How the Severity and Mechanism of Recurrent Laryngeal Nerve Dysfunction during Monitored Thyroidectomy Impact on Postoperative Voice

Tzu-Yen Huang; Wing-Hei Viola Yu; Feng-Yu Chiang; Che-Wei Wu; Shih-Chen Fu; An-Shun Tai; Yi-Chu Lin; Hsin-Yi Tseng; Ka-Wo Lee; Sheng-Hsuan Lin

doi:10.3390/cancers13215379

How the Severity and Mechanism of Recurrent Laryngeal Nerve Dysfunction during Monitored Thyroidectomy Impact on Postoperative Voice

Cancers (Basel). 2021 Oct 27;13(21):5379. doi: 10.3390/cancers13215379.

Authors

Tzu-Yen Huang^{1

2}, Wing-Hei Viola Yu¹, Feng-Yu Chiang^{3

4}, Che-Wei Wu^{1

5}, Shih-Chen Fu⁶, An-Shun Tai⁶, Yi-Chu Lin¹, Hsin-Yi Tseng¹, Ka-Wo Lee^{1

7}, Sheng-Hsuan Lin^{6

8}

Affiliations

¹ International Thyroid Surgery Center, Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
² Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan.
³ Department of Otolaryngology-Head and Neck Surgery, E-Da Hospital, Kaohsiung 824, Taiwan.
⁴ School of Medicine, College of Medicine, I-Shou University, Kaohsiung 824, Taiwan.
⁵ Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University Hospital, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 812, Taiwan.
⁶ Institute of Statistics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan.
⁷ Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Municipal Tatung Hospital, Kaohsiung Medical University Hospital, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 801, Taiwan.
⁸ Institute of Data Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan.

Abstract

Intraoperative neuromonitoring can qualify and quantify RLN function during thyroid surgery. This study investigated how the severity and mechanism of RLN dysfunction during monitored thyroid surgery affected postoperative voice. This retrospective study analyzed 1021 patients that received standardized monitored thyroidectomy. Patients had post-dissection RLN(R2) signal <50%, 50-90% and >90% decrease from pre-dissection RLN(R1) signal were classified into Group A-no/mild, B-moderate, and C-severe RLN dysfunction, respectively. Demographic characteristics, RLN injury mechanisms(mechanical/thermal) and voice analysis parameters were recorded. More patients in the group with higher severity of RLN dysfunction had malignant pathology results (A/B/C = 35%/48%/55%, p = 0.017), received neck dissection (A/B/C = 17%/31%/55%, p < 0.001), had thermal injury (p = 0.006), and had asymmetric vocal fold motion in long-term postoperative periods (A/B/C = 0%/8%/62%, p < 0.001). In postoperative periods, Group C patients had significantly worse voice outcomes in several voice parameters in comparison to Group A/B. Thermal injury was associated with larger voice impairments compared to mechanical injury. This report is the first to discuss the severity and mechanism of RLN dysfunction and postoperative voice in patients who received monitored thyroidectomy. To optimize voice and swallowing outcomes after thyroidectomy, avoiding thermal injury is mandatory, and mechanical injury must be identified early to avoid a more severe dysfunction.

Keywords: index of voice and swallowing handicap of thyroidectomy (IVST); intraoperative neuromonitoring (IONM); postoperative voice; recurrent laryngeal nerve (RLN); severity and mechanism of RLN dysfunction.

Abstract

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