Use of Intraoperative Methylene Blue Spray for Identification and Preservation of Vital Structures in Thyroidectomy:...

Introduction Although thyroidectomy is relatively safe, iatrogenic injury to the recurrent laryngeal nerve (RLN) and parathyroid glands (PGs) can cause major morbidity. Conventional visual identification can be challenging. This study aims to determine the utility of intraoperative methylene blue (MB) spray for the localization and preservation of these structures. Methods A comparative interventional study was conducted with 136 patients undergoing thyroidectomy for benign multinodular goitre. Patients were divided into an experimental group (topical MB spray, n = 68) and a control group (conventional dissection, n = 68). Primary outcomes were the frequency of RLN injury, assessed via postoperative laryngoscopy, and mean postoperative serum calcium levels measured 72 hours after the surgery. Results The mean serum calcium level on the first postoperative day was significantly higher in the group of MB spray (8.87 ±0.45 mg/dL) than that of the control group (8.21 ± 0.33 mg/dL; p < 0.001). There were no cases of RLN injury in the MB spray group compared with 11.8% in the control group (p = 0.006). These significant differences persisted across all patient subgroups. Conclusion Intraoperative MB spraying is helpful for accurate identification and preservation of RLNs and PGs during thyroidectomy. This technique results in higher postoperative calcium levels and a markedly reduced incidence of RLN injury, advocating for its routine use in thyroid surgery.