General and Endocrine Surgery, CHU Poitiers, University of Poitiers, 2 Rue de la Miletrie, 86021, Poitiers, France.
ABC Hospital, Mexico City, Mexico.
World J Surg. 2020 Feb;44(2):417-425. doi: 10.1007/s00268-019-05295-2.
Steroids are often used for the management of vocal cord palsy after thyroid surgery. There are no reports in the current literature of their intraoperative use, immediately after a loss of signal during neuromonitoring (LOS). We evaluate the impact of a single dose of 4 mg of dexamethasone on laryngeal nerve function, administrated at the time of a LOS during a nerve-monitored thyroidectomy.
A prospective not randomized study was performed, dividing patients in two groups, when a LOS was detected. LOS was defined as an electromyographic signal (EMG) inferior to 100 μV when stimulating the inferior laryngeal nerve, according to international guidelines. In group 1 (G1), surgeon waits for signal's recovery up to 20 min. Absence of a detectable signal after 20 min was predictive of vocal cord palsy; if it affected the first side of surgery the procedure was interrupted to avoid the risk of bilateral nerve palsy. In group 2 (G2), 4 mg of dexamethasone were injected within 10 min from a detected LOS, waiting 10 min for its effects. An EMG value > to 200 μV within 20' after steroid administration was predictive of full recovery and normal post-operatory vocal cord function. Vocal cords motility was checked at postoperative day 1 in all patients by an experienced ENT.
Between January 2017 and December 2018, 702 patients underwent thyroid surgery under intermittent intraoperative nerve monitoring by two expert surgeons. A LOS was found in 22 patients in G1 and 16 in G2. Four patients in G1 spontaneously recovered electric signal (18.2%), while in G2 a signal was recovered in 14/16 patients (87.5%) (p < 0.001). This immediate effect was monitored by EMG, showing the increase in potentials at 10, 15 and 20 min after injection. ENT evaluation found vocal cord palsy, respectively, in 18/22 and 1/16 patients (G1 vs G2, p < 0.001). One of the patients in G2 who recovered electric signal presented transient palsy, fully recovered at 2 months, while the two patients who had a signal < 200 μV did not present postoperative cord palsy. In G1, 10/18 palsy were definitive. No permanent palsies were presents in G2.
A single 4 mg iv dexamethasone injection within 10 min form a LOS during thyroid surgery exerts a therapeutic action, measurable by EMG modifications. It avoids vocal nerve palsy and the need of a staged thyroidectomy. It may also protect from permanent cord palsy, but the mechanism is unknown.
在甲状腺手术后，类固醇常被用于治疗声带麻痹。目前的文献中没有术中使用类固醇的报道，即在神经监测（LOS）期间信号丢失后立即使用。我们评估了在神经监测甲状腺切除术中 LOS 时给予单次 4mg 地塞米松对喉返神经功能的影响。
进行了一项前瞻性非随机研究，将患者分为两组，当出现 LOS 时。LOS 定义为根据国际指南刺激喉返神经时 EMG 信号低于 100μV。在第 1 组（G1）中，当信号恢复时，外科医生等待 20 分钟。如果 20 分钟后仍未检测到信号，则预测声带麻痹；如果它影响了手术的第一侧，则中断手术以避免双侧神经麻痹的风险。在第 2 组（G2）中，在检测到 LOS 后 10 分钟内给予 4mg 地塞米松，并等待 10 分钟以观察其效果。类固醇给药后 20 分钟内 EMG 值>200μV 预测完全恢复和正常术后声带功能。所有患者均在术后第 1 天由经验丰富的耳鼻喉科医生进行声带运动检查。
2017 年 1 月至 2018 年 12 月，两名专家外科医生对 702 例患者进行了间歇性术中神经监测下的甲状腺手术。在 G1 中发现 22 例患者出现 LOS，在 G2 中发现 16 例患者出现 LOS。G1 中有 4 例患者自发恢复电信号（18.2%），而 G2 中有 14/16 例患者（87.5%）恢复信号（p<0.001）。通过 EMG 监测到这种即时效应，显示注射后 10、15 和 20 分钟电位增加。耳鼻喉科评估分别在 22/22 例和 1/16 例患者中发现声带麻痹（G1 与 G2，p<0.001）。G2 中有 1 例恢复电信号的患者出现暂时性麻痹，2 个月后完全恢复，而 2 例 EMG 值<200μV 的患者术后未出现声带麻痹。G1 中有 10/18 例麻痹为永久性。G2 中无永久性麻痹。
在甲状腺手术中，LOS 出现后 10 分钟内给予单次 4mg 静脉内地塞米松可通过 EMG 改变产生治疗作用。它可避免喉返神经麻痹和分期甲状腺切除术的需要。它还可能防止永久性声带麻痹，但机制尚不清楚。
