What is a central and modified radical neck dissection?
A central neck dissection removes all the perithyroidal and tracheoesophageal groove nodes (level VI) from the hyoid bone superiorly down to the sternal notch. Laterally, the dissection extends from carotid to carotid artery. The lateral spread of disease usually involves the jugular lymph nodes (levels II–IV) and less commonly posterior (level V) nodes. A modified radical neck dissection, sometimes referred to as a functional dissection , removes all lymphatic tissue from level II to level IV (and sometimes V) and spares the internal jugular vein, sternocleidomastoid muscle, and spinal accessory nerve because sacrificing these structures (radical neck dissection) does not improve outcomes.