Uribe Juan S, Isaacs Robert E, Youssef Jim A, Khajavi Kaveh, Balzer Jeffrey R, Kanter Adam S, Küelling Fabrice A, Peterson Mark D
Department of Neurological Surgery and Brain Repair, University of South Florida, 2 Tampa General Circle, Tampa, FL, 33606, USA,
Eur Spine J. 2015 Apr;24 Suppl 3:378-85. doi: 10.1007/s00586-015-3871-8. Epub 2015 Apr 15.
This multicenter study aims to evaluate the utility of triggered electromyography (t-EMG) recorded throughout psoas retraction during lateral transpsoas interbody fusion to predict postoperative changes in motor function.
Three hundred and twenty-three patients undergoing L4-5 minimally invasive lateral interbody fusion from 21 sites were enrolled. Intraoperative data collection included initial t-EMG thresholds in response to posterior retractor blade stimulation and subsequent t-EMG threshold values collected every 5 min throughout retraction. Additional data collection included dimensions/duration of retraction as well as pre-and postoperative lower extremity neurologic exams.
Prior to expanding the retractor, the lowestt-EMG threshold was identified posterior to the retractor in 94 % of cases. Postoperatively, 13 (4.5 %) patients had a new motor weakness that was consistent with symptomatic neuropraxia (SN) of lumbar plexus nerves on the approach side. There were no significant differences between patients with or without a corresponding postoperative SN with respect to initial posterior blade reading (p = 0.600), or retraction dimensions (p > 0.05). Retraction time was significantly longer in those patients with SN vs. those without (p = 0.031). Stepwise logistic regression showed a significant positive relationship between the presence of new postoperative SN and total retraction time (p < 0.001), as well as change in t-EMG thresholds over time (p < 0.001), although false positive rates (increased threshold in patients with no new SN) remained high regardless of the absolute increase in threshold used to define an alarm criteria.
Prolonged retraction time and coincident increases in t-EMG thresholds are predictors of declining nerve integrity. Increasing t-EMG thresholds, while predictive of injury, were also observed in a large number of patients without iatrogenic injury, with a greater predictive value in cases with extended duration. In addition to a careful approach with minimal muscle retraction and consistent lumbar plexus directional retraction, the incidence of postoperative motor neuropraxia may be reduced by limiting retraction time and utilizing t-EMG throughout retraction, while understanding that the specificity of this monitoring technique is low during initial retraction and increases with longer retraction duration.
本多中心研究旨在评估在经腰大肌外侧椎间融合术中腰大肌牵开过程中记录的触发式肌电图（t-EMG）对预测术后运动功能变化的效用。
纳入了来自21个地点的323例行L4-5微创外侧椎间融合术的患者。术中数据收集包括对后牵开器叶片刺激的初始t-EMG阈值，以及在整个牵开过程中每5分钟收集的后续t-EMG阈值。额外的数据收集包括牵开的尺寸/持续时间以及术前和术后的下肢神经学检查。
在牵开器扩张之前，94%的病例在牵开器后方确定了最低的t-EMG阈值。术后，13例（4.5%）患者出现了新的运动无力，与手术入路侧腰丛神经的症状性神经失用症（SN）一致。有或没有相应术后SN的患者在初始后叶片读数（p = 0.600）或牵开尺寸（p > 0.05）方面没有显著差异。SN患者的牵开时间明显长于无SN患者（p = 0.031）。逐步逻辑回归显示，术后新SN的存在与总牵开时间（p < 0.001）以及t-EMG阈值随时间的变化（p < 0.001）之间存在显著正相关，尽管无论用于定义警报标准的阈值绝对增加多少，假阳性率（无新SN患者的阈值增加）仍然很高。
牵开时间延长和t-EMG阈值同时增加是神经完整性下降的预测指标。t-EMG阈值增加虽然可预测损伤，但在大量无医源性损伤的患者中也有观察到，在持续时间延长的病例中预测价值更大。除了采用小心的方法尽量减少肌肉牵开并持续向腰丛方向牵开外，通过限制牵开时间并在整个牵开过程中使用t-EMG，可能会降低术后运动性神经失用症的发生率，同时要明白这种监测技术在初始牵开时特异性较低，而随着牵开持续时间延长特异性会增加。
