Background: The aim of this study was to describe first experiences and changes in management using continuous intraoperative neuromonitoring (C-IONM) in thyroid and parathyroid surgery.
Method: Retrospective analysis of patients who underwent surgery with C-IONM since 2012. Surgical maneuvers were modified when electrophysiologic events occurred. Patients with persistent loss of signal (LOS) underwent postoperative laryngoscopy.
Results: One hundred and one patients (of 1586 neck surgeries) were included and 19 had events: In 13 these were temporary (resolved before end of surgery) and led to intraoperative modifications in surgical approach; in all cases traction was released, and in 8, recurrent laryngeal nerve (RLN) approach was changed [superior approach (2), inferior approach (2), both (4)]. Six patients had persistent LOS (5.9%, present at end of procedure), with RLN palsy (RLNP) on postoperative day 1: In three, LOS occurred at electrode placement on the vagus nerve, leading to distal placement of the electrode allowing ipsilateral dissection under continuous monitoring; all three had complete recovery at 6 months. In the three other patients, LOS occurred on the RLN: one probable thermal, one traction lesion and one accidental section of the anterior RLN branch. The RLN recovered within 6 months in two patients, and in the third, RLNP persisted after 6 months (1/101 = 1%).
Conclusion: C-IONM provides real-time evaluation of the RLN function, allowing for adaptation of surgical maneuvers to prevent RLNP. It seems particularly useful in difficult cases like redo neck surgery, invasive thyroid cancer and intrathoracic or large goiter. Care should be given at electrode placement on the vagus nerve.