Usefulness of piezoelectric sensor device for monitoring extraocular movement during endoscopic endonasal surgery to remove skull base tumor.

The present study was conducted to evaluate three modalities used to detect extraocular movement during endonasal endoscopic surgery for a skull base tumor to protect cranial nerves from damage; free-run electrooculography (EOG), piezoelectric sensor (PES), and triggered electromyography (t-EMG) monitoring. Twenty patients (8 males, 12 females; average age 61.8 years) treated for a skull base tumor at Nara Medical University from 2018 to 2021 were enrolled. The three modalities were assessed regarding detection of ocular movement during endoscopic endonasal surgery (EES) for a skull base tumor and the results compared. Oculomotor nerve detection by EOG, PES, and t-EMG was noted in 77.8%, 83.3%, and 33.3%, respectively, of the cases (p = 0.001), while abducent nerve detection was noted in 61.1%, 66.7%, and 16.7%, respectively, (p = 0.002), showing that PES has significantly greater sensitivity for detection of ocular movement. Gross total resection was achieved in nine (45%), near-total resection in three (15%), and partial resection in eight (40%) of the patients. To protect ocular movement function from damage during EES for a skull base tumor, the present findings indicate that among the three modalities tested, PES is compact and useful, and most safe for avoiding complications.