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PubMed2002

[Computerized 3-D model to study biomechanics of the middle ear using the finite element method].

Based on known data about the behavior of the sound transmission mechanism, we generate a model that reproduces the real mechanics of the middle ear by the finite elements method in the most exact manner possible. We designed a computerized model to simulate the biomechanic behavior of the ear drum/ossicular chain. The investigation focused on a possible clinical application, given that the variables necessary for simulation of several conditions can be introduced in our model: tympanic perforation, fixation of the ossicular chain, chain interruption, etc. Introducing the characteristics of the lesion virtually in a simulator program market is possible to reach conclusions about the conductive hypoacusis created and about therapeutic possibilities. The 3-D modelling of the tympanic membrane, malleus, incus and stapes is presented, considering form, weight, density, Young's module (N/m2) and Poisson coefficient for the different parts of each ossicle. The modeling of the union of the different tympanic-ossicular elements, including muscles and ligaments, is also shown.

Biomechanical Phenomena↗
PubMed1990

Lateral temporal bone resections.

Eighteen consecutive patients underwent a lateral temporal bone resection for the treatment of tumors originating in the auricle, the external auditory canal, the periauricular skin, or the parotid and were retrospectively analyzed. The different lateral temporal bone resections performed have been categorized into four types. The type I resection consists of the removal of the tympanic bone and the external auditory canal lateral to the tympanic membrane. The type II resection consists of the removal of the entire tympanic bone, the tympanic membrane, the incus, and the malleus, preserving the facial nerve and the inner ear. Type III resections remove, in addition to the those structures removed in type II resections, the distal facial nerve and fallopian canal, the mastoid tip, the styloid process, and the stylomastoid foramen. The type IV resection consists of the removal of only the mastoid tip and the inferior portion of the tympanic bone. When the techniques of lateral temporal bone resection are used appropriately, adequate surgical treatment of patients with selected advanced and recurrent malignant tumors of the external ear, the periauricular skin, and the parotid is possible with low morbidity and a high probability of local regional control.

Adult↗
PubMed2001

Multicenter audiometric results with the Vibrant Soundbridge, a semi-implantable hearing device for sensorineural hearing impairment.

The Vibrant Soundbridge, a semi-implantable hearing device for subjects with moderate to severe sensorineural hearing impairment was introduced commercially. First audiologic results are presented on 63 patients from 10 European implant centers. Hearing loss was at 0.5, 1, 2, and 4 kHz varying between 43 and 81 dB HL. The patients used the analogue audio processor, type 302. Measured sound-field gain was compared with NAL-R target values. For most patients an acceptable agreement was found. There was a subgroup of patients, however, with relatively low gain. The results suggest that this was related to the suboptimal positioning and fixation of the transducer to the incus.

Audiometry, Speech↗
PubMed1988

Cytomegalovirus detection by nonisotopic in situ DNA hybridization and viral antigen immunostaining using a two-color technique.

Rapid methods of specific viral diagnosis in formalin fixed, paraffin embedded tissues include identification of viral incusions in routinely stained histologic sections, immunologic staining of viral antigens, and in situ nucleic acid hybridization. To correlate in situ hybridization with immunologic detection methods, sequential two-color staining was used on tissues from 12 patients, each containing characteristic cytomegalovirus (CMV) inclusions, using a biotinylated CMV DNA probe in an avidin-alkaline phosphatase-linked reaction followed by avidin-biotin complex immunoperoxidase staining of CMV antigen. CMV genetic material was seen in all 17 tissues. CMV antigen was detected in 11 of 17 tissues (65%). The DNA hybridization technique provided more intense staining, detected greater numbers of inclusions, and had less background staining than the immunoperoxidase technique. The alkaline phosphatase reaction product was stable through subsequent immunostaining steps, and immunologic reactivity of CMV antigen was not significantly reduced by prior hybridization steps. CMV DNA probe was localized predominantly within cell nuclei, while CMV antigen immunostaining was predominantly cytoplasmic. It was concluded that sequential in situ hybridization and immunocytochemistry can be performed on standard histologic sections. Furthermore, it is likely that the majority of CMV nucleic acid detected by this tissue hybridization technique is unencapsidated, intranuclear viral DNA and not DNA contained within complete CMV nucleocapsids.

Antigens, Viral↗
PubMed1984

Otosclerosis in a black child: diagnostic acoustic impedance studies.

Otosclerosis classically describes an osteodystrophic change in the bony labyrinth and stapes footplate, of autosomal dominant inheritance, reported rare under the age of 5, extremely "rare" in the Oriental and Black race, "non-existent" in the American Indian, and with a clinical incidence of 5 per 1000 Caucasians. The differential diagnosis of a non-effusion conductive hearing loss in a child should include otosclerosis, congenital malleus or footplate fixation, tympanosclerotic fixation, congenital cholesteatoma, lysis of the incus long process, Paget's disease, osteogenesis imperfecta, and fibromuscular hyperplasia of the renal artery. Presented is a case report of a 14-year-old black male with bilateral clinical otosclerosis and a persistent stapedial artery. Preoperative multiple-frequency tympanometry and Zwislocki acoustic reactance and resistance analysis demonstrated absence of the "W" resonance pattern on high-frequency tympanometry and the classic friction and stiffness patterns of otosclerotic fixation. Repeat multiple-frequency tympanometry testing post-stapedectomy demonstrated prosthesis articulation. Prosthesis position can be monitored postoperatively by these acoustic impedance studies.

Acoustic Impedance Tests↗
PubMed1999

Spread of amniotic fluid cellular content within the neonate middle ear.

Six full-term neonatal temporal bones, with meconium contaminated amniotic fluid aspiration of varying degrees, were serially sectioned at 20 microm and every tenth section was stained by hematoxylin eosin and mounted on slides. All stained sections were studied, the data recorded and relevant details of all compartments photographed. In addition, four normal neonate temporal bones were studied, one by serial sectioning and three by microdissection. The lateral incudomalleal and tensor folds were present in all, membrane defects in the tensor fold were seen in two normal ears. Three ears in the aspiration group had much fetal tissue present rendering Prussak's space small. Four ears with aspiration had remnants of incus intercrural (medial) folds. The amniotic fluid cellular content (AFCC) was sparse or nonexistent in the supratubal recess, Prussak's space and hypotympanum. It concentrated to the areas around the stapes, to sinus tympani and round window niche, to lower lateral attic and posterior pouch, medial attic and in lesser amounts to superior attic, mastoid antrum and air cells. Massive amounts of AFCC in tympanic isthmus and posterior pouch may lead to formation of granulation tissue and blockage of the aeration pathways to attic proper and to Prussak's space. These changes may initiate the development of chronic secretory otitis media in infants.

Amniotic Fluid↗
PubMed1993

Auditory behaviour and brainstem histochemistry in adult rats with characterized ear damage after neonatal ossicle ablation or cochlear disruption.

Binaural and monaural ossicle ablation in neonate rats before the time of onset of auditory input resulted in hearing deficits as detected by behavioural responses to sound stimuli in these rats as young adults. Cochlear disruption at the same neonatal age similarly resulted in the absence of startle reflexes in many of the rats. When the middle and inner ears of the rats were analysed postmortem in serial sections, it was observed that most ears after neonatal ossicle ablation contained only small remnants of the malleus-incus unit, separated from the stapes; in other ears an apparent continuity of ossicles had been restored. The rats with blind-ending ear canals and ossicle atrophy were those that had shown little response to sound stimuli. In the cochlear-disrupted rats, those with modiolar damage and loss of most spiral ganglion cells had shown substantial impairment of sound perception, even in some rats with only monaural modiolar loss. The chronic conduction deficit caused by neonatal ossicle removal did not result in detectable differences in relative cytochrome oxidase activity in the dorsal cochlear nuclei and central nucleus of the inferior colliculus. For monaurally ossicle-ablated rats, quantitation of the average intensity of enzyme reaction product in sections of dorsal or ventral cochlear nuclei, or central nucleus, did not reveal a difference between operated and non-operated sides. However, in binaurally ossicle-ablated rats, the relative enzyme activity in the anteroventral cochlear nuclei was reduced in comparison to this nucleus in control rats. The volume of the anteroventral cochlear nucleus in rats that had had neonatal binaural cochlear disruption was reduced relative to the volume in control rats or in rats that had had binaural ossicle ablation (P < 0.001); the latter procedure did not result in a statistically significant difference from controls in AVCN volume. In cochlear-operated rats with monaural modiolar damage, the AVCN contralateral to the damaged cochlea had a lower mean level of cytochrome oxidase activity in its neurons measured individually than that for neurons in the ipsilateral AVCN. These results suggested the importance during development of input from contralateral cochlear neurons.

Acoustic Stimulation↗
PubMed1999

Malleus-to-footplate prosthetic interposition: experience with 265 patients.

Absence of the long process of the incus with or without absence of the stapes head accounts for more than 80% of ossicular discontinuities. Total or partial replacement prostheses, made of various materials, are interposed to restore the transfer function of the middle ear. To simplify ossicular reconstruction, reduce operative times and costs, improve functional outcomes, and avoid the risk of infections, we have adopted, during the past 10 years, a technique that makes use of a personally designed alloplastic prosthetic device. The prosthesis connects the malleus to the footplate, even in the presence of the stapes superstructure. This malleus-to-footplate prosthesis consists in a plastipore-coated steel piston and hydroxyapatite head, complete with a groove. The groove is placed beneath the malleus neck after dissection of the tensor tympani tendon and the shaft of the piston on the footplate. Two hundred ninety primary ossiculoplasties with the malleus-to-footplate prostheses were performed in 265 patients from 1986 to 1995 in the ENT Department of the University of Verona. The average postoperative air-bone gap at 0.5 to 3 kHz was 11 dB at 1 year and 14 dB at 5 years. These outcomes are significantly better than those personally obtained previously with ossicular or alloplastic prostheses. No extrusions occurred. The structural characteristics of the malleus-to-foot-plate prosthesis endow the prosthesis with a high degree of biocompatibility and stability and optimal sound-transfer function. The rationale for this particular ossiculoplasty procedure is discussed.

Adolescent↗
PubMed1981

Middle and inner ear changes in congenital rubella.

Temporal bone changes in a 14-month-old female infant with congenital rubella are described. The inner ears showed cochleo-saccular degeneration, with more severe involvement of the right side. Perivascular round cell infiltration was demonstrated in the base of the cochlea, stria vascularis, and superior ampullary cribriform region, consistent with viral infection. Whether the latter was related to the rubella or the the patient's terminal viral infection is undetermined. Predominant involvement of the cochlea saccule may have been related o their blood supply from the vestibulo-cochlear artery, which is a more direct continuation of the labyrinthine artery than are the other branches. Middle ear changes consisted of a fetal type of stapes, a small area of malleus head fixation on one side, and absence of the medial component of the posterior incudal ligament, with a joint-like attachment between the short process of the incus and the medial wall of the fossa incudis. This may be an abnormality, or it might represent a variation of normal development.

Ductus Arteriosus, Patent↗
PubMedDate not supplied

Middle ear structure in the chinchilla: a quantitative study.

The anatomic features of the chinchilla middle ear were identified and various aspects of the conductive apparatus were measured in a number of specimens by different methods. These aspects included area measures of the tympanic membrane, stapes footplate, oval window, and round window; middle-ear volume; dimensions of the ossicles, the length of their rotational axes as well as the malleus to incus lever ratio. We also weighed the ossicles. The findings are discussed with reference to their possible significance for auditory signal processing in the chinchilla.

Animals↗
PubMed2005

[Imaging of postoperative failures and complications in stapes surgery for otosclerosis].

Otosclerosis (OS) is a dysplasia of the otic capsule located in most cases on the anterior margin of the oval window or fissula ante fenestrum. Progressive conductive hearing loss is the major clinical symptom, due to stapedovestibular ankylosis. Stapes surgery is the only effective treatment of OS, with excellent functional results in more than 90% of cases. However, failures and complications of the surgery may be observed. In theses cases, the etiologic work-up includes imaging evaluation (CT and MRI). Imaging findings are extremely useful in the therapeutic decision. Surgical failure represents 80% of the causes for surgical revision. The main causes of failure are: displacement of the prosthesis, fibrosis of the oval window, erosion of the long process of the incus, incudo-mallear dislocation, obliterative otosclerosis. CT is essential for diagnosis. MR imaging is rarely indicated in the work-up of surgical failures. Labyrinthine complications account for less than 20% of surgical revisions. Etiologies of labyrinthine complications are: intravestibular penetration of the prosthesis, perilymphatic fistula, intra-vestibular granuloma, labyrinthitis and intravestibular bleeding. CT and MRI are complementary for the work up of these complications.

Adult↗
PubMed1999

Scaling of the cetacean middle ear.

Functionally interesting dimensions of the tympano-periotic complex were measured and compared in 18 odontocete and six mysticete species, ranging from small porpoises to the blue whale. We determined (i) the masses of the tympanic and periotic bones (T and P) and of the ossicles malleus, incus, and stapes (M, I and S), (ii) the volume occupied bythe tympanic bone (V), (iii) the areas of the tympanic plate and oval window (A1 and A2), (iv) the thickness of the tympanic plate (D), and (v) the densities of the ossicles (dM, dI, and dS). In most cases, roughly isometric scaling was found in both toothed and baleen whales. P is isometric to T, and the tympanic bone is structurally isometric in all species studied, although not within mysticetes as a group, shown by the isometric relations of V to T, of T(2/3) to A1, and of D to square root(A1). The essentially isometric scaling of the tympanic bone provides a basis for the functional models described by Hemilä et al. (1999). The relation of S to M+I is also isometric, but the relation of M+I+S to T is negatively allometric, as is the relation of A2 to A1, both with slopes close to 2/3. The possible functional implication of this allometry is unknown. The mean ossicular density is 2.64 g/cm3 for odontocetes, and 2.35 g/cm3 for mysticetes. The highly mineralized and convex tympanic plate provides cetaceans with a uniquely large and stiff sound collecting area.

Animals↗
PubMed1999

A model of the odontocete middle ear.

The high acoustic sensitivity of the bottlenose dolphin is physically defined and related to the anatomy of the middle ear. The paper presents a conceptual and parametric analysis of the demands imposed by this high sensitivity upon the middle ear mechanisms: the head and the middle ear structures must collect sound energy from a large area and concentrate it onto the oval window. Assuming that the specific input impedance of the mammalian cochlea is relatively constant, and smaller than the characteristic acoustic impedance of water, we find that the impedance matching task of the cetacean middle ear is very different from that of terrestrial mammals: instead of a large pressure amplification, cetaceans need amplification of particle velocity. Our mechanical four-bone model of the odontocete middle ear is based on the anatomy of the tympano-periotic complex and consists of four rigid bone units (tympanic bone, the malleus-incus complex, stapes, periotic bone) connected through elastic junctions. The velocity amplification is brought about by lever mechanisms and elastic couplings. The model produced velocity amplifications ranging from 7- to 23-fold when provided with middle ear parameters from the six odontocete species for which audiograms are available. The model reproduces the complete audiograms of these six species fairly well for frequencies up to about 100-120 kHz.

Animals↗
PubMed2001

Surgical strategy for cholesteatoma in children.

OBJECTIVE: We reviewed our experience with childhood cholesteatoma in children under 15 years old. Based on cumulative postoperative data, we propose a modified canal-wall-up technique in conjunction with a planned, staged operation. METHODS: From 1982 to 1997, 56 children with cholesteatoma (58 ears, total) underwent surgery in our department. In the early period (1982-1990), canal wall-down mastoidectomy was performed in 52% (21 of 40 ears), and canal wall-up mastoidectomy in 48% (the remaining 19 ears). In the late period (1991-1997), 18 ears with cholesteatoma underwent surgery. The canal-wall up mastoidectomy was performed in 89% (16 ears), and canal-wall-down mastoidectomy in the remaining 11% (two ears). RESULTS: In the early period (1982-1990), cholesteatoma recurred more frequently in the canal-wall-up mastoidectomy group than in the canal-wall down mastoidectomy group (53 vs. 14%). Other postoperative complications, such as erosion of the mastoid cavity, otorrhea, and perforation of the eardrum, occurred more frequently in the canal-wall-down mastoidectomy group than in the canal-wall-up mastoidectomy group. In the late period (1991-1997), in the canal-wall-up mastoidectomy group, ten ears underwent one-stage surgery. Planned staged tympanoplasty was completed in six ears. After one-stage surgery, four of ten ears experienced residual cholesteatoma. Two of the recurrent ears had undergone planned staged tympanoplasty. As revealed by postoperative computed tomography (CT) images, 12 of 15 ears had aeration in the attic and antrum as well as in the tympanic cavity. In these cases, no attic retraction pocket formation was observed. CONCLUSION: Our strategy for pediatric cholesteatoma in the future is to use canal-wall-up mastoidectomy when possible. If aeration in the attic and antrum is observed by preoperative CT-scan image and no erosion in the malleus and incus exists, the one-stage surgery will be chosen. If no aeration is observed by CT-scan and/or erosion exists in the surgical findings, planned staged tympanoplasty will be necessary. This strategy allows a high incidence of aeration of the attic and antrum, and prevents the formation of the attic retraction pocket while enabling the early detection of residual cholesteatoma by means of CT.

Adolescent↗
PubMed2002

Surgical treatment of 52 cases of auditory ossicular malformations.

OBJECTIVE: The aim of this study was to determine the relationship between hearing improvements and the pathological conditions of auditory ossicular malformations. METHODS: Fifty-two ears (49 patients) with auditory ossicular malformations without congenital aural atresia were studied. The classification of the pathological conditions was based on surgical findings. Group 1 showed defects in the incudo-stapedial (I-S) joint, Group 2, fixation of the stapes, Group 3, fixation of the malleus and incus and Group 4, defects in the I-S joint with fixation of the stapes. Hearing improvements at the final examination were designated as successful when both of the following were satisfied. (1) Air-bone gap was reduced to 20 dB or less. (2) Postoperative hearing gain exceeded 15 dB. RESULTS: Successful hearing improvements after operations were achieved in 20 ears (95%) in Group 1, 21 ears (91%) in Group 2, three ears (75%) in Group 3 and two ears (50%) in Group 4. They were observed in 88% of all cases. CONCLUSIONS: Postoperative hearing improvements of auditory ossicular malformations yielded good results, particularly in Groups 1 and 2. In retrospect, the unsuccessful cases with fixation of the stapes would have been improved if stapedectomy were chosen rather than mobilization. In defects to the long process of Group 4, we wished to perform a reconstruction using the malleus attachment piston after small-fenestra stapedectomy with regard to the long-term hearing results.

Adolescent↗
PubMed2002

Autoclaving the ossicles provides safe autografts in cholesteatoma.

OBJECTIVE: The choice of the graft in ossicular chain reconstruction during middle ear surgery for cholesteatoma is a subject still discussed on. In order to clarify the discussion of reuse of the autologous ossicles obtained during middle ear surgery for cholesteatoma, we evaluated the probability of residual disease histologically and the safety of the ossicles after autoclavization, the most promoting alternative method to eradicate residual cholesteatoma and infection on them. METHODS: The specimens used in this study were eroded twenty-seven ossicles (22 incuses, 5 malleoli) which were removed from the 27 consecutive patients operated because of cholesteatomatous middle ear disease. They were grouped as follows: Group 1, Fifteen ossicles examined histopathologically directly. Group 2, Five ossicles autoclaved for 20 min at 134 degrees C and then examined histopathologically. Group 3, Five ossicles autoclaved for 20 min at 134 degrees C after mechanical surface cleaning by a fine diamond drill, examined histopathologically. Group 4, Two ossicles removed from two different patients were placed in their mastoid cavities in order to be examined after access in the second-look operation. While one ossicle was only autoclaved, the other was mechanically cleaned by a drill before autoclavization (for 20 min at 134 degrees C). The ossicles were examined histopathologically after the removal at the second stage operation performed 12 months later. RESULTS: In Group 1, all ossicles showed evidence of periosteal thickening. Additional findings were surface cholesteatoma or epithelia in 13 ossicles, surface inflammation in 12 ossicles, granulation tissue in 10 ossicles, osteitis in six ossicles. In Group 2, all five ossicles had preserved their lamellar structure but, no vital cells were seen. The lacunes that had the osteocytes was almost completely empty. The inflammatory cells were eliminated from the ossicles. In Group 3, ossicles were found well preserved with their lamellar structures and contours, with empty lacunes and eliminated inflammatory cells. In Group 4, in two ossicles of this group the lacunes were replaced by the new migrated viable osteocytes with evidence of new bone formation and neovascularisation. No new inflammatory focus or epithelia were found on the surfaces of the ossicles. The shape and the contour of the ossicles remained unchanged. CONCLUSION: In cholesteatoma surgery, ossicles with minimal erosion and adequate thickness can be used after autoclavization. In this study, it was observed histopathologically that the autoclaving autologous ossicles before ossiculoplasty in cholesteatomatous middle ear is a safe and reliable method.

Cholesteatoma, Middle Ear↗
PubMed1996

Middle ear anomalies induced by hypertriazene administration in the mouse.

The middle ear is derived from various embryonic tissues. Many experiments using teratogens have been performed, employing the difference of each tissue's sensitivity to the teratogen and the tissue's critical time of development. Triazene, a foliate metabolism antagonist, produced anomalies in fetuses that resembled those associated with thalidomide in humans, the so-called the first and second branchial syndrome. In our experiment, we administrated 3,3-dimethyl-1-phenyltriazene, an inductor of triazene, to pregnant mice at 7 to 14 days of gestation resulting in unique fetal anomalies. We examined the development of the stapes, stapedial artery, facial nerve, and oval window using an optical microscopic and three-dimensional reconstruction. Middle ear and facial nerve anomalies in mice depend on the gestation day when triazene is administrated. The stapedial artery, oval window, facial nerve (horizontal segment), stapes footplate, and styloid process are affected on the 9th to 11th administration day, the annular stapedialis on the 10th to 11th day, and the malleus and incus on the 9th to 11th day. The use of the Vox View/Mac, allowed us to create three-dimensional pictures from two-dimensional slides providing an improved understanding of the relationships between anatomical structures.

Animals↗
PubMed2001

CT and MR imaging after middle ear surgery.

This article describes the current value of imaging in patients after stapes surgery and surgery after chronic otitis media including cholesteatoma. Possibilities and limits of computed tomography (CT) and MRI are described and most important investigation parameters are mentioned. After otosclerosis surgery, CT is the method of first choice in detection of reasons for vertigo and/or recurrent hearing loss in the later postoperative phase. CT may show the position and condition of prosthesis, scarring around the prosthesis and otospongiotic foci. Sometimes, it gives indirect hints for perilymphatic fistulas and incus necrosis. MRI is able to document inner ear complications. CT has a high negative predictive value in cases with a free cavity after mastoidectomy. Localized opacities or total occlusion are difficult to distinguish by CT alone. MRI provides important additional information in the differentiation of cholesterol granuloma, cholesteatoma, effusion, granulation and scar tissue.

Cholesteatoma↗