Controversy still exists concerning the extent of neck nodedissection in thyroid carcinoma patients. A modified neck dissection is usually performed for the treatment of thyroid carcinoma patients with positive lateral neck nodes. When performing a neck dissection, removal of the nodes superior to the spinal accessory nerve (level IIB) is difficult and time consuming. This study was performed to determine whether level IIB node dissection is always necessary in therapeutic neck dissection for metastatic papillary thyroid carcinoma.

A total of 200 neck dissections were performed in 175 papillary thyroid carcinoma patients with positive lateral neck nodes between September 2005 and June 2007. The patterns of lateral neck metastasis were analyzed with respect to neck level, but the level IIB nodes were studied as separate specimens. Potential factors predicting level IIB node metastasis were also evaluated.

The most common site of metastasis was level III, showing 95.0% (190/200), followed by level IV 66.0% (132/200), level IIA 54.0% (108/200), and level V 15.5% (31/200). Level IIB metastases were seen in 12 necks (6.0%) and seen only in the necks with positive level IIA nodes. In 11 of the 12 necks, the primary tumors were located in the upper pole of the thyroid.

Level IIB node dissection is not necessary when there is no level IIA metastasis. Even when there is level IIA metastasis, level IIB node dissection is not always necessary, unlessthe primary tumors are located in the upper pole of the thyroid.