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A new device is introduced for holding temporal bones during dissection. It is structurally very different, more practical and effective for securing the bone than the temporal bone holding bowl which has been in use so far.
The objective of this study is to describe the presentation and clinical course of two patients with temporal bone chondroblastoma, and to review the literature on temporal bone chondroblastoma to identify characteristic clinical and radiological presentations, and optimal treatment regimens. MEDLINE literature searches covering the period from 1966 to January 1998, in all languages, were performed as well as a review of the bibliographies of the identified studies. Strict inclusion criteria were upheld, In total 18 studies had patients whose data could be analyzed. From the 18 studies, 34 patients were identified, but only 21 cases met the inclusion criteria. Demographic, clinical presentation, radiological, operative and treatment parameters were analyzed in this cohort of patients. Ninety-five percent of patients were found to have invasion of the middle cranial fossa and 76% were found to have erosion into the superior aspect of the external auditory canal by temporal bone chondroblastoma. The characteristic growth pattern of temporal bone chondroblastoma may result from embryonal or cartilagenous rests entrapped in the tympanosquamous suture line in the middle fossa floor. Temporal bone chondroblastoma represents a pathology that does not arise from, or have a growth pattern resembling other pathologies in the temporal bone.
OBJECTIVE: 3D volume reconstruction of CT images can be used to measure temporal bone aeration. This study evaluates the technique with respect to reproducibility and acquisition parameters. MATERIAL AND METHODS: Helical CT images acquired from patients with radiographically normal temporal bones using standard clinical protocols were retrospectively analyzed. 3D image reconstruction was performed to measure the volume of air within the temporal bone. The appropriate threshold values for air were determined from reconstruction of a phantom with a known air volume imaged using the same clinical protocols. The appropriate air threshold values were applied to the clinical material. RESULTS: Air volume was measured according to an acquisition algorithm. The average volume in the temporal bone CT group was 5.56 ml, compared to 5.19 ml in the head CT group (p = 0.59). The correlation coefficient between examiners was > 0.92. There was a wide range of aeration volumes among individual ears (0.76-18.84 ml); however, paired temporal bones differed by an average of just 1.11 ml. CONCLUSIONS: The method of volume measurement from 3D reconstruction reported here is widely available, easy to perform and produces consistent results among examiners. Application of the technique to archival CT data is possible using corrections for air segmentation thresholds according to acquisition parameters.
Fibrous dysplasia, characterized by benign osteolytic and osteoblastic lesions may involve one or several bones. Recent investigators have suggested that it may be merely a phase of what have previously been thought to be several different bone diseases. Isolated fibrous dysplasia in the temporal bone is infrequent. Several reports of this disease have appeared in the literature of paleopathology, but none involved only the temporal bone. Monostotic involvement of the right temporal bone was discovered in the skull of an adult male recovered from an archeological site dating from the Late Mississippian period (A.D. 1,350-A.D. 1,650). It will provide an opportunity for preliminary documentation of the antiquity of this disease in the southeastern portion of the United States.
Tumours lesions of the temporal bone and of the cerebello-pontine angle are rare. This tumours can be separated into benign and malignant lesions. In this paper the CT and MRI characteristics of tumours of the temporal bone and the cerebello-pontane angle will be demonstrated. High resolution CT (HRCT) as usually performed in the axial plane are using a high resolution bone window level setting, coronal planes are the reconstructed from the axial data set or will be obtained directly. With the MRI FLAIR sequence in the axial plane the whole brain will be scanned either to depict or exclude a tumour invasion into the brain. After this,T2-weighted fast spin echo sequences or fat suppressed inversion recovery sequences in high resolution technique in the axial plane will be obtained from the temporal bone and axial T1-weighted spin echo sequences before and after the intravenous application of contrast material will be obtained of this region. Finally T1-weighted spin echo sequences in high resolution technique with fat suppression after the intravenous application of contrast material will be performed in the coronal plane. HRCT and MRI are both used to depict the most exact tumorous borders. HRCT excellently depicts the osseous changes for example exostosis of the external auditory canal, while also with HRCT osseous changes maybe characterized into more benign or malignant types. MRI has a very high soft tissue contrast and may therefore either characterize vascular space-occupying lesions for example glomus jugulare tumours or may differentiate between more benign or malignant lesions. In conclusion HRCT and MRI of the temporal bone are excellent methods to depict and mostly characterize tumour lesions and can help to differentiate between benign and malignant lesion. These imaging methods shall be used complementary and may have a great impact for the therapeutic planning.
Osteoblastoma is a benign bone lesion that mainly affects the long bones and rarely the temporal bones. Very few cases have been reported in the literature. This paper reviews the literature, discusses the differential diagnosis, clinical presentation, and CT scan findings of such a condition and details our experience with a young patient who had a temporal bone (mastoid process) osteoblastoma.
The temporal bones from fetuses with known autosomal trisomy syndromes were examined histopathologically after spontaneous or induced abortions. Fetal ages dated from the 17th to the 24th week of pregnancy. In all, 17 temporal bones from nine fetuses were studied and included seven cases of Down's syndrome and two of Edwards' syndrome. Temporal bones from fetuses with Down's syndrome had more abnormalities of the external and middle ears than of the inner ear. The bones from the fetuses with Edwards' syndrome showed abnormalities of the external or middle ear and retarded development of the inner ear (failed ossification of the otic capsule and unformed organ of Corti).
OBJECTIVE: To discuss the diagnosis and the therapy methods of congenital temporal bone cholesteatoma. METHOD: Reviewing and analyzing the clinical data and information about 16 cases of congenital temporal bone patients from 1980 to 2002. RESULT: The surgery were proceeded for removing cholesteatoma focus in all patients and the diagnosing were made by histopathologic investigation. Following for half to three years, 6 cases of facial nerve paralysis got partially or totally healing, hearing function improved in 5 cases, 2 cases relapsed and operation were made again for resecting, recrudescent cholesteatoma. There were no any subsequent symptoms happened. CONCLUSION: The diagnosis of congenial temporal bone cholesteatoma mainly base on the patient's clinical symptoms and manifestation, and imaging examination. MRI can clearly show cholesteatoma focus and other organs or tissues (including some encephalic frameworks) around it, which also is one of important inspection techniques for discriminating from congenital encephalic cholesteatoma near rock part of temporal bone. The drum integrity is not necessary condition for diagnosing this disease, the surgery approaches are selected by the size and position of focus. The key for preventing recrudescence is to drastically eliminate cholesteatoma tissues.
This study is concerned with the incidence and type of temporal bone anomalies that might be present in persons who, apart from their deafness, are normal. It also attempts to correlate demonstrated abnormalities with the etiology of deafness. Review of the results will permit a reassessment of the value of roentgenographic studies in the routine evaluation of deaf children. One hundred and four deaf students, 3 to 21 years of age, were studied by physical examination, audiometry, and temporal bone tomography. A pertinent history was requested, and appropriate medical records were obtained. Roentgenographically demonstrable abnormalities of the temporal bones were present in 19 students (18%) or 28 temporal bones (13%). Meningitis was the only entity to which a specific pathologic change could be ascribed. The number of abnormalities found in this population was significant and should re-emphasize the importance of temporal bone tomography in the total evaluation of deaf children.
Adenomatous lesions of the temporal bone represent a diverse group of neoplasms. At least three histopathologic patterns have been described: glandular; ribbon-like, or "festooning;" and aggressive papillary. Combinations of glandular and ribbon-like histologies in the same lesion are not uncommon. The glandular and ribbon-like histologies have been associated with carcinoid tumors, and the aggressive papillary tumor has been considered a separate entity. Recently, the endolymphatic sac has been proposed as the site of origin of the aggressive papillary lesions. Previous reports have described neuroendocrine properties with characteristics embracing the three histologic types. The authors postulate that the neural crest is the site of origin of this unusual group of neoplasms. Immunohistochemical analysis on the pathologic specimens of patients with adenomatous lesions of the temporal bone was performed to test this hypothesis. From 1975 to 1992 seven patients were treated at the Cleveland Clinic Foundation with a diagnosis of middle ear adenoma. A panel of special stains for neuroectodermal markers, including synaptophysin, chromogranin, neuron specific enolase, calcitonin, and serotonin was used on the paraffin-embedded formalin-fixed specimens. Three lesions were also evaluated by electron microscopy, all demonstrating dense core, intracytoplasmic granules. Three ribbon-like tumors were positive for synaptophysin and chromogranin, and two of these were positive for serotonin. One glandular tumor was positive for synaptophysin, and an aggressive papillary tumor was positive for synaptophysin and neuron specific enolase. An additional papillary tumor was referred following a third recurrence without accompanying immunohistochemical data. Cholesteatoma-like material was identified with a few glandular cells interspersed, all negative by immunohistochemical evaluation. The seventh specimen, initially diagnosed as papillary adenoma on light microscopy, was not studied by the aforementioned stains, and was later identified as a papilloma of sinonasal origin. The neural crest gives rise to pluripotential stem cells with widespread anatomic distribution, including the temporal bone. Because immunomarkers used in this study are specific for neuroectodermal differentiation, results suggest that temporal bone adenomas have neuroendocrine characteristics and could be derived from the specialized neuroectoderm of the neural crest.
The recent advances in MR imaging of the temporal bone brought about by the availability of intravenous contrast agents sensitive to the disruption of the blood-brain barrier have further expanded the role of MR imaging in the evaluation of this region. The main applications of contrast-enhanced MR imaging in the temporal bone are the evaluation of inflammatory and neoplastic processes of the labyrinth (in the general context of patients with sensorineural hearing loss or vertigo) peripheral seventh nerve palsies, and miscellaneous inflammatory and neoplastic conditions of the temporal bone itself.
OBJECTIVE: To discuss a rare but devastating complication following radiotherapy to the head and neck: radiation-induced malignancies of the temporal bone. STUDY DESIGN: A retrospective case review comprising five patients with radiation-induced tumors involving the temporal bone. SETTING: A tertiary referral center. PATIENTS: Patients with tumors involving the temporal bone who have satisfied the criteria for being considered radiation-associated. MAIN OUTCOME MEASURES: Initial tumor histology, radiation-induced tumor histology, latency between radiotherapy and diagnosis of the radiation-associated malignancy, amount of radiation received, therapeutic interventions, and survival statistics for each patient. RESULTS: Five cases of radiation-induced tumors of the temporal bone are presented (two osteosarcomas, two fibrosarcomas, and one squamous cell carcinoma). All five temporal bone tumors occurred in individuals that had previously received > 5,000 cGy of radiation. The initial histologic diagnoses included two astrocytomas, a glomus jugulare, a malignant meningioma, and a vestibular schwannoma. There was an average latency period of 15 years (range, 7-23 years) between completion of radiation and diagnosis of the malignancy. Four patients were treated with resection plus chemotherapy, and one decided against therapy. The prognosis was poor, with survival time of 7-14 months after the diagnosis of the radiation-induced tumor. Only one patient survived > 14 months and is currently free of disease, 3 years after diagnosis of the radiation-induced tumor. CONCLUSIONS: Although radiation-induced tumors of the temporal bone occur with a very low incidence, their prognosis is extremely poor. The remote possibility of a radiation-associated tumor should be factored in when deciding upon the most appropriate therapeutic modality for individuals with neoplasms of the CNS and head and neck. Such considerations are particularly germane when contemplating radiation therapy for a benign lesion (e.g., glomus jugulare, acoustic neuroma, or meningioma) in an individual with a long predicted lifespan.
The pneumatized articular eminence of the temporal bone (PAT) is a cavity similar to that seen in the mastoid process that occurs in the zygomatic process of the temporal bone. Panoramic radiographs of 1061 dental school patients were reviewed to determine the radiographic appearance and population characteristics of this finding; PAT was found in 28 patients (2.6%). The mean age of the patients was 32.5 years; there was no sex predilection and four patients showed this defect bilaterally. Two radiographic types of PAT were identified, unilocular and multilocular. Panoramic radiography appears to be an efficacious method to display the articular eminence for visualization of PAT. Due to the relatively common occurrence of PAT and the increasing amount of surgery of the temporomandibular joint, visualization of this defect becomes important for the clinician planning surgical manipulation of the articular eminence.
The pneumatization of 141 "normal" temporal bones on computed tomography (CT) was evaluated in 100 patients (age range, 6-85 years). Because of the controversy surrounding the sclerotic squamomastoid (mastoid), temporal bones with this finding were discarded. A CT index of pneumatization was based on the pneumatized area and the number of cells seen within a representative scanning section. Results suggest that squamomastoid pneumatization follows the classic normal distribution and does not correlate with age, gender, or laterality. A high degree of symmetry was found in 41 patients who had both ears examined. In 35% of all temporal bones, the petrous apex was pneumatized, concordant with the findings of other investigators. Pneumatization extending into other regions of the temporal bone corresponded linearly with squamomastoid pneumatization. Air-cell configuration was variable. Air-cell size tended to increase progressively from the mastoid antrum. The scutum "pseudotumor" appearance caused by incomplete pneumatization was seen frequently, and should not be mistaken for mastoiditis or an osteoma. Thick sections producing partial-volume effect may also produce this spurious finding. Therefore, when searching for mucosal thickening due to mastoiditis, large air cells should preferably be analyzed.
Six cases of osteoradionecrosis of the temporal bone are described. Persistent symptoms of otitis externa refractory to local treatment measures should alert the physician to the possibility of underlying osteoradionecrosis. Treatment of superficial parotidectomy and partial temporal bone resection with preservation of the facial nerve is indicated if local aggressive conservative measures fail to control the disease. Benign mixed tumors of the parotid gland should be treated surgically with avoidance of radiotherapy.
Systematic anatomical description of the various structures of the temporal bone have been performed based on dissection of 16 guinea pigs (32 temporal bones). It has been found that besides two main air spaces in the middle ear, the tympanic bulla and dorsal bulla described in literature, there are also additional air cells in the mastoid process and facial nerve region in the temporal bone of a guinea pig. Moreover recesses were found in the walls of the tympanic bulla that formed almost completely separated partitions of tympanic cavity. The malleus head, the body of the incus and the superior and lateral semicircular canals as well as the facial nerve are easily accessible from the dorsal bulla. From the ventral tympanic bulla, one can access both windows and the cochlea. The semicircular canals are relatively large, the lateral canal is largest and the posterior the smallest. The cochlea has thin bony wall, and is composed of 3.5-3.75 turns.
The endolymphatic ducts and sacs of 25 temporal bones with idiopathic endolymphatic hydrops from individuals with Meniere's disease were studied and compared with the same number of control bones without endolymphatic hydrops from individuals with no premortem history of otologic disease. The control bones were selected so that the sizes of their vestibular aqueducts matched those temporal bones from individuals with Meniere's disease. The endolymphatic ducts and sacs of all bones were studied by the medial view graphic reconstruction method and/or histological observation under a light microscope. In the endolymphatic duct and sac of many of the temporal bones from patients with Meniere's disease were noted a diminution of the width of the endolymphatic duct in its isthmus portion, an increase in the area of the collapsed lumen of the endolymphatic sac, fibrotic changes in the perisaccular loose connective tissue, and an increase in the quantity of intraluminal eosinophilic material. The frequencies with which these pathological findings were noted in bones from individuals with Meniere's disease and in control bones were statistically significantly different. No significant differences were observed under light microscopic study between these two groups with regard to the condition of the epithelial cells, the degree of rugosity of the endolymphatic sac, or the appearance of melanin-like pigmentation of hyalinization in the perisaccular connective tissue.
Axial and coronal high resolution computer tomography (HRCT) of the temporal bone is an important imaging technique to evaluate hearing loss. However the acquisition of the coronal imaging proves uncomfortable to the patient and is not always technically possible in old and ill patients. Clinical diagnoses of chronic otitis media, mastoiditis, cholesteatoma and cochlear otosclerosis in 10 patients were studied on a third generation CT scanner. Axial 1 mm HRCT slices were acquired and the images were transferred to an Advantage Windows workstation where two-dimensional (2D) multiplanar and sagittal maximum intensity projection (MIP) reformations were performed. Our aim was to study the ability of this technique to identify several small structures of the temporal bone in various diseases. In all cases the finer structures of the temporal bone were identified in axial HRCT images. The tegmen tympani, atticus and the cochlea were best seen in the 2D coronal reconstructions. The aditus ad antrum, facial canal, vestibule and the semicircular canals were best seen on 2D sagittal reconstructions. The joints between the bony ossicles of the middle ear was best seen in the sagittal MIP reconstructions. Our results suggest that axial HRCT, 2D multiplanar and MIP reconstructions of the temporal bone produce images with sufficient diagnostic quality in patients with hearing loss.