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PubMed1990

Fitness of civil aviation passengers to fly after ear surgery.

Movements of the tympanic membrane caused by changes in air pressure are conducted to the ossicles of the middle ear. The gliding mechanism of the malleus-incus articulation converts in-and-out movements of the eardrum into up-and-down movements of the stapes, thereby protecting the inner ear from static pressures. In certain ear operations, the replacement of a middle ear ossicle by a prosthesis disjoints the malleus-incus articulation or makes it rigid. Pressure is then transmitted in unattenuated form from the eardrum through the oval window to the inner ear. Impairment of pressure equilibration, for example due to obstructed eustachian tubes, can lead to prosthesis displacement with severe injury to the vestibulocochlear apparatus. Thus, patients should be advised to begin equilibration of pressure at the beginning of descent of commercial airlines or civil aviation flights, and to repeat it a brief intervals.

Acoustic Impedance Tests↗
PubMed1989

[Movement of the ear ossicles by middle ear muscle contraction].

Up to now, the function of the middle ear muscles has mainly been investigated from an acoustical point of view. However, the primary function of the middle-ear muscles, namely the induction of ossicular movements, has never been investigated systematically. For this purpose, the displacements of the ossicles, as induced by simulated muscle contractions, were measured microscopically in 13 fresh temporal bone preparations. Both muscles move all ossicles. The tensor tympani muscle pulls the umbo inwards about 100 microns. Due to the gliding motion in the malleus-incus joint, the stapes is thus pushed inwards by at the most 10 microns and, additionally, displaced anteriorly, antagonistic to the pull of the stapedius muscle. This muscle pulls the stapes backwards, lifting the anterior crus outwards and pushing the posterior crus inwards. This reduces the pressure on the cochlear fluids significantly as compared to our former concepts of the movement of the footplate, tilting outwards as a whole around an axis at the posterior pole. Furthermore, this outward displacement of the stapes is not prerequisite for the outward movement of the malleus-drumhead complex, which typically appears at the contraction of the stapedius muscle. The basic motion of the stapes is the movement backwards, which is 5 times greater and which matches the anatomic direction of the pull of the stapedius muscle. This explains the otherwise unlogical position of the stapedius muscle parallel to the footplate. Due to the gliding movement in the malleus-incus joint, this motion changes at the umbo into outward rotation, counteracting the tensor tympani muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Ear Ossicles↗
PubMed1989

[Structure of the middle ear in infants].

In section specimens of 20 infants aged 2 months to one year the morphology of the middle ear was studied in comparison with 20 adult cases aged 20-50 years. The differences were in size and shape of the tympanic cavity, eustachian tube, mastoid and middle ear ossicles. The comparison of dimensions of auditory ossicles in the infants and in adults shows that the length of malleus increases 11.9%, the length of manubrium mallei--11.5%, crus longum incudis--10.2%, the incus length--7.6%, incus width--8.2%, stapes length--4.5%, length of stapes basis--5.3%, width of stapes basis--7.5%. These data may be useful in pediatric otolaryngology.

Adult↗
PubMed1988

[High resolution computerized tomography in the study of traumatic pathology of the temporal bone].

Thirty-five patients with temporal bone fractures were examined; the fractures were sometimes associated with dislocation of the ossicular chain caused by road fatalities. Computed Tomography (CT) was performed either because of the presence of clinical symptoms associated with trauma of the temporal bone, or because of a hemotympanum discovered during a CT scan of the brain. Thirty-three fractures were detected: 19 longitudinal, 6 transverse, and 8 complex. An incudostapedial dislocation was also detected, together with a displacement of a stapedial prosthesis from the lenticular process of incus, and 3 incus-malleus dislocations associated with fractures. High resolution CT allows the precise definition of the course of the fractures, of the associated dislocation of the ossicular chain, and of facial nerve lesion, thus allowing a more accurate surgical intervention. In the examination of the temporal bone, high resolution CT is preferable to pluridirectional tomography because it is easier and faster to perform. Moreover, high resolution CT helps reduce the radiation dose, and yields higher-quality images with more accurate diagnostic information. High resolution CT also allows the brain and the temporal bone to be studied at the same time.

Adolescent↗
PubMed1988

[Experimental studies of static stress on the footplate in the reconstruction of the sound conduction system].

If a destroyed ossicular chain is substituted by a drum-to-footplate prosthesis (TORP), not only sound pressures but also static pressures are conducted via this new connection. To measure these effects in the area of the oval window, in isolated temporal bones the stapes was removed and substituted by a piece of plastipore, attached to the incus. This piece was connected by a very fine needle to a foil strain gauge, in order to registrate the effects of experimentally changed pressures in the external ear canal towards the inner ear. The incus was then also removed too and a TORP was introduced. Under the same measuring condition we found the conducted pressures ten times higher than in the previous situation. This can only be explained by movements in the incudo-malleal joint, if this is intact. Consequently patients with TORPs should avoid all situations of rapid changes of surrounding pressure, such as diving etc., especially if the tube function is impaired. These situations may be dangerous for the footplate and the inner ear. In fortunately rare cases perforations of the footplate were reported by some ear surgeons.

Biomechanical Phenomena↗
PubMed1987

[High-resolution computed tomography in stapes surgery].

Early and delayed complications in the inner or middle ear may follow stapedectomy or stapedotomy and may require revision surgery. Nowadays high resolution middle ear computed tomography (HR-MCT) using a special interpolation technique can demonstrate the smallest structures of the middle ear space, such as the long process of the incus and stapes. Stapes prostheses can also be seen in this way, but to identify the prothesis exactly it is necessary to determine the position of the piston hook in relation to the incus and of the piston shaft to the foot plate and scala vestibuli. Two points were of particular interest to us: HR-MCT identification of various metal and plastic pistons. Clinical significance of HR-MCT in complications following surgery. As the result of our experimental research on cadaver temporal bones, pistons must still be divided into four groups based on their demonstration by HR-MCT: Group I (e.g. Stainless Steel Cup Piston): whole piston visible. Group II (e.g. McGee Stainless Steel Piston): only piston shaft. Group III (Fisch Teflon-Platinum Piston): only hook visible. Group IV (e.g. Fisch Teflon-Wire Piston): piston hardly visible or not at all. In groups I-III it is possible to discover whether the piston is too long or too short, whether it is dislocated or has slipped. Group IV pistons, hooks from group II and the shaft from group III must be changed to allow detection by x-rays. With plastic pistons it might be possible to add an x-ray agent.2+ improvements in manufacture appear to be necessary, dislocation of various prostheses can now be shown.(ABSTRACT TRUNCATED AT 250 WORDS)

Ear, Middle↗
PubMed1979

[Tomographic incidence of the petrous bone by the controlateral suboccipital approach, in the plane of the ear-drum and in line with the general axis of the ossicules (author's transl)].

Definition and technique of the Dulac 7 incidence. Diagrams 1 and 2 give details of the anatomical orientations which define this incidence. It is:--centered on the head of the malleus,--orientated in the plane of the ossicules or in the neighbouring plane of the ear-drum,--parallel to the general axis of the ossicules,--close to the perpendicular to the tegment tympani. This incidence is easy to obtain with our technique, using a fixed intracranial centering point, The transversal linear scanning is very effective and can be completed in a very short period. It should be noted, however, that in obese subjects with short necks, the entry point of the incidence is difficult to obtain as there is interposition of the neck muscles. Under these conditions, one should try to be as close to this entry point as possible, knowing that the results are still valid. Tomographic anatomy. A close examination of the text of figures 6, 7, and 8 will familiarize the reader with the tomographic anatomy of this incidence. To summarize the important information obtained from the Dulac 7 incidence we should note that in tomographies of normal petrous bones:--the attic is always perfectly visible, expecially its internal and external walls throughout their total length, and more especially the anterior wall;--the ossicles (head of the malleus, body of the incus, and their articulation) are always perfectly visible and distinct;--the inferior processes of the malleus and incus are always visible;--the external wall of the attic is visible throughout its length, more especially the anterior and posterior portions;--the anterior and posterior contours of the external auditory canal are particularly well-defined. Finally, this incidence also gives clear images of the temporo-mandibular joint, the antral region, the superior canal, and the internal auditory canal. A large experience of this incidence is required before interpreting the image of the foramen ovale. Tomographic pathognomonic signs. The texts of figures 9 to 24 are sufficiently demonstrative of the richness of the pathological data obtained from this incidence, without needing to repeat them here. We would only add that the degree of calcification of the ossicles and the anterior wall of the attic can be precisely determined. This incidence, therefore, gives valuable information in almost all middle ear affections. It is also necessary in order to study the external auditory canal.

Ear Diseases↗
PubMed1984

[An error in the Reichert-Gaupp theory. A contribution to onto- and phylogenesis of the temporomandibular joint and ear ossicles in mammals].

The theory of Reichert- Gaupp is refuted by A) new embryological, B) some teratological and C) a new morphological and functional interpretation of palaeontological findings: A) Before the formation of the chondrocranium the still fibrous anlagen of the Meckel's cartilage and of the hyoidal (!) malleus-incus-complex are still sharply outlined each against other. The hyomandibular boundary between them is yet distinctly visible. B) In the malformations being reconducted to an arrest of development the malleus-incus-complex regularly shares the fate of the outer ear (II. visceral arch) but never the destiny of the face (I. visceral arch). The ossicle-chain is not only a functional but also an ontogenetic unit and consequently also a phylogenetic unit. C) The phylogenetic changes of the temporomandibulary joint (tmj) of the Therapsida result by steps out of autochthon (!) structures. The functional background is discussed. We see the articulare as homologue to the processus condylaris and the quadratum to the articular disk. The phylogenetic older quadrato -articular hinge-joint is preserved in the inferior part and the phylogenetic younger quadrato - squamosal slide-joint, which in the human embryo also develops 2 weeks later than the first, is situated superior to the ginglymus . Thus the Mammals have 2 tmj on each side but no squamoso -dental joint.

Aging↗
PubMed1980

[The influence of tympanoplasty on bone conduction (author's transl)].

Seldom tympanoplasty damages the inner ear in a substantial amount: From 1814 operations upon chronic inflamed ears 4 patients (0.22%) became deaf, among the other patients bone conduction (b.c.) in the mean increased at 1000 cps for + 0.8 dB and decreased at 4000 cps for - 2.2 dB. In 9.8% b.c. showed an improvement for 10 dB or more at 1000 and 4000 cps, 9.7% showed an corresponding deterioration. For patients it was confirmed on a statistical base, that the influence on bone conduction demonstrated by animal experiments (Tonndorf), was mainly the result of changing the compliance of oval window and of increasing ossicular inertia. By relieving a mobile stapes of an incus which was fixed in the attic, there results an improvement of mobility of the stapedial footplate with increasing b.c. at 1000 and 4000 cps. By interposition of an incus between tympanic membrane and stapes and by myringoplasty with fascia there results an increasing ossicular inertia with increasing b.c. at 1000 cps and decreasing b.c. at 4000 cps. Noise trauma, mechanical trauma and infection are only of slight importance, only in some single cases they will damage the inner ear in a substantial amount.

Bone Conduction↗
PubMed1995

[Experimental research of middle ear implant].

Click and tone burst were used to evoke the auditory brainstem responses of experimental animals. The stimulations of different sound intensities were used. Amplitudes, latencies and thresholds of normal ear were measured and the incus of right ear was removed and Nd-Fe-B middle ear implanted. The thresholds of normal ears were 14.74 +/- 4.12 dB nHL on average. The thresholds of removed incus were 57.00 +/- 8.64 dB nHL on average. The thresholds of the implanted middle ears were 16.25 +/- 8.56 dB nHL. It was found that the characterstics of frequency responses of the implanted middle ear cover the whole area of language frequency in the experiment. It accorded with the features of audibility of human ear.

Animals↗
PubMed1994

How I do primary and revision stapedectomy.

Localized anterior otosclerosis is found in about 80 percent of primary stapedectomy operations. For these patients, partial stapedectomy with vein graft is recommended. Obliterative otosclerosis is the pathology found in the remaining 20 percent of primary stapedectomy operations. In these cases, stapedectomy with lining membrane of the middle ear or vein graft is the procedure of choice. Revision stapedectomy may improve conductive hearing loss caused by (1) migration and/or dislocation of the prosthesis, (2) eversion of the lining membrane of the vestibule with resulting dislocation of the prosthesis and possible erosion of the lower incus, (3) bony closure of the oval window, or (4) epitympanic fixation of the incus and/or malleus. Successful operative techniques used in primary and revision stapedectomy are described.

Humans↗
PubMed1994

A contactless electromagnetic implantable middle ear device for sensorineural hearing loss.

Following basic science experiments, improvement of precision micromechanics and electronics design, and development of different prototypes, a contactless electromagnetic hearing device has been successfully implanted in cats (acute experiments). Chronic animal experiments using the cat as well as the rabbit are ongoing to test the components of the device. A highly efficient air core coil is used to vibrate a neodymium-iron-boron magnet cemented to the body of the incus. The parts of the system, including implanted electronics (hybrid circuit, solid state), are laser welded and hermetically sealed. The system allows for the generation of enough force which vibrates the magnet implanted on the incus. It would be suitable for the treatment of moderate to severe sensorineural hearing loss.

Animals↗
PubMed1995

Use of distortion product otoacoustic emissions to assess middle ear transducers in rhesus monkeys.

Distortion product otoacoustic emissions (DPOAEs) can provide an objective and noninvasive assessment of the peripheral cochlear function. Auditory brainstem responses measured from implanted rhesus monkeys have shown that middle ear transducers, coupled directly to the incus, are capable of delivering the signals to the central auditory system. The DPOAEs were used as a noninvasive method of assessing the frequency specificity of this mechanical transduction. In two rhesus monkeys implanted with the middle ear transducers, one primary stimulating tone (f1) was presented acoustically, and the other primary tone (f2) was presented by the transducer, which converted the signal into a mechanical motion of the probe tip attached to the body of the incus. The nonlinear characteristics of the cochlea produced the distortion product responses at the expected frequencies (2f1 - f2). This demonstrates the fidelity of the middle ear implant signal transduction in vivo. The DPOAEs also indicate minimal changes in the post-implant middle ear transmission. This study demonstrates that the DPOAEs can be used to assess the function of implanted middle ear transducers objectively and noninvasively.

Animals↗
PubMedDate not supplied

Stage-specific onset of condensation and matrix deposition for Meckel's and other first arch cartilages in inbred C57BL/6 mice.

Condensation is a multistep process, involving cell recruitment, cell-to-cell contact by cell adhesions, and concomitant changes in cell shape. Condensation of prechondrogenic cells down-regulates and/or inactivates cell proliferation and enhances the activities of cartilage-specific genes. Timing of onset and duration of condensation are thus important regulatory processes mediating cellular and molecular events during chondrogenesis. The present study was undertaken to examine timing of onset and duration of condensation and onset of matrix formation for first arch cartilages in inbred C57BL/6 mice. Because timing can only be reliably assessed in very precisely staged embryos, mice were mated for only 2 hr, pregnancy was determined by weight increase, and embryos were assigned to substages and divisions of Theiler's [1972] stages on the basis of external development of the frontonasal area, eyes, vibrissae, mandibular and hyoid auricular hillocks (pinna) and some internal structures [Miyake et al., 1996]. Condensation and matrix formation were determined using PNA lectin histochemistry, type II collagen immunohistochemistry, Mallory's trichrome, Hall and Brunt's quadruple and toluidine blue stains on serially sectioned embryos, and 3-D reconstruction. A single, continuous, first arch chondrogenic condensation was identified. It consisted of three components: 1) a rostral component for the symphysis; 2) a core component for the major portion of Meckel's cartilage; and 3) a caudal component for the caudo-lateral area of Meckel's cartilage and the two ear cartilages, the malleus and incus. The caudal component was further divided into rostral and caudal subcomponents which gave rise to the malleus and incus, respectively. Cellular arrangement differed among the three components, probably reflecting major axes of matrix growth. The condensation was only weakly recognized by peanut agglutinin lectin (PNA), unless sections were pretreated with neuraminidase, showing the masking effects of sialic acid. The core and caudal components of the condensation appeared at stage 20.12 and ended at stage 21.14 and 21.32, respectively. The symphysial component began at stage 20.2 and ended at stage 21.32. Deposition of sulfated proteoglycans began at stage 21.14 in the core component of the condensation--preceding slightly deposition of type II collagen--and at stage 21.32 in the symphysial and caudal components.

Animals↗
PubMed1996

[The usefulness of three-dimensional helical CT for the detection of abnormalities of the auditory ossicles].

To evaluate the usefulness of three-dimensional (3D) helical CT for the detection of abnormalities of the auditory ossicles, 3D helical CT of the middle ear was performed in seven patients with hearing disorder. It revealed that 4 patients had congenital deficiency of the auditory ossicles, 2 patients with chronic otitis media had shortening of the incus and one patient with head injury had doubtful fracture of the incus. This study indicated that 3D helical CT of the middle ear can represent the auditory ossicles objectively and can offer detailed diagnosis.

Adolescent↗
PubMedDate not supplied

The otologic manifestations of mandibulofacial dysostosis.

Sixteen patients (32 ears) with diagnoses of mandibulofacial dysostosis were reviewed. The characteristic otologic manifestations of the syndrome were delineated, found to be bilateral, and consist of the following: 1. Mild symmetric deformity of the auricle (grade 1 microtia). 2. Agenesis or hypoplastic development of the mastoid and mastoid antrum. 3. Absence of the external auditory canal. 4. Marked narrowing or agenesis of the middle ear cleft. 5. Agenesis or severe malformation of the malleus and incus. When present, the malleus and incus are most often rudimentary, fused to form a conglomerate mass, and ankylosed to either the atretic plate, epitympanum, or both. 6. Stapedial malformations which usually consist of a deformed suprastructure. 7. Frequently the tegmen assumes a more inferior (low lying) position than normal. 8. Occasionally, the facial nerve pursues an abnormal course and is located more anteriorly than would be expected. 9. A normal inner ear. 10. Normal bone conduction with a marked (greater than 50 dB) conductive hearing loss. 11. Marked disparity between the degree of auricular deformity (mild; grade 1 microtia) and the degree of deformity of the remaining first and second branchial arch derivatives that constitute the external and middle ears (severe).

Adolescent↗
PubMed1996

[The small fenestra vs large stapedectomy: comparative evaluation of failures and complications].

The Authors discuss post-operative failures and complications detected in their case-report of 1857 patients, operated for otosclerotic disease between 1982 and 1993 (399 large fenestra and 1458 small fenestra stapedotomies), with reference to the data from international literature. Their study reveals that the most frequent clinical event caused by complications arising is still hypoacusia of various degree, both conductive (2.7%) and sensorineural (6.6%); more precisely, conductive hearing loss points to revision surgery, while sensorineural lesions, often limited to high frequencies (5.7%), may unfortunately take the form of anacousia (0.9%). Some extra-auditory complications (temporary facial paralysis, ear drum perforation, disgeusia, tinnitus) are also present with relative frequency in stapes surgery (4.2%); among them, however, only impairment or appearance of tinnitus (0.6%) turn out to be a persistent disorder. Analysis of the results underlines that the complications rate is higher in the case of coexisting morphological anomalies (such as stenosis of the external ear canal, disjointing or amputation of the incus, difficulty in approaching the oval window, reobliteration of the oval window, facial nerve prolapse) or when intraoperative problems arise (excessive bleeding, profuse perylymph flow), which make the operation more difficult to perform. The data obtained in this study show that stapedotomy (using a 0.6 mm diameter prosthesis), gives a significantly lower rate of sensorineural complications (4.1%), than platinectomy (15.6%), because of the reduction of labirinthine traumatism. Lastly, the Authors performed 64 revision operations, evaluating intraoperative findings and hearing recovery rate. Causes of failure most frequently detected during revision surgery were: incus necrosis (24.6%) and prosthesis displacement (21.3%) with possible reobliteration of the oval window (23%); however it has not always been possible to detect pathogenesis of a postoperative conductive hearing loss. All things considered, results of revision surgery seem to be less satisfactory (56% improvements, 4.9% severe sensorineural hearing loss) than those obtained after the first operation.

Humans↗