OBJECTIVE: To evaluate the safety of the circular round window and discus anatomic landmarks of posterior wall of internal auditory canal by investigating the microscopic anatomy of internal auditory canal area of the retrosigmold approach, which can provide the anatomical basis for acoustic neutrinomas surgery. METHOD: Fifteen adult cadaver heads (30 sides) fixed with formalin were used in the study. The retrosigmold approach operations were imitated to dissect the blood vessels and nerves in internal auditory canal area by opening round bony window and removing posterior wall of internal auditory canal. RESULT: Fifteen specimens of 30 sides circular bone window were opened without injury with transverse sinus and sigmoid sinus. The vertical distance between the highest point of bone window margo superior and the lowest point of transverse sinus margo inferior was (4.02 ± 0.32) mm. The vertical distance from the most anterior point of bone window leading edge to the most posterior point of sigmoid sinus trailing edge was (6.31 ± 0.43) mm. The internal auditory canal tubercle located in the anterior superior position of internal auditory canal. The vertical distance from the highest point of internal auditory canal tubercle to the upper margin of internal auditory canal was (2.31 ± 0.32) mm. To expose the whole internal auditory canal, the length and width of the internal auditory canal posterior wall removal was (7.29 ± 0.32) mm, (4.12 ± 0.29) mm. Within this removal range, no case of cochlea, semicircular canal or venous was injured in 30 specimens. CONCLUSION The method of opening round window through retrosigmold approach is simple, practial and convenient. With little variation and easiness of location, the sinternal auditory canal tubercle can be used in the identification of the internal auditory canal. When exposing the whole internal auditory canal, the removal scope of the posterior wall should be paid more attention to, in order to avoid the damage of cochlea, semicircular canal and jugular bulb.
Adult ; Cranial Sinuses ; Ear Canal ; Ear, Inner ; Humans ; Round Window, Ear ; anatomy & histology ; Semicircular Canals ; anatomy & histology ; Temporal Bone

Cerebellopontine Angle ; anatomy & histology ; Ear, Inner ; anatomy & histology ; Humans ; Microsurgery ; Neuroma, Acoustic ; surgery

Cerebellopontine Angle ; anatomy & histology ; Ear, Inner ; anatomy & histology ; Humans ; Microsurgery ; Neuroma, Acoustic ; surgery

Adult ; Cranial Fossa, Middle ; anatomy & histology ; surgery ; Ear, Inner ; anatomy & histology ; surgery ; Facial Nerve ; anatomy & histology ; surgery ; Humans ; Male

Due to the lack of objective examination method, the diagnosis of Meniere's disease mainly relies on subjective symptoms. MRI of the inner ear after gadolinium injections had become a new technology in otology in recent years. The image can clearly distinguish perilymph from endolymph in the labyrinth and can be applied to the imaging diagnosis, evaluation of treatment and the pathogenesis research of Meniere's disease. This article is a review of the development and the application in clinical research of this new technology.
Ear, Inner ; anatomy & histology ; Gadolinium ; Humans ; Magnetic Resonance Imaging ; methods ; Meniere Disease ; diagnosis

OBJECTIVE: To study the microanatomy by endoscope-assisted via retrolabyrinthine approach. METHOD: Nineteen cadaveric heads fixed with formalin were dissected in our study. The data that endoscope could be extent and the distance between the important point were measured. By simulated the retrolabyrinthine approach, endoscope was placed to observe the nerves and vessels, the distance between nerves and the central point of the anterior edge of sigmoid sinus were measured. RESULT: The distance from the inferior margin of petrous ridge to the upper bound of endolymphatic sac was (9.93+/-1.52)mm; and from superior margin of petrous ridge to the inferior margin common bony crus was (4.64+/-0.91)mm;and from the intersection of posterior semicircular canal to the anterior wall of sigmoid was (7.85+/-1.47)mm on the left, and (5.69+/-1.68)mm on the right. The distance from inferior margin common bony crus to the anterior wall of sigmoid was (13.9+/-1.71)mm on the left, and (11.31+/-2.03)mm on the right. The trochlear nerve and abducent nerve could be observed under endoscope. The relationship between the trigeminal nerve, acoustic nerve and the vessels could be identified clearly. The distance from the central point of the anterior edge of sigmoid to the roots of the trigeminal nerve, facial nerve, vestibulocochlear nerve and glossopharyngeal nerve were (29.88+/-2.77) mm, (32.04+/-2.04) mm, (29.17+/-1.65) mm, (35.49+/-1.53) mm respectively. CONCLUSION The visual field of the cerebellopontine angle appear wider by the endoscope assisted retrolabyrinthine approach. Nerves, vessel, internal acoustic pore, jugular foramen region can be clearly seen. Some minimal invasive surgery can be done by this approach.
Adult ; Cerebellopontine Angle ; anatomy & histology ; surgery ; Ear, Inner ; surgery ; Endoscopes ; Female ; Humans ; Male

OBJECTIVE: To explore an useful and practical method for three-dimensional reconstruction of cochlear microstructure. METHOD: A digital image dataset of magnified forty times of human cochlear tissue can be get from the serial sections of transverse cedukol images of male cadavers temporal bone. Photoshop 6.0 and Amira 3.0 software were used to deal with the digital image dataset, such as image-connecting and image inner-location and three-dimensional reconstruction of cochlear and scala media. RESULT: The result of three-dimensional reconstruction of the cedukol images represents the anatomy of human cochlear and scala media transparently and objectively. CONCLUSION The three-dimensional reconstruction technique used in the study is practical for three-dimensional of inner ear microstructure.
Cochlea ; anatomy & histology ; Ear, Inner ; anatomy & histology ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; methods ; Male ; Microtomy ; methods ; Software

OBJECTIVETo study human vestibular cerebral representations by combining right-sided ice-water stimulation at 0 degree C with blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI) and to evaluate the value of this method in the functional localization of human vestibular cortex.

METHODSTwenty right-handed volunteers (12 men and 8 women) received unilateral irrigation of the right external auditory meatu for 15 s with 15 ml of water at 0 degrees C during fMRI in complete darkness. The functional imaging of brain cortex was acquired with a 1.5-T MRI scanner (Signa Infinity Twin + Excite; General Electric Co., USA). The successive functional images from each subject were analyzed as a group with statistical parametric mapping software (SPM 99).

RESULTSUltimately, data obtained from 17 subjects were analyzed (3 subjects were eliminated from data because of head movement exceeding 2 mm). The group analysis showed bilateral (particularly left-sided) cortical activation, associated with caloric stimulus involving in temporoparietal junction extending into the posterior insula, supramarginal gyrus in the inferior parietal lobe, precuneus, supplementary motor area (SMA), the ventrolateral portion of the occipital lobe, cuneus and lingual gyrus, superior temporal gyrus and cingular cortex.

CONCLUSIONSIce-water stimulation at 0 degree C in fMRI reveals a widespread cortical network involved in vestibular signal processing in human. As the functional localization of vestibular cortex could be determined precisely, ice-water stimulation at 0 degree C in fMRI would hold great promise as a sensitive and reproducible tool for the research in human vestibular cortex.

Adult ; Brain Mapping ; Cerebral Cortex ; anatomy & histology ; physiology ; Ear, Inner ; Female ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Vestibular Nuclei ; anatomy & histology ; physiology ; Young Adult

OBJECTIVE: To compare the use of 3D driven equilibrium (DRIVE) imaging with 3D balanced fast field echo (bFFE) imaging in the assessment of the anatomic structures of the internal auditory canal (IAC) and inner ear at 3 Tesla (T). MATERIALS AND METHODS: Thirty ears of 15 subjects (7 men and 8 women; age range, 22-71 years; average age, 50 years) without evidence of ear problems were examined on a whole-body 3T MR scanner with both 3D DRIVE and 3D bFFE sequences by using an 8-channel sensitivity encoding (SENSE) head coil. Two neuroradiologists reviewed both MR images with particular attention to the visibility of the anatomic structures, including four branches of the cranial nerves within the IAC, anatomic structures of the cochlea, vestibule, and three semicircular canals. RESULTS: Although both techniques provided images of relatively good quality, the 3D DRIVE sequence was somewhat superior to the 3D bFFE sequence. The discrepancies were more prominent for the basal turn of the cochlea, vestibule, and all semicircular canals, and were thought to be attributed to the presence of greater magnetic susceptibility artifacts inherent to gradient-echo techniques such as bFFE. CONCLUSION: Because of higher image quality and less susceptibility artifacts, we highly recommend the employment of 3D DRIVE imaging as the MR imaging choice for the IAC and inner ear.
Adult ; Aged ; Cochlea/anatomy & histology ; Ear, Inner/*anatomy & histology ; Female ; Humans ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging/*methods ; Male ; Middle Aged ; Semicircular Canals/anatomy & histology ; Vestibule, Labyrinth/anatomy & histology