Innervation of Human Cricopharyngeal Muscle By Recurrent Laryngeal and External Branch of Superior Laryngeal Nerve

Study Overview
=================
Brief Summary
-----------------
The investigators hypothesized that, external branch of the superior laryngeal nerve (EBSLN) and/or recurrent laryngeal nerve (RLN) contribute to the motor function of the human cricopharyngeal muscle (CP). The investigators aimed to assess the contribution of the laryngeal nerves (EBSLN and RLN) to the motor activity of the cricopharyngeal muscle, during thyroidectomy with intraoperative neuromonitoring (IONM).

Detailed Description
-----------------
This study group consisted of a consecutive patients undergoing thyroid surgery with intraoperative neuromonitoring (NIM 3.0 Nerve Monitoring Systeme (Medtronic Xomed, Jacksonville, FL, USA) ) for various diseases. In all patients, each side of the neck operated was considered as a separate entity in our study. EMG recordings were accomplished with a pair of needle electrodes inserted into the CP and mid-portion of the CT muscle that is located on the superior side of the RLN, which were plugged into the third and fourth channels of interface-connector box, respectively, at the end of the thyroidectomy or lobectomy. The investigators evaluated the innervation pattern of the CT muscle in an other study. Therefore the EBSLN is the main supplier of the CT muscle, the EMG findings of the CT muscle were used to confirm it, in this study. EBSLN, pharyngeal plexus (PP), RLN and vagus nerve were stimulated with a monopolar stimulator probe at 1 mA. While stimulating these nerves, the ipsilateral CP muscle was visually observed for possible contractions and electromyographic recordings were obtained with the 4-channel NIM 3.0 Nerve Monitoring System.

Official Title
-----------------
Descriptive In Vivo Study of Evaluating the Innervation of The Human Cricopharyngeal Muscle By The Recurrent Laryngeal Nerve and External Branch of The Superior Laryngeal Nerve

Conditions
-----------------
Larynx

Intervention / Treatment
-----------------
* Device: The NIM 3.0 Nerve Monitoring System


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: The patients who underwent thyroidectomy. Exclusion Criteria: Preoperative RLN palsy Thyroid cancer with massive extrathyroidal extension Intentional nerve transection because of cancer invasion The assessment failure of nerve function due to the technical deficiency of the IONM equipment

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Cricopharyngeal muscle innervation<br>The recurrent laryngeal nerve (RLN), vagus nerve, external branch of the superior laryngeal nerve (EBSLN) and pharyngeal plexus were stimulated intraoperatively by the NIM 3.0 Nerve Monitoring System (Medtronic Xomed, Jacksonville, FL, USA). Responses were evaluated by visual observation of the cricopharyngeal muscle and electromyographies via needle electrodes inserted into the cricopharyngeal muscle. | Device: The NIM 3.0 Nerve Monitoring System<br>* Electromyography recordings were accomplished with a pair of needle electrodes inserted through the CP muscle, which were plugged into the third and fourth channels of interface-connector box.The recurrent laryngeal nerve(RLN), vagus nerve, external branch of the superior laryngeal nerve(EBSLN) and pharyngeal plexus were stimulated with a current of 1 mA and a frequency of 4 MHz and the event threshold at 100 microV.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The cricopharyngeal muscle innervation pattern that is evaluated by visual contractions and EMG evoked potentials, with stimulation of the nerves |  | up to 9 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The comparison of the EMG amplitudes obtained with the stimulation of the recurrent laryngeal nerve (RLN), vagus nerve, external branch of the superior laryngeal nerve (EBSLN) and pharyngeal plexus. |  | up to 9 months | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
cricopharyngeal muscle, innervation by EBSLN, A prospective case-controlled study