Using Methylene Blue Spray during Thyroidectomy for Preserving Recurrent Laryngeal Nerve

Abstract Background: The main postoperative complication of thyroidectomy is recurrent laryngeal nerve (RLN) injury. RLN is identified by its relationships with inferiorthyroid artery, tracheoesophageal groove and ligament of Berry. This method may not be always accurate due to anatomical variations. Different adjuvant methods have been used to aid in the identification of the nerve. Nerve fibre staining with methylene blue (MB) is a known method during parotid surgery. Aim of Study: This study aimed to evaluate the value of using methylene blue spray during thyroidectomy to properly identify and preserve RLN during surgery to improve outcomes following thyroidectomy. Patients and Methods: This study was a prospective study doneon sixty two patients with benign and malignant goiter disorders who were admitted at Ain Shams University Hospital and underwent total thyroidectomy in the period from January 2021 to December 2021 at endocrine surgery unit. Patients with reoperative surgery, presence of preoperative cord dys-function were excluded from study. Patients were randomized into two groups with an equal number of candidates (n=31) using the lottery method. 31 patients underwent thyroidectomy as study group with methylene blue spray and other 31 patients were operated without methylene blue spray as control group. During the surgery, after ligation of superior pole of thyroid and the thyroid lobe could be deviated medially, One ml of 1% methylene blue solution (10mg) was sprayed over the thyroid bed and perithyroidal tissue. This area includes the parathyroid glands, inferior thyroid artery, veins and recurrent laryngeal nerve. The entire area was irrigated by normal saline solution to rinse the MB out of the surrounding tissue. After 10min, the thyroid bed was inspected for areas in which the blue color was rapidly absorbed. Comparisons between studied groups were collected. Results: Intraoperatively, recurrent laryngeal nerve was not stained and remained white in all cases while all other tissues were stained blue. RLN could be identified in all the patient, as an unstained structure in the tracheoesophageal groove. Four to seven minutes later the parathyroid glands washed out the blue stain and regain their original yellow color. It took nearly 15 minutes for the thyroid tissue to wash out the stain in all cases.
Conclusion: Intra-operative RLN identification by MB staining is safe, cheap and readily available method and could make thyroidectomy dissection less stressful.