Patients selection for awake neurosurgery

BACKGROUND: Based upon the surgical location and indication, including redundant regions, eloquent areas, deep brain stimulation, and epilepsy foci, some patients will benefit from an awake craniotomy, which allows completion of neurocognitive testing during the intra-operative period. This paper suggests patient selection criteria through a new decision algorithm. METHODS: We completed a retrospective chart review at Tampa General Hospital after IRB approval; data were obtained concerning total number of craniotomies, indications, and problems experienced for selection of awake vs. general anesthetic techniques. RESULTS: A total of 397 craniotomies were performed during the two years 2005 and 2006: among those 79 patients received an awake craniotomy (20%). We have utilized a sedation sequence which includes dexmedetomidine, propofol and LMA placement. A skull block is then performed to anesthetize pin placement, and desflurane and remifentanil are used for maintenance until the dural incision. At this time the inhalation agent is stopped and the LMA is removed while breathing spontaneously: the patient remains sedated on dexmedetomidine and remifentanil for the duration of the operation and can communicate effectively if closely coached. Analysis of all patient data led us to a decision tree to guide the surgeon and anesthesiologist in selecting the awake patients. DISCUSSION: We describe the sequence of steps and anesthetic agents which has proved successful for our group. Finally, the use of the proposed decision algorithm simplifies preoperative anesthetic selection and prevents erroneous assignment of inappropriate patients to an awake technique.