Intraoperative Electrocochleography of Posterior Fossa Tumors Producing Menière's Syndrome

Middle Ear Meningioma With Recurrence Secretory Otitis Media

Middle ear meningiomas (MEMs) are rare tumors that can present with nonspecific symptoms, posing challenges in diagnosis and management. This case report focuses on a middle-aged female patient who was misdiagnosed with secretory otitis media for 5 years. However, further evaluation through computed tomography imaging and subsequent pathologic biopsy revealed the presence of a MEM. The patient underwent surgical and gamma knife resection of the tumor and follow-up examination after 1 year showed no signs of recurrence. This case report highlights the importance of considering meningiomas in the differential diagnosis of middle ear pathologies and the need for careful preoperative planning for optimal outcomes. Overall, this case demonstrates that correct diagnosis and appropriate treatment can lead to successful management of MEMs.

Posterior petrous face meningiomas presenting with Ménière's-like syndrome: a case series and review of the literature

OBJECTIVE

Ménière's disease is an inner ear disorder classically characterized by fluctuating hearing loss, tinnitus, and aural fullness accompanied by episodic vertigo. While the pathogenesis of Ménière's remains under debate, histopathological analyses implicate endolymphatic sac dysfunction with inner ear fluid homeostatic dysregulation. Little is known about whether external impingement of the endolymphatic sac by tumors may present with Ménière's-like symptoms. The authors present a case series of 7 patients with posterior fossa meningiomas that involved the endolymphatic sac and new onset of Ménière's-like symptoms and review the literature on this rare clinical entity.

METHODS

A retrospective review of patients undergoing resection of a posterior petrous meningioma was performed at the authors' institution. Inclusion criteria were age older than 18 years; patients presenting with Ménière's-like symptoms, including episodic vertigo, aural fullness, tinnitus, and/or hearing loss; and tumor location overlying the endolymphatic sac.

RESULTS

There were 7 cases of posterior petrous face meningiomas involving the vestibular aperture presenting with Ménière's-like symptoms. Imaging and intraoperative examination confirmed no cranial nerve VIII compression or labyrinthine artery involvement accounting for audiovestibular symptoms. Of the 7 patients in the series, 6 experienced significant improvement or resolution of their vertigo, and all 7 had improvement or resolution of their tinnitus after resection. Of the 5 patients who had preoperative hearing loss, 2 experienced improvement or resolution of their ipsilateral preoperative hearing deficit, whereas the other 3 had unchanged hearing loss compared to preoperative evaluation.

CONCLUSIONS

Petrous face meningiomas overlying the endolymphatic sac can present with a Ménière's syndrome. Early recognition and microsurgical excision of these tumors is critical for resolution of most symptoms and stabilization of hearing loss.

Recording of electrocochleography from the facial nerve canal in mice

BACKGROUND

The ever-expanding arsenal of genetically modified mice has created experimental models for studying various mechanisms of deafness. Electrocochleography (ECochG) is a recording technique of cochlear potentials evoked by sound stimulation, which was widely used to evaluate the cochlear hearing function. However, there is currently a lack of information on long-term recording technology of ECochG in mice.

NEW METHOD

We describe in detail the surgical procedure of implanting electrode into the facial nerve canal in C57BL/6J mice for ECochG recording. The results of ECochG recorded by electrode in the facial nerve canal were compared with ECochG guided by electrode on the round window niche.

RESULTS

The surgical method of inserting the electrode into the facial nerve canal is relatively simple and can be completed within 15 min. The electrode inserted into the elongated facial nerve canal is stable and close to the auditory nerve trunk, so it is conducive to long-term auditory function monitoring. Hence, the ECochG guided by the electrode from the facial nerve canal can maintain a stable response for more than two weeks. In contrast, the ECochG guided by the electrode in the round window niche can only be maintained for a maximum of 20 min.

COMPARISON WITH EXISTING METHODS

In mice, existing recording techniques of ECochG from round window niche is limited by conductive hearing loss due to middle ear effusion or surgical damage.

CONCLUSIONS

ECochG recording from the facial nerve canal is suitable for long-term recording in mice. This electrode approach provides a repeatable and reliable measurement of ECochG.