Protective effect of intraoperative nerve monitoring against recurrent laryngeal nerve injury during re-exploration of the thyroid

BACKGROUND Previous thyroid or parathyroid surgery induces scarring or distorts anatomy, and increases the risk of recurrent laryngeal nerve (RLN) injury for a reoperation. The benefit of intraoperative nerve monitoring (IONM) for re-exploration (a second nerve exploration) and reoperation has not been established. METHODS Two hundred and ten patients were given a thyroid or parathyroid reoperation at our hospital between 2001 and 2010. Using IONM, we re-explored 56 patients who had been operated on before June 2007. The injury rate in these patients was compared with that of the 15 patients re-explored without IONM between 2001 and 2006. RESULTS Of the 70 nerves that were re-explored using IONM, only one was incidentally injured, significantly fewer than the three injured in the 15 nerves re-explored without using IONM (1.43% vs. 20%, P = 0.0164). CONCLUSIONS IONM helped prevent RLN damage when re-exploring nerves during thyroid and parathyroid surgery. We recommend the routine use of IONM in thyroid and parathyroid reoperations.