Olfactory Evoked Potential Produced by Electrical Stimulation for Monitoring Olfactory Function During Endonasal Endoscopic Surgery: A Preliminary Study.

Abstract

Purpose: The aim of this study is to develop an intraoperative olfactory monitoring system using olfactory evoked potential produced by electrical stimulation. Furthermore, the study seeks to ascertain the feasibility and safety of olfactory evoked potential. This study lays the groundwork for safeguarding olfactory function during surgical procedures.

Methods: We provided a detailed description of the procedure involving electrical stimulation of the olfactory mucosa to induce olfactory evoked potentials during endonasal endoscopic surgery under general anesthesia. This study enrolled 20 patients undergoing endonasal endoscopic surgery. Before surgery, all patients reported no olfactory complaints, and T&T olfactometry did not detect any olfactory disorders. Olfactory evoked potentials were recorded from various regions of the nasal mucosa and followed by analysis of waveform differentiation, latencies, and amplitudes.

Results: Typical "N1-P1-N2" three-phase waves, consistent with the waveforms of olfactory evoked potentials recorded in previous studies, were collected from the olfactory mucosa in each case. No significant alteration was observed in the patients' olfactory function pre- and postsurgery. The latencies of the "N1-P1-N2" waves recorded during the operation were 12.2 ± 6.9 ms, 28.9 ± 10.0 ms, and 47.1 ± 11.6 ms, respectively, whereas the amplitudes of the "N1-P1" and "P1-N2" waves measured 0.9 and 0.6 μV, respectively.

Conclusions: Intraoperative olfactory monitoring through olfactory evoked potential produced by electrical stimulation is achievable and safe.