Meningioma of the Internal Auditory Canal

1997 ◽  
Vol 106 (8) ◽  
pp. 657-661 ◽  
Author(s):  
Anthony G. Zeitouni ◽  
David Zagzag ◽  
Noel L. Cohen
Keyword(s):  
Acoustic Neuroma ◽  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Precursor Cells ◽  
Radiologic Finding ◽  
Histologic Evidence ◽  
Radiologic Findings ◽  
Tumor Genetics

Meningiomas are the second most common tumor to involve the cerebellopontine angle (CPA), but controversy exists as to whether they can arise within the internal auditory canal (IAC) or whether involvement of the IAC occurs secondarily by extension from the CPA. This paper reports on a patient with an enhancing IAC meningioma that then grew and on subsequent scans was found to involve the CPA. This case demonstrates that these tumors can arise within the IAC and can grow out to involve the CPA. These findings are discussed within the context of meningioma tumor genetics and the histologic evidence for precursor cells in the IAC. The radiologic findings useful in distinguishing an acoustic neuroma from a meningioma are reviewed in the light of this case. While an enhancing mass projecting into the IAC is most often an acoustic neuroma, this radiologic finding is not pathognomonic.

Asymmetry of the Internal Auditory Canals without Acoustic Neuroma

1978 ◽  
Vol 87 (6) ◽  
pp. 815-820 ◽  
Author(s):  
Kenneth D. Dolan ◽  
Richard W. Babin ◽  
Charles G. Jacoby
Keyword(s):  
Posterior Fossa ◽  
Acoustic Neuroma ◽  
Cerebellopontine Angle ◽  
Clinical Presentation ◽  
Internal Auditory Canal ◽  
Internal Auditory Meatus ◽  
Radiographic Appearance ◽  
The Past ◽  
Acoustic Neuromas ◽  
Normal Architecture

During the past five years, nine patients with “significant” unilateral enlargement of one internal auditory canal by polytomography were subsequently found to have freely filling canals on contrast posterior fossa myelography. The radiographic appearance of the enlarged canals varied greatly and included all the various configurations usually suggestive of acoustic neuroma. Likewise, the clinical presentation varied greatly from asymptomatic to highly suggestive of cerebellopontine angle tumor. This series underscores the essential nature of posterior fossa studies in the evaluation of potential acoustic neuromas and the variability of the normal architecture of the internal auditory meatus.

Preoperative Differentiation between Meningioma of the Cerebellopontine Angle and Acoustic Neuroma Using MRI

1993 ◽  
Vol 109 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Anil K. Lalwani ◽  
Robert K. Jackler
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
San Francisco ◽  
Acoustic Neuroma ◽  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Resonance Imaging ◽  
Mri Findings ◽  
Dural Tail ◽  
Magnetic Resonance Imaging Mri

Preoperative differentiation between acoustic neuroma (AN) and meningioma of the cerebellopontine angle (CPA) is important in selection of the surgical approach, successful tumor removal, and preservation of hearing and facial nerve. We retrospectively reviewed the magnetic resonance imaging (MRI) findings associated with 30 meningiomas involving the CPA (MCPA) encountered between 1987 to 1991 at the University of California, San Francisco. Magnetic resonance imaging was critical in differentiating meningioma from AN in the CPA. Typical findings on MRI associated with MCPA, differentiating them from ANs, Include: Meningiomas are sessile, possessing a broad base against the petrous face, whereas ANs are globular; they are often extrinsic and eccentric to the internal auditory canal (IAC); when involving the IAC, they usually do not erode the IAC; MCPAs demonstrate hyperostosis of the subjacent bone and possess intratumoral calcification; they involve adjacent intracranial spaces and structures; and meningiomas are characterized by a distinctive dural “tail” extending away from the tumor surface. While any one finding may not be diagnostic by itself, taken together the constellation of these findings is strongly Indicative of meningioma. In our experience, MRI with gadolinium enhancement was able to distinguish MCPA from AN in nearly every case.

Changes of the Auditory System after Cerebellopontine Angle Manipulations

Neurosurgery ◽  
1983 ◽  
Vol 12 (1) ◽  
pp. 80-85 ◽  
Author(s):  
Tetsuji Sekiya ◽  
Takashi Iwabuchi ◽  
Akira Andoh ◽  
Shigeki Kamata
Keyword(s):  
Auditory System ◽  
Acoustic Neuroma ◽  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Causative Factor ◽  
Cochlear Nerve ◽  
Cerebellar Hemisphere ◽  
Vascular Insufficiency ◽  
Dural Opening ◽  
Neurovascular Decompression

Abstract The current tendency in acoustic neuroma surgery to attempt the preservation of hearing function and the problem of accidental hearing loss caused by microsurgical neurovascular decompression operations for hemifacial spasm or trigeminal neuralgia prompted us to study the exact surgical vulnerability of the auditory system. The surgical procedures for operation on the cerebellopontine angle of dogs were carried out according to the sequence of the posterior fossa transmeatal operation for acoustic neuroma. The operation was tentatively divided into three stages: (a) craniectomy and dural opening, (b) cerebellar retraction, and (c) identification of the cochlear nerve in the unroofed internal auditory canal (IAC). The postoperative behavior of the auditory system was evaluated electrocochleographically (EcochG) and histologically. Overzealous retraction of the cerebellar hemisphere caused transient disturbance of the EcochG pattern. Mechanical stretching of both the cochlear nerve and the internal auditory artery may cause a disturbance in the synchronized discharge of the cochlear neurons. Various manipulations at the porus acusticus internus or the IAC (such as pinching the nerve with forceps or electrocoagulation) produced thoroughly distorted EcochG patterns. From the histological findings, the main causative factor for these labyrinthine damages was considered to be vascular insufficiency The current need for neurosurgical operations to preserve hearing is discussed in the light of these findings.

scholarly journals 3D Real IR MR Findings in Acoustic Neuromas: Altered Perilymph Metabolism

2021 ◽  
pp. 014556132110471
Author(s):  
Suming Shi ◽  
Ping Guo ◽  
Wenquan Li ◽  
Wuqing Wang
Keyword(s):  
Inner Ear ◽  
Acoustic Neuroma ◽  
Intravenous Administration ◽  
Semicircular Canal ◽  
Signal Intensity ◽  
Cerebellopontine Angle ◽  
Endolymphatic Hydrops ◽  
Internal Auditory Canal ◽  
Control Side ◽  
Acoustic Neuromas

Objectives This study aimed to investigate the perilymph metabolism by analyzing the 3D real IR MR findings in acoustic neuroma (AN) after intravenous administration of gadolinium (Gd). Methods Eleven patients (6 men and 5 women) diagnosed with AN were included, and 3D real IR MRI was performed 4 hours after intravenous Gd injection. The signal intensity and details of inner ear, tumor, and internal auditory canal (IAC) by MRI were analyzed. Results Four patients had tumors confined to the IAC, and 5 had tumors that extended to the cerebellopontine angle cistern. The signal intensity of the cochlea, vestibule, and IAC fundus was conspicuously enhanced in 3D real IR images than the control side. One patient had a tumor in the cochlea, in which the signal intensity of the semicircular canal and vestibule was increased. One patient had an intravestibular tumor in which the signal intensity of the semicircular canal was increased and the cochlea had endolymphatic hydrops in the affected ear. Conclusions The synchronously increased signal intensity in the inner ear and IAC may indicate that IAC may serve as a channel for removal of the perilymph in the inner ear; the blockage by the tumor may have changed the hydrodynamics of the perilymph to cause a longer retention of Gd in the inner ear.

Microsurgical Treatment of Meningiomas of the Cerebellopontine Angle with Internal Auditory Canal Extension

Skull Base ◽  
2009 ◽  
Vol 19 (01) ◽  
Author(s):  
Martin Chovanec ◽  
Eduard Zverina ◽  
Jan Betka ◽  
Jiri Skrivan ◽  
Jan Kluh ◽  
...  
Keyword(s):  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Microsurgical Treatment

Translabyrinthine Approach for Acoustic Neuroma

Neurosurgery ◽  
2004 ◽  
Vol 54 (2) ◽  
pp. 391-396 ◽  
Author(s):  
John Diaz Day ◽  
Douglas A. Chen ◽  
Moises Arriaga
Keyword(s):  
Surgical Treatment ◽  
Acoustic Neuroma ◽  
Cerebellopontine Angle ◽  
Hearing Preservation ◽  
Retrosigmoid Approach ◽  
The Past ◽  
Translabyrinthine Approach ◽  
Acoustic Neuromas

Abstract THE TRANSLABYRINTHINE APPROACH has been popularized during the past 30 years for the surgical treatment of acoustic neuromas. It serves as an alternative to the retrosigmoid approach in patients when hearing preservation is not a primary consideration. Patients with a tumor of any size may be treated by the translabyrinthine approach. The corridor of access to the cerebellopontine angle is shifted anteriorly in contrast to the retrosigmoid approach, resulting in minimized retraction of the cerebellum. Successful use of the approach relies on a number of technical nuances that are outlined in this article.

Facial Nerve Dissection by use of Acoustic (Loudspeaker) Facial EMG Monitoring

1986 ◽  
Vol 95 (4) ◽  
pp. 458-463 ◽  
Author(s):  
Sam E. Kinney ◽  
Richard Prass
Keyword(s):  
Facial Nerve ◽  
Acoustic Neuroma ◽  
Internal Auditory Canal ◽  
Subsequent Development ◽  
Lateral Approach ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Facial Emg ◽  
Acoustic Neuroma Surgery ◽  
Total Tumor Removal

The development of the surgical microscope in 1953, and the subsequent development of microsurgical instrumentation, signaled the beginning of modern-day acoustic neuroma surgery. Preservation of facial nerve function and total tumor removal is the goal of all acoustic neuroma surgery. The refinement of the translabyrinthine removal of acoustic neuromas by Dr. William House’ significantly improved preservation of facial nerve function. This is made possible by the anatomic identification of the facial nerve at the lateral end of the internal auditory canal. When the surgery is accomplished from a suboccipital or retrosigmoid approach, the facial nerve may be identified at the brain stem or within the internal auditory canal. Identifying the facial nerve from the posterior approach is not as anatomically precise as from the lateral approach through the labyrinth. The use of a facial nerve stimulator can greatly facilitate Identification of the facial nerve in these procedures.

Meningiomas Of the Internal Auditory Canal

Neurosurgery ◽  
2004 ◽  
Vol 55 (1) ◽  
pp. 119-128 ◽  
Author(s):  
Makoto Nakamura ◽  
Florian Roser ◽  
Sharham Mirzai ◽  
Cordula Matthies ◽  
Peter Vorkapic ◽  
...  
Keyword(s):  
Cerebellopontine Angle ◽  
Clinical Symptoms ◽  
Management Strategies ◽  
Internal Auditory Canal ◽  
Signs And Symptoms ◽  
Vestibular Schwannomas ◽  
Additional Patient ◽  
Surgical Removal ◽  
Neurosurgical Department ◽  
Vestibulocochlear Nerve

Abstract OBJECTIVE: Meningiomas arising primarily within the internal auditory canal (IAC) are notably rare. By far the most common tumors that are encountered in this region are neuromas. We report a series of eight patients with meningiomas of the IAC, analyzing the clinical presentations, surgical management strategies, and clinical outcomes. METHODS: The charts of the patients, including histories and audiograms, imaging studies, surgical records, discharge letters, histological records, and follow-up records, were reviewed. RESULTS: One thousand eight hundred meningiomas were operated on between 1978 and 2002 at the Neurosurgical Department of Nordstadt Hospital. Among them, there were 421 cerebellopontine angle meningiomas; 7 of these (1.7% of cerebellopontine angle meningiomas) were limited to the IAC. One additional patient underwent surgery at the Neurosurgical Department of the International Neuroscience Institute, where a total of 21 cerebellopontine angle meningiomas were treated surgically from 2001 to 2003. As a comparison, the incidence of intrameatal vestibular schwannomas during the same period, 1978 to 2002, was 168 of 2400 (7%). There were five women and three men, and the mean age was 49.3 years (range, 27–59 yr). Most patients had signs and symptoms of vestibulocochlear nerve disturbance at presentation. One patient had sought treatment previously for total hearing loss before surgery. No patient had a facial paresis at presentation. The neuroradiological workup revealed a homogeneously contrast-enhancing tumor on magnetic resonance imaging in all patients with hypointense or isointense signal intensity on T1- and T2-weighted images. Some intrameatal meningiomas showed broad attachment, and some showed a dural tail at the porus. In all patients, the tumor was removed through the lateral suboccipital retrosigmoid approach with drilling of the posterior wall of the IAC. Total removal was achieved in all cases. Severe infiltration of the facial and vestibulocochlear nerve was encountered in two patients. There was no operative mortality. Hearing was preserved in five of seven patients; one patient was deaf before surgery. Postoperative facial weakness was encountered temporarily in one patient. CONCLUSION: Although intrameatal meningiomas are quite rare, they must be considered in the differential diagnosis of intrameatal mass lesions. The clinical symptoms are very similar to those of vestibular schwannomas. A radiological differentiation from vestibular schwannomas is not always possible. Surgical removal of intrameatal meningiomas should aim at wide excision, including involved dura and bone, to prevent recurrences. The variation in the anatomy of the faciocochlear nerve bundle in relation to the tumor has to be kept in mind, and preservation of these structures should be the goal in every case.

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