[Role of carbon nanoparticles in patients with thyroid carcinoma undergoing total thyroidectomy plus bilateral...

To evaluate the role of carbon nanoparticles for dissecting lymph nodes and preserving parathyroid glands in patients with thyroid carcinoma undergoing total thyroidectomy plus bilateral central neck dissection.

A total of 86 patients with thyroid carcinoma undergoing primarily total thyroidectomy plus bilateral central neck dissection were randomly divided into trial and control groups. Carbon nanoparticles were injected into thyroid gland of trial group. Total lymph node, metastasis lymph node, black stained lymph node and black stained metastasis lymph node of trial group were counted in central compartment dissection specimens. And total lymph node and metastasis lymph node of control group were counted in central compartment dissection specimens. Parathyroid glands in central neck dissection specimens were counted in two groups. For two groups, serum total calcium and parathyroid hormone were measured pre-operation and 1 day, 3 days, 5 days, 1 month, 3 months and 6 months post-operation.

In trial group, the average counts of (10.19 ± 4.27) lymph nodes and (8.44 ± 4.31) black stained lymph nodes were more than those in control group at (6.26 ± 2.98) lymph nodes (all P < 0.01). Parathyroid gland was found in trial group (n = 7) and control group (n = 11). And the difference had no statistical significance (χ(2) = 1.124, P = 0.289). The preoperative serum levels of calcium and parathyroid hormone decreased within 6 months postoperatively in both groups (all P < 0.01). Without extracapsular invasion, serum levels of calcium and parathyroid hormone were higher in trial group than those in control group at 5 days, 1 month and 3 months post-operation (all P < 0.05). In an event of lymph node metastasis, serum levels of calcium (t = 3.446, P = 0.001) and parathyroid hormone (t = 2.441, P = 0.017) in trial group were higher than those in control group at 1 month post-operation. When there was extracapsular invasion or no lymph node metastasis, the serum levels of calcium and parathyroid hormone had no inter-group statistical differences within 6 months post-operation (all P > 0.05). When tumor size was less than or equal to 4 cm, the level of parathyroid hormone was higher in trial group than that in control group at 1 month post-operation (t = 2.703, P = 0.009). But no inter-group statistical differences existed within 6 months post-operation (all P > 0.05) when tumor size surpassed 4 cm. Regardless of tumor size, the serum levels of calcium in trial group were higher than those in control group at 1 month post-operation (all P < 0.01).

For thyroid carcinoma patients, total thyroidectomy plus bilateral central neck dissection increases the incidence of hypoparathyroidism. Lymph nodes of central compartment may be tagged by carbon nanoparticles so as to boost the detection rate of lymph node. In events of lymph node metastasis or no extracapsular invasion, carbon nanoparticles can adequately protect parathyroid functions.