Ketamine Sedation Facilitates Asleep DBS: a multicenter retrospective study

Abstract Deep brain stimulation (DBS) is commonly and safely performed for selective Parkinson’s disease patients. Many centers perform DBS lead positioning exclusively under local anesthesia, to allow for brain microelectrode recordings (MER) and testing of stimulation-related therapeutic and side effects. These measures enable physiological identification of the DBS targets based on electrophysiological properties like firing rates and patterns, optimization of lead placement accuracy, and intra-operative evaluation of therapeutic window. Nevertheless, due to the challenges of awake surgery, some centers use sedation or general anesthesia, despite the distortion of discharge properties, and potential impact on clinical outcomes. Thus, there is a need for a novel anesthesia regimen that enables sedation without compromising intra-operative monitoring. This study investigates the use of low-dose ketamine for conscious sedation during lead positioning in subthalamic nucleus (STN) DBS for Parkinson’s disease patients. Three anesthetic regimens were retrospectively compared in 38 surgeries across three DBS centers: 1) Interleaved propofol-ketamine (PK), 2) Interleaved propofol-awake (PA), and 3) Fully awake (AA). All anesthesia regimens achieved satisfactory MER. Automatic detection of STN borders and subdomains using a Hidden Markov Model was similar between the groups. Patients’ symptoms and cooperation during stimulation testing in the ketamine group was not altered. No major adverse effects were reported in the different anesthesia protocols. These results support the use of low-dose ketamine as a novel alternative for the existing DBS anesthesia regimens, optimizing patient’s experience while preserving lead placement accuracy. A prospective study should be performed to confirm these findings.