A large cohort study found that intraoperative nerve monitoring during thyroidectomy may be becoming standard practice in the United States, with usage increasing from 62.5% in 2016 to 75.9% in 2022. The research showed intraoperative nerve monitoring was associated with a slight reduction in recurrent laryngeal nerve injury risk but demonstrated no significant impact on other major complications.
In the study, published in JAMA Otolaryngology–Head & Neck Surgery, investigators analyzed 44,265 adult patients who underwent thyroidectomy between 2016 and 2022 using the National Surgical Quality Improvement Program database. Intraoperative nerve monitoring (IONM) was used in 69.2% of all cases during the study period. After controlling for patient factors through propensity score matching, IONM was associated with a 2% reduction in the risk of recurrent laryngeal nerve (RLN) injury (adjusted odds ratio [OR] = 0.98, 95% confidence interval [CI] = 0.97–0.99).
"Although IONM during thyroidectomy is common in the [United States], these results suggest that further research is needed to identify patients who would benefit the most from this technology," wrote lead study author Madison Hearn, MPH, and colleagues from Johns Hopkins University.
The overall incidence of RLN injury was 6.0%, with 0.2% requiring tracheostomy. The investigators found no significant associations between IONM use and postoperative hypocalcemia (adjusted OR = 1.00, 95% CI = 0.99–1.00) or neck hematoma (adjusted OR = 1.00, 95% CI = 0.99–1.00).
Subgroup analyses revealed that IONM provided a small protective effect, specifically among patients with differentiated thyroid cancer (adjusted OR = 0.96, 95% CI = 0.94–0.99) but showed no statistically significant benefit among patients with Graves' disease or prior neck surgery.
The increasing adoption of IONM aligns with previous survey data indicating growing acceptance among surgeons. The study found that a higher likelihood of IONM use was associated with Black race (adjusted OR = 1.37, 95% CI = 1.27–1.48), Hispanic ethnicity (adjusted OR = 1.32, 95% CI = 1.18–1.48), and outpatient surgery (adjusted OR = 1.40, 95% CI = 1.32–1.49).
"Because of the small magnitude of our effect size, it is difficult to conclude whether the observed reduction in odds of RLN injury associated with IONM is clinically meaningful," the study authors noted. "However, by using pooled data from a nationally representative sample over a period of 7 years, we were able to ascertain a clearer picture of the increasing prevalence of IONM and its potential influence on outcomes compared with previous studies," they added.
Study limitations included the inability to analyze hospital or surgeon characteristics or distinguish between intermittent vs continuous nerve monitoring. Additionally, the investigators indicated that RLN injury classification using NSQIP criteria may have included cases of superior laryngeal nerve injury or muscle tension dysphonia rather than true RLN paralysis.
The study was supported by grant R01AG076834 from the National Institute on Aging. The authors recommended future research focused on identifying specific patient subgroups most likely to benefit from IONM during thyroidectomy to promote high-value surgical practices.
Full disclosures can be found in the study.