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PubMed1984

Gamma-carboxyglutamate in normal and pathological human middle ear bones.

The presence of the amino acid gamma-carboxyglutamate (GLA) was established in human middle ear bones. Proteins containing GLA have been described as being associated with normal as well as pathological calcifications. The GLA content of human incus, malleus, and stapes with 1-2 nmol/mg bone is in the range previously reported for a variety of bone. A limited number of samples with middle ear pathology, including otosclerosis, did not show altered GLA levels.

1-Carboxyglutamic Acid↗
PubMed1981

[A comparative anatomic contribution to the development of the ossicles and the annular ligament (author's transl)].

The development of ossicles and annular ligament in the rat (Rattus norwegicus L.) is studied by means of light and TE microscopy. Initial stages of ossification are independent of vascularization of the cartilaginous anlage of the ossicles. During endochondral ossification of the incus and the malleus the cells are arranged in zones of growth, hypertrophic cells, and necrotic cells, which is similar to the ossifying epiphysis femoris. The ossification of the stapedial footplate resembles that of the endochondral layer of otic capsule and displays a non-zonal pattern of cellular transformation. Mesenchymal cells are arranged palisade-like in the region of the annular ligament during early stages of development. Later on, their ultrastructure corresponds to fibroblasts. Their number decreases with increasing age. It is discussed whether or not the stapedial footplate belongs embryologically to the labyrinthine block.

Aging↗
PubMed1977

Tympanoplasty in Korea (ossiculoplasty).

Three hundred and ninety three cases of ossicular reconstruction are presented. In the most favourable cases with both malleus handle and stapes present, this presents a closure of the air-bone gap to within 20 dB better than 80%. With connective tissue, underlay and fixation technique and staging are all important aspects of ossicular chain repair. Preservation of the function of the sound conduction mechanism in most favourable cases (malleus handle and stapes arch present) were improved by the employment of a sculptured, fitted incus prosthesis between the handle of the malleus and the head of the stapes.

Ear Ossicles↗
PubMed1992

A new model of equilibrium dysfunction in the rat induced by photochemical damage to the inner ear's microcirculation.

A new photochemical method was employed to damage the inner ear microcirculation in the rat. Under pentobarbital anesthesia, the middle ear was exposed by a ventral approach and the tympanic membrane and the malleus and incus were removed. The vestibule was then illuminated by a filtered xenon light (wave length: 540 nm) while rose bengal was infused intravenously. Microscopic examination revealed disintegration of the hair cells in the vestibule. Changes could be prevented by pretreatment with intravenous acetylsalicylic acid (ASA) or heparin. Twenty-four hours after the completion of photo-illumination the rats exhibited nystagmus toward the intact ear and showed rolling during the swimming test, both signs of equilibrium dysfunction. These findings were inhibited by ASA or heparin pretreatment. Our present results indicate that our method causes a photochemically induced occlusion in the rat's inner ear microcirculation and may be useful for evaluating the various effects of drugs on the inner ear.

Animals↗
PubMed1995

Ear malformations in the mouse embryo following maternal administration of triazene, with clinical implications.

Triazene administration to 10-day pregnant mice gave rise to severe ear abnormalities, including middle ear ossicle malformations. The head of the malleus and the body of the incus were sometimes absent. In some instances, the stapes appeared dysplastic. The stapedial artery was often quite dilated, as well as other cephalic vessels, but qualitatively normal. Severe inner ear abnormalities were observed, as well as auditory nerve disruption, which was associated with central nervous system lesions. Multiple haematomas were present in the embryonic face, but ear abnormalities occurred even in the absence of local hemorrhages. We postulate a direct effect of the teratogen on the branchial mesenchyme. This model seems to be useful for the comprehension of human middle ear abnormalities, but does not constitute a phenocopy of hemicranial microscomia.

Abnormalities, Drug-Induced↗
PubMed1992

Induced and genetic mouse middle ear ossicular malformations: a model for human malformative ossicular diseases and a tool for clarifying their normal ontogenesis.

Oral administration of 13-cis retinoic acid (RA) to pregnant mice on the 9th gestation day provokes important malformations of the middle ear ossicles, associated with a general kind of craniofacial dysmorphogenesis evoking the human mandibulofacial dysostosis. The malleus, incus and stapes are affected. The malleus exhibits a handle separated from its head and keeping a persistant relationship with the tubotympanic recess. The stapes makes no contact with the otic capsule. The malformation pattern is visible early as shown by the appearance of an abnormally curved Meckel's cartilage at day 12, followed by the development of atypically shaped ossicular anlagen. The mouse "far" (first arch malformation) mutation is responsible for minor ossicular abnormalities which disrupts the normal relationships between the stapes, Reichert's cartilage and stapedial muscle. The administration of RA to pregnant mice and the comparison with a genetically induced malformation (the mutation far) provides some interesting information about the postulated mechanisms of human middle ear dysmorphogenesis, as well as precious data about the features of normal ossicular primordia formation. The comparison of these features with human middle ear abnormalities as revealed by medical imaging sheds light on human malformation patterns and provides a better understanding of normal and abnormal radiologic ossicular aspects.

Abnormalities, Drug-Induced↗
PubMed2004

[Realistic early and late results after otosclerosis surgery and presentation of a technique involving almost no complications].

Although the modern technique of otosclerosis surgery introduced by John Shea on 1st May 1956 has already been used throughout the world for almost fifty years it has not been possible to bring in line the differing opinions of surgeons concerning the optimum operation technique, the problems of the fenestration of the footplate, material and form of stapes replacement prosthetics and kind and place of their anchoring on the incus. Moreover, there is considerable disagreement among surgeons on a realistic evaluation of the findings of early and late results. During the last few decades otosclerosis surgery has become the hallmark of modern ear surgery and has been practiced in very highly specialized departments as well as in outpatient departments. The author, who has been very active in otosclerosis surgery since 1959-since 1979 with a modified personal technique-, wishes to prove that it is both meaningful and essential to modify the operation technique further, which is based on his own experiences and on more than 100 international publications. In this paper he presents his modified method, which has been tested on 1800 ears since 1979, as well as the results, achieved in this way.

Auditory Threshold↗
PubMed2005

[Pitfalls in ossicular chain reconstruction].

Today, the reconstruction of the ossicular chain is standard in middle ear surgery. It is performed as a one step procedure in cases of non-inflamed middle ears, as well as in cases of chronic ear diseases. In contrast to the past, a large tympanic cavity is today regularly reconstructed, which contributes to a normally ventilated middle ear. Reconstruction of the ossicular chain is necessary to keep the tympanic membrane in its normal position.However, many modern prostheses are available with different designs and material properties. This article aims to give an overview of the acusto-mechanical and surgical aspects of ossicular chain reconstruction. After a description of normal middle ear vibration, the biomechanical background of the reconstructed middle ear (incus reconstruction, stapes reconstruction) is discussed.

Ear Diseases↗
PubMed2007

[First experiences with a new nickel-titanium piston with a shape memory feature].

BACKGROUND: The aim of this study was to describe a new stapes prosthesis with memory characteristics for wire crimping (SMart-Piston). PATIENTS AND METHODS: This technique was used in 15 patients (mean age 43.4 years; range 28-71) undergoing routine stapes surgery. SMart-Piston prostheses with a shaft diameter of 0.5 mm and length ranging from 4.25-4.5 mm were used. Heat induced wire crimping was performed by CO2 laser in five patients, and by bipolar diathermy forceps in ten patients. In 15 patients, postoperative audiological testing was performed at an average 21.9 days and in another 10 again after 435 days following surgery. RESULTS: The median observed air-bone-gap (ABG) postoperatively was 8.7 dB+/-7.7 dB. A total of 73% of all patients had an ABG of 10 dB or less, and all patients had less than 20 dB. In the ten patients controlled after 435 days, the ABG was 4.4 dB+/-2.4 dB. It was lower than 10 dB in all individuals. DISCUSSION: A critical point in every stapes surgery, the prosthesis fixation to the incus, is greatly facilitated by this novel technique. Long-term results in a larger group of patients are pending.

Adult↗
PubMed2007

[Rehabilitation of high frequency hearing loss: use of an active middle ear implant].

BACKGROUND: In spite of modern technology conventional hearing aids are only helpful in a limited number of patients with sensorineural hearing loss. In particular, patients presenting with moderate to severe high frequency hearing loss but only mild hearing loss in the low frequencies suffer from problems associated with conventional hearing aids such as occlusion of the ear canal and feedback. The aim of the study was the evaluation of rehabilitation of patients with high frequency hearing loss with the active middle ear implant Vibrant Soundbridge. PATIENTS AND METHODS: The Vibrant Soundbridge was surgically implanted into 30 patients, and the floating mass transducer was clipped onto the long process of the incus. Out of the 30 patients 9 presented with a ski slope audiogram of high frequency hearing loss of 25 dB within 1 octave in the frequency range 1000-8000 Hz. Main outcome measures were pure tone audiometry, speech audiometry in quiet and in noise. RESULTS: Residual hearing was preserved in all cases. Functional hearing gain was in proportion to the individual hearing losses and was remarkably high in the high frequencies up to 8000 Hz. Mean functional gain was 34 dB in the frequencies between 2000-8000 Hz. Speech recognition scores in quiet and in noise were significantly higher with the implant compared to the unaided situation. CONCLUSION: The middle ear implant Vibrant Soundbridge has been shown to be perform extremely well especially in the high frequencies. It offers a new solution for rehabilitation of high frequency hearing loss.

Adult↗
PubMed1997

[An implantable hearing aid for inner ear hearing loss. Short-term implantation of microphone and transducer].

A microphone constructed for implantation in the posterior wall of the auditory canal and a piezoelectric transducer serving as the main components of an implantable hearing aid were temporally implanted in five patients during middle ear surgery under local anesthesia. The microphone was positioned beneath the skin of the auditory canal such that it completely covered the microphone membrane. The vibratory element of the transducer was coupled to the malleus in four patients with normal ossicular chains and directly to the stapes in one patient with missing incus. The microphone and transducer were electrically connected with an external battery-driven signal amplifier. Speech material and music were presented in the operation room at a sound level of 65 dB SPL under free-field conditions. The patients had to estimate the quality of speech, music, and their own voice as well as the effects of bone-conducting noises. All patients were able to hear with the system. An intraoperative talk without vision contact was possible without any problems, as was understanding of numerals ("Freiburger Zahlentest"). Perception of music was judged as "clear and undistorted with all broadband component." The estimation was also valid for one patient with a sensorineural hearing loss. One patient declared the music to be "a little of unnatural." Bone-conducted sound was estimated as normal in two patients, better than without an implant in one patient with sensorineural hearing loss, and "somewhat metallic" in another patient. Hearing the own voice was considered "normal" in two cases "monotonous" in one case, and "a little bit roaring" in another case. An amplification factor that can be technically realized in an implantable hearing aid was necessary for one of the patients with sensorineural hearing loss to perceive music at a pleasant volume. On the basis of this study, essential requirements for the construction of a fully implantable hearing aid are fulfilled.

Adult↗
PubMed1998

[First implantation of a totally implantable electronic hearing aid in patients with inner ear hearing loss].

For the majority of patients with sensorineural hearing loss (SNHL) many available hearing aids often do not achieve satisfactory results. For these patients partially implantable hearing devices have been developed, allowing distortion-free hearing and speech intelligibility that may be superior to conventional hearing aids. The external parts of partial implants, however, may result in a patient's stigmatization. Furthermore, they do not use the acoustic properties of the external auditory canal. Recently, we published the successful development of the first totally implantable hearing device for the treatment of SNHL (HNO 46 [1998] 853-863). Here we report the first implantations of this unique, totally implantable electronic hearing system in patients with SNHL: Implex TICA LZ 3001. The implant microphone is implanted subcutaneously in the outer ear canal near the ear drum. The signal is processed by a digitally programmable multichannel audioprocessor located subcutaneously on the bony skull behind the ear. A piezoelectric transducer is coupled to the body of the incus and drives the ossicular chain by vibratory actions. Energy is provided by an implantable battery. Implanted patients describe hearing as being distortion-free and transparent. Speech intelligibility and the hearing of music are improved. Patients may achieve better speech discrimination, especially in the presence of background noise. The aid can be used during sports, including swimming. To our knowledge, this is the first report of the implantation of a totally implantable electronic hearing system in patients. These results encourage further implantations of the totally implantable hearing system in the course of an ongoing clinical study.

Audiometry, Speech↗
PubMed2001

[Hyperacusis after tympanoplasty].

A case of hyperacusis after tympanoplasty is presented. A 62-year-old woman experienced unilateral conductive hearing loss for about 60 years after antrotomy in infancy. Neurological or otoneurological symptoms were not evident. Tympanotomy showed a missing incus with discontinuity of the chain. Reconstruction was performed by interposition of a partial ossicular replacement prosthesis (PORP). The postoperative audiogram revealed minimal perceptive hearing loss in the high-frequency field in the operated ear. Several weeks after middle ear surgery, the patient complained of hyperacusis on the operated side, which persisted for more than 2 years. To alleviate the unpleasant sensations, an ear plug was used by the patient. In spite of the asymmetric hearing loss, no late onset auditory deprivation could be diagnosed. The pathophysiological causes of the hyperacusis have not yet been clarified. Possible reasons are discussed.

Audiometry, Pure-Tone↗
PubMed1998

CT of the temporal bone in the CHARGE association.

We reviewed the CT examinations of the temporal bone, performed with 1-mm-thick contiguous sections, of seven patients with the CHARGE association. We found abnormalities of the incus and stapes, with ossicular chain fixation, absence of the stapedius muscle and oval window, hypoplasia or dysplasia of the vestibule and absence of the semicircular canals in all ears. The pyramidal eminence and tympanic sinus were absent and there were anomalies of the cochlea in 13 of 14 ears. Absence of the semicircular canals is the most specific change in patients with the CHARGE association.

Abnormalities, Multiple↗
PubMed2004

An ENU-induced mutation in AP-2alpha leads to middle ear and ocular defects in Doarad mice.

One of the advantages of N-ethyl- N-nitrosourea (ENU)-induced mutagenesis is that, after randomly causing point mutations, a variety of alleles can be generated in genes leading to diverse phenotypes. For example, transcription factor AP-2alpha ( Tcfap2a) null homozygote mice show a large spectrum of developmental defects, among them missing middle ear bones and tympanic ring. This is the usual occurrence, where mutations causing middle ear anomalies usually coincide with other abnormalities. Using ENU-induced mutagenesis, we discovered a new dominant Tcfap2a mutant named Doarad ( Dor) that has a missense mutation in the PY motif of its transactivation domain, leading to a misshapen malleus, incus, and stapes without any other observable phenotype. Dor homozygous mice die perinatally, showing prominent abnormal facial structures and ocular defects. In vitro assays suggest that this mutation causes a "gain of function" in the transcriptional activation of AP-2alpha. These mice enable us to address more specifically the developmental role of Tcfap2a in the eye and middle ear and are the first report of a mutation in a gene specifically causing middle ear abnormalities, leading to conductive hearing loss.

Amino Acid Sequence↗
PubMed2005

Ossicular differentiation of airborne and seismic stimuli in the Cape golden mole (Chrysochloris asiatica).

Comparison between the middle ear anatomy of the Cape golden mole (Chrysochloris asiatica), which exhibits a club-shaped malleus head, and the Desert golden mole (Eremitalpa granti), with a ball-shaped malleus head, suggests differences in sensitivity to airborne sound. Scanning laser Doppler vibrometric measurements of the ossicular behavior in response to both vibration and airborne sound were made in C. asiatica. Two distinct vibrational modes were observed. In response to low-frequency vibration (70-200 Hz), the malleus oscillates about the ligament of the short process of the incus, whereas in response to high-frequency airborne sound (1-6 kHz) the ossicular chain rotates about the long axis of malleus. It is proposed that the club-shaped malleus head in C. asiatica constitutes an adaptation towards bimodal hearing-sensitivity to substrate vibrations and airborne sound. Possible functional differences between these two middle ear types are discussed.

Acoustic Stimulation↗
PubMed1998

Ionomeric cement implants in the middle ear of the baboon (Papio ursinus) as a primate model.

Faced with an inadequate supply of autogenous materials, the otologic surgeon may have to utilize various alloplastic materials to reconstruct bony middle ear structures. Allogenic materials have fallen into disfavor clinically because of the possible spread of infections. Implantation of the hybrid bone substitute ionomeric cement in viscous or hardened physical states into the middle ears of a primate animal model was undertaken in order to be able to approximate as closely as possible conditions found clinically. The posterior meatal wall was replaced by freshly mixed ionomeric cement in nine baboons (Papio ursinus). After repositioning the meatal flap, the residual skin defect was left to secondary epithelialization. After removal of the stapes superstructure, incus and malleus head, a columella of hardened ionomeric cement was trimmed to the appropriate size and inserted between the footplate and the malleus handle. In three cases the prosthesis shaft was fixed in position with freshly mixed cement near the footplate. The time of follow-up ranged from 47 to 277 days. Gross sections were obtained without decalcification (using a Zeiss saw microtome) and stained with Giemsa solution. In no instance was there any spontaneous epithelialization of the external meatus, although occasional granulation was seen to develop at the free edge of the flap and subepithelially. Epithelialization of the alloplastic columellae occurred as early as 42 days post-implantation. Over the middle ears reconstructed with the viscous cement, there was growth of a thickened epithelium that partially tended to granulate. On light microscopy, the bony footplate area was found to be unaffected by the cement that had been applied when still fluid. Our findings indicate that reconstruction of the posterior meatal wall with the viscous ionomeric cement can be useful clinically. The material does not become dislocated but, as with all other alloplastic materials, spontaneous overgrowth of the adjacent meatal skin is unlikely to occur. The early epithelialization of the columellae and their middle ear compatibility and biostability give support to the excellent tolerability of the ionomeric cement. At present, complications occurring during otoneurological application of the material necessitated its commercial withdrawal from the market in May 1995.

Animals↗
PubMed2002

Virtual endoscopy imaging of the middle ear cavity and ossicles.

Ten cadaver temporal bone blocks were studied with high-resolution computed tomography (HRCT) in order to produce topographic images, which are more informative than ordinary CT slices. Virtual endoscopic images were produced with separate, commercially available software, paying attention to the middle ear cavity and ossicles. Four major viewing locations for virtual endoscopy (the ear canal, hypotympanum, attic and eustachian tube) developed images acceptably. The malleus and incus were visualized properly. Small structures such as the lenticular process and the stapes sometimes failed to have good imaging. The eustachian tube and attic virtual views, which are usually not receptive to ordinary endoscopy, gave proper visualization of middle ear structures. Even the smallest structure, the stapes, can produce a virtual image.Virtual endoscopic images, or topographic images, of the middle ear and ossicles contribute to the understanding of the anatomy of the middle ear, thus enhancing the chances for successful surgery.

Adult↗