OBJECTIVES To increase the specificity of motor unit potential (MUPs) detection by using ultrasound guided electromyography (USG-EMG) in patients with muscle plegia due to traumatic nerve lesions. METHODS Forty-six patients with recent nerve trauma underwent baseline standard EMG (ST-EMG) evaluation with evidence of absent MUPs. In 41 of them, ST-EMG was repeated after 2-3 months (T1) and the patients were accordingly divided in two groups: ST-EMG+ (if MUPs were detected) or ST-EMG- (MUPs not detected). Then, ST-EMG- patients underwent muscle ultrasound evaluation (M-US) and, if isles of muscular contractility were found, they also had USG-EMG. The same protocol was repeated 4-6 months after baseline (T2). RESULTS At T1, 22/41 patients were ST-EMG+. While 19/41 were ST-EMG-; 9 of these patients had M-US consistent with residual muscular activity, for that reasons underwent USG-EMG with 7 of 9 demonstrating MUPs (at T2 all of these 7 patients resulted ST-EMG). In the other 2 patients, we found no MUPs at T1 but they became ST-EMG+ or USG-EMG positive at T2. The remaining 10 ST-EMG- patients had no EMG or US evidence of muscle contraction at T1, but at T2 2 of 10 became ST-EMG+ and 2 had USG-EMG showing MUPs. In the remaining 6 patients still M-US negative at T2, complete denervation was diagnosed. Concerning the 22 patients who were ST-EMG+ at T1, all but one showed increase of MUPs at T2. CONCLUSIONS In this study, we demonstrated the utility of US guidance when performing EMG evaluation in locating isles of muscular contractility in patients who have no detectable MUPs on EMG after nerve trauma. SIGNIFICANCE USG-EMG significantly increases the specificity of needle EMG allowing earlier detection of MUPs.

中文翻译：

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超声引导提高了截瘫肌针状肌电图的诊断率

目的 使用超声引导肌电图 (USG-EMG) 提高外伤性神经病变导致肌肉麻痹患者运动单位电位 (MUP) 检测的特异性。方法 46 名近期有神经损伤的患者接受了基线标准肌电图 (ST-EMG) 评估，并有证据表明没有 MUP。其中 41 人在 2-3 个月（T1）后重复 ST-EMG，并相应地将患者分为两组：ST-EMG+（如果检测到 MUP）或 ST-EMG-（未检测到 MUP）。然后，ST-EMG- 患者接受肌肉超声评估 (M-US)，如果发现肌肉收缩岛，他们也接受 USG-EMG。在基线 (T2) 后 4-6 个月重复相同的方案。结果 在 T1 时，22/41 名患者为 ST-EMG+。虽然 19/41 是 ST-EMG-；其中 9 名患者的 M-US 与残余肌肉活动一致，出于这个原因，9 名 MUP 中有 7 名接受了 USG-EMG（在 T2 时所有这 7 名患者都出现了 ST-EMG）。在另外 2 名患者中，我们在 T1 时没有发现 MUP，但他们在 T2 时变为 ST-EMG+ 或 USG-EMG 阳性。其余 10 名 ST-EMG- 患者在 T1 时没有 EMG 或 US 肌肉收缩证据，但在 T2 时，10 名中有 2 名变为 ST-EMG+，2 名 USG-EMG 显示 MUP。其余 6 名患者在 T2 时仍为 M-US，被诊断为完全去神经支配。关于在 T1 时为 ST-EMG + 的 22 名患者，除一名外，所有患者在 T2 时均显示 MUP 增加。结论 在本研究中，我们证明了在进行 EMG 评估时，US 指导在定位神经外伤后 EMG 上未检测到 MUP 的患者的肌肉收缩岛时的效用。