The risk factors for postoperative temporary vocal cord paralysis after thyroid cancer surgery: an observational retrospective cohort study.

Objective: To analyze the potential factors influencing new-onset postoperative transient vocal cord paralysis (VCP) in thyroid cancer patients.

Methods: Case information of 8340 thyroid cancer patients hospitalized at China-Japan Union Hospital of Jilin University, Jilin Province, China, in the Thyroid Surgery Department from January 2018 to December 2020 was collected retrospectively and analyzed. The possible influencing factors were analyzed using a χ2 test, rank-sum test, and multiple logistic regression analysis. A nomogram was used to construct the clinical prediction model that was validated in the validation set by receiver operating characteristic, calibration curves, and Decision curve analysis.

Results: The strengthening the reporting of cohort, cross-sectional, and case-control studies in surgery (STROCSS) guideline was followed to conduct a retrospective cohort study. A total of 8340 patients, including 1817 (21.8%) men and 6523 (78.2%) women, were enrolled in this study. The rate of temporary VCP was 3.6% (308/8340). Based on the results of postoperative laryngoscopy, the patients were divided into VCP group and non-VCP group. Comparative analysis between the groups revealed that potential factors associated with postoperative transient VCP were tumor location on the dorsal side of the gland ( P =0.042), ultrasound showing a maximum nodal diameter >1 cm ( P =0.002), multifocal carcinoma ( P <0.001), invasion of surrounding tissue ( P =0.005), lymph node metastases in the central compartment ( P =0.034), lateral cervical lymph node metastasis ( P <0.001), and prolonged operation ( P <0.001). A multiple logistic regression analysis showed that the independent risk factors in postoperative transient VCP were T stage (OR=1.411, P =0.013, 95% CI: 1.075-1.853), multifocal carcinoma (OR=1.532, P =0.013, 95% CI: 1.095-2.144), and duration of surgery (OR=1.009, P <0.001, 95% CI: 1.006-1.012). Finally, a clinical prediction model was established via a nomogram and was validated in the validation set, although its diagnostic efficacy needs to be improved further.

Conclusion: High T stage, multifocal carcinoma, and prolonged operation time may be independent risk factors for the occurrence of postoperative transient VCP in patients undergoing initial surgery for thyroid cancer.