IONM and thyroidectomy in benign thyroid disease. Analysis of adverse events.

The aim of this study is to identify statistically significant differences in the onset of postoperative complications in patients undergoing thyroid surgery for benign pathology, following the systematic introduction of intraoperative neuromonitoring (IONM) of the laryngeal nerves. In this study we have retrospectively analysed data of 604 consecutive patients underwent to thyroidectomy in the Unit of General Surgery - University Hospital of Parma between January 2011 and December 2017. All patients were divided in two groups: the first group of patients was operated without the use of IONM (Group A) the second group was operated after the introduction of the systematic use of IONM (Group B). We have compared the incidence of adverse events in these two groups, analysing the impact of IONM on the onset of the most frequent complications after thyroid surgery. We have considered the impact of other variables in both groups, such as thyroiditis, hyperfunction and gland sinking in mediastinum. No statistically significant differences in the incidence between Group A (patients operated without the use of IONM) and Group B (patients operated with the use of IONM) were detected, though a decreasing trend after the introduction of IONM was observed. No statistically significant differences were reported even analysing the influence of other patient's variables such as thyroiditis, hyperfunction and glandular sinking in mediastinum. Even if the number of patients considered is not sufficient to value statistically significant differences, the decreasing trend of the incidence of postoperative complications after introduction of IONM encourage us. The surgeon expertise is still the most relevant variable influencing the decreasing of postoperative complications, underlining the importance of the centralization of this kind of surgery in the high volume centres.