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

METHODSOne 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.

RESULTSThe 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.

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