Falowski Steven M
Director of Functional Neurosurgery, St. Luke's University Health Network, Bethlehem, PA, USA.
Neuromodulation. 2019 Feb;22(2):219-228. doi: 10.1111/ner.12781. Epub 2018 Apr 29.
Intraoperative neuromonitoring for spinal cord stimulation uses electromyography (EMG) responses to determine myotomal coverage as a marker for dermatomal coverage. These responses are utilized to determine the orientation of the electrode. Somatosensory evoked potential (SSEP) collision testing can also be used in which sensory signals are decreased and/or eliminated when stimulation is activated.
Fifteen patients were observed in the study. Each manufacturer had a minimum of three patients. Those included were Abbott BurstDR waveform, Boston Scientific burst stimulation, Medtronic high-dose stimulation, and Nevro high-frequency waveform. Efficacy of therapy was determined by a successful trial. Analysis performed during the permanent implant, included findings with traditional tonic stimulation, specific waveform and stimulation platforms, amplitude differences, and findings for both EMG responses and SSEP collision testing.
The Abbott BurstDR waveform produced the most findings. The amplitudes necessary to generate an observed EMG response were far lower than others, with a threshold of 10-20% of that seen in traditional tonic programming. The Medtronic high-dose programming and Nevro high-frequency waveform did not generate any observable EMG responses. Unique to Abbott BurstDR waveform was the onset of EMG activity in the distal muscle groups prior to proximal ones, as well as a hyperexcitability phenomenon acting as a primer generating signals at lower thresholds with more robust responses when returning to traditional tonic stimulation. EMG responses demonstrated propagation into one large EMG spike with BurstDR, while Boston Scientific burst stimulation had no propagation with separate spikes being consistent with traditional tonic stimulation.
This observational series demonstrated distinct differences between the waveforms and stimulation alluding to different mechanisms of action. Nevro high-frequency and Abbott BurstDR waveforms appear to be most different in action from traditional tonic stimulation while Abbotts BurstDR appears to be the most energy efficient generating signals at the lowest thresholds with a propagating effect that leads to a hyperexcitable or primed stimulation state.
脊髓刺激术中神经监测利用肌电图（EMG）反应来确定肌节覆盖范围，以此作为皮节覆盖范围的标志。这些反应被用于确定电极的方向。体感诱发电位（SSEP）碰撞测试也可使用，即当激活刺激时，感觉信号会减弱和/或消除。
本研究观察了15名患者。每个制造商至少有3名患者。其中包括雅培BurstDR波形、波士顿科学公司的爆发刺激、美敦力高剂量刺激和Nevro高频波形。治疗效果通过成功的试验来确定。在永久植入期间进行的分析包括传统强直刺激的结果、特定波形和刺激平台、振幅差异以及EMG反应和SSEP碰撞测试的结果。
雅培BurstDR波形产生的结果最多。产生观察到的EMG反应所需的振幅远低于其他波形，阈值为传统强直编程中所见阈值的10%-20%。美敦力高剂量编程和Nevro高频波形未产生任何可观察到的EMG反应。雅培BurstDR波形的独特之处在于，远端肌肉群的EMG活动先于近端肌肉群出现，以及一种过度兴奋现象，即作为一种引发剂，在较低阈值下产生信号，当恢复到传统强直刺激时反应更强。EMG反应显示，BurstDR会传播到一个大的EMG尖峰，而波士顿科学公司的爆发刺激没有传播，单独的尖峰与传统强直刺激一致。
这个观察系列表明不同波形和刺激之间存在明显差异，暗示了不同的作用机制。Nevro高频和雅培BurstDR波形在作用上似乎与传统强直刺激最为不同，而雅培的BurstDR波形似乎是最节能的，能在最低阈值下产生信号，并具有传播效应，导致过度兴奋或引发刺激状态。
