Objective: We report our experience using microelectrode recording (MER) in asleep vs. awake patients for DBS targeting

Background: MER has played a crucial role in mapping the intricate deep basal ganglia nuclei and is most commonly used in awake surgeries.  This is because anesthetics can alter the electrophysiological signatures of these nuclei, reducing MER value and limiting the information it provides. However, a subset of patients, particularly those with Parkinson’s disease (PD), prefer to sleep during surgery as off-medication PD symptoms and situational anxiety can cause distress.

Method: To maintain an optimal anesthetic state without compromising electrophysiological signal integrity, we developed a protocol that includes Remifentanil at 0.2 µg/kg/min and Sevoflurane at 0.7 MAC during the preparation phase. Fifteen minutes before MER, we transition to Remifentanil at 0.1 µg/kg/min and Sevoflurane at 0.5 MAC while maintaining a SEDline value between 35 and 45, ensuring that anesthetics with profound thalamocortical modulation are avoided. As the lead is advanced along the planned trajectory, the MER signal and LFP spectrums are monitored to confirm entry into and exit from the target nucleus while documenting the corresponding depths and kinesthetic response. Macro-stimulation testing at target depth helps minimize adverse effects.

Results: A cohort of 65 PD patients underwent either STN or GPi DBS implantation, in either an awake or asleep state. Intraoperatively, MER data along the trajectory were labeled with depths corresponding to nucleus borders. A small subset of the asleep patients did not have clear nuclear borders in MER, but had preserved kinesthetic testing, macro-stimulation testing or both. Post-operatively no patient reported intraoperative awareness. In a preliminary retrospective study, we analyzed the MER data collected from 5 awake and 5 asleep STN implantations out of this cohort. We then compared the asleep MER to the equivalent data from awake cases. Our qualitative analysis showed that the unique spiking patterns of the nuclei were largely preserved, though there was a small reduction in background activity and spiking rate. However, the contrast between the thalamus, zona incerta (ZI), STN, and substantia nigra reticulata (SNR) remained distinct enough to guide implantation effectively.

Conclusion: This prelim analysis suggests that MER can provide useful intraoperative data in asleep DBS to enhance implantation precision.

References: Kwon WK, Kim JH, Lee JH, Lim BG, Lee IO, Koh SB, Kwon TH. Microelectrode recording (MER) findings during sleep-awake anesthesia using dexmedetomidine in deep brain stimulation surgery for Parkinson’s disease. Clin Neurol Neurosurg. 2016 Apr;143:27-33. doi: 10.1016/j.clineuro.2016.02.005. Epub 2016 Feb 6. PMID: 26895206.
Zhao GR, Cheng YF, Feng KK, Wang M, Wang YG, Wu YZ, Yin SY. Clinical Study of Intraoperative Microelectrode Recordings during Awake and Asleep Subthalamic Nucleus Deep Brain Stimulation for Parkinson’s Disease: A Retrospective Cohort Study. Brain Sci. 2022 Oct 29;12(11):1469. doi: 10.3390/brainsci12111469. PMID: 36358395; PMCID: PMC9688350.
Erdman HB, Kornilov E, Kahana E, Zarchi O, Reiner J, Socher A, Strauss I, Firman S, Israel Z, Bergman H, Tamir I. Asleep DBS under ketamine sedation: Proof of concept. Neurobiol Dis. 2022 Aug;170:105747. doi: 10.1016/j.nbd.2022.105747. Epub 2022 May 10. PMID: 35550159.
Izzo A, Piano C, D’Ercole M, D’Alessandris QG, Tufo T, Fuggetta MF, Figà F, Martinelli R, Obersnel M, Pambianco F, Bove F, Perotti V, Bentivoglio AR, Olivi A, Montano N. Intraoperative microelectrode recording during asleep deep brain stimulation of subthalamic nucleus for Parkinson Disease. A case series with systematic review of the literature. Neurosurg Rev. 2024 Jul 20;47(1):342. doi: 10.1007/s10143-024-02563-1. PMID: 39031226; PMCID: PMC11271364.
Janssen, Marcus LF, and Michaël J. Bos. “Microelectrode assisted deep brain stimulation: Considerations for anesthesia.” Deep Brain Stimulation 4 (2024): 13-23.

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