IMPORTANCE: Intraoperative nerve monitoring (IONM) is not considered standard of care during thyroidectomy, and guidelines are vague about its use in the absence of strong evidence of superiority over visualization of the recurrent laryngeal nerve (RLN) alone. OBJECTIVE: To characterize patterns of IONM use during thyroidectomy in the US and evaluate the association of IONM with postoperative outcomes. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used the National Surgical Quality Improvement Program (NSQIP) thyroidectomy data from January 1, 2016, to December 31, 2022. A nationally representative sample included adult patients without poorly differentiated thyroid cancer who underwent thyroidectomy at multiple centers. Data were collected from the time of surgery until 30 postoperative days through January 31, 2023. EXPOSURE: IONM during thyroidectomy. MAIN OUTCOMES AND MEASURES: Prevalence of IONM during thyroidectomy and postoperative outcomes including RLN injury, hypocalcemia, and neck hematoma. RESULTS: A total of 44 265 patients undergoing thyroidectomy were included (77.2% female
mean [SD] age, 51.8 [15.2] years), with 30 633 (69.2%) using IONM. Common indications for surgery in the cohort were goiter (35.3%) and a single nodule or neoplasm (39.2%). The prevalence of IONM increased from 62.5% in 2016 to 75.9% in 2022. RLN injury occurred in 6.0% of cases. On propensity score-matched analyses, IONM was associated with decreased odds of RLN injury overall (adjusted odds ratio [AOR], 0.98
95% CI, 0.97-0.99) and decreased odds among patients with differentiated thyroid cancer (AOR, 0.96
95% CI, 0.94-0.99). IONM was not associated with postoperative hypocalcemia (AOR, 0.99
95% CI, 0.99-1.00) or neck hematoma (AOR, 1.00
95% CI, 0.99-1.00). CONCLUSIONS AND RELEVANCE: This cohort study found that IONM during thyroidectomy has become routine, and use has increased over the last 7 years. IONM was associated with a slightly decreased odds of RLN injury, but no difference in hypocalcemia or neck hematoma. Although IONM use is widespread, further research is needed to identify patients who would benefit the most from this technology.