title: Insertion of intra-oral electrodes for cranial nerve monitoring using a Crowe-Davis retractor.
abstract: Acoustic neuroma resection is an example of a neurosurgical procedure where the brainstem and multiple cranial nerves are at risk for injury. Electrode placement for monitoring of the glossopharyngeal and hypoglossal nerves during acoustic neuroma resection can be challenging. The purpose of this report is to illustrate the use of a device for intra-oral electrode placement for intraoperative monitoring of the glossopharyngeal and hypoglossal nerves. A 60-year-old male presented for acoustic neuroma resection. Under general anesthesia, a Crowe-Davis retractor was used to open the mouth, providing access to the posterior pharynx. For glossopharyngeal monitoring, two bent subdermal needle electrodes were inserted just lateral to the uvula. Two additional electrodes were inserted on the lateral tongue to monitor the hypoglossal nerve. Cranial nerves monitoring was conducted utilizing both free running and triggered electromyography of the trigeminal and facial nerves in addition to the lower cranial nerves. The tumor was resected successfully. Monitoring of the cranial nerves (including the glossopharyngeal and hypoglossal nerves) revealed no concerning responses. The Crowe-Davis retractor and the technique described allowed insertion of electrodes for neural monitoring, contributing to neural preservation.
authors.affiliation: Department of Anesthesiology, Mayo Clinic Arizona, 5777 E Mayo Blvd, Phoenix, AZ, 85054, USA. Trentman.terrence@mayo.edu.
authors.forename: Terrence L
authors.identifier: http://orcid.org/0000-0002-5677-0472
authors.initials: TL
authors.lastname: Trentman
authors.affiliation: Department of Anesthesiology, Mayo Clinic Arizona, 5777 E Mayo Blvd, Phoenix, AZ, 85054, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Thunberg
authors.affiliation: Department of Anesthesiology, Mayo Clinic Arizona, 5777 E Mayo Blvd, Phoenix, AZ, 85054, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Gorlin
authors.affiliation: Department of Anesthesiology and Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Antoun
authors.initials: A
authors.lastname: Koht
authors.affiliation: Department of Neurosurgery, Mayo Clinic Arizona, Phoenix, AZ, USA.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Zimmerman
authors.affiliation: Department of Neurosurgery, Mayo Clinic Arizona, Phoenix, AZ, USA.
authors.forename: Bernard
authors.initials: B
authors.lastname: Bendok
mesh_terms: D001933:Brain Stem / Q000503:physiopathology; D010244:Bulbar Palsy, Progressive / Q000503:physiopathology; D003391:Cranial Nerves / Q000503:physiopathology* / Q000601:surgery*; D004566:Electrodes; D004576:Electromyography; D005154:Facial Nerve; D005930:Glossopharyngeal Nerve / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation*; D009464:Neuroma, Acoustic / Q000503:physiopathology* / Q000601:surgery*; D019635:Neurosurgical Procedures; D012306:Risk; D013525:Surgical Instruments
keywords: Acoustic neuroma; Bulbar palsy; Cranial nerve monitoring; Glossopharyngeal nerve; Hypoglossal nerve