Predictive value of IOM in clipping of unruptured intracranial aneurysms - A prospective study from the surgeon's point of view

Lea Baumgart; Arthur Wagner; Anne-Sophie Dorier; Doris Droese; Amir K Aftahy; Maria Wostrack; Sebastian Ille; Bernhard Meyer; Sandro M Krieg

doi:10.1016/j.bas.2023.101759

Predictive value of IOM in clipping of unruptured intracranial aneurysms - A prospective study from the surgeon's point of view

Brain Spine. 2023 May 20:3:101759. doi: 10.1016/j.bas.2023.101759. eCollection 2023.

Authors

Lea Baumgart¹, Arthur Wagner¹, Anne-Sophie Dorier¹, Doris Droese², Amir K Aftahy¹, Maria Wostrack¹, Sebastian Ille¹, Bernhard Meyer¹, Sandro M Krieg¹

Affiliations

¹ Department of Neurosurgery, Technical University Munich School of Medicine, Munich, Germany.
² Department of Anaesthesiology, Technical University Munich School of Medicine, Munich, Germany.

Abstract

Introduction: Intraoperative neuromonitoring (IOM) of motor/somatosensory evoked potentials is a well-established approach for reducing ischemic complications after aneurysm clipping.

Research question: To determine the predictive validity of IOM for postoperative functional outcome and its perceived added value for intraoperative real-time feedback of functional impairment in the surgical treatment of unruptured intracranial aneurysms (UIAs).

Material and methods: Prospective study of patients scheduled for elective clipping of UIAs between 02/2019-02/2021. Transcranial motor evoked potentials (tcMEP) were used in all cases, a significant decline was defined as loss of ≥50% in amplitude or 50% latency increase. Clinical data were correlated to postoperative deficits. A surgeon's questionnaire was conceived.

Results: 47 patients were included, median age 57 years (range 26-76). IOM was successful in all cases. In 87.2%, IOM was stable throughout surgery, although 1 patient (2.4%) demonstrated a permanent postoperative neurological deficit. All patients with an intraoperatively reversible tcMEP-decline (12.7%) showed no surgery-related deficit, regardless of the decline duration (range 0.5-40.0 min; mean: 13.8). Temporary clipping (TC) was performed in 12 cases (25.5%), with a decline in amplitude in 4 patients. After clip-removal, all amplitudes returned to baseline. IOM provided the surgeon with a higher sense of security in 63.8%.

Discussion and conclusion: IOM remains invaluable during elective microsurgical clipping, particularly during TC of MCA and AcomA-aneurysms. It alerts the surgeon of impending ischemic injury and offers a way of maximizing the time frame for TC. IOM has highly increased surgeons' subjective feeling of security during the procedure.

Keywords: Clipping; Intraoperative neuromonitoring; Motor evoked potentials; Transcranial stimulation; Unruptured intracranial aneurysms.