Brainstem mapping with electrical stimulation allows functional identification of neural structures during resection of deep lesions. Single pulses or train of pulses are delivered to map cranial nerves and corticospinal tracts, respectively. We introduce a hybrid stimulation technique for mapping the brainstem. The stimulus consists of an electrical single pulse followed by a short train of 3–5 pulses at 500 Hz, at an interval of 60-75 ms. The responses to this stimulation pattern are recorded from appropriate cranial and limb muscles. Both the single pulse and the short train elicit electromyographic responses when motor fibers or motor nuclei of the cranial nerves are stimulated. Responses to the train but not to the preceding single pulse indicate activation of the descending motor tracts, in the mesencephalon and the pons. Conversely, in the medulla, limb responses to stimulation of the corticospinal tracts are elicited by a single pulse. Identification of the extra and intra-axial courses of the trigeminal motor and sensory fibers is possible by recording responses from the masseter and the tongue muscles. To date, either a pulse or a train is delivered during brainstem mapping, switching from one to the other modality according to the expected target structure. This procedure can be time-consuming and may even lead to false negative responses to the stimulation, eventually leading to inaccurate neurosurgical procedures. The novel hybrid pulse-train technique enhances the advantage of brainstem mapping procedure, minimizing pitfalls and improving patient safety.

中文翻译：

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神经外科神经生理学脑干标测的新方法

通过电刺激进行脑干标测可以在切除深层病变期间对神经结构进行功能识别。传递单个脉冲或脉冲串来分别绘制脑神经和皮质脊髓束的图。我们引入了一种混合刺激技术来绘制脑干图。刺激包括一个电单脉冲，随后是 500 Hz 的 3-5 个短脉冲序列，间隔为 60-75 ms。从适当的颅骨和四肢肌肉记录对这种刺激模式的反应。当刺激脑神经的运动纤维或运动核时，单脉冲和短脉冲都会引起肌电反应。对列车的反应而不是对前面的单个脉冲的反应表明中脑和脑桥中的下行运动束的激活。相反，在髓质中，肢体对皮质脊髓束刺激的反应是由单个脉冲引起的。通过记录咬肌和舌头肌肉的反应，可以识别三叉神经运动和感觉纤维的轴外和轴内路线。迄今为止，在脑干测绘过程中会传递脉冲或序列，根据预期的目标结构从一种模式切换到另一种模式。该过程可能非常耗时，甚至可能导致对刺激的假阴性反应，最终导致不准确的神经外科手术。新颖的混合脉冲序列技术增强了脑干标测程序的优势，最大限度地减少了陷阱并提高了患者的安全性。