Risk Factors for Recurrent Laryngeal Nerve Palsy in Thyroid Surgery: A Single Center Experience of 1147 Procedures with Intermittent Intraoperative Neuromonitoring

Background: Recurrent laryngeal nerve (RLN) palsy is one possible complication during thyroid surgery. Intraoperative neuromonitoring and visualization of the nerve during surgery are standard procedures to reduce the risk of RLN palsy. This study aims to investigate new factors for RLN palsy and review ones that are already known in the literature to help surgeons prepare for the procedure. Methods: A retrospective study design was used to analyze the data of 1147 patients from a certified center for thyroid surgery. All patients underwent either total thyroidectomy or hemithyroidectomy from 2016 to 2020. The acquired information was analyzed descriptively. A logistic regression was used to analyze the independent variables of interest with the binary variable RLN palsy (yes/no). For the second aim of this study, a multiple logistic regression was applied to analyze the combined significant known and new risk factors. Results: Surgery indication for Graves' disease (OR 14.34, p < 0.001), thyroid cancer (OR 2.39, p = 0.012), and recurrent goiter (OR 5.57, p < 0.001) increased the risk for RLN palsy significantly compared to nodular goiter in hemithyroidectomy. The duration of surgery correlated positively with a higher risk for RLN palsy (OR 1.009, p = 0.005). For gender, BMI, resection weight, left or right nerve at risk, and surgeon experience, no significant differences were found. Conclusion: Operations for Graves' disease, thyroid cancer, and recurrent goiter have the highest risk for RLN palsy and surgeons should be alerted. The longer the operation, the higher the risk of RLN palsy. The correlation between surgery method (hemithyroidectomy vs. thyroidectomy) and RLN palsy should be carefully considered due to possible bias.