Recording triggered EMG thresholds from axillary chest wall electrodes: a new refined technique for accurate upper thoracic (T2–T6) pedicle screw placement
Recording triggered EMG thresholds from axillary chest wall electrodes: a new refined technique for accurate upper thoracic (T2–T6) pedicle screw placement
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记录腋窝胸壁电极触发的肌电图阈值：一种用于准确放置上胸椎 (T2–T6) 椎弓根螺钉的全新改进技术
DOI：
10.1007/s00586-011-1800-z
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发表时间：
2011
影响因子：
2.8
通讯作者：
E. Hevia
中科院分区：
文献类型：
--
作者：
I. Regidor;G. Blas;C. Barrios;J. Burgos;E. Montes;S. García;E. Hevia
本研究旨在评估一种记录上胸椎椎弓根螺钉置入时腋窝胸壁电极触发肌电阈值的新技术的敏感性和安全性（T2-T6）。在92例青少年特发性脊柱侧凸患者中，总共677枚胸椎螺钉中有248枚（36.6%）放置在T2-T6水平。放置在腋窝中线的单个电极能够在手术期间记录每侧所有T2-T6肌组的电位。根据术中透视显示，术中有11颗螺钉因定位错误而被取下。术后通过CT扫描评估其余237颗螺钉的位置。椎弓根螺钉移位35枚（14.7%）。椎弓根内侧皮质破裂24例（10.1%）。6颗螺钉（2.5%）位于椎管内。定位良好螺钉的平均肌电阈值为24.44±11.30 mA，侵犯椎弓根内侧皮质的平均肌电阈值为17.98±8.24 mA (p < 0.01)，椎管内螺钉的平均肌电阈值为10.38±3.33 mA （p < 0.005）。低于12 mA的阈值，33.4%的螺钉（10/30）错位。此外，36%的t-EMG刺激阈值在6-12 mA范围内的椎弓根螺钉错位。综上所述，通过单腋电极记录tEMG来评估上胸椎弓根螺钉置入是高度可靠的。低于12ma的阈值应提醒外科医生怀疑螺钉错位。该技术简化了tEMG电位记录，便于在上胸水平安全放置椎弓根螺钉。
This study was aimed at evaluating the sensitivity and safety of a new technique to record triggered EMG thresholds from axillary chest wall electrodes when inserting pedicle screws in the upper thoracic spine (T2–T6). A total of 248 (36.6%) of a total of 677 thoracic screws were placed at the T2–T6 levels in 92 patients with adolescent idiopathic scoliosis. A single electrode placed at the axillary midline was able to record potentials during surgery from all T2–T6 myotomes at each side. Eleven screws were removed during surgery because of malposition according to intraoperative fluoroscopic views. Screw position was evaluated after surgery in the remaining 237 screws using a CT scan. Malposition was detected in 35 pedicle screws (14.7%). Pedicle medial cortex was breached in 24 (10.1%). Six screws (2.5%) were located inside the spinal canal. Mean EMG threshold was 24.44 ± 11.30 mA in well-positioned screws, 17.98 ± 8.24 mA (p < 0.01) in screws violating the pedicle medial cortex, and 10.38 ± 3.33 mA (p < 0.005) in screws located inside the spinal canal. Below a threshold of 12 mA, 33.4% of the screws (10/30) were malpositioned. Furthermore, 36% of the pedicle screws with t-EMG stimulation thresholds within the range 6–12 mA were malpositioned. In conclusion, assessment of upper thoracic pedicle screw placement by recording tEMG at a single axillary electrode was highly reliable. Thresholds below 12 mA should alert surgeons to suspect screw malposition. This technique simplifies tEMG potential recording to facilitate safe placement of pedicle screws at upper thoracic levels.