What is the purpose of iodine preparation before thyroid surgery?

The purpose of iodine preparation before thyroid surgery is primarily to decrease vascularity and size of the thyroid gland. Administration of iodine, typically in the form of iodide, accomplishes this by inducing a temporary reduction in the size of the thyroid gland and decreasing blood flow to the area. This is significant because a less vascular thyroid reduces the risk of excessive bleeding during surgery and makes the procedure safer for the patient.

By reducing the overall size of the gland, iodine preparations can also help in making surgical exposure easier for the surgeon, which may lead to a more efficient operation. This preparation is part of a broader strategy aimed at minimizing complications associated with thyroid surgeries. The use of iodine is part of a medical approach known as "thyroid storm" prevention, which is crucial in patients with hyperthyroidism or goiter before proceeding with surgery.

The other choices do not accurately reflect the primary function of iodine preparations in this context. Increasing hormone levels is contrary to the goal of managing hyperthyroid states, while postoperative recovery improvement and pain management are not direct purposes of iodine pre-operative preparations.