Continuous intraoperative neural monitoring of the recurrent nerves in thyroid surgery: a quantum leap in technology

Routine dissection and identification of the recurrent laryngeal nerve (RLN) in thyroid surgery are proven as safe and valuable methods of protecting it from operative injury (1). RLN visualization is considered the gold standard for prevention of RLN injury during thyroid surgery (2). It is recognized that the leading source of postoperative RLN dysfunction is not transection but it is nonstructural functional nerve injury (3-6). Since the introduction of intraoperative neural monitoring (IONM) in thyroid surgery, more than 50 years ago (7), the technology has considerably improved during the past decade (8-11). The use of intermittent stimulation of the RLN and the vagus nerve has now become a standard practice in numerous specialized centers around the globe. Modern nerve monitoring, whether intermittent [intermittent nerve monitoring (IIONM)] or continuous [continuous intraoperative neural monitoring (CIONM)], helps to identify the nerve, maps its course during thyroid dissection, diagnoses segmental (type 1) and diffuse (type 2) loss of signal (LOS), and offers basis for change of surgical strategy in the setting of LOS of the first side in a planned bilateral thyroid surgery (12)