Department of Orthopedics, Huashan Hospital, Fudan University, Shanghai, 200040, China.
Department of Physical Medicine and Rehabilitation, Upstate Medical University, State University of New York at Syracuse, Syracuse, NY 10212, USA.
Spine J. 2021 Nov;21(11):1900-1907. doi: 10.1016/j.spinee.2021.05.013. Epub 2021 May 17.
Total removal of spinal schwannomas is ideal but it sometimes requires tumor-involved root resection, which increases the risk of postoperative motor deterioration (PMD). Therefore, it is important for clinicians to predict the impact of tumor-involved root resection on motor function in spinal schwannomas.
To investigate the role of intraoperative electromyographic (EMG) techniques in decision-making of tumor-involved root resection for treating spinal schwannomas.
A retrospective analysis PATIENT SAMPLE: Sixty-eight patients with spinal schwannomas arising from C5-T1 or L3-S1 roots underwent total resection of schwannoma, including tumoral root.
Nerve root activation threshold, free-running EMG signals, visual analogue scale, and American Spinal Injury Association scale.
During evoked EMG, nerve root activation threshold for tumoral root stimulation was recorded from muscles anatomically corresponding to tumoral root. During free-running EMG, abnormal EMG signals were identified as irregularly recurrent, monomorphic signals, low frequency (<5 Hz) or absent discharges recorded from muscles innervated by tumoral root. Clinical assessments were performed before, 3 to 5 day's and six months' after operation.
Sixteen (16 of 68, 23.5%) patients showed PMD, and muscle strength improved or was not affected in the other 52 patients. Absent myogenic responses were observed in 19 patients with non-PMD, and nerve root activation threshold in non-PMD group was higher than that in PMD group (p<.05). Receiver operating characteristic curve revealed that cut-off value of nerve root activation threshold for distinguishing functional and nonfunctional roots was 11.8 mA. A larger number of patients without PMD than with PMD showed abnormal free-running EMG signals (p<.05). At postoperative 6-months' follow-up, ten patients with muscle weakness after tumor-involved root resection showed functional recovery (full vs. partial recovery: 5 vs. 5), and intraoperative nerve root activation threshold in these patients was higher than that in the other patients without functional recovery (p<.05). Furthermore, there is negative relationship between the duration for full recovery and nerve root activation threshold (p<.05).
Both evoked and free-running EMG can be used as supplementary tests for differentiating functional and nonfunctional tumoral roots in spinal schwannomas, and nerve root activation threshold may be also related to prognosis of patients with muscle weakness caused by tumor-involved root resection. Therefore, intraoperative EMG techniques may provide additional references in decision-making of tumor-involved root resection.
完全切除脊髓神经鞘瘤是理想的，但有时需要肿瘤累及神经根切除，这增加了术后运动恶化（PMD）的风险。因此，临床医生预测肿瘤累及神经根切除对脊髓神经鞘瘤运动功能的影响非常重要。
探讨术中肌电图（EMG）技术在决定治疗脊髓神经鞘瘤的肿瘤累及神经根切除中的作用。
回顾性分析
68 例 C5-T1 或 L3-S1 神经根起源的脊髓神经鞘瘤患者，行神经鞘瘤全切除，包括肿瘤累及神经根。
神经根激活阈值、自由运行 EMG 信号、视觉模拟量表和美国脊髓损伤协会量表。
在诱发电位 EMG 中，记录来自与肿瘤根相对应的肌肉的肿瘤根刺激的神经根激活阈值。在自由运行 EMG 中，将不规则复发性、单形性信号、频率低于 5 Hz（<5 Hz）或未记录到肿瘤根支配的肌肉放电的异常 EMG 信号识别为异常。在术前、术后 3 至 5 天和 6 个月进行临床评估。
16 例（16/68，23.5%）患者出现 PMD，52 例患者肌力改善或无影响。19 例非 PMD 患者未见肌源性反应，非 PMD 组神经根激活阈值高于 PMD 组（p<.05）。ROC 曲线显示，区分功能性和非功能性神经根的神经根激活阈值截断值为 11.8 mA。无 PMD 患者的异常自由运行 EMG 信号明显多于 PMD 患者（p<.05）。术后 6 个月随访时，10 例肿瘤累及神经根切除后肌无力患者出现功能恢复（完全恢复与部分恢复：5 例与 5 例），这些患者术中神经根激活阈值高于其他无功能恢复患者（p<.05）。此外，完全恢复的时间与神经根激活阈值呈负相关（p<.05）。
诱发电位和自由运行 EMG 均可作为区分脊髓神经鞘瘤功能性和非功能性肿瘤根的辅助检查，神经根激活阈值可能与肿瘤累及神经根切除后肌无力患者的预后相关。因此，术中 EMG 技术可为肿瘤累及神经根切除术的决策提供额外参考。
