Introduction: Intraoperative neurophysiology monitoring such as somatosensory evoked potentials (SEP) and motor evoked potentials (MEP) became popular to prevent ischemic complication during aneurysm surgery. However, surgeons often encounter cases of suspicious false positive and false negative of MEP/SEP monitoring from experience, but the incidence and risk factors for these events are not well established.
Methods: From January 2012 to April 2016, 1514 patients underwent unruptured intracranial aneurysm (UIA) surgery with intraoperative EP monitoring. Patients with previous brain lesion or neurologic deficits were excluded to avoid interfere of EP monitoring results. Correlation between immediate post-operative motor weakness and EP monitoring results were reviewed retrospectively. Sensitivity, specificity, and the positive and negative predictive values, incidence of false positive and false negative of intraoperative MEP monitoring were calculated.
Results: EP amplitude decrease of 50% or more compare to the baseline amplitude was defined as significant EP change. There were 10 cases of immediate post-operative motor weakness, however there was no significant EP change in 8 cases among them. Therefore, MEP results during UIA surgery resulted in a sensitivity of 0.10, a specificity of 0.94, a positive predictive value of 0.01, and a negative predictive value of 0.99. The incidence of false positive was 1.25%, whereas false negative was 0.53%.
Conclusions: The intraoperative EP monitoring has high specificity and negative predictive value. However, there are existence of false positive and false negative. Therefore, intraoperative EP monitoring combined with other intraoperative monitoring method will provide maximum safety during aneurysm surgery.
Patient Care: The intraoperative EP monitoring has high specificity and negative predictive value. Therefore, intraoperative EP monitoring combined with other intraoperative monitoring method will provide maximum safety during aneurysm surgery.
Learning Objectives: By the conclusion of this session, participants should be able to understand the efficacy, reliabilty and limitation of intraoprative EP monitoring.