Vagus nerve stimulation: quality control in thyroid and parathyroid surgery

Area of Science:

• Otolaryngology
• Neurosurgery
• Endocrinology

Background:

• The recurrent laryngeal nerve (RLN) is crucial for vocal fold function.
• Damage to the RLN during thyroid and parathyroid surgery can lead to vocal fold palsy.
• Accurate intraoperative identification and assessment of RLN integrity are essential.

Purpose of the Study:

• To evaluate the utility of the Neurosign 100 Nerve Monitor and vagus nerve stimulation for RLN identification and integrity assessment.
• To compare the effectiveness of vagus nerve stimulation versus direct RLN stimulation in detecting RLN damage.
• To assess the impact of these monitoring techniques on surgical confidence and patient outcomes.

Main Methods:

• Prospective evaluation of 40 patients undergoing thyroid and parathyroid surgery.
• Utilized the Neurosign 100 Nerve Monitor with endotracheal electrodes for RLN identification and integrity checks.
• Performed vagus nerve stimulation in 21 patients and direct RLN stimulation in one patient.
• Assessed vocal fold function pre- and post-operatively.

Main Results:

• Successfully identified 57 out of 59 recurrent laryngeal nerves.
• The nerve monitor confirmed RLN continuity in all but one case due to equipment error.
• Vagus nerve stimulation identified RLN damage in one patient, which was missed by direct RLN stimulation, resulting in transient vocal fold palsy.
• No adverse sequelae were reported from vagus nerve stimulation.

Conclusions:

• The Neurosign 100 Nerve Monitor aids in RLN identification and integrity assessment during neck surgery.
• Vagus nerve stimulation appears to be a more sensitive method for assessing RLN integrity than direct RLN stimulation.
• These monitoring tools enhance surgical confidence, particularly during bilateral procedures, but do not replace meticulous surgical technique.