Acharya Shankar, Palukuri Nagendra, Gupta Pravin, Kohli Manish
Department of Spine Surgery, Sir Ganga Ram Hospital , New Delhi , India.
Department of Anesthesiology, Sir Ganga Ram Hospital , New Delhi , India.
Front Surg. 2017 Feb 13;4:8. doi: 10.3389/fsurg.2017.00008. eCollection 2017.
Intraoperative neuromonitoring (IONM) has become a standard of care in spinal deformity surgeries to minimize the incidence of new onset neurological deficit. Stagnara wake up test and ankle clonus test are the oldest techniques described for spinal cord monitoring, but they cannot be solely relied upon as a neuromonitoring modality. Somatosensory evoked potentials monitor only dorsal tracts and give high false positive and negative alerts. Transcranial motor evoked potentials (TcMEPs) monitor the more useful motor pathways. The purpose of our study was to report the safety, efficacy, limitations of TcMEPs in spine deformity surgeries, and the role of a checklist.
Retrospective review of all spinal deformity surgeries performed with TcMEPs from 2011 to 2015.
All patients were subjected to IONM by TcMEPs during the spinal deformity surgery. Patients were included in the study only if complete operative reports and neuromonitoring data and postoperative neurological data were available for review. An alert was defined as 80% or more decrement in the motor evoked potential amplitude, or increase in threshold of 100 V or more from baseline. The systemic and surgical causes of IONM alerts and the postoperative neurological status were recorded.
In total, 61 patients underwent surgery for spinal deformities with TcMEPs. The average age was 12.6 years (6-36 years) and male:female ratio was 1:1.3. Diagnoses included idiopathic scoliosis ( = 35), congenital scoliosis ( = 13), congenital kyphosis ( = 7), congenital kyphoscoliosis ( = 4), post-infectious kyphosis ( = 1), and post-traumatic kyphosis ( = 1). The average kyphosis was 72° (45°-101°) and the average scoliosis was 84° (62°-128°). There were in total 33 alerts in 22 patients (36%). The most common causes were hypotension ( = 7), drug induced ( = 5), deformity correction ( = 5), osteotomies ( = 3), tachycardia ( = 1), screw placement ( = 2), and electrodes disconnection ( = 1). Reversal of the inciting event cause resulted in complete reversal of the alert in 90% of the times. Three patients showed persistent alerts, out of whom one had a positive wake up test and woke up with neurodeficit, which recovered over few weeks, while the other patients showed persistent alerts but woke up without any deficit. Sensitivity and specificity of TcMEP in deformity correction surgery were 100 and 96.6%, respectively, in our study.
IONM alerts are frequent during spinal deformity surgery. In our study, more than 50% of the alerts were associated with anesthetic management. IONM with TcMEPs is a safe and effective monitoring technique and wake up test still remains a valuable tool in cases of a persistent alert.
术中神经监测（IONM）已成为脊柱畸形手术中的一项护理标准，以尽量减少新发神经功能缺损的发生率。斯塔尼亚拉唤醒试验和踝阵挛试验是最早描述的脊髓监测技术，但不能仅将它们作为一种神经监测方式。体感诱发电位仅监测背侧束，且假阳性和假阴性警报率较高。经颅运动诱发电位（TcMEP）监测更有用的运动通路。我们研究的目的是报告TcMEP在脊柱畸形手术中的安全性、有效性、局限性以及检查表的作用。
对2011年至2015年期间采用TcMEP进行的所有脊柱畸形手术进行回顾性研究。
所有患者在脊柱畸形手术期间均接受了TcMEP的IONM监测。仅当有完整的手术报告、神经监测数据和术后神经学数据可供审查时，患者才被纳入研究。警报定义为运动诱发电位幅度下降80%或更多，或阈值较基线升高100V或更多。记录IONM警报的全身和手术原因以及术后神经学状态。
共有61例患者接受了采用TcMEP的脊柱畸形手术。平均年龄为12.6岁（6 - 36岁），男女比例为1:1.3。诊断包括特发性脊柱侧凸（n = 35）、先天性脊柱侧凸（n = 13）、先天性后凸（n = 7）、先天性脊柱后凸侧凸（n = 4）、感染后后凸（n = 1）和创伤后后凸（n = 1）。平均后凸为72°（45° - 101°），平均脊柱侧凸为84°（62° - 128°）。22例患者（36%）共出现33次警报。最常见的原因是低血压（n = 7）、药物诱导（n = 5）、畸形矫正（n = 5）、截骨术（n = 3）、心动过速（n = 1）、螺钉置入（n = 2）和电极断开（n = 1）。激发事件原因的逆转在90%的情况下导致警报完全逆转。3例患者出现持续性警报，其中1例唤醒试验阳性，醒来时伴有神经功能缺损，数周后恢复，而其他患者虽有持续性警报，但醒来时无任何缺损。在我们的研究中，TcMEP在畸形矫正手术中的敏感性和特异性分别为100%和96.6%。
脊柱畸形手术期间IONM警报频繁。在我们的研究中，超过50%的警报与麻醉管理有关。采用TcMEP的IONM是一种安全有效的监测技术，唤醒试验在持续性警报的情况下仍然是一种有价值的工具。
