a Department of Surgery , The University of Hong Kong , Hong Kong , China.
b Department of Medicine , The University of Hong Kong , Hong Kong , China.
Int J Hyperthermia. 2017 Dec;33(8):888-894. doi: 10.1080/02656736.2017.1328130. Epub 2017 Jun 6.
Vocal cord paresis (VCP) may occur following high intensity focused ultrasound (HIFU) of thyroid nodules. We hypothesised its occurrence relates to the distance of the focus point (FP) of the HIFU beams from the recurrent laryngeal nerve (RLN) and the thermal power that this point received. Their relationships were examined.
One hundred and three patients who underwent HIFU for symptomatic benign thyroid nodule from October 2015 to March 2017 were analysed. All treatment images were captured and were later watched by 2 reviewers to identify three FPs closest to the tracheoesophageal groove (TEG) on transverse sonographic view. TEG was taken as the RLN position. After identifying these FPs, their distance (mm) from the TEG, thermal power (W) used and depth from skin (mm) were recorded. These parameters were compared between those with and without VCP. VCP was defined as a cord with reduced or no movement.
Four (3.9%) patients suffered from a unilateral VCP afterwards but they all recovered fully within 6 weeks. There were no significant differences in baseline characteristics and treatment efficacy between the two groups. The distance from TEG (OR = 1.706, 95%CI = 1.001 to 2.915, p = 0.050) was the only significant factor for VCP. None of the other variables including thermal power were significant.
The incidence of VCP was 3.9% (4/103) and they completely recovered within 6 weeks. The distance between the FP and the TEG was the only related factor for VCP. The safe distance between FP and TEG should be ≥1.1 cm.
高强度聚焦超声（HIFU）治疗甲状腺结节后可能会发生声带麻痹（VCP）。我们假设其发生与 HIFU 光束的焦点（FP）与喉返神经（RLN）之间的距离以及该点接收到的热功率有关。研究了它们之间的关系。
分析了 2015 年 10 月至 2017 年 3 月期间因症状性良性甲状腺结节接受 HIFU 治疗的 103 例患者。捕获了所有治疗图像，然后由 2 位审阅者观看，以在横切面超声图像上识别出最接近气管食管沟（TEG）的 3 个 FP。TEG 被视为 RLN 位置。在识别出这些 FP 后，记录了它们距 TEG 的距离（mm）、使用的热功率（W）和距皮肤的深度（mm）。比较了两组间 VCP 的这些参数。VCP 定义为声带活动减弱或无活动。
4 名（3.9%）患者随后出现单侧 VCP，但均在 6 周内完全恢复。两组患者的基线特征和治疗效果无显著差异。距 TEG 的距离（OR=1.706，95%CI=1.001 至 2.915，p=0.050）是 VCP 的唯一显著因素。其他变量，包括热功率均无统计学意义。
VCP 的发生率为 3.9%（4/103），6 周内完全恢复。FP 与 TEG 之间的距离是 VCP 的唯一相关因素。FP 与 TEG 之间的安全距离应≥1.1cm。
