Table 2. Standardized operating procedures of IONM.

Abbreviations	Specific procedure	Current intensity (mA)	Mapping site
L1	Examine the larynx preoperatively to assess the basic condition of vocal fold function	–	–
V1	Map the VN before the start of procedures at the operative field	3.0	Distal end of the nerve (at the level of the inferior pole of the thyroid)
R1	Map the RLN after it is precisely located or initial exposed	1.0	Proximal end of the nerve (in the tracheoesophageal groove)
S1	Map the EBSLN before the handling of vessels at the superior pole of the thyroid	1.0	The sternothyroid-larynx triangle
S2	Map the EBSLN after the ligation of vessels at the superior pole of the thyroid	1.0	Innervation area
R2	Map the RLN upon the completion of procedures at the operative field	1.0	Proximal end of the exposed nerve
V2	Map the VN upon the completion of procedures at the operative field	3.0	Distal end of the nerve (at the level of the inferior pole of the thyroid)
L2	Examine the larynx postoperatively, as appropriate	–	–

IONM, intraoperative neuromonitoring; VN, vagus nerve; RLN, recurrent laryngeal nerve; EBSLN, external branch of the superior laryngeal nerve.