Radiographic Exhibit: Internal Auditory Canal Enlargement in Neurofibromatosis without Acoustic Neuroma

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.

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Hand-Held Thulium Laser Fiber and Ultrasonic Aspirator for Opening the Internal Auditory Canal During Acoustic Neuroma Microneurosurgery: Operative Technique

World Neurosurgery ◽

10.1016/j.wneu.2019.03.204 ◽

2019 ◽

Vol 126 ◽

pp. 497

Author(s):

Luciano Mastronardi ◽

Francesco Corrivetti ◽

Carlo Giacobbo Scavo ◽

Raffaelino Roperto ◽

Guglielmo Cacciotti ◽

...

Keyword(s):

Acoustic Neuroma ◽

Operative Technique ◽

Internal Auditory Canal ◽

Thulium Laser ◽

Ultrasonic Aspirator ◽

Laser Fiber

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The Abnormal Internal Auditory Canal: The Diagnosis of Acoustic Neuroma

Radiology ◽

10.1148/92.3.449 ◽

1969 ◽

Vol 92 (3) ◽

pp. 449-459 ◽

Cited By ~ 31

Author(s):

Galdino E. Valvassori

Keyword(s):

Acoustic Neuroma ◽

Internal Auditory Canal

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Asymmetry of the Internal Auditory Canals without Acoustic Neuroma

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348947808700608 ◽

1978 ◽

Vol 87 (6) ◽

pp. 815-820 ◽

Cited By ~ 7

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.

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Internal auditory canal enlargement (Giant IAC) and defective fundus in a child with congenital neurosensorial hearing loss

International Journal of Pediatric Otorhinolaryngology ◽

10.1016/j.ijporl.2007.02.028 ◽

2007 ◽

Vol 71 (6) ◽

pp. 991

Keyword(s):

Hearing Loss ◽

Internal Auditory Canal ◽

Canal Enlargement

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Meningioma of the Internal Auditory Canal

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348949710600808 ◽

1997 ◽

Vol 106 (8) ◽

pp. 657-661 ◽

Cited By ~ 17

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.

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