Anesthesia for deep brain stimulation system implantation: adapted protocol for awake and asleep surgery using microelectrode recordings.

PURPOSE: Deep brain stimulation (DBS), an effective treatment for movement disorders, usually involves lead implantation while the patient is awake and sedated. Recently, there has been interest in performing the procedure under general anesthesia (asleep). This report of a consecutive cohort of DBS patients describes anesthesia protocols for both awake and asleep procedures. METHODS: Consecutive patients with Parkinson's disease received subthalamic nucleus (STN) implants either moderately sedated or while intubated, using propofol and remifentanil. Microelectrode recordings were performed with up to five trajectories after discontinuing sedation in the awake group, or reducing sedation in the asleep group. Clinical outcome was compared between groups with the UPDRS III. RESULTS: The awake group (n = 17) received 3.5 mg/kg/h propofol and 11.6 µg/kg/h remifentanil. During recording, all anesthesia was stopped. The asleep group (n = 63) initially received 6.9 mg/kg/h propofol and 31.3 µg/kg/h remifentanil. During recording, this was reduced to 3.1 mg/kg/h propofol and 10.8 µg/kg/h remifentanil. Without parkinsonian medications or stimulation, 3-month UPDRS III ratings (ns = 16 and 52) were 40.8 in the awake group and 41.4 in the asleep group. Without medications but with stimulation turned on, ratings improved to 26.5 in the awake group and 26.3 in the asleep group. With both medications and stimulation, ratings improved further to 17.6 in the awake group and 15.3 in the asleep group. All within-group improvements from the off/off condition were statistically significant (all ps < 0.01). The degree of improvement with stimulation, with or without medications, was not significantly different in the awake vs. asleep groups (ps > 0.05). CONCLUSION: The above anesthesia protocols make possible an asleep implant procedure that can incorporate sufficient microelectrode recording. Together, this may increase patient comfort and improve clinical outcomes.

Determination of optimal time window for cortical mapping in awake craniotomy: assessment of intraoperative reaction speed.

Currently, there is no known time frame when the patients are the most responsive during awake craniotomy. The aim of this work is therefore to determine when the patient has the shortest reaction time and so to extrapolate the optimal time window for cortical mapping. In this analytic observational study, our group has recorded the reaction times of 35 patients undergoing an awake craniotomy and compared them with the preoperative baseline. The operations were performed according to a "sleep-awake-awake" protocol. Data collection was performed in parallel with standard methods for evaluation of language and cognitive functions. The preoperative reaction times of our patient cohort (average ± SD = 510 ± 124 ms) were significantly shorter than those measured during the operation 786 ± 280 ms, p < .001. A one-factor ANOVA within subjects showed a significant increase in reaction times; p < .001. Post hoc comparisons on a Bonferroni-corrected α-error level of .05 showed significant differences between the reaction speed during the 0-10 min time frame and the preoperative baseline, as well as the intraoperative reaction times during the 20-30 min, 30-40 min, and the t > 40 min time frames. In conclusion, measurement of intraoperative reaction speed seems to be a technically feasible method that is well tolerated by the patients. The intraoperative reaction speed performance was shown to be significantly slower than on the day before the operation. The patients seem to be the slowest directly after extubation and gradually wake up during the awake phase. The poorest wakefulness is demonstrated during the first 20 min after extubation.