Introduction: Localization of the dorsolateral zone (motor) of the subthalamic nucleus for deep brain stimulation
(DBS) in patients with Parkinson's disease (PD) is possible with tractography through the
connections from the M1/SMA. However, tractography has not been adequately validated for DBS
targeting. In this work, we analyze the overlapping between the patient-specific volume of tissue
activated (VTA) and the subthalamic target obtained by tractography correlated with the motor
improvement in patients with PD.
Methods: We include 6 patients underwent bilateral STN-DBS (12 electrodes) with more than a year of followup.
We obtained the motor zone of the STN using a method described by our group previously.
Based in the work of Mc Intyre et al., we used the Optivise ® software package to obtain the VTA of
each clinically effective electrode's contact of every patient. We obtained the UPDRS III score of
each side of the patients (12 scores). We computed the percentage of improvement based on the
pre and postoperative scores. Finally, we obtained the percentage of overlapping between the VTA
and tractographical target of the STN. We used the Spearman correlation to analyze the
relationship between the VTA/motor STN and the percentage of motor improvement.
Results: The Wilcoxon test revealed a statistically significant improvement of all patients after STN-DBS
(p=0.0024). Correlation analysis showed a positive correlation between the VTA/motor STN and the
percentage of motor improvement (r=0.58; moderate correlation) with a statically significant result
(p=0.048).
Conclusions: This study suggest that stimulation in the motor part of the STN obtained by tractography is
associated with a better motor improvement than stimulation outside of the motor part of the STN.
There is positive correlation between the electrical influence of this tractographical target with the
degree of motor improvement.
Patient Care: Further understanding of the accuracy in the targeting of the motor region of STN
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of volume of tissue activated models to study the clinical improvement in patients underwent DBS, 2) Identify the tractography-based target in patients with Parkinson's disease.