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PubMed1985

Temporal bone pathology in congenital anomalies of the oval window and the facial nerve.

Temporal bones of six infants with congenital ear anomalies were examined for abnormalities of the oval window and facial nerve. These temporal bones were classified into two groups according to the degree of malformation: group A, those with atresia or absence of the oval window; and, group B, those with hypoplasia of the stapes and annular ligament. Group A, consisting of five ears, were associated with severe middle ear anomalies such as the abnormal course of the facial nerve and absence of the stapes. In group B, consisting of seven ears, the stapes were present and the facial nerve presented minor anomalies such as obtuse angulation at the first genu, central migration of the geniculate ganglion cells, ectopic muscles and a wide bony dehiscence of the facial canal around the oval window. Probable origin of the anomalies in group A could mainly be due to maldevelopment of the facial nerve during an earlier embryonal period while that of group B could have developed after the ninth week of the fetal period and are mostly localized along the second branchial arch.

Abnormalities, Multiple↗
PubMed2004

[CT multiplan reconstruction images of disorder of stapes].

OBJECTIVE: To evaluate the clinical application of multi-planar reformation (MPR) for the stapes with multi-slice spinal thin-section CT in the patients with disorder of stapes before prosthetic ossicular reconstruction and their impact on surgical decision. METHODS: Axial CT scanning of temporal bone was undergone in 50 volunteers. Multiplan reformatted images included coronal, sagittal and oblique MPR, were made. All the MPR images were compared with each other in order to show which one could reveal the whole structures of stapes better. The height of stapes was measured with the oblique MPR. CT findings were evaluated in 102 cases with disorder of stapes. Prosthetic ossicular reconstruction was made in 65 cases. RESULTS: The full stapes cannot be shown in axial, coronal and sagittal MPR images, however, it was shown in oblique MPR in all the cases. The highness of stapes was (3.3 +/- 0.4) mm in the abnormal group. There was chronic otitis media in 69 cases (90 ears) and congenital abnormalities of the stapes in 33 cases (47 ears) which included the dispart of incudostapedial joint in 5 cases (7 ears), defect of head and crus of stapes in 9 cases (13 ears), defect of one side of crus in 3 cases (4 ears) and absence of the oval window in 16 cases (23 ears). CONCLUSIONS: Coronal and oblique MPR images from Axial Spiral CT Data are essential for the pre-operative planning of prosthetic ossicular reconstruction. The ship, structure or defect of stapes can be shown in the oblique MPR images. It is important for the patient to choose the type of operation.

Adolescent↗
PubMed1996

Fluorescein as an easy, low-cost, indirect, or reverse intraoperative marker to rule out perilymph versus local injection.

Clear fluid found in the dependent portions of the middle ear (round and oval windows) is generally assumed to be perilymph (PL). However, all clear fluid observed at middle ear exploration is not necessarily PL. PL should be distinguished from local injection. An accumulation of the local injection could be confused with perilymph fistula (PLF) diagnosis. There is no standard way of distinguishing perilymph from local injection, as both are clear, watery fluids. Fluorescein, tagged with a mixture of xylocaine and epinephrine (FLOTAX) was used as the local injection in 10 patients undergoing middle ear exploration for possible PLF.FLOTAX was injected into the vascular strip and ear canal skin in routine fashion. Transtympanic endoscopy and special Zeiss custom fluorescein filters were used to document any accumulation of fluid in the dependent portions of the middle ear and confirm whether any fluorescein (from the FLOTAX) was present. The middle ear was checked both before (endoscopically) and after raising the tympanomeatal flap. After the "local" injection, FLOTAX was observed to accumulate in dependent portions of the middle ear before raising the tympanomeatal flap in six of 10 ears. In the other four ears, FLOTAX slowly seeped into the middle ear cleft after the tympanomeatal flap was elevated and manipulated. Fluorescein can be used as an inexpensive, indirect intraoperative marker or "reverse test" for possible PLF. By eliminating a likely and common offender (local injection), any accumulation or reaccumulation of clear fluid that is not fluorescein tagged may more confidently be identified as possibly perilymph. The use of FLOTAX helps eliminate the confusion between the local injection and potential PLF. It does not in any way eliminate the possibility of other transudates from incisions, allergic reactions, or other manipulation of the tympanomeatal flap or middle ear mucosa.

Anesthetics, Local↗
PubMed1992

Transmission of change in the atmospheric pressure of the external ear to the perilymph.

In experiments using guinea pigs, the middle ear and perilymphatic pressures were simultaneously registered in response to pressure change in the external ear canal. In the first experiment, pressure was slowly loaded in the ear canal in the range of 200 mm H2O to -200 mm H2O. Pressure transmission to the perilymph was smaller when the bulla was open to the outside than when it was closed. It was significantly impaired by disruption of the ossicular chain and especially by closure of the round window. The data indicate that air volume in the middle ear cavity plays an important role in transmission of slowly changing atmospheric pressures. In the second experiment, the eustachian tube was closed and the pressure was changed in the range of 1000 mm H2O to -1000 mm H2O. The middle ear and perilymphatic pressures increased or decreased corresponding to the loading pressure in the range of 400 mm H2O and -200 mm H2O. Beyond these levels, response rate of the middle ear pressure decreased and perilymphatic pressure declined in spite of further increase in loading pressure. The increase in pressure difference between the middle ear and the inner ear might cause disruption of the round and/or oval windows.

Animals↗
PubMed1992

Computer-aided three-dimensional reconstruction and measurement of microfissures.

The spatial anatomy of microfissures in the round and oval window areas was investigated in 24 randomly selected normal human temporal bones by our computer-aided three-dimensional reconstruction and measurement method. Microfissures that communicated with the middle ear surface in the round window area were seen in 21 cases (87%) and were located on the posteromediosuperior aspect of the round window niche; whereas microfissures in the oval window area, seen in seven cases (29%), were located at various sites, but mostly in the area below the oval window. Of the 21 microfissures seen in the round window niche, only four were found to be visible through the aperture of the round window niche when viewed from the lateral direction. The mean lengths of the microfissures seen on the middle ear surface in the round and oval window areas were 0.95 +/- 0.66 mm and 0.74 +/- 0.44 mm, respectively. The microfissures in the round window area were significantly longer in individuals 20 years of age and older, than in those less than 20 years (Wilcoxon test, t = 21.5, p less than 0.01); this tendency for microfissures to be longer in older subjects was also found for microfissures in the oval window area. The possible clinical and pathologic significance of these results is discussed.

Adolescent↗
PubMed1985

Fibrin tissue adhesive and glass ceramic strut for ossicular chain replacement. Electrophysiologic and histologic findings.

The tolerance of the inner ear to fibrin tissue adhesive was tested. In experimental surgery on thirty-four chinchilla ears, Fibrin Sealant was applied to the inner ear contents by closing the oval window with a connective tissue graft dipped in the adhesive and gluing a Macor glass ceramic strut between this graft and tympanic membrane. No inner ear changes or tissue damage were found. The loss in auditory sensitivity monitored by auditory brain stem response thresholds was commensurate with the amount of loss to be expected with ossicular chain replacement. The findings suggest that this tissue glue can be safely applied to the labyrinth.

Animals↗
PubMed1981

Revision stapedectomy: a review of 258 cases.

We reviewed the records of 258 revision stapedectomy operations performed at the Otological Medical Group during an eight year period. Displacement of the prosthesis to the inferior edge of the window was the commonest cause of failure (41%) and occurred predominately in wire-Gelfoam pad cases. An oval window fistula, a short prosthesis or bony closure of the window were causes of failure in 9% each. Incus necrosis was the cause of failure in 5%. Less than 50% of the operations resulted in postoperative conductive deficit of 10 db or less. The results were better than this in incus bypass procedures, in revisions of cases in which a tissue graft was used over the oval window and in revisions of ears initially operated on elsewhere. Severe sensorineural hearing impairment was the result in 7% of the operations and half of these impairments were dead ears. The majority of these adverse results followed a repeat drill out of obliterative otosclerosis or followed reopening of the oval window in patients with a postoperative inner ear problem other than a fistula. We concluded that 1. revision stapedectomy is a less satisfactory procedure than primary stapedectomy; 2. there is rarely an indication for a repeat drill out of obliterative otosclerosis; and 3. the oval window membrane usually should not be disturbed in revision stapedectomy in a patient with inner ear symptoms unless there is a fistula.

Adult↗
PubMed2001

Histopathology of residual and recurrent conductive hearing loss after stapedectomy.

HYPOTHESIS: Histopathologic examination of temporal bones from patients who had undergone stapedectomy may provide information concerning the causes of both residual and recurrent conductive hearing loss (CHL). BACKGROUND: Although closure of the air-bone gap to within 10 dB occurs in approximately 90% of primary stapedectomies, a residual CHL occurs in approximately 10% and recurrent CHL may occur in up to 35% of cases. Putative causes of failure of surgery as determined during revision include erosion of the incus, bony regrowth at the oval window, and displacement of the prosthesis. Most reports on the histopathologic findings of temporal bones from such patients have focused on complications of surgery, with little attempt to correlate postoperative air-bone gap with the observed histopathology. METHODS: A retrospective review of the author's collection of temporal bones ascertained 22 cases with postoperative CHL of 10 dB or greater (air-bone gap averaged at 500, 1,000, 2,000, 3,000, and 4,000 Hz, using postoperative air- and bone-conduction levels) after stapedectomy. These temporal bones were prepared by standard methodology for light microscopy. RESULTS: Of the 22 cases with postoperative CHL equal to or greater than 10 dB, there were 19 with residual CHL, 2 with recurrent CHL, and 1 with both residual and recurrent CHL. The most common histopathologic correlates of residual and recurrent hearing loss included resorptive osteitis of the incus (64%); obliteration of the round window by otosclerosis (23%); the prosthesis lying on a residual footplate fragment (23%); the prosthesis abutting the bony margin of the oval window (18%); adhesions in the middle ear (14%); and new bone formation in the oval window (14%). CONCLUSIONS: Histopathologic examination of temporal bones from patients who in life had undergone stapedectomy provides useful information concerning causes of both residual and recurrent CHL. These data provide a basis for improving both surgical technique and prosthesis design.

Adult↗
PubMed2005

[Temporal bone histopathology in a patient suspected of inner ear extension of otitis media].

We report the histopathological findings in the temporal bone of a 30-year-old female who died of cervical esophageal carcinoma. The temporal bone sections revealed severe bilateral suppurative labyrinthitis and otitis media that presumably occurred immediately before her death. Many inflammatory cells were present in the middle ear, particularly around the stapes and the round window niche. They had also infiltrated the inner ear via the annular ligament of the stapes and the round window membrane. Inflammatory cell accumulation was also observed in the peri- and endolymphatic spaces, and it was most severe in the basal turn. Most of the inner and outer hair cells were preserved, but some had degenerated or were missing. Numerous round cells were observed in the modiolus, and some of the spiral ganglion cells had degenerated. On the basis of these findings, we concluded that bacterial otitis media had extended in to the inner ear via the oval window and round window membrane and had resulted in suppurative labyrinthitis. These findings are consistent with those of stage II suppurative labyrinthitis according to the classification of Schuknecht.

Adult↗
PubMed2005

Abnormal facial nerve course associated with stapes fixation or oval window absence: report of two cases.

Congenital minor ear malformations are very uncommon. Their etiology can be explained by the embryological development of the middle ear structures. Their classification, diagnosis and treatment pose certain problems. We report on one case of congenital stapes fixation and one case of oval window absence, both associated with an abnormal facial nerve course. Good long-term results show that performing a platinotomy or vestibulotomy in cases of congenital stapes fixation or oval window absence can be a relatively safe procedure, even in presence of deviated facial nerve course. The literature and present classifications of minor ear malformations are discussed.

Audiometry↗
PubMed2002

Temporal bone histopathology related to cochlear implantation in congenital malformation of the bony cochlea.

HYPOTHESIS: Histopathologic findings in temporal bones with congenital malformations of the bony cochlea may provide insight into cochlear implantation planning, surgical approach, and complications. BACKGROUND: Patients with congenitally malformed cochleae account for an increasing percentage of candidates for cochlear implantation. Few studies on the relationship between histopathologic findings of temporal bones with malformation of the bony cochlea and cochlear implantation have been reported. METHODS: We studied 21 temporal bones from 12 cases with congenital malformations of the bony cochlea. Ages ranged from stillborn to 50 years. Length of the cochleae and dimensions of facial recesses were measured with light microscopy. Other malformations associated with a shortened cochlea were determined, emphasizing how they affect cochlear implantation. RESULTS: The average length of the malformed cochlear duct was 22.84 +/- 0.69 mm. Average dimensions of facial recesses were not significantly different between malformed cochleae and the controls. Other malformations included enlarged cochlear aqueduct (43%), abnormal facial nerve course (57%), enlarged vestibular aqueduct (52%), aplasia of the middle ear (19%), malformed ossicles (67%), abnormal oval window (57%), and abnormal round window (29%). CONCLUSION: A shortened cochlear duct may cause an incomplete insertion of the implant electrode. Because dimensions of the facial recesses are similar to normal cases, a facial recess surgical approach is recommended. An enlarged cochlear aqueduct may cause perilymphatic oozing or gushing on fenestration of the cochlea. An anomalous course of the facial nerve is a common finding. Tympanic malformations such as round and oval window deformities and small middle ear cleft should be noted preoperatively to better guide surgery.

Adolescent↗
PubMed2003

[HRCT findings in congenital aural atresia].

PURPOSE: To define high resolution computed tomography findings in the external, middle and inner ear of patients with congenital aural atresia and to emphasize the importance of these findings in the preoperative evaluation. MATERIALS AND METHODS: Twenty one patients with congenital aural atresia (14 male, 7 female) aged between 1-30 years were evaluated with high resolution computed tomography of the temporal bone. A Toshiba TCT-600 scanner was used in 11 cases, and a Xvision/GX scanner was used in 10 cases. Sections 1 mm thick were obtained in axial and coronal projections using high bone detail algorithms. Sagittal reformations were also made when necessary. RESULTS: Forty-two ears in 21 patients with congenital aural atresia were studied. These included 8 patients with high bilateral and 13 with unilateral congenital aural atresia in which 8 patients had right sided and 5 patients had left sided atresia. Stenosis of the external auditory canal was found in 11 ears, complete atresia was found in 13 ears, incomplete atresia was found in 1 ear. There was varied ossicular deformity in 18 ears. Anomalies of the stapes and oval window were found in 6 ears. An anteriorly located mastoid segment of the facial nerve canal was identified in 11 ears. An inferiorly located tympanic segment of the facial nerve canal was identified in 2 ears, and 3 ears had an abnormal posterior orientation of the mandibular condyles. Only 2 patients had associated inner ear deformity. CONCLUSION: High resolution computed tomography is an effective method for the evaluation of the anomalies of the external, middle and inner ear in patients with congenital aural atresia and for planning the surgical treatment.

Adolescent↗
PubMed2000

Congenital absence of the oval window: radiologic diagnosis and associated anomalies.

BACKGROUND AND PURPOSE: In most children with conductive hearing loss, acquired otitis media and/or middle ear effusion are ultimately diagnosed. Congenital conductive hearing loss is a rare condition; absence of the oval window is an unusual pathogenesis for this type of hearing impairment and can be associated with an anomalous horizontal facial nerve canal. Our goal was to describe the imaging features of congenital absence of the oval window, to determine the frequency with which anomalous development of the horizontal facial nerve canal occurs, and to review the developmental error responsible for this malformation. METHODS: Nine temporal bones in seven patients (5 to 36 years old) were found to have an inadequately formed oval window on high-resolution CT scans; seven ears showed complete lack of oval window formation, and two showed partial absence of the oval window. Records were reviewed for clinical information, and images were examined for associated anomalies. RESULTS: Six of nine ears with abnormal oval window formation showed malposition of the horizontal facial nerve canal. In each of these, the canal was abnormally low, overlying the expected location of the oval window; three of the canals lacked a visible bony covering. Seven of the nine ears were found to have a dysplastic or absent stapes. CONCLUSION: Congenital absence of the oval window can be diagnosed on CT studies. In the present series, this anomaly was associated with a grossly aberrant horizontal facial nerve canal in six of nine involved ears. Familiarity with the developmental sequence of oval window formation fosters an understanding of these anomalies. Preoperative recognition is important clinically, as a low facial nerve will block surgical access to the oval window and its presence will alter patient management.

Adolescent↗
PubMed2003

Imaging of a congenital perilymphatic fistula.

A 7-year-old boy with a history of purulent meningitis and watery rhinorrhea was studied using computed tomography (CT) and magnetic resonance imaging (MRI). He had a common cavity in the left inner ear. With high-resolution heavily T2-weighted MRI, leakage of the inner ear fluid into the middle ear at the oval window area through a congenital perilymphatic fistula could be visualized. Surgery to close the fistula showed a perforation in the stapes footplate.

Child↗
PubMed1976

Optimal temperatures for inner-ear performance in gekkonoid lizards.

Temperature effects on the cochlear alternating potentials are described in lizards of the Eublepharidae (4 spp. and subspp.), Diplodactylinae (2 spp.), Gekkoninae (7 spp. and subspp.) and Sphaerodactylidae (1 sp.). Pure tones (50-15,000 Hz) were applied to the anaesthetized gecko's external ear. Sound intensity needed for a standard response was plotted (db versus frequency). A total of 249 such sensitivity functions were obtained from 50 animals, at temperatures of 15-40 degrees C. For each species, an optimal sensitivity function is definable by its extreme sensitivity and relative smoothness. This is obtained throughout a specific optimal temperature range. At lower temperatures, the function is less sensitive and its best sensitivity is at a lower frequency. The specific optimal cochlear temperature range resembles the specific ecological temperature preferendum where known. Both are broader in gekkonoid than in iguanid lizards. The temperature effects on the sensitivity function occur even with aerial or mechanical stimulation at the oval window after middle ear extirpation. Hence they arise in the inner ear. Their magnitude (db/ degrees C) is half that known from auditory nerve potentials. When accurate auditory data are desired, the specific optimal temperature and its possible seasonal variation require consideration. This increases the need for proper identification of subjects by name and origin, and for monitoring experimental thermal parameters, including pre-experimental acclimation.

Acoustic Stimulation↗