Electrical Stimulation for Intraoperative Evaluation of Thoracic Pedicle Screw Placement
Electrical Stimulation for Intraoperative Evaluation of Thoracic Pedicle Screw Placement
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DOI：
10.1097/01.brs.0000049926.43292.93
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发表时间：
2003-03
期刊：
影响因子：
3
通讯作者：
Yong-bing Shi;M. Binette;W. Martin;J. M. Pearson;R. Hart
中科院分区：
文献类型：
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作者：
Yong-bing Shi;M. Binette;W. Martin;J. M. Pearson;R. Hart
研究设计.术中电刺激胸椎椎弓根螺钉，同时记录相关肌群的肌电图（EMG）活动。术后使用计算机断层扫描（CT）评价螺钉位置。将CT结果与诱发肌电图阈值进行比较。objective.报告我们在1999年5月至2001年3月期间对22例接受胸椎节段脊柱内固定术的患者进行胸椎椎弓根螺钉刺激的经验。背景数据总结。在腰骶椎手术中，椎弓根螺钉刺激用于术中评估螺钉放置已被报道。诱发肌电图阈值> 10或11 mA与椎体皮质侵犯和术后并发症的可能性增加相关。在术后CT扫描中，峰值> 15 mA提供了98%的准确螺钉定位置信度。方法.根据螺钉放置的水平，记录尺侧腕屈肌、肋间肌或腹肌群的诱发肌电图活动。术后CT扫描由一名骨科脊柱外科医生、一名骨科高级住院医师和一名肌肉骨骼放射科医生阅读。结果报告了87枚螺钉的结果。术后CT扫描显示5枚螺钉（5.7%）穿透。6枚螺钉（6.9%）的刺激阈值≤ 11 mA，其中3枚显示皮质穿透。阈值> 11 mA的81枚螺钉中，79枚（97.5%）位于椎体内。22例患者均未出现术后神经系统并发症。结论这些结果与以往腰骶椎弓根螺钉的研究结果一致。在该系列中，刺激阈值> 11 mA具有97.5%的阴性预测值，表明皮质破坏极不可能。尽管螺钉放置的判断不应仅取决于刺激阈值，但椎弓根螺钉刺激可以在涉及使用胸椎椎弓根螺钉的手术中提供关于螺钉放置的快速和有用的术中信息。
Study Design. Thoracic pedicle screws were stimulated electrically while recording electromyography (EMG) activity in associated muscle groups intraoperatively. Screw position was then evaluated after surgery using computed tomography (CT). The CT results were compared with evoked EMG threshold values. Objective. To report our experience with pedicle screw stimulation in thoracic vertebrae in 22 patients who underwent thoracic level spinal instrumentation from May 1999 to March 2001. Summary of Background Data. Pedicle screw stimulation for intraoperative assessment of screw placement has been reported in lumbosacral spinal procedures. Evoked EMG thresholds >10 or 11 mA are associated with increased probability of vertebral cortex violation and postoperative complications. Thresholds >15 mA provide a 98% confidence of accurate screw positioning on postoperative CT scans. Methods. Evoked EMG activity was recorded from ulnar carpal flexors, intercostals, or abdominal muscle groups, depending on the level of screw placement. Postoperative CT scans were read by a staff orthopedic spine surgeon, a senior resident in orthopedics, and a musculoskeletal radiologist. Results. Results of 87 screws are reported. Five screws (5.7%) showed penetration on postoperative CT scans. Six screws (6.9%) had stimulation thresholds ≤11 mA, of which three showed cortical breakthrough. Of the 81 screws with thresholds >11 mA, 79 (97.5%) were within the vertebra. No postoperative neurologic complications were noted in any of the 22 patients. Conclusion. These results are consistent with previous studies of lumbosacral pedicle screws. In this series, stimulation thresholds >11 mA have a 97.5% negative predictive value, suggesting that cortical violation is highly unlikely. Although judgment of screw placement should not depend solely on stimulation thresholds, pedicle screw stimulation may provide rapid and useful intraoperative information on screw placement during procedures involving the use of thoracic pedicle screws.