Möttönen Timo, Katisko Jani, Haapasalo Joonas, Tähtinen Timo, Saastamoinen Antti, Peltola Jukka, Öhman Juha, Lehtimäki Kai
Department of Neurosciences and Rehabilitation, Tampere University Hospital, Tampere, Finland.
Stereotact Funct Neurosurg. 2016;94(2):86-92. doi: 10.1159/000444761. Epub 2016 Apr 20.
Deep brain stimulation (DBS) of the anterior nucleus of the thalamus) (ANT) has been suggested as a treatment option in refractory epilepsy. The targeting of ANT is especially challenging due to its poor visualization in commonly used MRI sequences, lack of easily observable symptom relief during surgery and high degree of anatomical variation between individuals.
To study whether intraoperative microelectrode recording (MER), a method widely used in movement disorder surgery, provides clinically relevant information during the ANT-DBS implantation procedure.
A total of 186 MER samples from 5 patients and 10 thalami obtained from ANT-DBS surgery for refractory epilepsy were analyzed with respect to the signal characteristics and location in 3-tesla (3T) MRI STIR (short T1 inversion recovery) images. The location of each MER sample was calculated relative to visible borders of the ANT after correction of the sample locations according to the position of the final DBS electrode in postoperative CT-MRI fusion images.
We found that the lateral aspect of the ANT lacked spiking activity consistent with the presence of white matter. The spike frequency in samples correlating with location at the ANT showed significantly lower spike frequency compared to samples correlating with location at the ventral anterior nucleus (median 3.0 and 7.0 spikes/2 s; p < 0.05), but spike bursts were morphologically similar in appearance. Trajectories entering the dorsomedial nucleus according to 3T MRI STIR images showed a yet different firing pattern with more low-amplitude regular activity.
Our data suggest that MER provides clinically relevant information during implantation surgery by demonstrating both nucleus-specific neuronal firing patterns and white matter laminae between different nuclear groups.
丘脑前核（ANT）的深部脑刺激（DBS）已被提议作为难治性癫痫的一种治疗选择。由于在常用的MRI序列中ANT可视化不佳、手术过程中缺乏易于观察到的症状缓解以及个体之间解剖变异程度高，ANT的靶向定位尤其具有挑战性。
研究术中微电极记录（MER），一种在运动障碍手术中广泛使用的方法，在ANT-DBS植入手术过程中是否能提供临床相关信息。
对5例患者和10个丘脑的186个MER样本进行分析，这些样本来自用于难治性癫痫的ANT-DBS手术，分析其在3特斯拉（3T）MRI短T1反转恢复（STIR）图像中的信号特征和位置。根据术后CT-MRI融合图像中最终DBS电极的位置校正样本位置后，计算每个MER样本相对于ANT可见边界的位置。
我们发现ANT的外侧缺乏与白质存在一致的棘波活动。与ANT位置相关的样本中的棘波频率显著低于与腹前核位置相关的样本（中位数分别为3.0和7.0个棘波/2秒；p<0.05），但棘波簇在形态上外观相似。根据3T MRI STIR图像进入背内侧核的轨迹显示出不同的放电模式，有更多低振幅规则活动。
我们的数据表明，MER通过展示不同核团之间的核特异性神经元放电模式和白质层，在植入手术过程中提供了临床相关信息。
