Although none of the patients demonstrated RLN injury and only one had EBSLN injury, 30% reported subjective voice changes one week postoperatively and 14% reported voice changes at 3 months.
8% of patients with EBSLN injury and vocal incompetence eventually developed muscle tension dysphonia in their compensatory effort to generate a stronger voice.
We evaluated the clinical efficacy of LNM during total endoscopic thyroidectomy via the breast approach and found a significant improvement in the RLN and EBSLN detection rates with this modality.
EBSLN is also at risk of inadvertent injury during thyroidectomy, although clinical trials have shown a low injury rate .
The position of the EBSLN is variable, and the nerve is not always located and identified during surgery.
Only 1 patient exhibited obvious laryngoscopic evidence of EBSLN dysfunction, but EMG was not performed in this study.
The anatomic course of the EBSLN can be variable, and it may be altered by the size and pathology of the thyroid.
RLN and EBSLN location and preservation techniques include intraoperative electrophysiologic monitoring by surface or needle electrodes, direct observation of the vocal folds via fiberoptic or direct laryngoscopy, and recording muscle contraction and nerve integrity with a nerve monitor.
For EBSLN monitoring, needle electrodes are placed into the cricothyroid muscle and sutured into place (figure 2).