A curvilinear incision was made behind the ear for a retromastoid approach. A spinal drain was placed to aid with brain relaxation.
Surgery was performed in lateral position, with the left side up [ Video 1 After discussion at the multidisciplinary skull base tumor board, it was decided to schedule her for a suboccipital craniectomy to remove the exostosis on the lower aspect of the internal auditory canal. Semicircular canals, vestibule, cochlea, and ossicles appeared intact. Thin-cut temporal bone computed tomography (CT) and magnetic resonance imaging (MRI) revealed an asymmetric narrowing of the left porus acousticus due to a bony overgrowth at the anterior inferior wall of the left internal auditory canal. She was otherwise intact on neurological examination. Past medical history was notable for thoracic outlet syndrome.
These symptoms were significantly impacting her quality of life. Audiometric testing revealed minimal, bilateral low-frequency hearing loss, and videonystagmography demonstrated a 67% reduced vestibular response in the left ear. In addition, she experienced dizziness triggered on sitting up and physical activity. CLINICAL PRESENTATIONĪ 19-year-old female presented to a Neurotologic colleague with a several-month history of discomfort of the left ear that was exacerbated on left lateral gaze. Thus, the purpose of this report is to describe the clinical presentation, including signs and symptoms, surgical approach, and postsurgical outcome in a patient who was treated at our institution with unilateral exostosis of the internal auditory canal. Symptoms include decreased hearing, tinnitus, and vertigo, which can be disabling. Despite their rarity, when they occur, exostoses of the internal auditory canal can present with severe symptoms related to compression of the cranial nerve seven and eight complex. They are less common than exostoses of the external auditory canal, which are readily encountered in standard otolaryngology clinics around the United States. Not to be confused with osteomas of the external auditory canal, which are slow- growing tumors that arise from the tympano-squamous suture, exostoses of the internal auditory canal are broad-based elevations found anywhere in the tympanic bone. Keywords: Exostoses, exostosis, hearing loss, internal auditory canal, osteoma, vertigoĮxostoses of the internal auditory canal are rare, and sometimes seen only on postmortem examinations. Severe cases can be treated successfully with surgery with minimal or no complications and excellent outcome. Imaging, particularly with thin-cut computed tomography, is invaluable in making the correct diagnosis. She experienced complete resolution of symptoms.Ĭonclusions:Exostoses of the internal auditory canal, although rare, can present with severe symptoms of dizziness, hearing loss, and vestibular hypofunction based on the extent of cranial nerve compression. After extensive counseling, the patient elected to undergo a suboccipital craniectomy to remove the internal auditory canal exostosis. She underwent extensive evaluation including audiometric testing, videonystagmography, and neuroimaging, which confirmed left auditory and vestibular hypofunction and compression of the contents of the internal auditory canal from the exostosis.
The purpose of this case report is to discuss the presentation and outcomes in a patient who presented with this disorder.Ĭase Description:A 19-year-old female presented to the neurotologist with left ear discomfort, pain with left lateral gaze, and dizziness. Background:Exostoses of the internal auditory canal is a rare finding that may present with disabling symptoms of dizziness, hearing loss, and vestibular dysfunction based on the extent of cranial nerve compression.
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