gms | German Medical Science

Objective: The majority of deep brain stimulation (DBS) procedures of the subthalamic nucleus (STN) for Parkinson's disease are performed as an awake craniotomy in an attempt to optimize functional lead localization through intraoperative clinical testing. Many patients are reluctant to proceed to awake surgery and would prefer to have the procedure done in general anesthesia. Apart from practicability and comfort issues, awake surgeries might impose additional risks in terms of difficult airway control in emergencies, such as seizures or airway compromise.

Method: We have retrospectively reviewed patients undergoing STN-DBS procedures within the last five years and have identified patients that were implanted in general anesthesia. We have compared these to patients that underwent awake craniotomies within the same time frame in terms of indication for general anesthesia, technique, intraoperative microelectrode recording, possibility of limited macrostimulation, complications, and clinical outcome.

Results: Of 109 patients undergoing bilateral STN lead placement (total of 218 leads), seven patients were implanted in general anesthesia (6.4%). Reasons included panic and anxiety disorders in three, dystonic antecollis off medication in two, recent history of seizure activity, and explicit patient's request. Anesthesia was performed with propofol and remifentanil or with propofol alone. Nevertheless, during microelectrode recordings, we found reliable STN potentials in all patients and a total of 37 microelectrodes. For macrostimulation, we used bispectral index (BIS) monitoring of depth of anesthesia in three of the seven patients and aimed for a BIS number of 70 to 75. In one of these three patients tremor cessation was observed, in two contralateral contractions guided final lead placement. Postoperative stimulation effects were similar compared to awake surgery (pre- and post-UPDRS), no revision of electrode placement was needed.

Conclusions: We have previously shown that lead positioning is corrected by intraoperative macrostimulation in 42% of cases. We have now operated a subset of patients under light general anesthesia for different reasons and were able to perform microelectrode recordings and limited macrostimulation. Short-term clinical benefits are comparable to patients undergoing awake craniotomies.