Department of Neurosurgery, Clinical Neurosciences Center and Huntsman Cancer Institute, University of Utah, 175 N. Medical Drive East, Salt Lake City, 84132 UT, United States.
Department of Neurosurgery, Clinical Neurosciences Center and Huntsman Cancer Institute, University of Utah, 175 N. Medical Drive East, Salt Lake City, 84132 UT, United States.
Spine J. 2019 Feb;19(2):206-211. doi: 10.1016/j.spinee.2018.06.353. Epub 2018 Jun 28.
Lumbar pedicle screw placement can be technically challenging. Malpositioned screws occur in up to 15% of patients and could result in radiculopathy or instrumentation failure.
To compare intraoperative electromyography (EMG) and image guidance using an O-arm for identifying pedicle breach during elective lumbar fusion.
Prospective observational study.
All adult patients undergoing elective lumbar spinal fusion operations for degenerative spine disorders (including adjacent segment degeneration, degenerative scoliosis, and symptomatic spondylosis and spondylolisthesis) at a single institution from July 1, 2014, to December 1, 2015, were prospectively tracked.
Pedicle breach.
Pedicle screws from L2-S1 were placed using C-arm assisted freehand technique. All screws were stimulated with EMG and evaluated using the O-arm intraoperative imaging system. Electromyography data were compared with intraoperative images to assess the accuracy of identifying pedicle breaches. No funding was received for this work.
One thousand six lumbar pedicles screws were placed from L2 to S1 in 164 consecutive cases. The mean patient age was 59.2 years. Thirty-five breaches (15 lateral and 20 medial) were visualized with O-arm imaging and confirmed by palpation (3.5% of screws placed). Of the breaches, 14 screws stimulated below the 12-mA threshold, nine screws stimulated between 12 and 20 mA, and 12 screws did not generate an EMG response. Forty screws stimulated below a 12-mA threshold but showed no breach on imaging. Using the 12-mA threshold, the sensitivity of EMG was 40%, specificity was 96%, positive predictive value was 26%, and negative predictive value was 98%. All 35 breached screws were corrected during surgery. There were no postoperative symptoms caused by breached screws and no patients required reoperation.
Our findings indicate that EMG may not be a highly reliable tool in determining an anatomical breach during placement of lumbar pedicle screws. O-arm may be better for detecting either medial or lateral breaches than EMG stimulation if there are concerns about screw placement or for confirmation of placement before leaving the operating room.
腰椎椎弓根螺钉的置钉技术具有一定挑战性。高达 15%的患者可能出现螺钉位置不当，从而导致神经根病或器械失败。
比较术中肌电图（EMG）和 O 臂影像导航在择期腰椎融合术中识别椎弓根破裂的作用。
前瞻性观察性研究。
2014 年 7 月 1 日至 2015 年 12 月 1 日，在一家机构中，对所有接受退行性脊柱疾病（包括邻近节段退变、退行性脊柱侧凸、有症状的颈椎病和脊椎滑脱）择期行腰椎脊柱融合术的成年患者进行前瞻性跟踪。
椎弓根破裂。
使用 C 臂辅助徒手技术放置 L2-S1 的椎弓根螺钉。所有螺钉均采用 EMG 进行刺激，并使用 O 臂术中成像系统进行评估。将肌电图数据与术中图像进行比较，以评估识别椎弓根破裂的准确性。
164 例连续病例中，共放置了 1640 个 L2-S1 腰椎椎弓根螺钉。患者平均年龄为 59.2 岁。O 臂成像显示 35 处（15 处外侧和 20 处内侧）破裂，并通过触诊确认（置钉的螺钉中占 3.5%）。其中 14 枚螺钉刺激阈值低于 12 mA，9 枚螺钉刺激阈值在 12-20 mA 之间，12 枚螺钉无肌电图反应。40 枚刺激阈值低于 12 mA，但影像学未见破裂。以 12 mA 为阈值，EMG 的灵敏度为 40%，特异性为 96%，阳性预测值为 26%，阴性预测值为 98%。所有 35 枚破裂的螺钉均在术中得到纠正。没有因破裂螺钉引起的术后症状，也没有患者需要再次手术。
我们的研究结果表明，在放置腰椎椎弓根螺钉时，肌电图可能不是一种确定解剖学破裂的高度可靠工具。如果对螺钉位置有疑虑，或者在离开手术室之前需要确认位置，O 臂可能比 EMG 刺激更适合检测内侧或外侧破裂。
