Role of Intraoperative Neurophysiologic Monitoring in Internal Carotid Artery Injury During Endoscopic Endonasal Skull Base Surgery

In the present study, we investigated the role of intraoperative neuromonitoring (IONM) in internal carotid artery (ICA) injury during endoscopic endonasal skull base surgery (EESBS). The study group included all 13 patients who had experienced an ICA injury during EESBS with IONM from 2004 to 2017. The medical records were reviewed for the perioperative data. The IONM reports were reviewed to evaluate the baseline somatosensory evoked potentials (SSEP), electroencephalography (EEG), and brainstem auditory evoked potentials (BAEP) and their significant changes related to ICA injury and/or the subsequent surgical/endovascular interventions. All 13 patients had undergone SSEP and 7 patients had BAEP monitoring during surgery. EEG was added during emergent angiography following the surgery for 5 patients. Two patients showed significant SSEP changes, and one showed significant SSEP and EEG changes, indicating cerebral hypoperfusion. Of these 3 patients, patient 1 had experienced irreversible SSEP loss with postoperative stroke. Patients 2 and 3 had SSEP and/or EEG changes that had recovered to baseline after interventions without postoperative deficits. Despite ICA injury, 10 patients showed no significant SSEP and/or EEG changes, and all 7 patients with BAEP monitoring showed no significant BAEP changes, indicating adequate cerebral and brainstem perfusion, respectively. The injured ICA was sacrificed in 4 patients, of whom 3 showed stable SSEP and 1 had experienced irreversible SSEP loss. IONM correlated with the postoperative neurologic examination findings in all cases, adequately predicting the neurologic outcomes after ICA injury. SSEP and EEG monitoring can accurately detect cerebral hypoperfusion and provide real-time feedback during surgery. SSEP and EEG changes predicted for neurologic outcomes and guide surgical decisions regarding the preservation or sacrifice of the ICA. Comprehensive multimodality monitoring according to the surgical risks can serve to detect and guide the management of ICA injury in EESBS.