摘要目的:评估甲状腺切除术中神经监测(IONM)发生信号丢失(LOS)对于喉返神经(RLN)损伤的预测作用。方法:检索PubMed、Web of Science、中国知网和万方医学网数据库中公开发布的有关甲状腺切除术IONM的文献，检索时限为2023年4月30日之前，英文检索词包括"Thyroid Gland surgery""Thyroidectomy""Intraoperative Neuromonitoring""Intraoperative Nerve Monitoring""Recurrent laryngeal nerve"。中文检索词包括"甲状腺切除术""甲状腺手术""喉返神经""术中神经监测"等。由2位评价员独立筛选文献、提取材料和评价纳入研究的偏倚风险，如有不同意见，通过协商方式解决，必要时询问第三方研究员意见再行决定。采用Review Manager 5.4软件进行Meta分析。结果:本研究共纳入33篇研究，对纳入的全部文献(即33篇文献)进行主要结局指标分析，但只对其中26篇文献进行次要结局指标分析。Meta分析结果显示IONM发生LOS的阳性预测值为65%[ OR＝1.88，95% CI：1.36～2.60]。将纳入研究的33篇文献按照研究所用的IONM类型分为I-IONM组、C-IONM组和I-IONM和C-IONM混合组，亚组分析结果显示I-IONM组、C-IONM组和I-IONM组和C-IONM混合组LOS的阳性预测值分别为62%[ OR＝1.63，95% CI：1.05～2.52]、75%[ OR＝2.93，95% CI：1.64～5.22]、70%[ OR＝2.38，95% CI：1.77～3.12]；将纳入的33篇文献按照研究进行地区分为亚洲组、欧洲组、北美洲组和大洋洲进行分析，亚组分析结果显示各组LOS的阳性预测值分别为50%[ OR＝1.01，95% CI：0.44～2.31]、70%[ OR＝2.29，95% CI：1.60～3.28]、82%[ OR＝4.68，95% CI：3.79～5.78]和83%[ OR＝4.81，95% CI：3.10～7.46]。对26篇文献进行次要结局指标的Meta分析，分析结果显示LOS的阴性预测值为99.6%[ RD＝1.51，95% CI：1.48～1.53]；敏感性为89%[ RD＝1.24，95% CI：1.11～1.37]；特异性为98%[ RD＝1.43，95% CI：1.40～1.47]。 结论:甲状腺切除术中应用IONM时发生LOS对于RLN损伤具有一定的阳性预测作用，同时LOS的发生对RLN损伤具有很高的阴性预测作用、敏感性和特异性。

abstractsObjective:To evaluate the predictive effect of the loss of signal (LOS) on the recurrent laryngeal nerve (RLN) injury.Methods:The literatures on PubMed, Web of Science, CNKI, and Wanfang Medical Network database were published before 30 April 2023. English search terms included "thyroid gland surgery" "thyroidectomy" "intraoperative neuromonitoring" "intraoperative nerve monitoring" and "recurrent laryngeal nerve". Chinese search terms included "thyroidectomy", "thyroid surgery" "recurrent laryngeal nerve" "intraoperative nerve monitoring". Two evaluators screened the literature, extracted the materials and evaluated the risk of bias of the study independently. If there were different opinions, researchers should resolve which through consultation and ask the third-party researcher when necessary. The Meta-analysis was performed with the Review Manager 5.4 software.Results:A total of thirty-three studies were included and were all analyzed for primary outcome measures while only twenty-six of which were analyzed for secondary outcome measures. Meta-analysis showed that the positive predictive value of LOS in intraoperative nerve monitoring (IONM) was 65% [ OR=1.88, 95% CI: 1.36-2.60]. Then these thirty-three articles included in IONM were divided into I-IONM, C-IONM and mixed groups. Subgroup analysis showed that the positive predictive value of LOS in I-IONM, C-IONM and mixed groups were 62% [ OR=1.63, 95% CI: 1.05-2.52], 75% [ OR=2.93, 95% CI: 1.64-5.22] and 70% [ OR=2.38, 95% CI: 1.77-3.12] respectively. When these thirty-three included articles were divided into Asian, European, North American and Oceania, subgroup analysis showed that the positive predictive value of LOS was 50% [ OR=1.01, 95% CI: 0.44-2.31], 70% [ OR=2.29, 95% CI: 1.60-3.28], 82% [ OR=4.68, 95% CI: 3.79-5.78] and 83% [ OR=4.81, 95% CI: 3.10-7.46] respectively. Meta-analysis of secondary outcome measures in twenty-six articles showed that the negative predictive value of LOS was 99.6% [ RD=1.51, 95% CI: 1.48-1.53], with the sensitivity of 89% [ RD=1.24, 95% CI: 1.11-1.37] and specificity of 98%[ RD=1.43, 95% CI: 1.40-1.47]. Conclusion:The occurrence of LOS during IONM in thyroidectomy has a positive prediction effect and a higher negative prediction effect, sensitivity and specificity on RLN injury.