[Efficiency of carbon nanoparticles in level VI lymphadenectomy for thyroid carcinoma and prevention of postoperative hypoparathyroidism].

OBJECTIVE: To assess the efficiency of carbon nanoparticle in guiding level VI lymphadenectomy and parathyroid preservation in thyroidectomy for carcinoma.

METHODS: One hundred and nine patients with well differentiated thyroid carcinoma, in whom thyroidectomy and bilateral lymphadenectomy for level VI were carried out at the same time, were prospectively studied. Fourty-five cases received carbon nanoparticle injecion in thyroid consistitued trial group, while sixty-four underwent conventional surgery as control group. The numbers of total dissected lymph nodes, metastasis lymph nodes, black-stained lymph nodes, detected parathyroids and mistakenly removed parathyroids were counted respectively. The PTH levels were measured at 1 d, 5 d and 30 d after surgery, respectively. Student's t test and Chi-square analysis were used for analyzing data.

RESULTS: The number of lymph node found in the trial group in level VI was checked out as (9.7 ± 1.7) each side, whereas that of the control group was (6.7 ± 1.9) each side. The discrepancy of two groups was statistical meaningful (t = 23.14, P < 0.001). The discrepancy of the rate of lymph node black-stained 90.5% (738/815), incidence of metastasis of the black-stained lymph nodes 45.9% (339/738) and that without black-staining 13.0% (10/77), was statistical meaningful (χ(2) = 30.91, P < 0.001). On average, the trial group showed (1.8 ± 0.9) parathyroid each side, and had 5.9% (5/84) of mistakenly removed incidence , on contrary, the control group showed (1.8 ± 1.0) parathyroid each side, and had 8.2% (11/134) of mistakenly removed incidence averagely as well. The discrepancy of two groups was statistical meaningful. In the trial group, the amount of PTH 1 d, 5 d and 30 d postoperatively were 7.30, 11.19 and 30.50 ng/L respectively, while that of the control group were 7.51, 10.90 and 28.30 ng/L respectively. The amount discrepancy between the two groups was not differences. No permanent recurrent nerve paralysis was found in both groups.

CONCLUSION: Carbon nanoparticle may improve the detected rate of metastasis lymph nodes, but may not be helpful to the prevention of postoperative hypoparathyrosim.