Intraoperative monitoring of the abducens nerve in extended endonasal endoscopic approach: a pilot study technical report.
BACKGROUND
To determine the reliability and usefulness of intraoperative monitoring of the abducens nerve during extended endonasal endoscopic skull base tumor resection.


METHODS
We performed abducens nerve intraoperative monitoring in 8 patients with giant clival lesions recording with needle electrodes sutured directly into the lateral rectus muscles of the eye to evaluate spontaneous electromyographic activity and triggered responses following stimulation of the abducens nerves.


RESULTS
A total of 16 abducens nerves were successfully recorded during endoscopic endonasal skull base surgeries. Neurotonic discharges were seen in two patients (12% [2/16] abducens nerves). Compound muscle action potentials of the abducens nerves were evoked with 0.1-4mA and maintained without changes during the neurosurgical procedures. No patient had new neurological deficits or ophthalmological complications post-surgery.


CONCLUSIONS
Intraoperative monitoring of the abducens nerve during the extended endonasal endoscopic approach to skull base tumors appears to be a safe method with the potential to prevent neural injury through the evaluation of neurotonic discharges and triggered responses.
Neurophysiology Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico. Electronic address: pegaso31@yahoo.com.
Daniel
D
San-juan
Neurosurgery Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico.
Juan
J
Barges-Coll
Neurosurgery Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico.
Juan Luis
JL
Gómez Amador
Neuro-otology Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico.
Marite Palma
MP
Díaz
Neuro-otology Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico.
Alfredo Vega
AV
Alarcón
Neuro-ophthalmology Service, National Institute of Neurology and Neurosurgery, Mexico City, Mexico.
Enrique
E
Escanio
Comprehensive Epilepsy Center of Long Island, St. Charles Hospital, Port Jefferson, NY, USA.
David J
DJ
Anschel
Neurosurgery Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico.
Javier Avendaño Méndez
JA
Padilla
Neurosurgery Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico.
Victor Alcocer
VA
Barradas
Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexico.
Marco Antonio
MA
Alcantar Aguilar
Neurophysiology Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico.
Maricarmen Fernández
MF
González-Aragón
D000010:Abducens Nerve / Q000502:physiology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004566:Electrodes; D004576:Electromyography / Q000379:methods; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D018482:Muscle, Skeletal; D009666:Nose; D010865:Pilot Projects; D015203:Reproducibility of Results; D019292:Skull Base Neoplasms / Q000601:surgery*
Abducens nerve; Intraoperative monitoring; Skull base surgery