Background: Microelectrode recording (MER) is widely used during deep brain stimulation (DBS) procedures because MER can identify structural borders and eloquent structures, localize somatotopic arrangements, and provide an outline of the three-dimensional shapes of target nuclei. However, MER may cause intracranial hemorrhage. We preformed single track MER during DBS procedures, analyzed the accuracy of electrode positioning with MRI, and compared the amount of air and the potential risk of intracranial hemorrhage.
Method: A total of 46 electrodes were placed in 23 patients who suffered from advanced Parkinson's disease and who underwent bilateral subthalamic nucleus DBS using single track MER. Each patient's Unified Parkinson's Disease Rating Scale (UPDRS) score and levo-dopa equivalent dosage (LED) were estimated pre- and postoperatively. The accuracy of electrode positioning and fontal air thickness was measured by a pre- or postoperative magnetic resonance imaging (MRI) merging technique.
Findings: The mean electrode positioning error was 0.92 mm (0.3-2.94 mm). The mean frontal air thickness on postoperative MRI was 3.85 mm (0-10.3 mm), which did not affect the electrode accuracy statistically (p = 0.730). A total of nine electrodes required repositioning after single-track MER because they affected microstimulation or because an abnormally short STN length was observed during MER. In this series, one patient suffered from an intracranial hemorrhage after surgery that appeared to be due to venous infarction rather than related to MER.
Conclusions: Although MER can facilitate accurate positioning of electrodes, multi-track MER may increase the risk of intracranial hemorrhage. The accuracy of electrode positioning appears to be acceptable under single track MER during STN DBS with careful electrophysiological and neurological monitoring. The risk of intracranial hemorrhage appears to be minimal, especially in elderly patients with atrophic brains.