Effects of waveform shape and electrode material on KiloHertz frequency alternating current block of mammalian peripheral nerve.
Effects of waveform shape and electrode material on KiloHertz frequency alternating current block of mammalian peripheral nerve.
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DOI：
10.1186/s42234-022-00093-z
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发表时间：
2022-07-27
影响因子：
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通讯作者：
Bhadra, Niloy
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作者：
Green, David B;Kilgore, Joseph A;Bender, Shane A;Daniels, Robert J;Gunzler, Douglas D;Vrabec, Tina L;Bhadra, Niloy
千赫频率的交流电波形在周围神经中产生传导阻滞。目前尚不清楚波形形状如何影响阻滞结果，以及波形效应是否与频率相关。我们使用两种类型的电极来确定波形形状的影响。对12只大鼠进行了急性体内实验。双极电极用于电阻断坐骨神经中的运动神经冲动，如使用来自腓肠肌的力输出所测量的。在6个频率（10-60 kHz）下输送三种阻断波形（正弦、方形和三角形）。将裸铂电极与炭黑涂覆的电极进行比较。我们确定了可以完全阻断运动神经传导的最小幅度（阻滞阈值），并测量了起始反应的特性，这是阻滞开始时神经激活的短暂时期。将体内结果与使用神经元模拟环境进行的计算建模进行比较，神经元模拟环境使用针对千赫兹频率范围内的刺激而修改的神经膜模型。对于大多数参数，体内测试和模拟显示了相似的结果：对于所有三种波形，阻滞阈值随频率线性增加。波形之间的阻滞阈值显著不同;方波最低，三角波最高。当转换为每周期充电时，方波每相所需的电荷最大，三角波最少。发作参数受阻断频率的影响，但不受波形形状的影响。仅在体内进行电极比较。具有炭黑涂层的电极在所有阻断频率上给出了显著较低的阻断阈值和降低的起始响应。对于10和20 kHz，炭黑涂层显著降低了神经阻滞所需的电荷。我们的结论是，在20 kHz或更高的频率的正弦和方波将是最佳的。炭黑或其他高电荷容量电极的未来研究可用于实现具有较低BT和起始的嵌段。这些发现将对临床神经阻滞系统的设计具有重要意义。
KiloHertz frequency alternating current waveforms produce conduction block in peripheral nerves. It is not clearly known how the waveform shape affects block outcomes, and if waveform effects are frequency dependent. We determined the effects of waveform shape using two types of electrodes. Acute in-vivo experiments were performed on 12 rats. Bipolar electrodes were used to electrically block motor nerve impulses in the sciatic nerve, as measured using force output from the gastrocnemius muscle. Three blocking waveforms were delivered (sinusoidal, square and triangular) at 6 frequencies (10–60 kHz). Bare platinum electrodes were compared with carbon black coated electrodes. We determined the minimum amplitude that could completely block motor nerve conduction (block threshold), and measured properties of the onset response, which is a transient period of nerve activation at the start of block. In-vivo results were compared with computational modeling conducted using the NEURON simulation environment using a nerve membrane model modified for stimulation in the kilohertz frequency range. For the majority of parameters, in-vivo testing and simulations showed similar results: Block thresholds increased linearly with frequency for all three waveforms. Block thresholds were significantly different between waveforms; lowest for the square waveform and highest for triangular waveform. When converted to charge per cycle, square waveforms required the maximum charge per phase, and triangular waveforms the least. Onset parameters were affected by blocking frequency but not by waveform shape. Electrode comparisons were performed only in-vivo. Electrodes with carbon black coatings gave significantly lower block thresholds and reduced onset responses across all blocking frequencies. For 10 and 20 kHz, carbon black coating significantly reduced the charge required for nerve block. We conclude that both sinusoidal and square waveforms at frequencies of 20 kHz or higher would be optimal. Future investigation of carbon black or other high charge capacity electrodes may be useful in achieving block with lower BTs and onsets. These findings will be of importance for designing clinical nerve block systems.