Kerezoudis Panagiotis, Wirrell Elaine, Miller Kai
Neurological Surgery, Mayo Clinic, Rochester, USA.
Child and Adolescent Neurology, Mayo Clinic, Rochester, USA.
Cureus. 2020 Jan 30;12(1):e6823. doi: 10.7759/cureus.6823.
Responsive nerve stimulation (RNS) represents a safe and effective treatment option for patients with medically refractory temporal lobe epilepsy. In cases of long intraparenchymal course and posterior-anterior electrode direction through occipital burr holes, disciplined stereotaxy is essential for stimulation of the appropriate target. A 13-year-old female with a history of multifocal, independent, bitemporal-onset seizures since 12 months of age showing evidence of left-sided mesial temporal sclerosis on MRI, underwent placement of bilateral mesial temporal RNS leads. An O-arm spin was performed after the placement and the images obtained were fused to the preoperative CT images. It demonstrated curvature of the leads, with some deviation from the planned trajectory, but no deviation from the target, that was worse on the left side, compared to the right; the left lead was placed first, followed by the right lead. Following discussion with our epilepsy neurology colleagues in the operating room, electrophysiological measurements from the implanted leads showed cleared epileptic activity and therefore no repositioning was pursued. Our hypothesis at that time was that cerebrospinal fluid leakage distorted the underlying ventricular anatomy causing some curvature in the lead during transventricular course and prolonged consideration during surgery. In conclusion, transventricular trajectories during RNS lead placement may lead to cerebrospinal fluid loss and associated lead deformation. The distal aspect of the lead may nonetheless reside in the desired surgical target. Neuromonitoring for epileptic signature can provide reassurance with regard to accurate lead placement, obviating the need for lead repositioning. Surgeons should also recognize that fused imaging may confuse inferred anatomic position from preoperative MRI with actual anatomy post brain shift.
反应性神经刺激（RNS）是药物难治性颞叶癫痫患者的一种安全有效的治疗选择。对于脑实质内走行较长且通过枕部骨孔向后向前电极方向的情况，规范的立体定向对于刺激合适靶点至关重要。一名13岁女性，自12个月大起有多灶性、独立的双侧颞叶发作史，MRI显示左侧内侧颞叶硬化，接受了双侧内侧颞叶RNS电极置入。置入后进行了O型臂扫描，并将获得的图像与术前CT图像融合。结果显示电极有弯曲，与计划轨迹有一些偏差，但未偏离靶点，左侧比右侧更严重；左侧电极先置入，随后是右侧电极。在手术室与癫痫神经科同事讨论后，植入电极的电生理测量显示癫痫活动已清除，因此未进行重新定位。我们当时的假设是，脑脊液漏使潜在的脑室解剖结构变形，导致经脑室过程中电极出现一些弯曲，手术中需要更长时间考虑。总之，RNS电极置入过程中的经脑室轨迹可能导致脑脊液丢失及相关电极变形。尽管如此，电极的远端仍可能位于期望的手术靶点。对癫痫特征进行神经监测可确保电极放置准确，无需重新定位。外科医生还应认识到，融合成像可能会将术前MRI推断的解剖位置与脑移位后的实际解剖结构混淆。
