Category: Parkinsonism, Others
Objective: This study attempts to validate the relationship between Direct-D, indirect-ID coordinates for STN in Indian subjects. Also, this study tries to compare the D, ID & MER based targets and compare with final targets.
Background: The relationship between the D, ID targets of STN has never been validated in the Indian subjects. Among the many possible ways to localise targets for DBS; ID, D & MER methods are used. Also, the best lead as shown by these three methods may not be the same as the final lead placed. The true incidence of this discordance are looked for in this study.
Method: 73 consecutive cases(146 targets) of STN DBS for PD were studied. The STN was localised based on atlas based relationship with AC-PC line(ID), pre-op MRI (D) & intra-op MER. The degree of deviation in X,Y,and Z axes between D & ID targets were calculated. 69 cases with known bilateral final lead placement positions were used
for evaluation. The best leads based on MER on both sides were compared with the the final leads placed.
Results: Average displacement of D targets compared to ID targets was 1.10 mm more medially, 1.37 mm more anteriorly & 1.24mm more inferiorly on Right side and 1.21mm more medially, 1.39mm more anteriorly & 1.33mm more inferiorly on Left side. On the right side, greater than 2mm variations were noted in 4 cases in X axis, 20 cases in Y axis and 18 cases in Z axis, & on left side in 10, 20 and 18 cases respectively. The best leads (based on good MER recordings) were -C(34/69),A(20),M(18),P(13),L(4) on right side & on left side C(36),A(26),P(21),M(11),L(5). The final lead placements on right side were C(51/69),A(5),P(5),M(8),L(0) & on left side were C(48/69),A(10),P(4),M(5),L(2).The final lead positioning was performed based on good MER recordings along with absence of side effects at higher strengths of current stimulation.
Conclusion: Considerable deviation between D & ID values in the studied Indian population was seen. Also, lead placement purely based on MER also may not be able to titrate the risks of side effects associated with stimulation at higher strength current. Intra-operative clinical assessment at each electrode and strength of electric current yields the best possible combination for a safe and proper lead positioning.
To cite this abstract in AMA style:
A. Uppar, D. Srinivas, R. Yadav, P. Pal, V. Holla. Validation of Direct/Indirect targets with intra-operative clinical assessment in the Indian population & comparison with image guided and MER based targeting for Subthalamic Nucleus(STN) based Deep Brain Stimulation(DBS) in Parkinson’s disease(PD) [abstract]. Mov Disord. 2022; 37 (suppl 2). https://www.mdsabstracts.org/abstract/validation-of-direct-indirect-targets-with-intra-operative-clinical-assessment-in-the-indian-population-comparison-with-image-guided-and-mer-based-targeting-for-subthalamic-nucleusstn-based-deep-b/. Accessed November 21, 2024.« Back to 2022 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/validation-of-direct-indirect-targets-with-intra-operative-clinical-assessment-in-the-indian-population-comparison-with-image-guided-and-mer-based-targeting-for-subthalamic-nucleusstn-based-deep-b/