Nerve monitoring in thyroid surgery: is it worthwhile?

This study analysed the use of the commercially available Neurosign 100(R) Nerve Monitor during thyroidectomy. Consecutive patients undergoing thyroid ectomy were monitored. The nerve response prior to and after thyroidectomy were compared as were the relative benefits of mono and bipolar electrodes. Twenty-one consecutive patients over 9 months were assessed. The threshold for stimulation of the recurrent laryngeal nerve was never more than 0.5 m A (range 0.2-0.5 mA) for the bipolar and 1.5 mA (range 0.2-1.5 mA) for the unipolar electrode. The threshold for the superior laryngeal nerve was 1 mA and 1.5 mA, respectively. Following resection, stimulation levels of the l aryngeal nerves were unchanged. Use of the Neurosign 100(R) Nerve Monitor i s helpful in laryngeal nerve localization and confirmation. The bipolar ele ctrode set at 30 Hz. and 0.5 mA for the recurrent laryngeal nerve and 1.0 m A for the superior laryngeal nerve is recommended. Threshold comparison bef ore and after resection would appear to have a prognostic value.