Department of Stereotactic and Functional Neurosurgery, University of Cologne Faculty of Medicine and University Hospital Cologne, Cologne, Germany,
Department of Neurology, University of Cologne Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
Stereotact Funct Neurosurg. 2021;99(1):65-74. doi: 10.1159/000509781. Epub 2020 Oct 20.
Directional leads are increasingly used in deep brain stimulation. They allow shaping the electrical field in the axial plane. These new possibilities increase the complexity of programming. Thus, optimized programming approaches are needed to assist clinical testing and to obtain full clinical benefit.
This simulation study investigates to what extent the electrical field can be shaped by directional steering to compensate for lead malposition.
Binary volumes of tissue activated (VTA) were simulated, by using a finite element method approach, for different amplitude distributions on the three directional electrodes. VTAs were shifted from 0 to 2 mm at different shift angles with respect to the lead orientation, to determine the best compensation of a target volume.
Malpositions of 1 mm can be compensated with the highest gain of overlap with directional leads. For larger shifts, an improvement of overlap of 10-30% is possible, depending on the stimulation amplitude and shift angle of the lead. Lead orientation and shift determine the amplitude distribution of the electrodes.
To get full benefit from directional leads, both the shift angle as well as the shift to target volume are required to choose the correct amplitude distribution on the electrodes. Current directional leads have limitations when compensating malpositions >1 mm; however, they still outperform conventional leads in reducing overstimulation. Further, their main advantage probably lies in the reduction of side effects. Databases like the one from this simulation could serve for optimized lead programming algorithms in the future.
立体定向电极在脑深部刺激中应用越来越广泛。它允许在轴面内对电场进行塑形。这些新的可能性增加了编程的复杂性。因此，需要优化编程方法来协助临床测试并获得充分的临床获益。
本模拟研究旨在探讨通过定向转向来补偿导联错位的程度，从而在多大程度上可以对电场进行塑形。
通过有限元方法模拟不同幅度分布在三个定向电极上的二进制组织激活（VTA）。将 VTA 从 0 移至相对于导联方向的 2mm 不同偏移角度，以确定目标体积的最佳补偿。
可以通过使用定向导联来补偿 1mm 的错位，其重叠增益最大。对于较大的偏移，根据刺激幅度和导联的偏移角度，重叠度可提高 10-30%。导联的方向和偏移决定了电极的幅度分布。
要充分利用定向导联的优势，需要选择正确的电极上的幅度分布，既要考虑偏移角度，也要考虑目标体积的偏移。当前的定向导联在补偿大于 1mm 的错位时存在局限性；然而，它们在减少过度刺激方面仍然优于传统导联。此外，它们的主要优势可能在于减少副作用。像这个模拟中的数据库可以为未来的优化导联编程算法提供服务。
