Modified Segment Oriented Cervical Lymph Node Dissection for Thyroid Cancer

The commonest mode of locoregional spread of thyroid cancer is to the regional nodal basin. The frequency of lymph node metastases varies among different pathological types of thyroid cancers. The lymph node metastases are very common in papillary thyroid cancers but infrequent in follicular thyroid cancers. Noguchi (1970) considered the pattern of lymph node spread was systematic with the paratracheal or central compartment being the first nodal station. But the pattern of lymph node spread is not always systematic and skip metastases are frequent. The extend of nodal disease is generally limited to nodes below the hyoid level and the submandibular area is usually spared. The lymph node dissection is known as segment-oriented selective neck dissection removing lymph nodes in Level IV, Level III, and Level II-A stations. Dissection extends to Level V station when lymph nodes are found along with the transverse cervical artery. Level II-B stations rarely harbour metastatic nodes except for contiguous spread from the II-B area. Removal of nodes in Level II-B is advisable when metastatic nodes are found in Level II-A stations Level VI nodes are removed along with thyroidectomy when neck dissection is performed concurrently. Level I nodes are seldom removed.