Diagnostic impact of monitoring transcranial motor-evoked potentials to prevent ischemic complications during endovascular treatment for intracranial aneurysms

The present study aimed to determine the incidence of intraprocedural motor-evoked potential (MEP) changes and to correlate them with intraprocedural ischemic complications and postprocedural neurological deficits in patients after endovascular intracranial aneurysm treatment. This study analyzed data from 164 consecutive patients who underwent endovascular coil embolization to treat intracranial aneurysms under transcranial MEP monitoring. We analyzed associations between significant changes in MEP defined as > 50% decrease in amplitude, and intraprocedural complications as well as postoperative neurological deficits. Factors associated with postprocedural neurological deficits were also assessed. The treated aneurysms were predominantly located in the anterior circulation (71%). Fourteen (9%) were located at perforators or branches that supplied the pyramidal tract. Intraprocedural complications developed in eight (5%) patients, and four of eight (50%) patients occurred postprocedural neurological deficits. Significant intraprocedural MEP changes occurred during seven of eight endovascular procedures associated with intraprocedural complications and salvage procedures were performed immediately. Among these changes, four transient MEP changes, recovered within 10 min, were not associated with postprocedural neurological deficits, whereas three permanent MEP changes were associated with postprocedural neurological deficits and mRS ≥ 1 at discharge. Aneurysms located at perforators/branches supplying the pyramidal tract, and permanent intraprocedural MEP changes were associated with postprocedural neurological deficits. We conclude that intraprocedural transcranial MEP monitoring can reliably identify ischemic changes and can initiate prompt salvage procedures during endovascular aneurysm treatment.