Influence of Propofol and Fentanyl on Deep Brain Stimulation of the Subthalamic Nucleus

We investigated the effect of propofol and fentanyl on microelectrode recording (MER) and its clinical applicability during subthalamic nucleus (STN) deep brain stimulation (DBS) surgery. We analyzed 8 patients with Parkinson's disease, underwent bilateral STN DBS with MER. Their left sides were done under awake and then their right sides were done with a continuous infusion of propofol and fentanyl under local anesthesia. The electrode position was evaluated by preoperative MRI and postoperative CT. The clinical outcomes were assessed at six months after surgery. We isolated single unit activities from the left and the right side MERs. There was no significant difference in the mean firing rate between the left side MERs (38.7±16.8 spikes/sec, n=78) and the right side MERs (35.5±17.2 spikes/sec, n=66). The bursting pattern of spikes was more frequently observed in the right STN than in the left STN. All the electrode positions were within the STNs on both sides and the off-time Unified Parkinson's Disease Rating Scale part III scores at six months after surgery decreased by 67% of the preoperative level. In this study, a continuous infusion of propofol and fentanyl did not significantly interfere with the MER signals from the STN. The results of this study suggest that propofol and fentanyl can be used for STN DBS in patients with advanced Parkinson's disease improving the overall experience of the patients. Graphical Abstract Keywords: Parkinson Disease, Microelectrodes, Propofol, Fentanyl, Subthalamic Nucleus, Deep Brain Stimulation INTRODUCTION Deep brain stimulation (DBS) of the subthalamic nucleus (STN) reduces motor disability, motor fluctuations and levodopa-induced dyskinesias (1). Intraoperative microelectrode recordings (MER) and clinical monitoring with electrical stimulation of the STN have been recommended for the accurate positioning of the electrodes in the STN (2, 3). These procedures have the STN DBS done usually under local anesthesia (LA). It is reported that the intraoperative use of propofol can alleviate the patients' discomfort but interfere with the electrophysiological signals (4, 5, 6). However, it has not been thoroughly evaluated regarding how much it influences the electrical signals of MER during the STN DBS and the accuracy of positioning the electrodes after surgery. The purpose of this study was to investigate the influence of propofol and fentanyl on microelectrode recording and their applicability in STN DBS.