Open AccessAnalysis of Normative Vagal and Recurrent Laryngeal Nerve Electrophysiological Data
Author(s) -
Eimear Phelan,
Slough Chris,
Randolph Gregory W.
Publication year - 2011
Publication title -
otolaryngology–head and neck surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.232
H-Index - 121
eISSN - 1097-6817
pISSN - 0194-5998
DOI - 10.1177/0194599811416318a61
Subject(s) - vagus nerve stimulation , vagus nerve , recurrent laryngeal nerve , medicine , anesthesia , superior laryngeal nerve , electrophysiology , stimulation , surgery , larynx , thyroid
Objective 1) Provide normative electrophysiological vagal and recurrent laryngeal nerve reference range values for intraoperative nerve monitoring in humans. 2) Highlight potential documentation implications of intraoperative nerve monitoring. Method Consecutive monitored adult patients undergoing thyroid, parathyroid, and related neck surgery were included in this IRB approved study performed over an 8 month period. All patients had a preoperative and postoperative laryngeal examination to assess vocal cord function. Patients with an abnormal preoperative laryngeal examination were excluded. Results In 64 patients the mean amplitude of the RLN (704mV, SD ± 512.7mV) was greater than the vagus nerve (524.5mV, SD± 388.0mV). The mean latency of the left and right RLN were 3.36ms (SD ± 0.92) and 3.45ms (SD ± 0.62) respectively. The mean latency of the left vagus was 7.48ms (SD ± 1.32), and the right vagus was 6.65ms (SD ± 1.28). The mean threshold intensity of stimulation of the right (0.41 mV, SD 0.20 mV) and left vagus (0.40 mV, SD 0.23 mV) were similar. The mean threshold of stimulation was higher in the right RLN (0.51 mV, SD 0.44). Amplitudes tended to be higher in females. Conclusion Normative vagal and RLN data is presented. The mean amplitude of the RLN was greater than the vagus nerve. The mean latency of the left vagus is longer than the right side. The threshold of stimulation is well below the standard stimulation current of 1 to 2 milliamps.