Intraoperative neuromonitoring and postoperative bilateral laryngealparalysis in total thyroidectomy. Systematic review and meta-analysis

Introduction and objective: Despite being unusual, bilateral paralysis of recurrent laryngeal nerve is a complication that has large morbidity and mortality rates within thyroid surgery. The visual identi-fication of recurrent laryngeal nerve remains the gold standard in the procedure. The main aim is to evaluate if the intraoperative neuromonitoring reduces the bilateral laryngeal paralysis risk during total thyroidectomy, through systematic review and meta-analysis. Method: The method consists of the systematic review of studies that included series of total thyroidectomy with and without neuromonitoring, without date or language restriction in PubMed, BVS, Cochrane, Clinical trials and WoS. The prevalence of bilateral paralysis of recurrent laryngeal nerve was evaluated. A descriptive study of the included variables and a meta-analysis following the aleatory effects model were conducted. Results: A number of 45 studies were selected and analysed into two subgroups: retrospective series (31 studies) and prospective series (14 studies); with a total of 197161 patients. The prospective series resulted homogenous and with low publishing bias, with a total of 11149 patients. In prospective studies, the observed difference between the risk of bilateral paralysis of recurrent laryngeal nerve with and without intraoperative neuromonitoring equates to a RAR of 2.1 % and a NNT of 487.15. Conclusions: Neuromonitoring reduces the risk of developing vocal cord palsy.