[Neurophysiological identification of the cranial nerves in endoscopic endonasal surgery of skull base tumors].
Intraoperative identification of the cranial nerves is a useful technique in removal of skull base tumors through the endoscopic endonasal approach. Searching through the scientific literature found one pilot study on the use of triggered electromyography (t-EMG) for identification of the VIth nerve in endonasal endoscopic surgery of skull base tumors (D. San-Juan, et al, 2014).



The study objective was to prevent iatrogenic injuries to the cranial nerves without reducing the completeness of tumor tissue resection.



In 2014, 5 patients were operated on using the endoscopic endonasal approach. Surgeries were performed for large skull base chordomas (2 cases) and trigeminal nerve neurinomas located in the cavernous sinus (3). Intraoperatively, identification of the cranial nerves was performed by triggered electromyography using a bipolar electrode (except 1 case of chordoma where a monopolar electrode was used). Evaluation of the functional activity of the cranial nerves was carried out both preoperatively and postoperatively.



Tumor resection was total in 4 out of 5 cases and subtotal (chordoma) in 1 case. Intraoperatively, the IIIrd (2 patients), Vth (2), and VIth (4) cranial nerves were identified. No deterioration in the function of the intraoperatively identified nerves was observed in the postoperative period. In one case, no responses from the VIth nerve on the right (in the cavernous sinus region) were intraoperatively obtained, and deep paresis (up to plegia) of the nerve-innervated muscles developed in the postoperative period. The nerve function was not impaired before surgery.



The t-EMG technique is promising and requires further research.
Burdenko Neurosurgical Institute, Moscow, Russia.
A N
AN
Shkarubo
Burdenko Neurosurgical Institute, Moscow, Russia.
A A
AA
Ogurtsova
Burdenko Neurosurgical Institute, Moscow, Russia.
D A
DA
Moshchev
Burdenko Neurosurgical Institute, Moscow, Russia.
A Yu
AY
Lubnin
Burdenko Neurosurgical Institute, Moscow, Russia.
D N
DN
Andreev
Burdenko Neurosurgical Institute, Moscow, Russia.
K V
KV
Koval'
Sechenov First Moscow State Medical University, Moscow, Russia.
I V
IV
Chernov
D000368:Aged; D002817:Chordoma / Q000601:surgery*; D003391:Cranial Nerves / Q000502:physiology / Q000601:surgery*; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057605:Natural Orifice Endoscopic Surgery / Q000009:adverse effects / Q000379:methods*; D009442:Neurilemmoma / Q000601:surgery*; D010291:Paresis / Q000209:etiology / Q000517:prevention & control; D011183:Postoperative Complications; D019292:Skull Base Neoplasms / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000009:adverse effects / Q000379:methods*