Neurophysiological detection of impending spinal cord injury during scoliosis surgery.
Neurophysiological detection of impending spinal cord injury during scoliosis surgery.
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DOI：
10.2106/jbjs.f.01476
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发表时间：
2007-11
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通讯作者：
Daniel M. Schwartz;J. Auerbach;J. Dormans;J. Flynn;D. Drummond;J. Bowe;S. Laufer;Suken A. Shah;J. R. Bowen;P. Pizzutillo;Kristofer J. Jones
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作者：
Daniel M. Schwartz;J. Auerbach;J. Dormans;J. Flynn;D. Drummond;J. Bowe;S. Laufer;Suken A. Shah;J. R. Bowen;P. Pizzutillo;Kristofer J. Jones
背景尽管许多报道证实了术中体感诱发电位监测在降低脊柱侧弯矫形术中医源性脊髓损伤发生率方面的有效性，但这些传入神经生理信号只能间接提供运动束损伤的证据，因为它们监测后柱功能。早期使用经颅运动诱发电位直接监测皮质脊髓运动束的报道表明，该方法在改善对新出现的脊髓损伤的检测方面具有很大的前景。我们试图比较这两种监测方法在脊柱侧弯手术中检测即将发生的医源性神经损伤的效果。方法回顾2000~2004年在4个儿科脊柱中心收治的1121例青少年特发性脊柱侧凸患者的术中神经生理监测资料。同一组经验丰富的外科神经生理学家在全静脉麻醉下使用标准化的多模式技术监测所有患者的脊髓功能。相关的神经生理学改变(警报)被定义为与基线相比，躯体感觉诱发电位的幅度(单侧或双侧)下降至少50%，经颅电动诱发电位的幅度至少下降65%。结果在1121例患者中，38例(3.4%)的记录符合相关信号变化(即警报)的标准。在这38名患者中，17名患者的经颅电运动诱发电位的幅度抑制超过65%，而体感诱发电位没有任何改变的证据。在38名患者中，有9名患者的信号改变与低血压有关，并随着血压的升高而纠正。其余29名患者的警觉与手术操作直接相关。节段性血管夹闭后出现3个警报，其余26个与后路内固定和矫正有关。在这26名患者中，有9名(35%)出现与器械相关的警报，即0.8%的队列患者醒来时出现一过性运动和/或感觉障碍。9例患者中有7例仅表现为运动障碍，术中监测所有患者的经颅运动诱发电位，其中2例仅有感觉症状。体感诱发电位监测未能在7名确诊为运动障碍的患者中识别出4名患者存在运动障碍。此外，当体感诱发电位发生变化时，它们平均落后于经颅电动运动诱发电位的变化约5分钟。在对警报做出适当反应后，所有9名患者的运动或感觉障碍在1至90天内得到缓解。结论除体感诱发电位外，经颅电运动诱发电位可直接监测脊髓运动束。经颅电运动诱发电位对低血压或血管损伤引起的脊髓血流量改变非常敏感。此外，经颅电运动诱发电位的变化比体感诱发电位的变化更早被检测到，从而有助于更快地识别即将发生的脊髓损伤。
BACKGROUND Despite the many reports attesting to the efficacy of intraoperative somatosensory evoked potential monitoring in reducing the prevalence of iatrogenic spinal cord injury during corrective scoliosis surgery, these afferent neurophysiological signals can provide only indirect evidence of injury to the motor tracts since they monitor posterior column function. Early reports on the use of transcranial electric motor evoked potentials to monitor the corticospinal motor tracts directly suggested that the method holds great promise for improving detection of emerging spinal cord injury. We sought to compare the efficacy of these two methods of monitoring to detect impending iatrogenic neural injury during scoliosis surgery. METHODS We reviewed the intraoperative neurophysiological monitoring records of 1121 consecutive patients (834 female and 287 male) with adolescent idiopathic scoliosis (mean age, 13.9 years) treated between 2000 and 2004 at four pediatric spine centers. The same group of experienced surgical neurophysiologists monitored spinal cord function in all patients with use of a standardized multimodality technique with the patient under total intravenous anesthesia. A relevant neurophysiological change (an alert) was defined as a reduction in amplitude (unilateral or bilateral) of at least 50% for somatosensory evoked potentials and at least 65% for transcranial electric motor evoked potentials compared with baseline. RESULTS Thirty-eight (3.4%) of the 1121 patients had recordings that met the criteria for a relevant signal change (i.e., an alert). Of those thirty-eight patients, seventeen showed suppression of the amplitude of transcranial electric motor evoked potentials in excess of 65% without any evidence of changes in somatosensory evoked potentials. In nine of the thirty-eight patients, the signal change was related to hypotension and was corrected with augmentation of the blood pressure. The remaining twenty-nine patients had an alert that was related directly to a surgical maneuver. Three alerts occurred following segmental vessel clamping, and the remaining twenty-six were related to posterior instrumentation and correction. Nine (35%) of these twenty-six patients with an instrumentation-related alert, or 0.8% of the cohort, awoke with a transient motor and/or sensory deficit. Seven of these nine patients presented solely with a motor deficit, which was detected by intraoperative monitoring of transcranial electric motor evoked potentials in all cases, and two patients had only sensory symptoms. Somatosensory evoked potential monitoring failed to identify a motor deficit in four of the seven patients with a confirmed motor deficit. Furthermore, when changes in somatosensory evoked potentials occurred, they lagged behind the changes in transcranial electric motor evoked potentials by an average of approximately five minutes. With an appropriate response to the alert, the motor or sensory deficit resolved in all nine patients within one to ninety days. CONCLUSIONS This study underscores the advantage of monitoring the spinal cord motor tracts directly by recording transcranial electric motor evoked potentials in addition to somatosensory evoked potentials. Transcranial electric motor evoked potentials are exquisitely sensitive to altered spinal cord blood flow due to either hypotension or a vascular insult. Moreover, changes in transcranial electric motor evoked potentials are detected earlier than are changes in somatosensory evoked potentials, thereby facilitating more rapid identification of impending spinal cord injury.