1Department of Neurosurgery, Sheba Medical Center, Ramat-Gan, Israel, affiliated with Sackler School of Medicine, Tel Aviv University, Tel Aviv; and.
2Surgical Monitoring Services Ltd., Beit Shemesh, Israel.
Neurosurg Focus. 2021 May;50(5):E21. doi: 10.3171/2021.2.FOCUS201084.
The use of intraoperative neuromonitoring (IONM) has become an imperative adjunct to the resection of intramedullary spinal cord tumors (IMSCTs). While the diagnostic utility of IONM during the immediate postoperative period has been previously studied, its long-term diagnostic accuracy has seldom been thoroughly assessed. The aim of this study was to evaluate long-term variations in the diagnostic accuracy of transcranial motor evoked potentials (tcMEPs), somatosensory evoked potentials (SSEPs), and D-wave recordings during IMSCT excision.
The authors performed a retrospective evaluation of imaging studies, patient charts, operative reports, and IONM recordings of patients who were operated on for gross-total or subtotal resection of IMSCTs at a single institution between 2012 and 2018. Variations in the specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) for postoperative functional outcome (McCormick Scale) were analyzed at postoperative day 1 (POD1), 6 weeks postoperatively (PO-6 weeks), and at the latest follow-up.
Overall, 28 patients were included. The mean length of follow-up was 19 ± 23.4 months. Persistent motor attenuations occurred in 71.4% of the cohort. MEP was the most sensitive modality (78.6%, 87.5%, and 85.7% sensitivity at POD1, PO-6 weeks, and last follow-up, respectively). The specificity of the D-wave was the most consistent over time (100%, 83.35%, and 90% specificity at the aforementioned time points). The PPV of motor recordings decreased over time (58% vs 33% and 100% vs 0 for tcMEP and D-wave at POD1 and last follow-up, respectively), while their NPV consistently increased (67% vs 89% and 70% vs 100% for tcMEP and D-wave at POD1 and last follow-up, respectively).
The diagnostic accuracy of IONM in the resection of IMSCTs varies during the postoperative period. The decrease in the PPV of motor recordings over time suggests that this method is more predictive of short-term rather than long-term neurological deficits. The increasing NPV of motor recordings indicates a higher diagnostic accuracy in the identification of patients who preserve neurological function, albeit with an increased proportion of false-negative alarms for the immediate postoperative period. These variations should be considered in the surgical decision-making process when weighing the risk of resection-associated neurological injury against the implications of incomplete tumor resection.
术中神经监测（IONM）已成为脊髓髓内肿瘤（IMSCT）切除的必要辅助手段。虽然 IONM 在术后即刻的诊断效用已得到先前研究的证实，但对其长期诊断准确性的评估却很少进行全面评估。本研究旨在评估在单一机构于 2012 年至 2018 年间接受 IMSCT 大体或次全切除手术的患者，在术后第 1 天（POD1）、术后 6 周（PO-6 周）和末次随访时，经颅运动诱发电位（tcMEPs）、体感诱发电位（SSEPs）和 D 波记录的诊断准确性的长期变化。
作者对在一家机构接受 IMSCT 大体或次全切除术的患者的影像学研究、患者图表、手术报告和 IONM 记录进行了回顾性评估。在术后功能结局（McCormick 量表）方面，分析了术后第 1 天（POD1）、术后 6 周（PO-6 周）和末次随访时，特异性、敏感性、阳性预测值（PPV）和阴性预测值（NPV）的变化。
总体而言，纳入了 28 名患者。平均随访时间为 19±23.4 个月。71.4%的患者持续出现运动衰减。MEP 是最敏感的模式（POD1、PO-6 周和末次随访时的敏感性分别为 78.6%、87.5%和 85.7%）。D 波的特异性随时间的推移最为一致（上述各时间点的特异性分别为 100%、83.35%和 90%）。运动记录的 PPV 随时间推移而降低（POD1 和末次随访时 tcMEP 和 D 波的分别为 58%比 33%和 100%比 0），而 NPV 则持续升高（POD1 和末次随访时 tcMEP 和 D 波的分别为 67%比 89%和 70%比 100%）。
IONM 在 IMSCT 切除过程中的诊断准确性在术后期间会发生变化。运动记录的 PPV 随时间推移而降低表明，该方法更能预测短期而非长期神经功能缺损。运动记录的 NPV 升高表明，在识别保留神经功能的患者方面具有更高的诊断准确性，尽管在术后即刻会出现更多的假阴性报警。在权衡切除相关神经损伤的风险与不完全肿瘤切除的影响时，这些变化应在手术决策过程中加以考虑。
