To evaluate the effect of electromyographic activity changes during intraoperative neuromonitoring(IONM) and extent of thyroid surgery on esophageal motility after surgery.

Thirty-six patients underwent thyroid lobectomy(n=9),total thyroidectomy(TT)(n=15),or TT+central lymph node dissection (CLND)(n=12); all patients underwent thyroidectomy using IONM, and high-resolution manometry(HRM) was performed within 1 week before and 6 months after surgery. Clinicopathological, HRM, and IONM data were also recorded and compared.

The incidence of preoperative and postoperative dysphagia was 39% and 53%, respectively, and the upper esophageal sphincter resting pressure (UESRP) decreased significantly postoperatively (p=0.03).The rates of dysphagia in patients with postoperative decreased(n=25) and increased(n=11)UESRP were 48% and 63%,respectively(P =0.38). The reduction rates in UESRP in patients who underwent TT, lobectomy, and TT+CNLD were 44%, 16%, and 8.7%, respectively.The reduction rate was significantly different in TTvsTT+CLND groups(44%vs16%;p=0.032).Nodule diameter and thyroid volume were significantly higher in the TT group than in the TT + CLND group(p=0,002, p=0,0001). A decrease in both N.Vagus amplitude and no change in RLN amplitude were detected in the TT group compared to the TT+CLND group, and a significant increase in left N.Vagus latency was found in the TT+CLND group compared to that in the TT group(p=0.009).

There was a significant decrease in the UESRP after thyroid surgery, and the most prominent decrease occurred in the TT group, which had a larger nodule diameter and thyroid volume than the other two groups.No significant correlation was found between the UESRP changes and postoperative