• If the muscle relaxant used during surgery will affect the operation of RLN monitoring system. [ Time Frame: during operation ] [ Designated as safety issue: No ]
  

• Can RLN monitoring system accurately predict the function of RLN Can RLN monitoring system decrease the RLN palsy rate after thyroidectomy [ Time Frame: early postoperation period ] [ Designated as safety issue: No ]
  
• Can standardization of IONM procedures further lower the RLN palsy rate [ Time Frame: early postoperation period ] [ Designated as safety issue: No ]
  
• Dose IONM help to decrease the RLN palsy rate during difficult thyroid operations [ Time Frame: early postoperation period ] [ Designated as safety issue: No ]
  

OBJECTIVES/HYPOTHESIS:

The purpose of this study will explore the advantages and applications of electrodes used for monitoring of the recurrent laryngeal nerve (RLN) in thyroid surgery. We want to know that if the monitoring system will decrease the rate of recurrent laryngeal nerve palsy.

STUDY DESIGN:

One hundred patients who undergoing thyroid surgery will be collected in this study. Patients will be intubated for general anesthesia with a Medtronic Xomed Nerve Integrity Monitor (NIM) EMG endotracheal tube (Jacksonville, Fla) that had 2 electrodes imbedded in the wall of the endotracheal tube. These wires were placed up against each vocal cord. Two grounding wires(needle No. 26) were placed up in the subcutaneous tissues of both shoulders. The electrode wires, grounding wires, and nerve stimulator were connected to a monitoring device (Medtronic NIM-Response) that recoded a visual evoked potential and audible beep to each muscle contraction of a vocal cord. A Medtronic Xomed Prass monopolar nerve stimulator wand was used to test the RLN intraoperatively and was set at 0.5mA. Direct physical touching of the RLN with nerve stimulator using pulsed current would produce an audible "beep-beep-beep".

CONCLUSION:

This study will be conducted in cooperation with Department of anesthesiology. The following subjects will be collected and elucidated:

1. If the muscle relaxant used during surgery will affect the operation of RLN monitoring system.
2. Can RLN monitoring system accurately identify the RLN
3. Can RLN monitoring system accurately predict the function of RLN
4. Can RLN monitoring system decrease the RLN palsy rate after thyroidectomy
5. Application of RLN monitoring to determine the safety and the benefit of vagal stimulation at the beginning and the end of thyroid operation
6. Application of RLN monitoring to determine whether extensive dissection of RLN increases the risk of nerve injury.

At least four papers will be written after this study with the topics as followings:

1. Influence of muscle relaxation on neuromonitoring of the recurrent laryngeal nerve during thyroid surgery
2. Intraoperative neuromonitoring of the recurrent laryngeal nerve during thyroid surgery: Plaudits and pitfalls 3. Vagal stimulation during intraoperative neuromonitoring of the recurrent laryngeal nerve in thyroid operation.

4. Does extensive dissection of recurrent laryngeal nerve during thyroid operation increase the risk of nerve injury? Our experience with the application of intraoperative neuromonitoring