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PubMed1987

Malignancies of the external ear canal and temporal bone: surgical techniques and results.

A combined therapy approach to malignancies of the external auditory canal and middle ear has been developed. A technique of external canal resection and gross tumor removal from the middle ear, parotid gland, and superior cervical lymph nodes is followed by postoperative full-therapy irradiation. This combined approach has been used in 30 patients with malignancies involving the external auditory canal and temporal bone. The preoperative evaluation and surgical technique, including the intraoperative decision-making process, is described. Twenty-four patients had squamous cell carcinoma of the external auditory canal, and two patients had basal cell carcinoma. There was one patient each with adenocystic carcinoma, acinic cell carcinoma, high grade mucoepidermoid carcinoma, and a giant cell tumor of bone. This group of patients was broken down into three groups based on the extent of disease as determined at surgery. Overall control of disease, both locally and distant, for the 30 patients was 66%. There were 12 patients with disease limited to the ear canal. These patients had a 91% survival of this disease process. Seven patients were determined to have limited extension beyond the ear canal. These were treated with combined therapy with an overall control of disease of 72%. Eleven patients had extensive disease outside of middle ear into the carotid jugular spine, stylomastoid foramen, and skull base, with a survival rate of 45%. It is concluded that a step-wise removal of all gross tumor, as opposed to an en bloc dissection of the temporal bone and skull base, followed by full-therapy irradiation gives equally as good, or even better, long-term survival for this malignancy of the external auditory canal and middle ear.

Adult↗
PubMed1985

Histopathology of the temporal bone in osteogenesis imperfecta congenita: a report of 5 cases.

The histopathologic findings in 8 temporal bones from 5 patients with osteogenesis imperfecta congenita are reported. The otic capsule, bony walls of middle ear, and ossicles showed evidence of both deficient and abnormal ossification. Microfractures were found in the otic capsule and in the anterior process and handle of the malleus, in addition to their common location at the crura of the stapes. The cochlear and vestibular end-organs appeared normal. Pathologic changes compatible with otosclerosis were not seen. The possible implication of these changes on hearing and balance is discussed.

Ear, Inner↗
PubMed2004

Comparison of the implantability of electronic hearing devices in a virtual reality planning environment and in human temporal bones.

OBJECTIVE: To develop a procedure using a virtual reality (VR) environment that permitted us to simulate the preoperative fitting of an electronic implantable hearing device (IHD) and assess its implantability. MATERIAL AND METHODS: This was an experimental, prospective study based on VR simulations involving the pre- and postoperative comparison of the implantability of an IHD. The preoperative possibility of implanting an IHD in a VR environment was compared with the postoperative implantability of the device in the temporal bones of human cadavers and patients. Study groups were analyzed according to the criteria "VR implantation" and "real surgery" using contingency tables. RESULTS: A computer simulation method based on CT images was developed for the preoperative planning of the implantation. The VR simulation proved feasible in all cases (15 temporal bones and 24 patients). There was no significant difference between the process of implanting the IHD in patients or in the VR environment. These results indicate that VR-based test fittings of an IHD allow prediction of the implantability of an IHD prior to actual surgery. CONCLUSION: We have described the development of a novel VR procedure for predicting the implantability of hearing devices in otoneurosurgical applications. The VR procedure can be applied universally and may also be used for other parts of the body.

Adult↗
PubMed1984

The treatment of glomus tumors in the temporal bone by megavoltage radiation.

Forty-five patients with glomus tumors in the temporal bone region were treated by radiation therapy. Only three patients had recurrence or progression of tumor during the follow-up period of 3 to 23 years (median, 10 years). No patient died from uncontrolled glomus tumor. The majority of patients noted symptomatic relief after radiation, but objective neurologic deficits usually remained unchanged or showed only partial improvement. The most commonly used radiation dose was 3500 cGy tumor dose delivered in 15 fractions in 3 weeks by a homolateral wedge technique from megavoltage radiation apparatus. This dose is less than that usually recommended for glomus tumors. From these results and from review of the literature, it is suggested that a moderate radiation dose of 3500 cGy in 3 weeks is effective treatment for glomus tumors, even if complete tumor involution does not occur.

Adolescent↗
PubMedDate not supplied

Temporal bone histopathology of necrotizing external otitis. A case report.

Histopathological examination of the temporal bone of an individual with necrotizing external otitis revealed severe inflammation with necrosis in the subcutaneous granulation tissue in the external auditory canal. Erosion of the bony walls of the canal had created a defect in the anterior wall, through which infection spread to the preauricular region. The lateral part of the middle ear cavity was also filled with granulation tissue and purulent exudate. A dehiscence of the horizontal portion of the facial canal had apparently allowed spread of an inflammatory round cell infiltrate along the facial nerve up to the fundus of the internal auditory canal. The only evidence of inner ear pathology was the presence of eosinophilic fluid material in the perilymphatic spaces of the labyrinth. A review of other reports of cases of necrotizing external otitis seems to show that this is the only instance of this disease in which infection spread from the external canal through the tympanic membrane to the middle ear and thence to the internal auditory canal.

Aged↗
PubMedDate not supplied

Sudden deafness: histopathologic correlation in temporal bone.

The histopathological study of two cases of sudden deafness is presented. The temporal bones showed cochleosaccular abnormality. The most striking pathological changes were collapse of the organ of Corti, atrophy of the tectorial membrane, atrophy of the stria vascularis, decrease in the number of the cochlear nerves, collapse of the saccular membrane and partial absence of the sensory epithelial layer in the saccular macula. These changes are quite similar in type to those occurring in labyrinthitis of known viral etiology and to those in previously reported cases of sudden deafness which were assumed to be of viral origin. This evidence suggests that a viral infection was the most probable etiology of sudden deafness in these ears. In addition, unusual findings of endolymphatic hydrops limited to the extreme basal end of the cochlear duct were found in Case 1. A patent cochlear aqueduct and circumscribed perilymphatic labyrinthine ossification in the superior seimicircular canal were also observed. With these histopathological findings, the possibility of viral infection via the meninges as well as via the hematogenous route into the inner ear is proposed.

Cochlea↗
PubMed1999

Pneumatic processes in the temporal bone of chimpanzee (Pan troglodytes) and gorilla (Gorilla gorilla).

The ontogeny of human temporal bone pneumatization has been well studied from both comparative and clinical perspectives. While a difference in the extent of air cell distribution has been noted in our closest living relatives, chimpanzees and gorillas, the processes responsible have been relatively unexplored. To examine these processes, a large, age-graded series of hominoid skulls was radiographed and the progress of pneumatization recorded. Additionally, a subsample of 30 chimpanzees and 12 gorillas was subjected to high-resolution CT scanning. Neonatal specimens show a well-developed mastoid antrum, as well as a capacious hypotympanum extending into the petrous apex. In African apes, as in humans, the mastoid antrum serves as the focus for air cell expansion into the mastoid and immediately adjacent areas. In chimpanzees and gorillas, however, a pronounced lateral structure, described as the squamous antrum, serves as the focus of pneumatization for anterior structures such as the squamous and zygomatic. The diminution of this structure in Homo sapiens explains the difference in air cell distribution in these regions.

Anatomy, Cross-Sectional↗
PubMed1988

Conduction of thermal stimuli in the human temporal bone.

Temperature changes at different locations in the labyrinth were measured in human temporal bone preparations after syringing with water. In order to simulate physiological conditions, the preparations were placed in a water bath at 37 degrees C. The maximum temperature changes in the horizontal semicircular canal after syringing with temperatures symmetrical to body temperature (44 degrees or 30 degrees C) were found to be clearly asymmetrical (with mean values of 0.6 and -0.3K). From measurements in the external auditory meatus, findings showed that the reference temperature was 34 degrees C in front of the tympanic membrane, which explains the asymmetry recorded. Measurements at different locations showed that the temperature first changes in the regions of the ampullae of the horizontal and the superior semicircular canals. In the vestibule the onset and decay of the temperature change is delayed. The time courses of the temperature difference between locations demonstrate that the temperature difference across the horizontal semicircular canal, which would be responsible for any convective effect in the endolymph, is of shorter duration than the absolute temperature change, which would be responsible for any temperature-mediated volume changes.

Adult↗
PubMed1998

[Value of Schüller conventional roentgen diagnosis and computerized tomography of the temporal bone in preoperative diagnosis of the Tübingen implantable cochlear amplifier].

Recently, the transducer and microphone of a cochlea amplifier implant (CAI) for the treatment of sensorineural cochlear hearing loss have been developed further for implantation into the mastoid cavity. At present, the University of Tuebingen implantable cochlea amplifier consists of an implantable microphone and an implantable piezoelectric transducer. It has been implanted into the first patients. Successful future application of this new implant depends on the suitable fit of the CAI within a patient's mastoid cavity. Using conventional X-ray and CT scans, we analyzed 50 cadaver specimens of the temporal bone before total mastoidectomy. After total mastoidectomy, the volume of the mastoid cavity was measured using CT scans and water volume determination. Finally, the CAI was implanted into those temporal bones that were large enough to house it. Our results demonstrate that the degree of pneumatization in the conventional Schüller X-ray is already a good parameter for preoperative evaluation.

Cochlear Implantation↗
PubMed2006

A new implantable middle ear hearing device for mixed hearing loss: A feasibility study in human temporal bones.

HYPOTHESIS: To assess the feasibility of a new, active middle ear device in temporal bones (TB). BACKGROUND: This device is designed for patients with mixed hearing loss subsequent to chronic middle ear infection, surgery, or trauma. This Bell-Vibroplasty is built from a VIBRANT MED-EL Vibrant Soundbridge and a Kurz Bell titanium partial ossicular replacement prosthesis. METHODS: In three fresh TBs, healthy and reconstructed middle ears were analyzed by means of laser Doppler interferometry. The sound transmission properties of a partial ossicular replacement prosthesis and a passive and an active Bell-Vibroplasty were compared with healthy middle ear function. RESULTS: The measurements provided reliable results with small standard deviations and good signal-to-noise ratios. The performance levels of the partial ossicular replacement prosthesis and of the passive Bell-Vibroplasty were comparable with that of healthy middle ear function. The activated Bell-Vibroplasty provided linear function and a flat frequency response within the measured frequency range (500 Hz-8 kHz), with peak deviations of less than 10 dB. The maximum output of the Bell-Vibroplasty was equivalent to 125-dB sound pressure level. CONCLUSION: Bell-Vibroplasty is feasible in TBs. Bell-Vibroplasty performance in TBs is sufficient to allow for a clinical trial as a next step.

Acoustic Stimulation↗
PubMed2006

Two temporal bone computed tomography measurements increase recognition of malformations and predict sensorineural hearing loss.

OBJECTIVES/HYPOTHESIS: The objectives of this prospective study were to assess the reproducibility of the measurements of the cochlea and lateral semicircular canal (LSCC) and to determine if abnormal measurements predict sensorineural hearing loss (SNHL). METHODS: Two readers independently measured the cochlear height on coronal section and the LSCC bony island width on axial section on 109 temporal bone computed tomography scans; audiologic data on these patients were collected independently from medical records. Inter- and intrareader variability was evaluated using intraclass correlation coefficients (ICCs) based on a random-effects model. The positive and negative predictive values of abnormal measurement for hearing loss were determined. RESULTS: There was excellent inter- and intraobserver agreement for both measurements (ICC >80%). The average cochlear height was 5.1 mm (normal range, 4.4-5.9 mm) and average LSCC bony island width was 3.7 mm (normal range, 2.6-4.8 mm). Review of the original radiology reports demonstrated that both cochlear hypoplasia and LSSC dysplasia were overlooked in >50% of patients with both abnormal measurements and SNHL. Cochlear hypoplasia (< 4.4 mm) had a positive predictive value of 100% for SNHL, whereas cochlear hyperplasia and bony island dysplasia were less predictive. CONCLUSION: The measurements of coronal cochlear height and axial LSCC bony width have excellent reproducibility and identify bony labyrinth abnormalities missed by visual inspection alone. In addition, cochlear hypoplasia is highly predictive of SNHL. To reliably identify inner ear malformations, measurement of the cochlear height and LSCC bony island width, in addition to the vestibular aqueduct, should be routinely performed on all temporal bone studies.

Adolescent↗
PubMed1985

[Position and variations in the position of the canal system in the temporal bone. I. The canals of the pars petrosa between the margo superior and the meatus acusticus internus].

The canals of the temporal bone were measured on 103 objects at different levels. The distances (mean and extremes) were estimated as well as the width of the following: the facial canal, semicircular canals, vestibule, internal acoustic meatus, sigmoid sinus, superior bulb of the jugular vein, carotid canal, eustachian tube, perilymphatic and endolymphatic ducts and sac, glossopharyngeal nerve and mastoid cells.

Genetic Variation↗
PubMed1999

Evaluation of a cement incus replacement prosthesis in a temporal bone model.

In reconstruction of the ossicular chain for a damaged incus, it is important that the incus replacement prosthesis (IRP) length is ideal in order to provide optimal tension between the tympanic membrane or malleus and stapes head to achieve the best post-operative hearing result. Even though the length of commercially available IRPs can be adjusted, it still may be difficult to achieve clinically. We describe experiments in a human temporal bone model using dental cement as an IRP after removal of the incus. This cement IRP (CIRP) hardens in situ and becomes the length of the gap to be spanned so that tension should be ideal. Two different CIRPs were studied; one was a conventional rod-type CIRP connecting either the umbo or mid-malleus handle to the stapes head. The second was a Y-shaped CIRP (Y-CIRP), connecting two sites on the malleus to the stapes head. The wide Y-CIRP connected the malleus head and umbo to the stapes head, while the narrow Y-CIRP connected the malleus neck and mid-handle to the stapes head. The acoustic performance of these experimental CIRPs was studied using a laser Doppler vibrometer system in 12 fresh human temporal bones. The CIRP demonstrated better acoustic performance than conventional IRPs studied previously in the same model. While all the CIRPs showed similar function below 2.0 kHz, the narrow Y-CIRP appeared best above 3.0 kHz. A prosthesis of this type may have an acoustic advantage over conventional IRPs.

Acoustic Stimulation↗
PubMed2005

Malleus-to-footplate versus malleus-to-stapes-head ossicular reconstruction prostheses: temporal bone pressure gain measurements and clinical audiological data.

HYPOTHESIS: Several clinical reports suggest that if the stapes superstructure is intact, ossicular reconstruction should be made to the stapes head rather than the footplate to achieve a better hearing outcome. To test this hypothesis, we compared the in situ mechanical performance of hydroxylapatite (HA) malleus-to-stapes-head (MSH) ossicular reconstruction prosthesis (ORP) with malleus-to-footplate (MFP) ORP, both manufactured by Project HEAR. BACKGROUND: ORPs are commonly used to replace a missing or deficient incus. However, hearing outcomes are highly variable, depending on the ORP material, design, surgical technique, and ORP positioning. METHODS: Cochleo-vestibular pressure measurements in human cadaveric temporal bones for the HA MFP ORP have been reported by Puria et al. (2005). In the present study, the ear canal pressure Pe and cochleovestibular pressure Pv were measured in cadaveric temporal bones with intact incus, removed incus, and MSH ORP reconstruction. The relative loss in gain, Lmsh, is defined as the ratio of Pv with reconstructed MSH ORP to intact incus and compared with Lmfp. A retrospective clinical audit of the pre- and postoperative audiologic results of patients who had undergone ossiculoplasty with either MSH or MFP ORP was conducted for comparison. RESULTS: For the 0.5 to 3 kHz frequency range, Lmsh magnitude is 6.2 dB lower than the Lmfp magnitude (p = 0.05). The retrospective audit of audiologic results after ossiculoplasty with either MSH or MFP ORP revealed a similar difference in gain between the two ORP designs with air-bone gap differences of 7.6 dB (p = 0.04) and air conduction threshold differences of 8.0 dB (p = 0.13) for these patients. CONCLUSION: The MFP ORP showed better average pressure gain compared with the MSH ORP across the speech frequencies. Surgeons performing ossiculoplasty with designs similar to Project HEAR HA ORPs, where there is direct columella-like connection between the malleus and stapes, should consider using the MFP ORP design to achieve a better postoperative audiologic result, even when the stapes superstructure is intact.

Aged↗
PubMed2000

The effects of temporal bone on transcranial Doppler ultrasound beam shape.

A knowledge of beam shape is desirable for many Doppler ultrasound applications, and is especially important for transcranial Doppler recordings where the beam may undergo significant distortion by the skull. Although it may not be possible to determine the precise beam shape for individual cases due to variations in the physical characteristics of the media in the beam path, information about the range of beam shapes that are likely to arise for in vivo recordings from the middle cerebral artery may in future allow limits of uncertainty to be derived, and may even allow partial correction in some cases. In order to assess the potential intersubject variation in beam sensitivity across the middle cerebral artery, the beam shapes generated by four commercial Transcranial Doppler transducers and the effects on beam shape of four different samples of temporal bone were investigated. The results demonstrate that there seems to be relatively little difference in the beam shapes of commercial transducers, but that the distortion effects of temporal bone are variable and unpredictable.

Adult↗
PubMed1996

Submillimeter magnetic resonance imaging of the temporal bone in Meniere's disease.

The pathoetiology of Meniere's disease remains elusive. Histopathologic and imaging studies have implicated congenital or developmental abnormality of the endolymphatic duct as a likely predisposing factor to the development of endolymphatic hydrops and clinical Meniere's disease. Recently, improved high-resolution magnetic resonance imaging (MRI) protocols have allowed better demonstration of the soft tissues of the endolymphatic duct and sac. This study is a prospective evaluation of the ability of submillimeter MRI to detect the endolymphatic duct in Meniere's disease patients and control subjects. In addition, the development of the temporal bone in the region of the endolymphatic sac and duct is evaluated by measurements of the distance from the posterior semicircular canal to the subarachnoid space and the distance from the vestibule to the subarachnoid space. Visualization of the endolymphatic duct was found to be significantly less frequent in the Meniere's disease patients (29%) than in the control subjects (91%). Temporal bone measurements in the region of the endolymphatic duct showed patients with Meniere's disease to have smaller dimensions than control subjects.

Adult↗
PubMed1987

Monostotic fibrous dysplasia of the temporal bone.

Fibrous dysplasia is a rare but interesting benign condition of the bones which affects either a single bone or multiple bones, with or without endocrine abnormalities. Only 75 cases affecting the temporal bone have been reported in the world literature, and to these we add another case. Although systemic involvement in the form of endocrine abnormalities and skin pigmentation has been reported in the past, no case has yet been reported with a congenitally absent kidney in the monostotic form of the disease.

Fibrous Dysplasia of Bone↗