Continuous monitoring of the recurrent laryngeal nerve in thyroid surgery : a critical appraisal

Background and Purpose: Intraoperative neuromonitoring (IONM) contributes in several ways to recurrent laryngeal nerve (RLN) protection. Notwithstanding these advantages, surgeons must be aware that the current, intermittent, mode of IONM (I-IONM) has relevant limitations. To overcome these I-IONM limitations, a continuous IONM (C-IONM) technology has been proposed. Methods: A PubMed indexed literature review of the current limitations of I-IONM is presented and a commentary about C-IONM is provided presenting the preliminary results of research on this topic. Main findings: I-IONM, despite the advantages it produces, presents some important limitations; to overcome these drawbacks a C-IONM technology has been introduced. Conclusions: RLN traction injury is still the most common cause of RLN injury and is difficult to avoid with the application of I-IONM in thyroid surgery. C-IONM is useful to prevent the imminent traction injury by detecting progressive decreases in electromyographic amplitude combined with progressive latency increases. C-IONM seems to be a technological improvement. Likely, C-IONM by vagal nerve stimulation should enhance the standardization process, RLN intraoperative information, documentation, protection, training, and research in modern thyroid surgery. Although C-IONM is a promising technology at the cutting edge of research in thyroid surgery, we need more studies to assess in an evidence-based way all its advantages.