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PubMed1987

Magnetic resonance imaging in temporal bone fracture.

In seven patients with temporal bone fractures examined by both CT and MRI, thin section CT proved superior to MRI in demonstrating the full extent of the fractures and the status of the ossicular chain. MR studies were able to demonstrate fractures, when these fractures contained blood or CSF, and the presence of ossicular dislocation in one case where the middle ear was completely filled with CSF or blood. Admixture of air in the middle ear gave a false impression of ossicular dislocation, while air in the fracture obscured portions of it. MR proved superior to CT in the evaluation of intracranial contents by showing 5 additional subdural hematomas, 2 epidural hematomas and 2 hemorrhagic contusions.

Adolescent↗

PubMed2001

[Retraction of the endolymphatic membranes in temporal bones of the Wittmaack and Tufts collections].

BACKGROUND: In histologic studies, the volumetric status of the intralabyrinthine fluids is judged by the position of the endolymphatic membranes. Bulging of the membranes, commonly known as endolymphatic hydrops, is assumed to be caused by excess of endolymph. The opposite situation, retraction of the membranes is, however, only incidentally described and relatively little attention has been paid to its significance. Almost one hundred years ago Wittmaack described retraction of the endolymphatic membranes, which has since been considered to be preparation artifact--a concept that essentially remains unchallenged. To test the validity of this long premise, we examined two sets of temporal bones from different centers. MATERIAL AND METHODS: We studied the following collections: 1. The Wittmaack collection in Hamburg, Germany. The original material of 67 temporal bones (patient ages 0-92 years, average age 35.2 years) on which Wittmaack based his opinions. 2. For comparison and to exclude age related phenomena, 125 temporal bones from 73 children between the ages newborn to ten years (average age 13.4 months, median 1.5 months) from the temporal bone collection of the Department of Otolaryngology Tufts University School of Medicine. All specimens were studied by light microscopy. Retraction was defined as depression of Reissner's membrane toward the stria vascularis and the Organ of Corti in more than one cochlear turn and was graded into mild, moderate and severe. Additionally the saccule, utricle and semicircular ducts were examined for collapse. RESULTS: The reevaluation of the 67 temporal bones described by Wittmaack, including those of 7 children below the age of 10 years, showed retraction of Reissner's membrane in 81% compared to 33% of the temporal bones from the Tufts collection. In contrast to the high incidence of retraction in the cochlear duct, fewer saccules (12%) and utricles (4%) were collapsed in the Tufts collection. In the Wittmaack collection no significant differences between the underlying diseases were found, however in the Tufts collection the group of children who suffered from extracochlear infections and malignancies had a higher frequency of retraction. CONCLUSION: Mild retraction might be to some extent physiologic or even artifactual. Severe retraction, however, is a definitive finding that is a part of a local or regional otopathologic process. Of material, it is quite possible that Wittmaack's original observations of what he called "hypotonic collapse" was of viral origin (viruses were not known during Wittmaack's time), ototoxicity or even of genetic origin.

Adolescent↗

PubMed2004

[Evaluation of the insertion-trauma of the Nucleus Contour Advance electrode-array in a human temporal bone model].

BACKGROUND: The development of intracochlear electrode arrays is aiming at a placement close to the modiolus with an insertion as atraumatic as possible. A new perimodiolar electrode model the Nucleus Contour Advance was to be evaluated regarding the possible intracochlear trauma. METHODS: The implantation of the Contour Advance electrode was performed in 11 frozen native temporal bones. Beneath a regular insertion in 5 temporal bones in 6 cases the insertion was carried out using the "advance-off-stylett" technique with a fixed stylett. The temporal bones were embedded in metacrylate based resin for histomorphological evaluation. The evaluation was performed regarding to the intracochlear placement close to the modiolus and the damage to intracochlear fine structures (basilar membrane, osseus spiral lamina). RESULTS: In 2 out of 11 cases we found a perforation from the scala tympani to the scala vestibuli independent of the insertion-technique. A severe intracochlear trauma was observed in one case with fracture of osseus spiral lamina using the AOS-technique. A close position to the modiolus could be achieved by insertion the scala tympani without perforation of the basilar membrane. CONCLUSIONS: The Nucleus Contour Advance electrode array showed minimal trauma in human temporal bones by using a standard insertion technique. By using the freehand AOS-technique a severe cochlear trauma is possible. Therefore further development in electrode design and the use of an insertion-tool is recommended.

Basilar Membrane↗

PubMed2006

A comparison of temporal bone fracture classification systems.

OBJECTIVES: To compare the traditional and otic capsule classification system of temporal bone fractures for clinical relevance. DESIGN: A retrospective review of all patients with a radiological diagnosis of a skull-base fracture over a 5-year period. SETTING: All patients were seen at Beaumont Hospital, the national tertiary referral centre for Neuro-otology. PARTICIPANTS: Patients with a clinical diagnosis of skull fracture were identified from the hospitals in patient enquiry (HIPE) database. Of 338 patients, 31 (9%) were identified as having a temporal bone fracture on high-resolution CT scanning. MAIN OUTCOME AND MEASURES: The rate and distribution of each major clinical complications within each classification system to establish if either one was more clinically useful. RESULTS: Fractures were classified as mixed in 14 (45%), longitudinal in 9 (29%) and horizontal in 8 (26%). Alternatively, 2 (7%) were otic capsule violating and 29 (93%) were otic capsule sparing. Seventeen patients (54.8%) sustained a hearing loss. Seven patients (23%) sustained a facial nerve injury. Four (13%) developed a cerebrospinal fluid (CSF) leak. Of all clinical findings only sensorineural hearing loss occurred significantly more often in the horizontal as opposed to the longitudinal group (P = 0.029) and in the otic violating as opposed to the otic sparing group (P = 0.013). CONCLUSIONS: We acknowledge that the relatively small size of our cohort diminishes the statistical power of our conclusions. However, we found that the otic capsule-based classification system was not significantly better than the traditional system in predicting the likelihood of sustaining specific injuries from fractures of the temporal bone.

Brain Injuries↗

PubMed1989

Temporal bone computed tomography in the preoperative evaluation for cochlear implantation.

High resolution computed tomography of the temporal bone is performed routinely in the preoperative evaluation for cochlear implantation. A retrospective review was performed to determine the effect of these studies. The clinical significance was determined through consultation with the referring otolaryngologist and review of the operative reports. Twelve examinations were reviewed. Abnormalities were identified in 12 of the 24 ears examined (eight of 12 patients studied). In two patients the CT examination strongly influenced the selection of the ear to be implanted. In four additional cases information felt to be useful in preoperative planning was provided. Useful information related to potential complications with the mechanical insertion of the electrode apparatus. We conclude that temporal bone abnormalities are common in the population undergoing cochlear implantation and that high resolution temporal bone CT is essential in preoperative evaluation. The CT scan should be interpreted with adequate knowledge of the operative procedure to evaluate any possible barriers to the mechanical insertion of the internal components of the system.

Cochlear Implants↗

PubMed2006

Giant cell reparative granuloma of the temporal bone treated with calcitonin.

OBJECTIVE: A case report of a giant cell reparative granuloma involving the temporal bone successfully treated with calcitonin. STUDY DESIGN: Case report. SETTING: Teaching hospital, tertiary referral center. PATIENT, INTERVENTION, AND RESULTS: A 62-year-old man was referred to the otolaryngology department with an extensive temporal bone lesion confirmed by biopsy to be a giant cell reparative granuloma. As an alternative to surgery, calcitonin therapy was commenced. After 12 months of treatment, clinical and audiological parameters had returned to normal, and radiological appearances had shown significant bony remodeling. These parameters remain stable 24 months after cessation of treatment. CONCLUSION: Calcitonin is a safe and economical medical treatment, which should be considered for destructive giant cell granulomas of the temporal bone.

Audiometry, Pure-Tone↗

PubMed2003

3-D reconstruction of the vestibular endorgans in pediatric temporal bones.

We investigated the vestibular endorgans in three children using 3-D reconstructions from histological sections. The right temporal bone of a newborn child without peripheral vestibular pathology was used as reference model and the temporal bones from a child with Goldenhar syndrome and a child with Pierre Robin sequence with known peripheral vestibular pathology were studied. All five temporal bones were prepared by the celloidin technique and sectioned at 20 microm. Each available section was digitized with a slide scanner. The imaging data were layered anatomically correctly and rendered in a 3-D software. With this technique all vestibular endorgans were reconstructed and measured. The standard deviations in distances ranged between 0.5 and 1.2% and in angles between 0.1 and 2.9 degrees. Both maculae were curved in the longitudinal and transverse axes which described a curve of approximately 35 degrees. The angles between the semicircular ducts varied between 97 and 110 degrees. The pathological models demonstrated a distorted configuration of the semicircular canals and differed substantially from the reference model in most of the measured distances and angles. The method presented is capable of generating 3-D models of the vestibular system from histological sections with an acceptable precision without previously inserted reference marks. Archival celloidin sections are widely available and will be an important resource in understanding the detailed 3-D geometry of the vestibular system which has not yet been accomplished.

Goldenhar Syndrome↗

PubMed2004

Rapid prototyping of temporal bone for surgical training and medical education.

OBJECTIVE: The skills of ear surgery are best developed by dissecting a temporal bone. However, only a limited number of trainees can be afforded this opportunity because of the scarcity of available bones. The aim of this study was to investigate the validity of a prototype temporal bone model for surgical training and education. MATERIAL AND METHODS: A simulated 3D model of a human temporal bone was made using a selective laser sintering method. The powder layers were laser-fused based on detailed CT data and accumulated to create a 3D structure. Conventional surgical instruments were used to dissect the model under a microscope. RESULTS: The model was as hard as real bone and surface structures were accurately reproduced. The model could be shaved using a surgical drill, burr and suction irrigator in the same way as a real bone. The malleus and incus were reproduced. The semicircular canals and the oval and round window niches were identified. Cavity structures, such as the semicircular canal, vestibule, antrum and air cells, were filled with powder which had to be removed using a pick and suction irrigator during dissection. A magnified model was useful for educating medical students. CONCLUSION: This prototype 3D model made using selective laser sintering serves as a good educational tool for middle ear surgery.

Humans↗

PubMed1998

[An experimental study of tumor cell infiltration into temporal bones--route into the inner ear from the arachnoid space].

In humans, metastatic tumors which invaded the temporal bones have been studied in regard to the relationship between histopathologic findings and clinical symptoms. On the other hand, there is no experimental study using an animal model for tumor infiltration into the temporal bone. This study was designed to establish such an animal model and examine the temporal bones histopathologically. Rat thymic lymphoma cell (FTL-A2) were inoculated into the cisterna magna of Wistar rats. The animals were decapitated under deep anesthesia with pentobarbital sodium from the 1st to 8th day after inoculation. Their heads were fixed with Heiden-hain SuSa solution, decalcified, dehydrated, embedded in celloidin, and sectioned horizontally at a thickness of 25 microns. These were stained with hematoxylin and eosin, and histologically examined by light microscopy. Inoculated tumor cells showed active viability in the arachnoid space at a rate of 98%. Two major routes of tumor cell infiltration into the inner ear were found: the cochlear aqueduct and the internal auditory canal. At the early stage after the inoculation, tumor cells infiltrated the scala tympani through the cochlear aqueduct. Invading the fiber of the cochlear nerve, tumor cells infiltrated Rosenthal's canal via the tractus spiralis foraminosus, and passed through Rosenthal's canal and the osseous spiral lamina into the scala tymani. However, tumor cells did not infiltrate the organ of Corti through the habenula perporata. Tractus spiralis foraminosus and habenula perforata functioned as a barrier against tumor infiltration. In a few cases, tumor cells infiltrated over the macula cribrosa into the subepithelial space of the utricule and saccule. The macula cribrosa functioned as a barrier.

Acoustic Maculae↗

PubMed1995

Normal variations of the temporal bone on high-resolution CT: their incidence and clinical significance.

We evaluated normal variations of the temporal bone on high-resolution computed tomograms (HR-CTs) and investigated their incidence. HR-CTs of the temporal bones of 325 patients were retrospectively reviewed. Six groups of variants, which were considered important for presurgical planning, were evaluated on HR-CTs. These included: (1) an incomplete bony covering of a high-positioned jugular bulb; (2) severe asymmetry of the jugular foramen; (3) an anteriorly located sigmoid sinus; (4) a deep sinus tympani; (5) a large internal auditory canal; and (6) a large cochlear aqueduct. The frequency of the variations were as follows: (1) 2.4%; (2) 4.0%; (3) 1.6%; (4) 5.9%; (5) 2.3%; and (6) 3.0%. Bilateral involvement with variation (4), (5) and (6) was frequently seen. Normal anatomical variations of the temporal bone are therefore not rare and awareness of the possible variants is necessary before surgery of the inner ear, middle ear and posterior fossa.

Adolescent↗

PubMed2003

Large cystic fibrous dysplasia of the temporal bone: case report and review of literature.

Fibrous dysplasia is an uncommon benign disorder of unknown aetiology. It most likely represents a disorder of normal bone development. As it may occasionally involve the temporal bone, and encroach on the middle cranial fossa, it is of interest to the neurosurgeon. Fibrous dysplasia of the cystic variety is very uncommon. We report a case of a large cystic fibrous dysplasia involving predominantly the squamous temporal bone. The radiology and histology are discussed, and its differentiation from other lesions.

Craniotomy↗

PubMed1998

[Extraction, amplification, recombination and sequencing of the mitochondrial DNA from celloidin embedded human temporal bone sections].

OBJECTIVE: To establish an analytical method of DNA extracted from human celloidin-embedded temporal bone sections by molecular biologic technique. METHODS: Polymerase chain reaction (PCR) with different primers, special amplification methods or coorperated with enzyme restricted reactions was adapted to detect several types of genetic mutations from 9 human celloidin-embedded temporal bone sections. The pGEM-T vector was used for the recombination and cloning of the amplified DNA fragment. RESULTS: The 135 bp fragments of normal mtDNA were detected from all of the 9 cases. The 316bp fragment related to mtDNA 4977bp deletion was also detected in two cases who suffered from presbycusis before death by the nested PCR. The result of sequencing confirmed the accuracy of PCR. CONCLUSION: The application of molecular biologic techniques in temporal bone research is important in improving the quality and value of retrospective study of ear diseases and has resulted in findings of the relevant mutant or pathogenetic genes in the ear diseases such as presbycusis, ototoxic deafness, otosclerosis and viral infections of the ear.

Adolescent↗

PubMed2006

Audiovestibular evolution in a patient undergoing surgical resection of a temporal bone myxoma.

Primary myxoma in the head and neck region occurs mostly in the maxilla and mandible, and rarely in the temporal bone. A 32-year-old female patient with temporal bone myxoma manifested as acute vertigo, headache, and tinnitus on the right ear. Audiometry and auditory brainstem response revealed normal responses, bilaterally. Vestibular function test displayed spontaneous nystagmus beating toward the left side. Absent ice water caloric response was disclosed on the right ear, whereas vestibular evoked myogenic potential test showed normal responses, bilaterally. MRI scan demonstrated a well-enhanced mass at the anterior middle portion of the right temporal bone with intracranial extension. Tumor excision via craniotomy was performed, and the histopathological study confirmed as myxoma. One year after operation, follow-up audiovestibular function tests revealed normal responses, except for 23 dB conductive hearing loss on the right ear.

Adult↗

PubMed1975

Temporal bone resection. Review of 100 cases.

One hundred cases of temporal bone resection for cancer of the ear were reviewed retrospectively, allowing for a survival five-year follow-up period in all cases. Operative technique previously described varied from case to case but essentially involved subtotal resection of the mastoid, petrous pyramid and squamosa of the temporal bone, temporomandibular joint, base of zygoma, and attached adjacent soft tissues. The procedure sacrifices the facial nerve and hearing in the involved ear. Preoperative radiation or a sandwich technique of preoperative and postoperative radiation was used. Many complications were encountered, but with hypotensive agents, high-speed air drills, and adequate coverage of the defect, the death rate was reduced from 10% in 1954 to 5% in recent years. The overall five-year cure rate was 27%, with a 25% cure rate for squamous carcinoma.

Aged↗

PubMed1999

Temporal bone fractures: otic capsule sparing versus otic capsule violating clinical and radiographic considerations.

OBJECTIVE: To assess the practicality and utility of the traditional classification system for temporal bone fracture (transverse vs. longitudinal) in the modern Level I trauma setting and to determine whether a newer system of designation (otic capsule sparing vs. otic capsule violating fracture) is practical from a clinical and radiographic standpoint. METHODS: The University of Massachusetts Medical Center Trauma Registry was reviewed for the years 1995 to 1997. Patients identified as sustaining closed head injury were reviewed for basilar skull fracture and temporal bone fracture. Clinical and radiographic records were evaluated by using the two classification schemes. RESULTS: A total of 2,977 patients were treated at the trauma center during this time. Ninety (3%) patients sustained a temporal bone fracture. The classic characterization of transverse versus longitudinal fracture (20% vs. 80%, respectively) was unable to be determined in this group; therefore, clinical correlation to complications using that paradigm was not possible. By using the otic capsule violating versus sparing designation, an important difference in clinical sequelae and intracranial complications became apparent. Compared with otic capsule sparing fractures, patients with otic capsule violating fractures were approximately two times more likely to develop facial paralysis, four times more likely to develop CSF leak, and seven times more likely to experience profound hearing loss, as well as more likely to sustain intracranial complications including epidural hematoma and subarachnoid hemorrhage. CONCLUSION: The use of a classification system for temporal bone fractures that emphasizes violation or lack of violation of the otic capsule seems to offer the advantage of radiographic utility and stratification of clinical severity, including severity of Glasgow Coma Scale scores and intracranial complications such as subarachnoid hemorrhage and epidural hematoma.

Cerebrospinal Fluid Otorrhea↗

PubMed2005

Use of ultra-high-resolution data for temporal bone dissection simulation.

OBJECTIVES: For the past 5 years, our group has been developing a virtual temporal bone dissection environment for training otologic surgeons. Throughout the course of our development, a recurring challenge is the acquisition of high-resolution, multimodal, and multi-scale data sets that are used for the visual as well as haptic (sense of touch) display. This study presents several new techniques in temporal bone imaging and their use as data for surgical simulation. METHODS: At our institution (OSU), we are fortunate to have a high-field (8 Tesla) magnetic resonance imaging (MRI) research magnet that provides an order of magnitude higher resolution compared to clinical 1.5T MRI scanners. Magnetic resonance imaging has traditionally been superb at delineating soft tissue structure, and certainly, the 8T unit does indeed do this at a resolution of 100-200 microm(3). To delineate the bony structure of the mastoid and middle ear, computed tomography (CT) has traditionally been used because of the high signal-to-noise ratio delineating bone signal from air and soft tissue. We have partnered with researchers at other institutions (CCF) to make use of a "microCT" that provides a resolution of 214 x 214 x 390 micrometers of bony structure. RESULTS: This report provides a description of the 2 methodologies and presentation of the striking image data capable of being generated. See images presented. CONCLUSIONS: Using these 2 new and innovative imaging modalities, we provide an order of magnitude greater resolution to the visual and haptic display in our temporal bone dissection simulation environment.

Cadaver↗

PubMed2002

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

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

Adolescent↗

PubMed2005

An "endosteal electrode" for cochlear implantation in cases with residual hearing? Feasibility study: preliminary temporal bone experiments.

BACKGROUND: Over the years, an increasing number of patients with some degree of residual hearing have received cochlear implants. In these cases, the marginal benefit provided by hearing aids alone is not sufficient; however, as experience has already shown, when hearing aids are used in combination with a cochlear implant, more benefit may be obtained. As a prerequisite, this requires that residual hair cell function must remain intact postoperatively. One of the European pioneers of cochlear implants, Ernst Lehnhardt, questioned whether residual hearing might better be preserved if the implanted electrode permits the fluid-filled inner ear space to remain intact. Subsequently, he proposed insertion of a very flat electrode array design into the extraluminal space between the spiral ligament and the bony cochlear wall (endosteum). OBJECTIVE: Our study aimed to determine whether it is feasible to insert an endosteal electrode model intracochlearly but extraluminarily, anatomically, and ultimately surgically and to determine the impact on surrounding intracochlear structures. METHODS: Insertion of two silicon models of an endosteal electrode were carried out in 15 human temporal bones. Histologic examination of the temporal bones after electrode insertion was performed on both fresh and fixed specimens to determine whether the desired anatomic site of insertion was achieved. In combination with light reflected and electron microscopic techniques, the extent to which the surrounding structures were impacted was also examined. RESULTS: Successful insertion of the prototype silicon endosteal electrodes was performed intracochlearly and extraluminarly in 11 of the 15 temporal bone specimens, confirming the anatomic feasibility of insertion into the crevice between the spiral ligament and endosteum. CONCLUSIONS: On the basis of the anatomy of the human temporal bone, insertion of an "endosteal electrode" is feasible. Subsequently, in vivo animal studies are needed to determine the physical effects of insertion of an endosteal electrode design prototype upon the functionality of the surrounding intracochlear structures and in particularly the ability to preserve hearing function.

Cochlea↗