The Role of Microelectrode Recording (MER) in STN DBS Electrode Implantation

Abstract

The purpose of this paper is to study the correlation of microelectrode recording with the final tract chosen during bilateral STN DBS performed at a specialized centre in South India. Deep brain stimulation (DBS) of bilateral subthalamic nuclei (STN) is an efficient method of rehabilitation in subjects (diseased conditions–patients) with advanced idiopathic Parkinson disease (PD). Accurate targeting of STN neurons and placement of microelectrodes are paramount importance for optimal results after STNDBS. Stereo tactic assessment, intra-operative microelectrode recording and intra-operative stimulation effects have all been used in targeting, albeit the individual role of each modality is still not known. Microelectrode recordings (MER) of STN were detected in a mean of 3.5 ±1.1 channels on right hemisphere and 3.6 ±1.04 on left hemisphere. Final channel selected were most commonly central seen in 42.3% followed by anterior in 33.7%. Concordance of final tract with the channel having the highest recording was 58.7%, with the channel showing maximum depth of recording was 48% and with either was 64%. Absence of any recording in the final tract chosen was seen in 6.52%, in these subjects the tract was chosen based on stimulation results. The depths of microelectrodes were detected by MER in 75.6%. Thus, MER is useful to detect-confirm the tract in which DBS electrodes are placed and is most useful in determining the depth of electrodes placement but has to be taken in consideration with effects seen on macro-stimulation.