed for the umbo under positive static pressures in the ear canal (EC) and the stapes footplate center under both positive and negative static EC pressures. The additional attenuation of vibration reached 4~7 dB for the umbo under positive static EC pressures and the stapes footplate center under negative EC pressures, and 7~11 dB for the stapes footplate center under positive EC pressures. The results of this study indicate an adaptive mechanism of the flexible IMJ in the human middle ear to changes of static EC pressure by reducing the attenuation of the middle-ear sound transmission. Such results are expected to be used for diagnosis of the IMJ stiffening and to be applied to design of middle-ear prostheses.
Topics: Ear, Middle; Humans; Incus; Malleus; Pressure; Sound; Stapes; Temporal Bone; Vibration
PubMed: 34038827
DOI: 10.1016/j.heares.2021.108272 -
Otology & Neurotology : Official... Apr 2017We hypothesize that current clinical treatment strategies for the disarticulated or eroded incus have the effect of combining the incus and stapes of the human middle...
HYPOTHESIS
We hypothesize that current clinical treatment strategies for the disarticulated or eroded incus have the effect of combining the incus and stapes of the human middle ear (ME) into one rigid structure, which, while capable of adequately transmitting lower-frequency sounds, fails for higher frequencies.
BACKGROUND
ME damage causes conductive hearing loss (CHL) and while great progress has been made in repairing or reconstructing damaged MEs, the outcomes are often far from ideal.
METHODS
Temporal bones (TBs) from human cadavers, a laser Doppler vibrometer (LDV), and a fiber-optic based micro-pressure sensor were used to characterize ME transmission under various ME conditions: normal; with a disarticulated incus; repaired using medical glue; or reconstructed using a partial ossicular replacement prosthesis (PORP).
RESULTS
Repairing the disarticulated incus using medical glue, or replacing the incus using a commercial PORP, provided similar restoration of ME function including almost perfect function at frequencies below 4 kHz, but with more than a 20-dB loss at higher frequencies. Associated phase responses under these conditions sometimes varied and seemed dependent on the degree of coupling of the PORP to the remaining ME structure. A new ME-prosthesis design may be required to allow the stapes to move in three-dimensional (3-D) space to correct this deficiency at higher frequencies.
CONCLUSIONS
Fixation of the incus to the stapes or ossicular reconstruction using a PORP limited the efficiency of sound transmission at high frequencies.
Topics: Cadaver; Ear, Middle; Hearing Loss, Conductive; Humans; Incus; Ossicular Prosthesis; Sound; Stapes; Temporal Bone
PubMed: 28079680
DOI: 10.1097/MAO.0000000000001330 -
Journal of Speech and Hearing Research Jun 1970
Topics: Acoustics; Adult; Audiometry; Ear Diseases; Ear, Middle; Humans; Male; Methods; Otosclerosis; Reflex
PubMed: 5421450
DOI: 10.1044/jshr.1302.317 -
The Anatomical Record Aug 1994The contribution of middle-ear development to the overall development of hearing has not been explored in great detail. This presentation describes the maturation of...
BACKGROUND
The contribution of middle-ear development to the overall development of hearing has not been explored in great detail. This presentation describes the maturation of conductive elements in the rat middle ear, and provides the basis on which future studies of middle-ear functional development will follow.
METHODS
The middle-ear apparatus was examined at nine different ages (between 1 and 80 days postpartum) in Long Evans rats. At each age elements of the conducting apparatus was observed with either light or scanning electron microscopy (SEM), and quantitative measurements were made from video enhanced photomicrographs. Tympanic membrane area and cone depth, the length of the malleus and incus arms, ossicular weight, stapes foot plate and oval window areas, and bulla volume were all measured. Development of the area and lever ratios were derived from these measurements. The data were fitted to exponential equations and the time in days required to reach 90% of the adult level determined.
RESULTS
The pars tensa achieved 90% of total area by 17 days. The oval window achieved the 90% criterion by 13 days, while the area ratio was within 10% of its adult size by 8 days. The ossicles took between 26 and 34 days, while bulla volume took 59 days to reach the 90% level.
CONCLUSIONS
Middle-ear growth was very orderly and systematic in the data reported. When maturation of the area ratio was considered against development of the endocochlear potential or the round window compound action potential, it was clear that the growth of this important aspect of the middle ear preceded the onset of cochlear function.
Topics: Aging; Animals; Ear, Middle; Female; Incus; Malleus; Microscopy, Electron, Scanning; Oval Window, Ear; Pregnancy; Rats; Stapes; Tympanic Membrane
PubMed: 7978370
DOI: 10.1002/ar.1092390413 -
Otolaryngologic Clinics of North America Jun 1971
Review
Topics: Abnormalities, Multiple; Ear, Middle; Female; Humans; Pregnancy; Syndrome
PubMed: 5006525
DOI: No ID Found -
The Annals of Otology, Rhinology, and... May 1995Partial pressures of the gases in the middle ears of 14 guinea pigs were measured continuously on-line with a specially designed mass spectrometer. The average values...
Partial pressures of the gases in the middle ears of 14 guinea pigs were measured continuously on-line with a specially designed mass spectrometer. The average values were carbon dioxide 67.55 mm Hg, oxygen 48.91 mm Hg, and nitrogen 596.54 mm Hg. These values confirm earlier measurements and show that the gas composition of the middle ear differs basically from that of air and resembles that of venous blood. These findings are indicative of bilateral diffusion between the middle ear cavity and the blood. We propose that under physiologic as well as under pathologic (ie, atelectatic) conditions, the gas content of the middle ear is also controlled by diffusion. This mechanism fits well with the fluctuating character of atelectatic ears. Thus, a negative middle ear pressure could be secondary to excessive loss of gases through increased and excessive diffusion, although additional mechanisms are probably also involved. A likely contributing factor is poor pneumatization of the mastoid, with consequent absence of a physiologic pressure regulation mechanism by its pneumatic system.
Topics: Animals; Argon; Blood Gas Analysis; Carbon Dioxide; Ear, Middle; Eustachian Tube; Female; Guinea Pigs; Middle Ear Ventilation; Nitrogen; Oxygen; Partial Pressure; Pilot Projects; Pulmonary Atelectasis
PubMed: 7747907
DOI: 10.1177/000348949510400506 -
The Annals of Otology, Rhinology, and... 1976Twenty-six children presenting bilateral secretory otitis media (SOM) had ventilating tubes inserted into both middle ears. Mucus was, however, aspirated only from one... (Comparative Study)
Comparative Study
Twenty-six children presenting bilateral secretory otitis media (SOM) had ventilating tubes inserted into both middle ears. Mucus was, however, aspirated only from one ear, the right side. The vast majority of ears right and left were seen to have cleared their effusion equally well regardless of whether they were aspirated on not. This experiment points toward the essential intactness of the mucociliary system and the patency of the lumen of the Eustachian tube in SOM. Promotion of middle ear clearance through ventilation, which reminds one of the second opening in a beer can, does obviously suggest the relief of some negative pressure. Direct manometric measurements of SOM middle pressure were performed in 41 ears showing negative pressure averaging --1.7 mm H2O, this range being two orders of magnitude less than tympanometric measurements. Normal ears did not have even such a small negative pressure. The validity of these direct manometric measurements was checked against a model of the middle ear. Tympanometry, which is a valid diagnostic tool, does indicate in all probability the presence of middle ear effusion due to its rheologic effects on the drum and ossicles rather than the measure of actual middle ear pressures. This is determined by the fact that direct needling of the middle ear, or even the insertion of a ventilating tube, did not change tympanometric values but aspiration of part of the effusion did: indeed the latter tended to bring manometry to normal values.
Topics: Child, Preschool; Ear, Middle; Exudates and Transudates; Humans; Intubation; Manometry; Models, Biological; Otitis Media; Pressure; Rheology
PubMed: 1267369
DOI: 10.1177/00034894760850S212 -
Folia Morphologica 2021The purpose of this study was to provide a description of gross middle ear morphology in water buffaloes, augmented with additional data on the osseous structures of...
BACKGROUND
The purpose of this study was to provide a description of gross middle ear morphology in water buffaloes, augmented with additional data on the osseous structures of middle ear derived from cone-beam computed tomography (CBCT).
MATERIALS AND METHODS
Skulls of 10 young adult male water buffaloes were used to examine their middle ears.
RESULTS
Anatomical features noted included the presence of tympanic cells in the tympanic bulla, the location of malleus head and neck, and all of incus in the dorsal epitympanic recess, the oval tympanic membrane, absence of a prominent notch on the articular surface of malleus, positional variations of the lateral process of malleus relative to the muscular process and muscular process relative to the rostral process of malleus, absence of complete coverage of the articular facet of malleus head by incus body, and presence of the lenticular process of incus. In CBCT images, the osseous part of external acoustic meatus, the petrous part of temporal bone and the details of the ossicles were seen, except for stapes.
CONCLUSIONS
Although tympanic membrane, malleus and stapes of water buffaloes are similar to those of ox, the incus of water buffaloes is more similar to that of goats. The heaviest ossicles among the ruminants studied belonged to water buffaloes; the mean length of malleus head and neck, total length and width of incus body as well as length of stapes head were greatest in water buffaloes too. The auditory ossicles of water buffaloes show 'transitional type' morphological characteristics. These features suggest a relatively wide frequency range of hearing, but not one biased towards especially low or especially high frequencies.
Topics: Animals; Buffaloes; Cone-Beam Computed Tomography; Ear, Middle; Incus; Male; Malleus
PubMed: 32207849
DOI: 10.5603/FM.a2020.0036