8. Neurophysiological monitoring and pharmacological provocative test in the endovascular treatment of brain arteriovenous malformations

Abstract

Neurophysiological monitoring and pharmacological provocative test in the endovascular treatment of brain arteriovenous malformations. The improvement of endovascular techniques increase embolization indications for cerebral arteriovenous malformations (AVMs). Intraoperative monitoring (IOM) techniques are very useful to reduce risks by a step-by-step check of the patient during treatment. We report a series of 5 patients affected by brain AVMs who underwent embolization assisted by IOM and superselective provocative pharmacological test (PTs) with intraarterial amobarbital. We used different IOM setting (MEPs, SEPs, BAERs and VEPs) in relation to the localization of AVM, which was rolandic in 2 patients, brainstem in 2 patients and occipital cortex in one case. We performed six endovascular procedures in five patients, carrying out nine PTs. Changes in IOM signals were detected in 3 out of 5 patients, leading to the decision to partially embolize one AVM and to avoid embolization of 2 other AVMs. No one experienced new permanent neurological deficit. In two patients we achieved complete nidus embolization; in the third patient another endovascular procedure is scheduled with complete resolution of AVM. In any patients we have false negative PTs. The use of IOM during embolization of AVM close to eloquent brain areas, implemented by PTs, is a valuable tool, which allows minimizing the risk of postoperative neurological deficits.