Background: Chronic spinal cord injury (SCI) portends a low probability of recovery, especially in the most severe subset of motor-complete injuries. Active spinal cord stimulation with or without intensive locomotor training has been reported to restore movement after traumatic SCI. Only three cases have been reported where participants developed restored volitional movement with active stimulation turned off after a period of chronic stimulation and only after intensive rehabilitation with locomotor training. It is unknown whether restoration of movement without stimulation is possible after stimulation alone. Objective: We describe the development of spontaneous volitional movement (SVM) without active stimulation in a subset of participants in the Epidural Stimulation After Neurologic Damage (ESTAND) trial, in which locomotor training is not prescribed as part of the study protocol, and subject’s rehabilitation therapies are not modified. Methods: Volitional movement was evaluated with the Brain Motor Control Assessment using sEMG recordings and visual examination at baseline and at follow-up visits with and without stimulation. Additional functional assessment with a motor-assisted bicycle exercise at follow-up with and without stimulation identified generated work with and without effort. Results: The first seven participants had ASIA Impairment Scale (AIS) A or B thoracic SCI, a mean age of 42 years, and 7.7 years post-injury on average. Four patients developed evidence of sustained volitional movement, even in the absence of active stimulation after undergoing chronic epidural spinal cord stimulation (eSCS). Significant increases in volitional power were found between those observed to spontaneously move without stimulation and those unable (p < 0.0005). The likelihood of recovery of spontaneous volitional control was correlated with spasticity scores prior to the start of eSCS therapy (p = 0.048). Volitional power progressively improved over time (p = 0.016). Additionally, cycling was possible without stimulation (p < 0.005). Conclusion: While some SVM after eSCS has been reported in the literature, this study demonstrates sustained restoration without active stimulation after long-term eSCS stimulation in chronic and complete SCI in a subset of participants. This finding supports previous studies suggesting that “complete” SCI is likely not as common as previously believed, if it exists at all in the absence of transection and that preserved pathways are substrates for eSCS-mediated recovery in clinically motor-complete SCI. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT03026816.

中文翻译：

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慢性完全性脊髓损伤后的长期脊髓刺激使没有刺激的意志运动成为可能

背景：慢性脊髓损伤 (SCI) 预示着恢复的可能性很低，尤其是在最严重的运动完全性损伤中。据报道，有或没有强化运动训练的主动脊髓刺激可以在创伤性 SCI 后恢复运动。仅报告了三个案例，参与者在经过一段时间的慢性刺激和运动训练强化康复后，在关闭主动刺激的情况下恢复了意志运动。目前尚不清楚单独刺激后是否可以在没有刺激的情况下恢复运动。目标：我们描述了神经损伤后硬膜外刺激 (ESTAND) 试验的一部分参与者在没有主动刺激的情况下自发意志运动 (SVM) 的发展，其中运动训练没有作为研究方案的一部分，并且受试者的康复疗法没有被修改。方法：在基线和有和无刺激的随访中，使用 sEMG 记录和视觉检查，通过脑运动控制评估来评估意志运动。在有和没有刺激的后续行动中，通过运动辅助自行车锻炼进行额外的功能评估，确定有无努力产生的工作。结果：前 7 名参与者的 ASIA 损伤量表 (AIS) A 或 B 胸部 SCI，平均年龄 42 岁，平均受伤后 7.7 年。即使在接受慢性硬膜外脊髓刺激 (eSCS) 后没有主动刺激的情况下，4 名患者也出现了持续自主运动的证据。在观察到在没有刺激的情况下自发运动的人和不能运动的人之间发现意志力显着增加（p < 0.0005）。自发性意志控制恢复的可能性与 eSCS 治疗开始前的痉挛评分相关 (p = 0.048)。随着时间的推移，意志力逐渐提高（p = 0.016）。此外，在没有刺激的情况下也可以骑自行车（p < 0.005）。结论：虽然文献中报道了 eSCS 后的一些 SVM，但本研究表明，在一部分参与者的慢性和完全 SCI 中，长期 eSCS 刺激后无需主动刺激即可持续恢复。这一发现支持了之前的研究，表明“完全”的 SCI 可能不像之前认为的那样普遍 如果它在没有横断的情况下存在，并且保留的通路是临床运动完全性 SCI 中 eSCS 介导的恢复的底物。临床试验注册：www.ClinicalTrials.gov，标识符 NCT03026816。