Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota, USA.
Department of Biostatistics, University of Minnesota, Minneapolis, Minnesota, USA.
J Neurol Neurosurg Psychiatry. 2015 Apr;86(4):398-403. doi: 10.1136/jnnp-2013-307284. Epub 2014 Jun 16.
The location of the optimal target for deep brain stimulation (DBS) of the subthalamic nucleus (STN) remains controversial. Electrode impedance affects tissue activation by DBS and has been found to vary by contact number, but no studies have examined association between impedance and anatomic location.
To evaluate the relationship between electrode impedance and anatomic contact location, and to assess the clinical significance of impedance.
We gathered retrospective impedance data from 101 electrodes in 73 patients with Parkinson's disease. We determined contact location using microelectrode recording (MER) and high-field 7T MRI, and assessed the relationship between impedance and contact location.
For contact location as assessed via MER, impedance was significantly higher for contacts in STN, at baseline (111 Ω vs STN border, p=0.03; 169 Ω vs white matter, p<0.001) and over time (90 Ω vs STN border, p<0.001; 54 Ω vs white matter, p<0.001). Over time, impedance was lowest in contacts situated at STN border (p=0.03). Impedance did not vary by contact location as assessed via imaging. Location determination was 75% consistent between MER and imaging. Impedance was inversely related to absolute symptom reduction during stimulation (-2.5 motor portion of the Unified Parkinson's Disease Rating Scale (mUPDRS) points per 1000 Ω, p=0.01).
In the vicinity of DBS electrodes chronically implanted in STN, impedance is lower at the rostral STN border and in white matter, than in STN. This finding suggests that current reaches white matter fibres more readily than neuronal cell bodies in STN, which may help explain anatomic variation in stimulation efficacy.
深部脑刺激（DBS）丘脑底核（STN）的最佳目标位置仍存在争议。电极阻抗会影响 DBS 引起的组织激活，且已发现其随接触数量而变化，但尚无研究探讨阻抗与解剖位置之间的关系。
评估电极阻抗与解剖接触位置之间的关系，并评估阻抗的临床意义。
我们从 73 名帕金森病患者的 101 个电极中收集了回顾性阻抗数据。我们使用微电极记录（MER）和高磁场 7T MRI 确定接触位置，并评估了阻抗与接触位置之间的关系。
就 MER 评估的接触位置而言，STN 内接触点的阻抗在基线时（111 Ω 比 STN 边界，p=0.03；169 Ω 比白质，p<0.001）和随时间推移（90 Ω 比 STN 边界，p<0.001；54 Ω 比白质，p<0.001）显著更高。随着时间的推移，位于 STN 边界的接触点的阻抗最低（p=0.03）。阻抗在通过影像学评估的接触位置上没有差异。MER 和影像学的位置确定结果有 75%的一致性。阻抗与刺激时的绝对症状缓解呈负相关（每 1000 Ω 减少 2.5 个帕金森病统一评定量表（mUPDRS）运动部分评分，p=0.01）。
在慢性植入 STN 的 DBS 电极附近，STN 前部边界和白质中的阻抗比 STN 中的低。这一发现表明，电流比 STN 中的神经元细胞体更容易到达白质纤维，这可能有助于解释刺激疗效的解剖变异。
