Automated Periodic Stimulation Electrode Installation: A Technique to Surgically Implant An Automated Stimulation Device on the Vagus Nerve in a Porcine Model

Overview

In this video, we demonstrate the procedure for the installation of an automated periodic stimulation electrode on the vagus nerve for monitoring nerves during thyroid surgeries in a porcine model. This helps in the correct identification of the target nerve during surgical procedures.

Protocol

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.

1. Surgical procedure

1. Begin with an anesthetized pig intubated with an electromyography (EMG) tube. Wear sterile surgical gloves and use povidone iodine with cotton swabs to disinfect the neck surgical site.
2. Make a transverse collar incision about 10-15 cm in length with a scalpel to expose the neck and the larynx.
3. Raise the subplatysmal flap 1 cm cranially from the clavicle to the hyoid bone.
4. Remove the strap muscles and visualize the tracheal rings and nerves. Use monopolar and bipolar electrocautery to assist the surgical dissection and hemostasis.
5. Localize, identify, and carefully expose the external branch of the superior laryngeal nerve (EBSLN), recurrent laryngeal nerve (RLN), and vagus nerve (VN) with a handheld stimulation probe.
6. Position an automated periodic stimulation (APS) electrode on one side of VN for stimulating during continuous intraoperative neural monitoring (CIONM). Connect the APS electrode with the monitoring system. Set pulsed stimuli to 1 Hz, 100 µs, and 1 mA.

Materials

Name	Company	Catalog Number	Comments
Criticare systems	nGenuity	8100E	physiologic monitoring, including capnography, electrocardiography (ECG) and monitoring of oxygenation (SaO2)
Intraoperative NIM nerve monitoring systems	Medtronic	NIM-Response 3.0	monitor EMG activity from multiple muscles. If there is a change in nerve function, the NIM system may provide audible and visual warnings to help reduce the risk of nerve damage.
Standard Prass Flush-Tip Monopolar Stimulator Probe	Medtronic	8225101	Tips and Handles. For locating and mapping cranial nerves in the surgical field, the single-use Standard Prass Monopolar Stimulating Probe features a flush 0.5 mm tip diameter. The probe is insulated to the tip to prevent current shunting. Individually sterile packaged.
APS (Automatic Periodic Stimulation) Electrode*	Medtronic	8228052 / 8228053	2 mm/ 3mm. The APS Electrode offers continuous, real-time monitoring. The electrode is placed on the nerve and can provide early warning of a change in nerve function.