Recurrent Laryngeal Nerve's Motor Function: Sometimes Motor Fibers May Also Be Located in The Posterior Branch

Descriptive in Vivo Study of Evaluating the Motor Function of Recurrent Laryngeal Nerve's Extralaryngeal Branching Electromyographically.

The investigators hypothesized that, sometimes the posterior branch of the recurrent laryngeal nerve may also have motor function. The investigators aimed to evaluate motor function of the branches in the branching recurrent laryngeal nerves in this study.

This study group consisted of consecutive patients, undergoing thyroid and parathyroid surgery with IONM. Both anterior and posterior branches of the recurrent laryngeal nerves were assessed separately by both electromyography endotracheal tube for adduction and finger palpation for detection of laryngeal twitch due to posterior cricoarytenoid abduction. The recurrent laryngeal nerves having motor function only in the anterior branches were defined as group 1, whereas the nerves having motor function both in the anterior and posterior branches were as group 2.

Inclusion Criteria:

1. Patients who underwent parathyroid/thyroid surgery with intraoperative neuromonitoring ,
2. Patients who had normal vocal cord functions preoperatively. -

Exclusion Criteria:

1. Preoperative recurrent laryngeal nerve palsy,

2. Intentional nerve transection because of cancer invasion,

3. Assessment failure of recurrent laryngeal nerve function due to the deficiency of the intraoperative neuromonitoring equipment,.

4. Parathyroidectomy operations that recurrent laryngeal nerves were not fully dissected.

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