Objective: We tested whether the position of the electrode for deep brain stimulation (DBS) could be assessed relative to subthalamic nucleus (STN) dorsal boundaries by using the combination of postoperative transcranial B-mode sonography (TCS) and intraoperative microelectrode recordings (MER).

Background: Precise placement of the electrode for STN-DBS in Parkinson´s disease is indispensable for its maximum clinical efficacy. The dorsal STN is regarded as the key structure. MER are routinely used intraoperatively to determine the dorsal and ventral STN boundaries estimating the trajectory length through the STN. Postoperative assessment of the DBS electrode position relative to the STN ventral boundary may be performed with TCS.

Method: The DBS electrode position in the STN was estimated: electrode length [7.5mm] – ((length of STN-MER [mm]) – (TCS distance DBS electrode tip to STN ventral boundary [mm])). This was compared to our “gold standard”, that is the intraoperative determination of the DBS electrode position relative to the MRI-defined stereotactic target point and the functional STN boundaries as assessed by MER.

Results: We could show a high and clinically relevant consistency between the compared methods. Differences in estimated electrode positions (n=12) between the methods were of median 0.65mm [range -1.35 mm to 1.25 mm], which was below the length of one ring contact of the stimulation electrode (1.5mm) in all electrodes. Differences between the methods showed no tendency to get larger (or smaller) while the average of both methods (0.4mm [SD±0.86]), the best estimation of the true value, increases (Bland Altman Plot; linear regression of means vs differences; p=0.4293 for a slope “non- zero”; one outlier in the dataset).

Conclusion: The combination of postoperative brainstem TCS and intraoperative MER may be regarded as a promising novel tool to reliably determine the electrode position for permanent DBS in relation to the dorsal boundaries of the STN at any given time point after surgery which may result in reduced postoperative programming time, improvement in DBS clinical efficacy and could detect primary or secondary misplaced electrodes.

« Back to 2022 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/combining-intraoperative-microelectrode-recordings-with-postoperative-transcranial-b-mode-sonography-of-the-brainstem-to-estimate-the-anatomical-position-of-the-electrode-for-chronic-subthalamic-nucle/