Department of Neurosurgery, Erasmus MC, Rotterdam, The Netherlands.
Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands.
Neuromodulation. 2021 Jun;24(4):719-728. doi: 10.1111/ner.13379. Epub 2021 Mar 22.
While integrity of spinal pathways below injury is generally thought to be an important factor in the success-rate of neuromodulation strategies for spinal cord injury (SCI), it is still unclear how the integrity of these pathways conveying the effects of stimulation should be assessed. In one of our institutional case series of five patients receiving dorsal root ganglion (DRG)-stimulation for elicitation of immediate motor response in motor complete SCI, only two out of five patients presented as responders, showing immediate muscle activation upon DRG-stimulation. The current study focuses on post hoc clinical-neurophysiological tests performed within this patient series to illustrate their use for prediction of spinal pathway integrity, and presumably, responder-status.
In a series of three nonresponders and two responders (all male, American Spinal Injury Association [ASIA] impairment scale [AIS] A/B), a test-battery consisting of questionnaires, clinical measurements, as well as a series of neurophysiological measurements was performed less than eight months after participation in the initial study.
Nonresponders presented with a complete absence of spasticity and absence of leg reflexes. Additionally, nonresponders presented with close to no compound muscle action potentials (CMAPs) or Hofmann(H)-reflexes. In contrast, both responders presented with clear spasticity, elicitable leg reflexes, CMAPs, H-reflexes, and sensory nerve action potentials, although not always consistent for all tested muscles.
Post hoc neurophysiological measurements were limited in clearly separating responders from nonresponders. Clinically, complete absence of spasticity-related complaints in the nonresponders was a distinguishing factor between responders and nonresponders in this case series, which mimics prior reports of epidural electrical stimulation, potentially illustrating similarities in mechanisms of action between the two techniques. However, the problem remains that explicit use and report of preinclusion clinical-neurophysiological measurements is missing in SCI literature. Identifying proper ways to assess these criteria might therefore be unnecessarily difficult, especially for nonestablished neuromodulation techniques.
虽然人们普遍认为，脊髓损伤（SCI）神经调节策略成功与否的一个重要因素是损伤以下脊髓通路的完整性，但仍不清楚应如何评估传递刺激效果的这些通路的完整性。在我们的一个机构病例系列中，有五例患者因运动完全性 SCI 而接受背根神经节（DRG）刺激以引发即时运动反应，只有两例患者表现出即时肌肉激活的反应，为响应者。本研究重点介绍了该患者系列内进行的事后临床神经生理学测试，以说明其用于预测脊髓通路完整性和响应者状态的用途。
在一个由三名无反应者和两名响应者（均为男性，美国脊髓损伤协会 [ASIA] 损伤量表 [AIS] A/B）组成的系列中，在参与初始研究不到八个月的时间内，进行了由问卷、临床测量以及一系列神经生理学测量组成的测试。
无反应者表现出完全没有痉挛和腿部反射缺失。此外，无反应者的复合肌肉动作电位（CMAP）或 Hoffmann（H）反射几乎不存在。相比之下，两名响应者都表现出明显的痉挛、可引出的腿部反射、CMAP、H 反射和感觉神经动作电位，尽管并非所有测试肌肉的反应都一致。
事后神经生理学测量在明确区分响应者和无反应者方面存在局限性。临床上，无反应者没有与痉挛相关的投诉，这是该病例系列中响应者和无反应者之间的区别因素，这与硬膜外电刺激的先前报告类似，可能说明了两种技术之间作用机制的相似性。然而，问题仍然是 SCI 文献中缺少明确使用和报告纳入前临床神经生理学测量。因此，确定评估这些标准的适当方法可能会变得不必要地困难，尤其是对于非既定的神经调节技术。
