Background: Preoperative identification and visualization of tumor infiltration of the recurrent laryngeal nerve (RLN) in patients with thyroid cancer is important. The purpose of our study was to evaluate the reliability and feasibility of preoperative assessment by ultrasound and to identify ultrasound imaging features potentially associated with tumor infiltration of the RLN.
Methods: In this prospective study, patients undergoing thyroid cancer surgery at our institution between August 2020 and January 2021 were included, and preoperative ultrasound visualization of the RLN and thyroid lesions was performed. RLN infiltration was also confirmed surgically in all cases. Five patients with enlarged lymph nodes were selected to undergo injection of carbon nanoparticles to confirm the correctness of RLN identification by preoperative ultrasound. The repeatability of RLN assessment by ultrasound was evaluated by comparing the correlation between pre- and intraoperative, intra- and inter-group assessments. Parameters of normal RLNs according to age, sex, and body mass index were established. Finally, ultrasound imaging features of patients with RLN tumor infiltration were analyzed to identify potential risk predictors.
Results: According to the ultrasonic assessment, RLNs of 70 patients appeared normal, while 14 of those patients appeared to be infiltrated by tumors. During surgery, the 70 cases of normal RLNs were confirmed, but only 8 of the 14 suspected cases of infiltration were confirmed. In all five patients injected with carbon nanoparticles, the location of RLNs adjacent to the marked lymph nodes observed by surgeons corresponded to the RLN location identified by preoperative ultrasound. The repeatability of RLN estimation varied from moderate to excellent. There were no significant differences in cross-sectional area, width, or thickness of normal RLNs according to age, sex, or body mass index. Indistinct margin with tumor, incontinuous shape as ultrasound features by the analysis of patients with surgically confirmed RLN infiltration were associated with tumor invasion.
Conclusion: We show that preoperative ultrasound can be applied to visualize the RLN and may help predict tumor infiltration of the RLN.



中文翻译：

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甲状腺癌手术中喉返神经的术前可视化超声评估：影像学的可靠性和风险特征

背景：甲状腺癌患者的喉返神经 (RLN) 肿瘤浸润的术前识别和可视化非常重要。我们研究的目的是评估超声术前评估的可靠性和可行性，并确定可能与 RLN 肿瘤浸润相关的超声成像特征。
方法：在这项前瞻性研究中，纳入了 2020 年 8 月至 2021 年 1 月在我院接受甲状腺癌手术的患者，并进行了 RLN 和甲状腺病变的术前超声可视化。在所有病例中也通过手术证实了 RLN 浸润。选取5例淋巴结肿大的患者进行纳米碳注射，以确认术前超声对RLN识别的正确性。通过比较术前和术中、组内和组间评估之间的相关性来评估超声评估 RLN 的可重复性。建立了根据年龄、性别和体重指数的正常 RLN 参数。最后，分析了 RLN 肿瘤浸润患者的超声成像特征，以确定潜在的风险预测因素。
结果：根据超声评估，70 名患者的 RLN 看起来正常，而其中 14 名患者似乎被肿瘤浸润。术中确诊70例正常RLN，但14例疑似浸润病例中仅8例确诊。在所有注射碳纳米颗粒的五名患者中，外科医生观察到的与标记淋巴结相邻的 RLN 的位置对应于术前超声确定的 RLN 位置。RLN 估计的可重复性从中等到极好不等。根据年龄、性别或体重指数，正常 RLN 的横截面积、宽度或厚度没有显着差异。与肿瘤边缘不明显，
结论：我们表明术前超声可用于显示 RLN，并可能有助于预测 RLN 的肿瘤浸润。