A Surgical Procedure for Thyroidectomy: Para-Tracheal Capsular Dissection and its Benefit in the Protection of the Parathyroid Gland.

Para-tracheal capsular dissection, conducted adjacent to the trachea, is postulated to mitigate the risk of parathyroid gland injury. This study compares postoperative parathyroid function following para-tracheal and conventional capsular dissection in thyroidectomy procedures. A retrospective analysis was performed on the medical records of 142 patients who underwent bilateral thyroidectomy with capsular dissection. In this randomized trial, 76 patients received para-tracheal capsular dissection, while 66 underwent the conventional approach. All patients were administered carbon nanoparticles as a lymphatic tracer, and their serum parathyroid hormone (PTH) and calcium (Ca2+) levels were evaluated postoperatively. Those presenting with serum PTH and/or Ca2+ levels below the normal range on the first postoperative day received management and follow-up. On the first postoperative day, the para-tracheal group exhibited significantly higher serum PTH levels (2.26 pmol/L, interquartile range [IQR] 1.46-3.53 pmol/L) compared to the conventional group (2.00 pmol/L, IQR 0.93-2.95 pmol/L, P = 0.04). Additionally, the para-tracheal group demonstrated a lesser reduction in PTH levels (47% vs. 58% from the pre-surgical level, P = 0.06). The proportion of patients with low PTH levels on the first postoperative day was significantly lower in the para-tracheal group (21/76, 27.6%) than in the conventional group (29/66, 43.9%; P < 0.05). There was no significant difference in serum Ca2+ levels between the groups on the first postoperative day, indicating that calcium supplement prophylaxis could prevent hypocalcemia. Follow-up results showed a significant reduction in transient hypoparathyroidism in the para-tracheal group (0/76) compared to the conventional group (4/66, P = 0.04, Fisher's exact test). The incidence of permanent hypoparathyroidism was also lower in the para-tracheal group (0/76) compared to the conventional group (2/66, P = 0.21, Fisher's exact test). Para-tracheal capsular dissection appears to offer superior protection of the parathyroid glands compared to conventional dissection, potentially reducing the risk of both transient and permanent postoperative hypoparathyroidism.