Institute of Neurology and Neurosurgery, Albert Einstein College of Medicine, New York, New York, USA.
Department of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia.
J Neurol Neurosurg Psychiatry. 2018 Jul;89(7):754-761. doi: 10.1136/jnnp-2017-317172. Epub 2018 Feb 7.
Anatomical identification of the corticospinal tract (CT) and the dorsal column (DC) of the exposed spinal cord is difficult when anatomical landmarks are distorted by tumour growth. Neurophysiological identification is complicated by the fact that direct stimulation of the DC may result in muscle motor responses due to the centrally activated H-reflex. This study aims to provide a technique for intraoperative neurophysiological differentiation between CT and DC in the exposed spinal cord.
Recordings were obtained from 32 consecutive patients undergoing spinal cord tumour surgery from July 2015 to March 2017. A double train stimulation paradigm with an intertrain interval of 60 ms was devised with recording of responses from limb muscles.
In non-spastic patients (55% of cohort) an identical second response was noted following the first CT response, but the second response was absent after DC stimulation. In patients with pre-existing spasticity (45%), CT stimulation again resulted in two identical responses, whereas DC stimulation generated a second response that differed substantially from the first one. The recovery times of interneurons in the spinal cord grey matter were much shorter for the CT than those for the DC. Therefore, when a second stimulus train was applied 60 ms after the first, the CT-fibre interneurons had already recovered ready to generate a second response, whereas the DC interneurons were still in the refractory period.
Mapping of the spinal cord using double train stimulation allows neurophysiological distinction of CT from DC pathways during spinal cord surgery in patients with and without pre-existing spasticity.
当解剖学标志因肿瘤生长而扭曲时，暴露脊髓的皮质脊髓束 (CT) 和背柱 (DC) 的解剖识别变得困难。由于中央激活的 H 反射，直接刺激 DC 可能导致肌肉运动反应，这使得神经生理学识别变得复杂。本研究旨在提供一种在暴露脊髓手术中用于术中神经生理学区分 CT 和 DC 的技术。
从 2015 年 7 月至 2017 年 3 月连续对 32 例脊髓肿瘤手术患者进行了记录。设计了一个具有 60ms 间隔的双刺激列车刺激范式，并记录来自肢体肌肉的反应。
在非痉挛患者（队列的 55%）中，在第一次 CT 反应后注意到第二个相同的反应，但在 DC 刺激后第二个反应消失。在存在预先存在的痉挛的患者（45%）中，CT 刺激再次产生两个相同的反应，而 DC 刺激产生的第二个反应与第一个反应有很大不同。脊髓灰质中中间神经元的恢复时间对于 CT 比 DC 要短得多。因此，当在第一次刺激后 60ms 施加第二次刺激列车时，CT 纤维中间神经元已经恢复准备好产生第二个反应，而 DC 中间神经元仍处于不应期。
使用双刺激列车刺激对脊髓进行映射，可在存在和不存在预先存在的痉挛的脊髓肿瘤手术患者中实现 CT 和 DC 通路的神经生理学区分。
