Postoperative recurrent laryngeal nerve paralysis in thyroid carcinoma surgery

Recurrent laryngeal nerve (RLN) paralysis is a significant complication of thyroid surgery. Even with meticulous nerve preservation, postoperative RLN paralysis can still occur. We investigate risk factors for postoperative RLN paralysis among the patients with thyroid carcinoma. Between 2017 and 2023, 216 patients underwent surgery for thyroid carcinoma at Kumamoto University Hospital. Among these, 26 patients displayed preoperative vocal cord paralysis. Records for the remaining 190 patients were reviewed retrospectively to identify risk factors for postoperative RLN paralysis. Among the 190 cases, 16 required RLN resection during surgery due to tumor invasion. Out of the remaining 174 patients who preserved RLN, 29 suffered temporary and 7 permanent postoperative RLN paralysis. Tracheal invasion was identified as a significant risk factor for the need to resect RLN during surgery, even in the absence of preoperative RLN paralysis (OR 7.0, P = 0.038). For patients suffering postoperative RLN paralysis even though preserving RLN during surgery, RLN shaving (OR 42.8, P < 0.001) and blood loss (OR 1.51 per 100 mL increase, p = 0.024) were identified as an independent factor. Excluding RLN shaving cases, blood loss was an independent factor. Patients with suspected tracheal invasion preoperatively are at high risk of requiring intraoperative RLN resection. Among the patients with thyroid carcinoma who preserved RLN during surgery, the cases in which nerve preservation was achieved by shaving technique and those with greater intraoperative bleeding had a higher risk of postoperative RLN paralysis. • In patients with thyroid carcinoma without preoperative recurrent laryngeal nerve (RLN) paralysis, we investigated the risk factors for postoperative RLN paralysis. • Although a high incidence of palsy after nerve preservation by shaving technique is inevitable, the only independent risk factor for postoperative palsy, despite standard nerve preservation, was intraoperative blood loss. • In cases where preoperative imaging suggests tracheal invasion by the tumor, there is a high possibility that the RLN will need to be resected during the surgery.