Intraoperative electrophysiologic identification of the nervus intermedius. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. [Otol Neurotol] Journal article | | Title | Intraoperative electrophysiologic identification of the nervus intermedius. | | Author(s) | Ashram YA, Jackler RK, Pitts LH, Yingling CD | | Institution | Department of Physiology, Alexandria University School of Medicine, Alexandria, Egypt. | | Source | Otol Neurotol 2005 Mar; 26(2):274-9. | | MeSH | Adolescent
Adult
Afferent Pathways
Aged
Ageusia
Blinking
Child
Chorda Tympani Nerve
Cranial Nerve Injuries
Cranial Nerves
Ear
Electrodiagnosis
Electromyography
Facial Nerve
Facial Nerve Injuries
Facial Paralysis
Female
Humans
Male
Middle Aged
Monitoring, Intraoperative
Nasolacrimal Duct
Neuroma, Acoustic
Postoperative Complications
Prognosis
Reaction Time
Retrospective Studies
Sensory Thresholds
Tears
| | Abstract | OBJECTIVE: Although enormous attention has been directed to the localization and preservation of the facial nerve in acoustic neuroma surgery, the nervus intermedius has largely been ignored. In this article, we describe a method for intraoperative electrophysiologic identification of the nervus intermedius.
STUDY DESIGN: Retrospective case review.
SETTING: University hospital (tertiary care center).
PATIENTS: Thirty-three patients who underwent intraoperative facial nerve monitoring for various cerebellopontine angle procedures. Recording electrodes were placed in the orbicularis oculi and orbicularis oris muscles. A constant-voltage stimulator was used to stimulate both the facial nerve and the nervus intermedius.
INTERVENTIONS: None.
MAIN OUTCOME MEASURE: Electrophysiologic response after stimulation of the nervus intermedius.
RESULTS: Stimulation of the nervus intermedius produced long-latency, low-amplitude response recorded only on the orbicularis oris channel. The response had a mean threshold 0.4 V, a mean latency of 11.1 ms, and a mean amplitude of 11.1 microV, all significantly different from responses to stimulation the facial nerve.
CONCLUSION: Knowledge of electrophysiologic features of nervus intermedius stimulation can help protect the facial nerve during cerebellopontine angle surgery. The surgeon must recognize that stimulation of the nervus intermedius can cause electromyographic activity in the facial nerve monitoring channels, but the main trunk of the facial nerve may lie in entirely different location in the cerebellopontine angle. | | Language | eng | | Pub Type(s) | Journal Article
| | PubMed ID | 15793419 |
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