Anesthesia for functional neurosurgery: the role of dexmedetomidine.

PURPOSE OF REVIEW The purpose of this review is to summarize current approaches to the anesthetic management of functional neurosurgery and to describe the application of an alpha-2-adrenergic agonist dexmedetomidine in the anesthetic management of functional neurosurgical procedures. RECENT FINDINGS Dexmedetomidine, an alpha-2-adrenergic agonist, causes a unique kind of sedation, acting on the subcortical areas, which resembles natural sleep without respiratory depression. Experimental data demonstrate both cerebral vasoconstriction and vasodilatation, depending on the model and dose studied. At the clinically relevant doses, dexmedetomidine decreases cerebral blood flow and cerebral metabolic rate of oxygen in healthy volunteers. Clinical experience of dexmedetomidine use in functional neurosurgery is limited to small case-series. Nevertheless, these reports indicate that use of dexmedetomidine does not interfere with electrophysiologic monitoring, thus allowing brain mapping during awake craniotomy and microelectrode recording during implantation of deep-brain stimulators. SUMMARY Dexmedetomidine has been demonstrated to provide a successful sedation without impairment of electrophysiologic monitoring in functional neurosurgery. Prospective randomized studies are warranted to delineate an optimal regimen of dexmedetomidine sedation and any dose-related influence on neurophysiologic function.