Injury of the recurrent laryngeal nerve (RLN) is one of the most serious complications of thyroid surgery. Intraoperative neuromonitoring (IONM) has been introduced to verify RLN function integrity and may be a helpful adjunct in nerve dissection.
To determine whether the use of IONM can reduce the incidence of RLN injury in patients undergoing total thyroidectomy.
Design, Setting, and Participants
This cohort study included 2556 patients who underwent total thyroidectomy between January 2002 and December 2012 in the Department of Otolaryngology–Head and Neck Surgery of Venizeleio General Hospital, Heraklion, Greece. Patients who had IONM during the procedure (n = 1481) were compared with patients who underwent surgery with nerve visualization alone (n = 1075). All patients underwent indirect laryngoscopy–fiberoptic nasopharyngoscopy both preoperatively and on day 2 after surgery to assess vocal cord motility.
Main Outcomes and Measures
Use of IONM and incidence of RLN injury.
A total of 2556 patients (2028 women and 528 men [5112 RLNs at risk]; mean [SD] age, 51.35 [14.18] years; age range, 18-89 years) underwent total thyroidectomy. Univariate analysis showed that the use of IONM resulted in a significant reduction in RLN injury incidence (3.3% vs 0.7%) with a relative risk reduction of 2.6% (odds ratio [OR], 5.15; 95% CI, 3.12-8.49; number needed to treat, 19). Multivariate logistic regression showed that no use of IONM was an independent risk factor for RLN injury in patients who underwent total thyroidectomy (adjusted OR [AOR], 5.44; 95% CI, 3.26-9.09). Additional risk factors for RLN injury were operative time (AOR, 12.91; 95% CI, 6.66-25.06), maximum diameter greater than 45 mm of right thyroid lobe (AOR, 4.91; 95% CI, 3.12-8.56) and left thyroid lobe (AOR, 2.24; 95% CI, 1.39-4.32), extrathyroid extension (AOR, 3.26; 95% CI, 1.62-6.59), incidental parathyroidectomy (AOR, 3.30; 95% CI, 2.13-5.09), and tumor size larger than 10 mm (AOR, 3.24; 95% CI, 1.59-6.62).
Conclusions and Relevance
Our findings showed that the use of IONM decreased significantly both temporary and permanent RLN injuries. The technology of IONM is safe and reliable, and this technique is an important adjunct in nerve dissection and functional neural integrity. The routine use of IONM reduced pitfalls and provided guidance for our surgeons in difficult cases, reoperations, and high-risk patients.