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Computed tomographic scan demonstrating narrowing of the left external auditory canal caused by an expansile bone lesion of the temporal bone (curved arrow). The regional bone was characterized by a "ground-glass" appearance. A small cholesteatoma is located between the tympanic membrane and the bony lesion (black arrow).
Between 1965 and 1984, 20 patients with chemodectomas of the temporal bone were seen at The Methodist Hospital in Houston, Texas and at the Cancer Therapy and Research Center in San Antonio, Texas, Ten patients were treated with radiation therapy alone, seven with surgery and post-operative radiation, one with pre-operative radiation, and two with radiation therapy following surgical recurrence. Most patients had advanced tumors at presentation. Radiation doses ranged from 22.5 Gy to 50.0 Gy. The most frequent dose was 45.0 Gy, given in 225 cGy fractions, 9.0 Gy per week. The most common radiation portal arrangement was oblique fields with paired wedges. There were no local failures or significant radiation induced complications among the patients with benign chemodectomas. The follow-up period ranged from 3 to 23 years (mean 11 years). Only one patient developed systemic metastases and progression of the primary temporal bone chemodectoma. These results and a review of the literature demonstrate that radiation therapy alone is a safe and effective treatment modality for chemodectomas of the temporal bone.
OBJECTIVE: To evaluate the relationships between temporal bone abnormalities and the severity of microtia in Japanese patients using objective grading systems. DESIGN: Retrospective case series study conducted between 1992 and 2003. SETTING: Academic, tertiary care, referral medical center. PATIENTS: One hundred forty-two ears of 109 Japanese patients (85 male and 24 female patients; mean age, 12.8 years [range, 2-36 years]) with microtia. MAIN OUTCOME MEASURES: The severity of microtia was classified according to Marx classification. Developmental abnormalities of the temporal bone were evaluated by a computed tomographic (CT) scoring system modified after the system used by Jahrsdoerfer and colleagues, using high-resolution CT scans of the temporal bone. Correlations between the scores obtained from these 2 grading systems were evaluated using a nonparametric statistical method. RESULTS: Male preponderance and incidence of bilateral cases of approximately 30% were observed in our Japanese patients with microtia. There was no significant difference in the severity of microtia between unilateral and bilateral cases. The mean +/- SEM total points in the CT scoring system (full marks, 10) was 7.9 +/- 0.4 for grade I microtia, 6.6 +/- 0.6 for grade II, and 6.4 +/- 0.3 for grade III; the total points correlated inversely with the microtia grade. Development of the auricle correlated significantly with aeration in the middle ear spaces but not with ossicular development or formation of the oval/round windows. Proportion of acceptable surgical candidates according to the CT scoring system (>5 points) was 79% for grade I microtia, 52% for grade II microtia, and 65% for grade III microtia. CONCLUSION: The principle "the better developed the auricle, the better developed middle ear" was confirmed in Japanese patients with microtia; however, even with grade II/III microtia, more than half of the patients were considered suitable for atresia surgery.
Rhabdomyosarcoma, the most common soft tissue sarcoma of childhood, involves the temporal bone in approximately 7% of reported cases. Until recently, the outcome of this disease was always fatal. The recent Intergroup Rhabdomyosarcoma Study Group (IRS-I) reported on the efficacy of multimodality therapy consisting of multiagent chemotherapy, radiation, and surgical resection when indicated. Twelve patients with rhabdomyosarcoma involving the temporal bone were treated between 1966 and 1988. Three patients were treated according to the IRS-I protocols and the remaining nine patients received various combinations of treatment modalities. Ten patients succumbed to their disease, most with distant metastases or intracranial extension. Two patients are alive; one at 5 1/2 years and one at 19 years. It is apparent that, although survival for rhabdomyosarcoma in general has improved with the use of IRS-I protocols, prognosis remains poor for disease involving the temporal bone and other parameningeal sites.
"Primary" ear and temporal bone meningiomas are tumors that are frequently misdiagnosed and unrecognized, resulting in inappropriate clinical management. To date, a large clinicopathologic study of meningiomas in this anatomic site has not been reported. Thirty-six cases of ear and temporal bone meningiomas diagnosed between 1970 and 1996 were retrieved from our files. Histologic features were reviewed, immunohistochemical analysis was performed (n = 19), and patient follow-up was obtained (n = 35). The patients included 24 females and 12 males, aged 10-80 years (mean, 49.6 years), with female patients presenting at an older age (mean, 52.0 years) than male patients (mean, 44.8 years). Patients presented clinically with hearing changes (n = 20), otitis (n = 7), pain (n = 5), and/or dizziness/vertigo (n = 3). Symptoms were present for an average of 24.6 months. The tumors affected the middle ear (n = 25), external auditory canal (n = 4), or a combination of temporal bone and middle ear (n = 7). The tumors ranged in size from 0.5 to 4.5 cm in greatest dimension (mean, 1.2 cm). Radiographic studies demonstrated a central nervous system connection in 2 patients. Histologically, the tumors demonstrated features similar to those of intracranial meningiomas, including meningothelial (n = 33), psammomatous (n = 2), and atypical (n = 1). An associated cholesteatoma was identified in 9 cases. Immunohistochemical studies confirmed the diagnosis of meningioma with positive reactions for epithelial membrane antigen (79%) and vimentin (100%). The differential diagnosis includes paraganglioma, schwannoma, carcinoma, melanoma, and middle ear adenoma. Surgical excision was used in all patients. Ten patients developed a recurrence from 5 months to 2 years later. Five patients died with recurrent disease (mean, 3.5 years), and the remaining 30 patients were alive (n = 25, mean: 19.0 years) or had died (n = 5, mean: 9.5 years) of unrelated causes without evidence of disease. We conclude that extracranial ear and temporal bone meningiomas are rare tumors histologically similar to their intracranial counterparts. They behave as slow-growing neoplasms with a good overall prognosis (raw 5-y survival, 83%). Extent of surgical excision is probably the most important factor in determining outlook because recurrences develop in 28% of cases.
Admittance component curves were studied in a series of 14 fresh human temporal bones with perfectly normal tympanic membrane, before and after experimental lesions. The lesions were all performed in successive steps in each temporal bone and consisted in section of ligaments and tendons, interruptions and fixations of the ossicular chain. The results obtained demonstrate that the tympanograms traced in fresh human temporal bones, before and after experimental lesions, are quite similar to those observed respectively in normal and pathological living ears. (a) The 'pre-experimental' tympanograms showed A-type curves with peak and admittance component values well within the range of normal living ears; (b) the tympanogram peak values increased very little and remained in the range of normal ears also after section of ligaments and tendons; (c) the ossicular chain interruptions always resulted in A-type curves at 220 Hz and in W-pattern ones at 660 Hz wherever the interruptions occurred; (d) the ossicular chain fixations always exhibited A-type tympanograms with decreased peak and admittance component values; (e) finally, the condition of the Eustachian tube, closed or opened, did not change the shape of the tympanograms; the notch depth of the curves traced with opened tube, became higher than those obtained with closed tube.
The postnatal growth of the human temporal bone was examined by direct anatomical measurements on 60 cadaver specimens of all ages. The bones were dissected as one would perform cochlear implant surgery using a posterior tympanotomy approach. Nineteen anatomical/surgical landmarks with implications for cochlear implant surgery were identified on each bone and the distance between these points measured. The temporal bone was found to be a complex structure, phylogenetically, anatomically and functionally consisting of four different parts with independent postnatal development. The inner and middle ears were adult size at birth. The external auditory canal and most parts of the temporal bone were subject to significant lateral growth. The size of the pneumatised mastoid increased in all directions. In the facial recess, however, no postnatal growth was observed. Between birth and adulthood an average of 12 mm (SD 5 mm) of growth was seen directly between the sino-dural angle and the round window, the landmarks approximating the implantation site for the receiver-stimulator and the electrode entry point into the inner ear. However, if an electrode leadwire is fixed at a cortical fixation site such as the posterosuperior point of Macewen's triangle, the leadwire would be subject to approximately 20 mm of growth. These results indicate that a paediatric cochlear implant design incorporating an expandable leadwire to accommodate this growth should allow up to 25 mm of leadwire lengthening. The fossa incudis showed no growth relative to the round window and was found to be a convenient fixation site for the electrode array close to the cochlea. From an anatomical and surgical point of view, cochlear implantation in very young children is feasible, provided the electrode array is secured and the design accommodates for controlled leadwire lengthening.
Cochlear implantation is a treatment for patients with severe sensorineural hearing loss/deafness, who get no help from ordinary hearing aids. The cochlear implant is surgically placed under the skin near the ear and a very thin electrode array is introduced into the cochlea of the inner ear, where it stimulates the remaining nerve fibers (1,2). The operation is complicated; it is performed with the aid of a microscope, and involves drilling very close to vital vessels and important nerves. The method was introduced in Sweden in 1984 by Professor Göran Bredberg, then at Stockholm Söder Hospital. High resolution computed tomography (CT) of the temporal bone is a part of the preoperative evaluation preceding cochlear implantation. It is a method for visualizing the bony structures of the middle and inner ear - to diagnose pathology and to describe the anatomy. In Stockholm, these examinations have usually been performed at the Radiology Department of Stockholm Söder Hospital. Examinations of cochlear implant candidates from other parts of Sweden and from abroad are also sent there for special reviewing. The first work concerns CT of the temporal bone and cochlear implant surgery in children with CHARGE association. This is a rare condition with multiple congenital abnormalities, sometimes lethal. Children with CHARGE have different combinations of disabilities, of which impairments of vision and hearing, as well as balance problems and facial palsy can lead to developmental delay. There have been few reports of radiological temporal bone changes and none of cochlear implant surgery for this group. The work includes a report of the findings on preoperative CT and at surgery, as well as post-implant results in two children. A review of the latest diagnostic criteria of CHARGE and the temporal bone changes found in international literature is also included. The conclusion was that certain combinations of temporal bone changes in CHARGE are, if not specific, at least extremely rare in other materials. CT can visualize these changes and be used as a diagnostic tool. This is important, since some of the associated disabilities are not so obvious from the start. Early treatment is vital for the child's development. This work also shows that cochlear implantation may help some of these often very isolated children to communicate. The second work is a radioanatomic study of one of the structures of the inner ear - the bony canal for the cochlear nerve. It involves measurements of the dimensions of the canal on 117 silicone rubber casts of the temporal bone (from a unique collection of casts at Uppsala temporal bone laboratory) and on 50 clinical CT-studies (100 ears). The purpose was to show the normal variation, which is of use in the appraisal of congenital temporal bone malformations on CT. Based on our results we propose that if the canal is less than 1.4 mm, as measured on CT, the possibility of cochlear nerve abnormality should be considered. This is of interest since aplasia of the cochlear nerve is a contraindication to cochlear implantation. If the canal is wider than 3.0 mm, then other anomalies may coexist, with the risk of CSF gusher when a cochleostomy or stapedectomy is performed.
OBJECTIVE: To assess the accuracy of computer-aided surgery for common neurotologic approaches to the temporal bone. STUDY DESIGN AND SETTING: Cadaveric heads were dissected by using standard neurotologic approaches to the temporal bone including translabyrinthine, middle fossa, and retrosigmoid. Dissected anatomic landmarks from each approach were compared with CT images that were obtained before dissection on the VectorVision 2 system (BrainLAB Corp, Munich, Germany) and the variability measured from digital images. Each approach was performed 5 times, with each anatomic landmark measured 3 times from each approach. RESULTS: The accuracy of the computer-aided surgery system was less than 1 mm for all anatomic points measured. Forty-two of the 49 measured points were accurate to less than 0.5 mm. CONCLUSIONS: Computer-aided surgery of the temporal bone using common neurotologic approaches can be performed accurately and reliably in cadaver specimens. SIGNIFICANCE: The utility and limitations of computer-aided surgery in the temporal bone are discussed. EBM RATING: B-2.
OBJECTIVES: To assess the topographic relationship between the pneumatic spaces of the temporal bone and the temporomandibular joint (TMJ) using high-resolution CT. METHODS: Findings from 100 consecutive patients who had undergone high-resolution axial CT of the base of the skull were reviewed on a digital imaging workstation. Additional multiplanar reformatted images were created in the sagittal and coronal planes through the TMJ. The extension of the pneumatic spaces of the temporal bone and their relation to the TMJ were determined on both sides. RESULTS: The extent of pneumatisation of the temporal bone varied considerably. The roof of the TMJ fossa was pneumatised in 51 patients. The articular eminence contained air spaces in 12 patients, the root of the zygomatic process in five patients. Air cells in the peritubal area extended into the medial wall of the glenoid fossa 53 patients. In approximately 25% the extent of pneumatisation showed marked asymmetry. CONCLUSIONS: Pneumatisation of the temporal bone frequently extends close to the TMJ. Knowledge of these air spaces is helpful for the interpretation of imaging studies such as panoramic radiographs and to understand the spread of pathological processes into the joint.
Meningiomas should be considered in the differential diagnosis of space-occupying lesions of the temporal bone. Five cases of meningiomas of the temporal bone are described and the literature reviewed. These tumours may stimulate Schwannomas and glomus tumours in their presentation and radiological findings. The tumours were managed by combining standard neurosurgical approaches with temporal bone and skull base techniques.
OBJECTIVES: To evaluate the clinical, audiologic, and temporal bone computed tomograpic findings in patients with hemifacial microsomia and to use the OMENS (each letter of the acronym indicates 1 of the following 5 dysmorphic manifestations: O, orbital asymmetry; M, mandibular hypoplasia; E, auricular deformity; N, nerve involvement; and S, soft tissue deficiency) grading system to assess possible correlations between the severity of dysmorphic features with the type of abnormalities in the temporal bone and with degree of hearing deficit. DESIGN: Retrospective study. SETTING: Tertiary care children's hospital. PATIENT: Forty patients with hemifacial microsomia. RESULT: Mandibular hypoplasia and auricular abnormalities were the most common clinical manifestations, present in 39 patients (97%) and 38 patients (95%), respectively. Conductive hearing loss was noted in 35 patients (86%) and sensorineural hearing loss in 4 patients (10%). Facial nerve weakness was present in 20 patients (50%). Twenty patients had unilateral aural atresia, 12 patients had unilateral aural stenosis, and 7 patients had bilateral anomalies. Moderate hypoplasia or atresia of the middle ear was noted in 36 patients (90%) and ossicles were malformed in 30 patients (75%). Hypoplasia of the oval window was the most common inner ear abnormality. CONCLUSIONS: Severity of craniofacial features (total OMENS score) significantly correlated with the degree of temporal bone abnormality, but no correlation was noted with the degree or type of hearing loss. We recommend the following: (1) use of the OMENS classification system for documentation and analysis of dysmorphic finding in hemifacial microsomia; (2) complete audiologic evaluation in all patients with hemifacial microsomia regardless of the type of craniofacial abnormalities; and (3) temporal bone computed tomography for further evaluation of hearing deficit.
It is well known that hearing loss is often associated with anomalads, syndromes involving multiple anomalies. The incidence is especially high in severe cases of facial and visceral malformations. However, otologic features remain unclear in patients with a sequence of various anomalies which can not be classified into any known syndrome. We examined 11 temporal bones from 6 patients with severe visceral anomalies, which could not be classified into any known systemic bone diseases, chromosomal abnormalities, or congenital metabolic disorders. Temporal bone pathology was compared with external and visceral anomalies in each case. The temporal bones had been removed at autopsy, fixed in 10% formaldehyde, decalcified and embedded in celloidin. Serial horizontal sections were made at 20 microns and every tenth section was stained with hematoxylin eosin. Most abnormalities in the middle and inner ear were found to have an ectodermal or mesodermal origin. Inner ear abnormalities were noted in 6 temporal bones from 3 patients; the predominant feature was hypoplasia of the semicircular canals. Middle ear abnormalities excluding residual mesenchymal tissue were noted in 5 temporal bones from 4 patients; the predominant feature was an abnormal course of the facial nerve. It was also suspected that auricular and maxillomandibular abnormalities, which are often associated with severe visceral anomalies, indicate a high incidence of disorders affecting the auditory and vestibular systems.
The focus of the present investigation was to study, via molecular biology techniques, the character of the DNA present in individual archival celloidin-embedded human temporal bone sections. Polymerase chain reaction (PCR) amplification of 92 base pair (bp), 121 bp, and 471 bp regions of mitochondrial DNA (mtDNA) extracted from a single archival celloidin-embedded human temporal bone section was used to assess the length of the template DNA extracted. The effects of digestion time and sample motion during the extraction method on DNA concentration was also studied. These data are crucial to determine the limits of applying PCR technology to amplify specific genomic DNA targets located within the human inner ear. Further development of these methods will allow additional molecular temporal bone pathologic studies to be completed and, more specifically, hypotheses regarding the molecular etiopathogenesis of many auditory, vestibular, and facial nerve disorders, such as autoimmune hearing loss, congenital hearing losses, Meniere's disease, otosclerosis, or Bell's palsy could be tested. The results described should be of great value to those investigators extracting DNA from archival individual human temporal bone sections for PCR assays of specific genetic alterations or infectious agents associated with temporal bone pathologies.
The quantitative relationships between the position of the mastoid segment of the facial nerve, mastoid pneumatization and the positions of neighbouring structures are undetermined. Using high resolution computed tomography (HRCT), the positions of these structures were measured in 66 normal temporal bones. A new method for measuring the volume of pneumatization in the temporal bone based on the serial digital images of CT was designed. The method of partial correlation analysis was used to find the real relationship of the two variables. The results suggest that the factors that influence the position of the mastoid segment of the facial nerve are complicated and multiple. The development of the cranium including the temporal bone, the temporal bone pneumatization and the variable position of the jugular bulb are considered to be important factors.
A 16 year-old female was admitted to our hospital because of left temporal bone fracture and brain contusion in the left temporal lobe. CSF otorrhea was also present for a week. Four years later, when she was 20 years old, she was noticed to have a white mass in the left external auditory canal. One and a half year later, left CSF otorrhea reappeared, and she was readmitted to our hospital. High resolution coronal CT revealed that the left temporal bone fracture had opened widely and brain tissue had herniated into the left external auditory canal. Metrizamide CT cisternography showed that CSF was leaking around the mass. Operative findings have shown that there were two dural defects, both of which were 2 cm in diameter, and brain tissue surrounded by arachnoid membrane had herniated through these defect. The herniated brain tissue was removed, and both dural- and osteo-plasty were successfully carried out. This case indicates that dissociation of temporal bone fracture and laceration of dura mater may cause herniation of brain tissue and CSF otorrhea years later.
OBJECTIVE: Although there have been numerous reports on the relationship between the period of aminoglycoside administration and cochlear damage in animals, to date there have been no such studies in humans. The purpose of this study is to observe the early and late cochlear effects of aminoglycoside administration on hair cells, spiral ganglion cells, stria vascularis, and spiral ligament. METHODS: Specimens were divided into three groups. Group I included "normal" temporal bones with no histopathologic findings of otitis media and no history of otologic or ototoxic drug administration. Group II consisted of temporal bones that received aminoglycosides within 2 weeks before death and group III of temporal bones that had aminoglycosides from 2 weeks to 6 months prior to death. Patients in groups II and III received gentamycin, kanamycin or tobramycin. Temporal bones were excluded from groups II and III if patients had a history of otologic disease or other ototoxic drugs. All temporal bones were examined under light microscopy. Standard cytocochleograms and spiral ganglion cell reconstructions were done on all temporal bones. Morphometric measurements of areas of stria vascularis were made in all turns of the cochlea on mid-modiolar sections. Spiral ligament was divided into four segments according to the locations of different types of fibrocytes. The mean loss of fibrocytes in each segment was estimated. RESULTS: The percentages of intact outer hair cells in the basal turn were significantly greater in group I compared to groups II and III. The mean area of the stria vascularis in the apical turn was significantly less in groups II and III compared to group I. CONCLUSION: This study demonstrates that in a short period (within 2 weeks) after aminoglycoside administration, a decrease in hair cells and in the area of the stria vascularis occurred.
When we treat patients of otitis media, it is important to know the pathogenesis of otitis media. Therefore histopathological change of epithelium and bone in each site of tympanic cavity was observed using human temporal bones. Histopathological change of epithelium was classified as: acute, subacute and chronic in eighteen sites of tympanic cavity. Histopathological change of bone was observed in thirteen sites of tympanic cavity. And the frequency of histopathological change of epithelium and bone in each site was compared. A review of 350 temporal bones collected from autopsy cases revealed 171 (49.1%) to have otitis media, and a review of 170 temporal bones of otitis media cases revealed 165 (97.1%) to have bone changes. Differences in frequency of histopathological change of epithelium and bone existed in each site. Histopathological change in inferior portion of mastoid cells, round window niche and tympanic sinus was more frequent than in the other sites. Change of epithelium: in acute inflammation, no differences in frequency of histopathological change existed; in subacute inflammation and chronic inflammation, differences in frequency of histopathological change existed in each site. Change of bone: most changes were bone formation and bone reconstruction, but there was no clear finding that bone formation narrowed tympanic cavity without mastoid cells. Osseous destruction was found in mastoidectomy cases and cholesteatoma cases. It is thought that the frequency of inflammation is related to structure of cavity, aeration, immunologic activity or structure of the epithelium, and that the pathogenesis of otitis media, especially in chronic otitis media, is different in each site of tympanic cavity. It is thought that because the subjects of this study were not operated cases but autopsy cases, slight bone change was very frequent, but severe bone change, was rare. And we examined the pathogenesis of tympanic cavity of each case of acute inflammation and chronic inflammation of pars tensa and cases where there were no findings of inflammation in the pars tensa. In most cases of acute inflammation of pars tensa, inflammation of tympanic cavity was acute; in chronic inflammation of pars tensa, chronic. It was interesting that, in cases of normal pars tensa, inflammation was frequently found in tympanic cavity. Therefore, it is important to pay attention to the possibility of inflammation in tympanic cavity, even if the tympanic membrane appears normal.