Microfractures of the otic capsule. The possible role of masticatory stress

Microfractures of the temporal bone have been recognized for more than seventy years and occur in certain well-defined areas of the otic capsule. The etiology and significance of these microfractures has been debated since their discovery. The most commonly held theory is that they result from stresses within the otic capsule that develop with growth. An alternative explanation might be that they result from masticatory stress placed upon the temporal bone. Fifty serially-sectioned temporal bones from the Ontario Temporal Bone Bank were examined in this study for the presence of microfractures. Our findings as to the most common sites of microfractures agree with previous studies. It is proposed that the constant stress placed upon the petrous temporal bone by the act of mastication is directed by the anatomy of the external, middle and inner ear through certain definite pathways, including the Fallopian canal, the bony semicircular canals and the cochlea. The most common sites of these fractures represent sites of weakness in the path of these directed forces within the otic capsule, and the statistically significant increase in the number of fractures with age lends support to the masticatory stress theory.     

The endolymphatic sac in the Mondini disorder

Summary The endolymphatic sacs are described in temporal bone specimens from a 31-year-old man with bilateral Mondini disorder. The ducts and sacs are thin-walled, cyst-like structures with complete absence of loose vascular perisac tissue, and are directly apposed to the bone of the vestibular aqueduct. Histological evidence of severe bone erosion is present in these specimens and is most marked in the intermediate and distal portions of the vestibular aqueduct. It is also present in the foveal region of the posterior temporal bone surface underlying the sac. Erosion of the bony wall of the paravestibular canaliculus (PVC) is demonstrable, with incorporation of the vein of the PVC inside the margin of the widened vestibular aqueduct. These findings suggest a causal relationship between pressure within the endolymphatic duct and sac and erosion of the surrounding bone. The absence of endolymphatic hydrops of the cochlea and vestibular organs in the Mondini disorder constrast significantly with the endolymphatic hydrops seen in Meniere's disease.Supported by The Hope for Hearing Foundation, UCLA     

The endolymphatic sac in the Mondini disorder

The endolymphatic sacs are described in temporal bone specimens from a 31-year-old man with bilateral Mondini disorder. The ducts and sacs are thin-walled, cyst-like structures with complete absence of loose vascular perisac tissue, and are directly apposed to the bone of the vestibular aqueduct. Histological evidence of severe bone erosion is present in these specimens and is most marked in the intermediate and distal portions of the vestibular aqueduct. It is also present in the foveal region of the posterior temporal bone surface underlying the sac. Erosion of the bony wall of the paravestibular canaliculus (PVC) is demonstrable, with incorporation of the vein of the PVC inside the margin of the widened vestibular aqueduct. These findings suggest a causal relationship between pressure within the endolymphatic duct and sac and erosion of the surrounding bone. The absence of endolymphatic hydrops of the cochlea and vestibular organs in the Mondini disorder contrast significantly with the endolymphatic hydrops seen in Meniere's disease.     

A dural fistula as a rare cause for a pulse-synchronized tinnitus aurium

Pulse-synchronized tinnitus aurium is commonly caused by vascular processes within the area of the temporal bone. With a microphone or a stethoscope in the external ear or on the mastoid perceptible noises can be heard by the physician. The most important differential diagnoses of an objective tinnitus are paraganglioma of the glomus jugulare or the glomus tympanicum, vascular stenosis, arteriovenouse malformations, aneurysms and atypic findings of the bulbus venae jugularis interna of the temporal bone. In case of a pulse-synchronized tinnitus purposeful use of neuroradiological diagnostic can lead to a correct diagnosis. The indication for invasive intervention of dural fistulas depends on the number and the hemodynamic relevance of these fistulas and on individual suffering of the patient. Even if it does not succeed, all to embolize AV-short-circuits, it is possible to reduce the intensity of the tinnitus in order to continue with conservative therapy.     

Pathology and pathophysiology of Meniere's disease

Histopathologic study of the human temporal bone entails microscopic examination and analysis of a series of histologic sections. This is currently the most effective method for observing the pathologic conditions of MD by examining the entire inner ear. Complete temporal bone histopathology cannot be replaced by either clinical pathologic study of small biopsy specimens obtained during surgery, or experimental animal studies that can create endolymphatic hydrops but not create MD. We believe that the histopathologic findings together with clinical information on MD is valuable in enhancing our understanding of the pathophysiology of the inner ear in MD. For example, a hypoplastic VA and ES in MD seem to indicate that there may be congenital predisposing factors in the development of MD. The exact pathologic findings characteristic of MD remains unclear, however. Many of the temporal bone specimens were obtained years after patients were diagnosed with MD and those specimens were involved with moderate postmortem changes. For these reasons, further collection of temporal bone specimens with fewer postmortem changes, obtained within a shorter premortem time period between occurrence of the disease and the time of the patients' death, and from patients with a well-characterized clinical history of MD, is imperative. Contemporary temporal bone studies now include in situ hybridization histochemistry or polymerase chain reaction (PCR) analysis for protein, enzymes, or viral antigens that can be directed at specimens from patients with MD [54,55]. It is hoped that in the near future such advanced research studies with human temporal bone histology sections will support and enhance the significant contribution of temporal bone histopathology to clinical otology.     

An unusual case of congenital choleasteatoma in the mastoid with epidural abscess and cutaneous fistula

A unique case of congenital choleasteatoma within the mastoid region of the temporal bone is described. The patient presented with a cutane ous fistula into the external auditory canal and epidural abscess. The clinical, radiological, histopathological and operative findings are discussed. A review of the literature shows only one report of a similar case.     

Metastases to temporal bones from primary nonsystemic malignant neoplasms

OBJECTIVES: To compare histopathological and clinical findings of metastasis to the temporal bone with previous reports and to determine the prevalence of these metastases in patients with nonsystemic cancer. STUDY DESIGN: Retrospective. METHODS: Autopsy records of 864 patients were screened to select those with primary nondisseminated malignant neoplasms. These were evaluated histopathologically for metastasis to and site of involvement within the temporal bone, and histological characteristics of the tumor. Clinical records and autopsy reports were reviewed for demographic data, clinical course, otologic and vestibular manifestations, site of primary and its histological features, extent of metastasis, and mode of spread. RESULTS: Of 212 patients with primary nondisseminated malignant neoplasms, 47 had metastases to the temporal bone (76 temporal bones). Twenty different primary tumors had metastasized, most commonly breast cancer. Hearing loss was the most common otologic symptom (seen in 19 patients [40%]), while 17 (36%) had no otologic or vestibular symptoms. Temporal bone involvement was bilateral in 29 patients (62%). Most metastases to the temporal bone demonstrated hematogenous spread in 58 temporal bones (76.7%), and petrous apex was the most common site of metastases in 63 temporal bones (82.9%). Temporal bone metastases were not observed in cases where the primary tumor was adequately treated. CONCLUSIONS: In the largest series to date, we found temporal bone metastases more frequently than previously reported. Absence of temporal bone involvement in cases in which the primary tumor was adequately treated stresses the need for early management of cancer. Metastatic disease must be considered as a cause of hearing loss in patients with a history of malignant neoplasm.     

Middle latency auditory evoked potentials in temporal lobe disorders.

Middle latency auditory evoked potentials (MAEP) were recorded in 30 normal subjects and in 19 age-matched patients with temporal lobe lesions. MAEP appeared to be differentially affected by the specific structures involved within the temporal lobe. In the majority of patients with lesions involving the auditory area and/or auditory radiation, Na-Pa amplitude was significantly reduced over the involved hemisphere. No similar reduction in amplitude was noted in subjects with lesions not involving the auditory structures within the temporal lobe. We also observed a shift in a Pa latency over the involved hemisphere in patients with temporal lobe lesions involving the auditory structures. This latency shift was less pronounced than the amplitude reduction. The generators of MAEP in humans are discussed according to these findings and to the available literature. Normal intersubject variability of the conventional amplitude measures, and the occasional myogenic contamination of the response, limits establishing reliable criteria for abnormality that can be applied clinically for the diagnosis of patients with temporal lobe disorders.     

Two cases of intratemporal facial nerve neurilemmomas

The patients with neurilemmomas of the facial nerve within the temporal bone were treated. Although most of cases of the facial nerve neurilemmoma in the temporal bone present with a facial palsy, a few cases have normal facial nerve function and are especially difficult to diagnose preoperatively because of few symptoms. Case 1, a 31-year-old man, developed progressive left facial palsy with protrusion of the posterior wall of the external auditory meatus over a five-month period. Case 2, a 64-year-old man, complained of only fullness and tinnitus of the right ear without any facial nerve symptoms. Polytomography of the temporal bone demonstrated no abnormal findings in both cases. However, computed tomography revealed a soft-tissue density area in the left mastoid cavity with destruction of the posterior wall of the external auditory meatus in case 1. A similar soft-tissue density mass was found in the right tympanic cavity in case 2, suggesting the presence of the tumor in the temporal bone. At operation, the tumors were found to originate from the vertical portion of the facial nerve in both cases. It was assumed that normally existing dehiscences of fallopian canal might account for why some patients have normal facial nerve function.     

Chondromyxoid fibroma of the mastoid facial nerve canal mimicking a facial nerve schwannoma

Chondromyxoid fibroma of the skull base is a rare entity. Involvement of the temporal bone is particularly rare. We present an unusual case of progressive facial nerve paralysis with imaging and clinical findings most suggestive of a facial nerve schwannoma. The lesion was tubular in appearance, expanded the mastoid facial nerve canal, protruded out of the stylomastoid foramen, and enhanced homogeneously. The only unusual imaging feature was minor calcification within the tumor. Surgery revealed an irregular, cystic lesion. Pathology diagnosed a chondromyxoid fibroma involving the mastoid portion of the facial nerve canal, destroying the facial nerve. Laryngoscope, 2009     

The role of spatial location in auditory search

The majority of research findings to date indicate that spatial cues play a minor role in enhancing listeners' ability to parse and detect a sound of interest when it is presented in a complex auditory scene comprising multiple simultaneous sounds. Frequency and temporal differences between sound streams provide more reliable cues for scene analysis as well as for directing attention to relevant auditory 'objects' in complex displays. The present study used naturalistic sounds with varying spectro-temporal profiles to examine whether spatial separation of sound sources can enhance target detection in an auditory search paradigm. The arrays of sounds were presented in virtual auditory space over headphones. The results of Experiment 1 suggest that target detection is enhanced when sound sources are spatially separated relative to when they are presented at the same location. Experiment 2 demonstrated that this effect is most prominent within the first 250 ms of exposure to the array of sounds. These findings suggest that spatial cues may be effective for enhancing early processes such as stream segregation, rather than simply directing attention to objects that have already been segmented.     

Histiocytosis X of the ear and temporal bone: review of 22 cases.

Histiocytosis X encompasses three syndromes characterized by the idiopathic proliferation of histiocytes: eosinophilic granuloma, Hand-Schuller-Christian syndrome, and Letterer-Siwe disease. At the Mayo Clinic between 1926 and 1978, 22 patients with histiocytosis X had involvement of the ear or temporal bone. These patients comprised 15% of all patients with histiocytosis X seen during that period. The ages at onset of the disease ranged from 2 months to 49 years. The most frequent otologic symptom was aural discharge (15 patients), followed in frequency by swelling in the temporal region (11 patients), vertigo (6 patients), and deafness (5 patients). Clinical findings included otitis media (13 patients), otitis externa with or without granulation tissue (10 patients), and osteolytic lesions of the temporal bone (9 patients). A high index of suspicion is required to recognize the otologic manifestations of histiocytosis X for two reasons: the systemic manifestations of the disease are often so dramatic that the ear findings are overlooked, and the otologic findings of histiocytosis X can mimic more common diseases, including simple otitis externa, aural polyps, acute mastoiditis, chronic otitis media, and metastatic lesions.     

Congenital cholesteatoma of the mastoid temporal bone

OBJECTIVE: Congenital mastoid cholesteatomas are rare lesions of the temporal bone. The clinical presentation of these lesions is variable, making them difficult to identify preoperatively. We evaluated our series of mastoid congenital cholesteatomas (CCs) in an effort to better define the clinical presentation, imaging characteristics, and surgical challenges specific to this lesion. STUDY DESIGN: Retrospective chart and radiologic study review. METHODS: The medical records of patients with the diagnosis of mastoid CC on radiologic imaging over a 15-year period were reviewed. All had surgical and pathologic confirmation. Eight patients underwent preoperative computed tomography (CT). Six also underwent magnetic resonance (MR) scanning. Demographic information, clinical presentation, imaging results, and operative findings were recorded. RESULTS: Nine patients with the diagnosis of mastoid CC satisfying the inclusion criteria were found. Clinical findings were variable, with the most common presentation being an incidental finding. Imaging findings were more uniform. All CT scans demonstrated an expansile, well-circumscribed mass centered within the mastoid portion of the temporal bone. All MR scans showed a well-circumscribed mass with high intensity on T2-weighted images with precontrasted T1 sequences showing the lesion to be isointense or slightly hyperintense to cerebrospinal fluid (CSF). Operative findings included lateral mastoid cortex erosion, sigmoid sinus exposure, ossicular destruction, facial nerve exposure, and associated postauricular abscess. Management of these lesions is reviewed. CONCLUSION: Congenital mastoid cholesteatomas have a variable and nonspecific clinical presentation. Surgical challenges arise from the indolent nature of this clinical entity, which belies the extent of otologic involvement. Imaging with CT and magnetic resonance imaging are diagnostic, defines the extent of these lesions, and facilitates preoperative surgical planning.     

Embryonal rhabdomyosarcoma of the temporal bone

The most common soft-tissue sarcoma in infants and children is rhabdomyosarcoma. The head and neck is the most common site of involvement; temporal bone involvement has been seen in about 7% of reported cases. Multimodality therapy--surgery, multiagent chemotherapy, and radiotherapy-yields sufficiently good results. The author reports a case of embryonal rhabdomyosarcoma of the temporal bone with cranial nerve palsies and extension into the parapharyngeal space in a 4-year-old boy. Despite surgery and chemotherapy, the patient died of his disease within 3 months of presentation.     

Postnatal Persistence of Epidermoid Rests in the Human Middle Ear

It is widely believed that congenital cholesteatoma originates from epidermoid cell rests in the temporal bone. Congenital cholesteatomas of the anterior-superior middle ear may arise from such a rest, known as the epidermoid formation (EF), which has been described by Michaels and others. The EF is thought to disappear by 33 weeks' gestation in most cases; however, if it persists beyond fetal life, it may provide a nidus for cholesteatoma formation. The authors studied human temporal bones from individuals ranging from 20 weeks' gestation to 5 years of age to investigate pre- and postnatal occurrence of the EF. A total of 106 temporal bones were surveyed; 76 of these were fetal specimens and 30 were postnatal. EFs were present in 14 (18.4%) of the fetal specimens; they were identified in four(13.3%) of the postnatal temporal bones, with the oldest being 2 years, 7 months of age. Multiple EFs within a single temporal bone were also present in some cases. Although the EFs were composed of cells morphologically identical to those of the external ear canal epidermis, none of the specimens showed keratinization. These findings support the contention that EFs do occasionally persist into postnatal life and may be a source of cholesteatoma. However, a clear transition from epidermoid formation to unequivocal cholesteatoma has not yet been demonstrated.     

The temporal bone in multiple myeloma

Multiple myeloma is a malignant disease of the skeleton. Anatomically, any bone may ultimately come to be involved in a given case. In a literature review, no published series of temporal bone findings have been reported. In this study, otohistopathologic changes associated with multiple myeloma are analyzed and reported in 15 temporal bones from 8 patients. The bone marrow of 13 temporal bones was involved by the tumor. Osteolysis was evident in 11 temporal bones. Serous otitis media (SOM) or purulent otitis media (POM) was seen in 13 ears with 12 showing mastoid effusions. Eight ears exhibited pathological changes in inner ears, including degeneration of the organ of Corti, atrophy of stria vascularis, decreased ganglion cells, and labyrinthine hydrops. The inner ear changes were most severe in 2 patients who had otologic symptoms. Infiltration of myeloma cells was not apparent in the middle ear mucosa or the inner ears.     

Bilateral longitudinal temporal bone fractures: A retrospective review of seventeen cases

The types of temporal bone fractures, longitudinal and transverse, are reviewed. All cases of bilateral temporal bone fractures at Parkland Memorial Hospital in Dallas over a 10-year period from 1968 to 1978 are reviewed and discussed by the authors. One hundred sixty patients with the diagnosis of base of skull fractures were studied. Fifty-nine of these were temporal bone fractures and 17 of the 59 were bilateral. Of all the base of skull fractures, 10% were bilateral temporal bone fractures and 29% of all temporal bone fractures were bilateral. For each case the method of injury, the extent of damage to hearing and facial nerve function, presence of CSF otorrhea, X-ray findings, and additional complications are summarized and the results discussed. The operative findings of facial nerve decompressions are carefully reviewed. The authors' method of caring for temporal bone fractures is presented.     

Extracanalicular osteomas of the temporal bone

Extracanalicular osteomas of the temporal bone are rare neoplasms. Eight new cases are reported and a review of the literature is presented. These tumors are benign, slow growing, and composed predominantly of mature bone. Although they may occur anywhere in the temporal bone, they are prevalent in the mastoid and squama. Except for cortical lesions that are seen initially as cosmetic deformities, these tumors are usually unsuspected roentgenographic findings. Treatment is indicated for symptomatic osteomas. Mastoid lesions are readily excised. Tumors involving the middle and inner ear are most frequently small and tend to remain stable in size; consequently they are usually managed expectantly.     

Extralabyrinthine Manifestations of DFNA9

DFNA9 is an autosomal dominant cause of non-syndromic adult-onset sensorineural hearing loss with associated variable vestibular dysfunction caused by mutations in the COCH gene. DFNA9 has previously been characterized by the presence of unique histopathologic features limited to the cochlear and vestibular labyrinth. This report describes newly discovered extralabyrinthine findings within the middle ear in DFNA9 and discusses their implications. The histopathologic anatomy of extralabyrinthine structures was reviewed in 12 temporal bones from seven individuals with DFNA9 and compared with age-matched controls. All temporal bones with DFNA9 had abnormal deposits within the tympanic membrane, incudomalleal joint, and incudostapedial joint. Hematoxylin and eosin stain and Movat’s pentachrome stain both revealed different staining patterns of the extralabyrinthine deposits compared with the intralabyrinthine deposits suggesting that the composition of the deposits varies with location. The deposits within the tympanic membrane resembled cartilage morphologically and stained positively for aggrecan, an extracellular matrix protein found in cartilage. However, the cellular component of the tympanic membrane deposits did not stain with immunomarkers for chondrocytes (s100 and connective tissue growth factor). These novel findings in DFNA9 have implications for the phenotypic expression of the disorder and the clinical workup of adult-onset sensorineural hearing loss.     

The integration of laughter and speech in vocal communication: a dynamic systems perspective.

Laughter in infant-directed speech was examined in 13 mother-infant pairs to investigate the possible co-occurrence of speech and laughter. Contrary to previous findings in adult-adult social interaction, all mothers produced speech simultaneously with laughter in up to 50% of laughs. In most of these speech-laughs the onset of laugh and speech was simultaneous. Laughter occurred on both function and content words and was more likely to occur on approximately 2 words and on utterances that were statements rather than questions or exclamations. Laughter and speech are different outcomes produced from a reorganization of the same vocal/anatomical parameters. A 3rd outcome is possible in the form of speech-laughs utilizing features from both laughter and speech. In speech-laughs, the duration of the vocalization was more likely to increase, and the changes in the utterance were likely to include 1 or more of the features of vowel elongation, syllabic pulsation, breathiness, and pitch change. These findings and individual variations in the resulting vocal output are discussed from a dynamic systems perspective. It is argued that neither speech nor laughter is dominant when both are combined, but that this is a more complex vocal outcome produced with idiosyncratic flexibility within stable temporal and physiological constraints.