Contribution of intraoperative neural monitoring to preservation of the external branch of the superior laryngeal nerve: a randomized prospective clinical trial

作者：Uludag Mehmet; Aygun Nurcihan; Kartal Kinyas; Citgez Bulent; Besler Evren; Yetkin Gurkan; Kaya Cemal; Ozsahin Hamdi; Mihmanli Mehmet; Isgor Adnan

来源：Langenbeck's Archives of Surgery, 2017, 402(6): 965-976.

DOI：10.1007/s00423-016-1544-7

• External branch of the superior laryngeal nerve
• EBSLN
• EBSLN injury
• Intraoperative neuromonitoring
• Cricothyroid muscle
• Intraoperative electromyography
• Nerve identification
• Voice change
• Cernea classification
• Friedman classification

Purpose The purpose of this study was to evaluate the effect of intraoperative neuromonitoring (IONM) on the injury rate of the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy.
Methods A total of 133 consenting patients (98 female, 35 male; mean age, 45.6 +/- 11.7 years) undergoing thyroidectomy were randomly assigned to 2 groups. In group 1 (n = 65 patients, 105 nerves), superior thyroid pole dissection was performed with no attempt to identify the EBSLN; in group 2 (n = 68 patients, 106 nerves), IONM was used to identify the EBSLN during surgery. EBSLN function was evaluated by intraoperative electromyography of the cricothyroid muscle. The EBSLN Voice Impairment Index-5 (VII-5) was conducted preoperatively and at 1, 3, and 6 months postoperatively. The primary outcome was the prevalence of EBSLN injury. The secondary outcomes were the identification rate of the EBSLN using IONM and changes in postoperative voice performance.
Results EBSLN injury was detected in eight (12.3%) patients and nine (8.6%) nerves in group 1 and in one (1.5%) patient and one (0.9%) nerve in group 2 (patients, p = 0.015; nerves, p = 0.010). IONM contributed significantly to visual (p < 0.001) and functional (p < 0.001) nerve identification in group 2. The VII-5 indicated more voice changes in group 1 than 2 at 1, 3, and 6 months postoperatively (p = 0.012, p = 0.015, and p = 0.02, respectively).
Conclusion IONM contributes to visual and functional identification of the EBSLN and decreases the rate of EBSLN injury during superior pole dissection. Routine use of IONM to identify the EBSLN will minimize the risk of injury during thyroidectomy.

• 出版日期2017-9