EFFECTIVENESS OF INTRAOPERATIVE TOPICAL METHYLENE BLUE SPRAY FOR PARATHYROID GLAND PRESERVATION DURING THYROIDECTOMY: A SHORT PROSPECTIVE OBSERVATIONAL STUDY

Abstract

Background: Post-thyroidectomy hypocalcemia remains one of the most common complications following thyroid surgery and is primarily related to inadvertent injury, devascularization, or failure to identify the parathyroid glands intraoperatively. Although several advanced imaging modalities have been developed to improve parathyroid preservation, their routine use is often limited by cost and availability. Topical methylene blue spray has emerged as a simple, inexpensive, and readily available technique that may facilitate intraoperative identification of parathyroid glands and improve postoperative outcomes. Methods: A prospective observational study was conducted among 60 patients undergoing thyroidectomy for benign and malignant thyroid disorders at a tertiary care teaching hospital. Following standard thyroidectomy, topical methylene blue spray was applied intraoperatively to assist parathyroid gland identification. Baseline serum calcium and parathyroid hormone (PTH) levels were measured preoperatively and reassessed on postoperative day one (POD-1) and postoperative day three (POD-3). The number of parathyroid glands identified, operative outcomes, postoperative biochemical changes, preservation rates, and complications were analyzed. Results: Females constituted 70.0% of the study population, and multinodular goiter was the most common indication for surgery (40.0%). Complete identification of all four parathyroid glands was achieved in 66.7% of patients, while successful preservation was observed in 93.3% of cases. Mean serum calcium decreased from 9.42 ± 0.48 mg/dL preoperatively to 8.74 ± 0.51 mg/dL on POD-1 and improved to 8.96 ± 0.45 mg/dL on POD-3. Mean PTH levels declined from 48.6 ± 11.2 pg/mL to 38.2 ± 9.4 pg/mL on POD-1 before recovering to 42.6 ± 8.8 pg/mL on POD-3. Transient hypocalcemia occurred in only 6.7% of patients, and no cases of permanent hypocalcemia were observed. Procedure-related complications were minimal. Conclusion: Intraoperative topical methylene blue spray is a safe, effective, and cost-efficient adjunct for parathyroid gland identification during thyroidectomy. The technique demonstrated high preservation rates, low postoperative hypocalcemia, favorable biochemical recovery, and minimal complications, supporting its use as a practical alternative for parathyroid preservation, particularly in resource-limited surgical settings.