Neck dissection classification
There are several types of neck dissections which can classified as follows:
Radical neck dissection
Radical neck dissection is considered to be the standard basic procedure for cervical lymphadenectomy. All other procedures represent one or more alterations of this procedure. The dissection involves removal of all ipsilateral cervical lymph node groups extending from the inferior border of the mandible to the clavicle, from the lateral border of the sternohyoid muscle, hyoid bone and contralateral anterior belly of the digastric muscle medially, to the anterior border of the trapezius muscle laterally. Included are all lymph nodes from Levels I through to V. The spinal accessory nerve, internal jugular vein and sternocleidomastoid muscle are also removed.
A radical neck dissection does not include removal of:
- sub-occipital nodes
- peri-parotid nodes (except infraparotid nodes located in the posterior aspect of the submandibular triangle)
- buccinator nodes
- retropharyngeal nodes or
- midline visceral (anterior compartment) nodes.
Modified radical neck dissection
Modified radical neck dissection refers to the excision of all lymph nodes routinely removed by the radical neck dissection, with preservation of one or more nonlymphatic structures: i.e., spinal accessory nerve, internal jugular vein (IJV) and sternocleidomastoid muscle (SCM). The structure(s) preserved should be specifically named, e.g. “modified radical neck dissection with preservation of the spinal accessory nerve.”
Selective neck dissection
Selective neck dissection (SND) refers to a cervical lymphadenectomy in which there is preservation of one or more of the lymph node groups that are routinely removed in the radical neck dissection. The lymph nodes groups removed are based on the patterns of metastases that are predictable relative to the primary site of disease. For oral cavity cancers, the lymph nodes at greatest risk are located in Levels I, II, and III. The lymph nodes at greatest risk for oropharyngeal, hypopharyngeal, and laryngeal cancers are located in Levels II, III, and IV, and for thyroid cancer, are in Level VI.
Extended radical neck dissection
Extended radical neck dissection (ERND) refers to the removal of one
or more additional lymph node groups or non-lymphatic structures,
or both, not encompassed by the radical neck dissection.
Examples of such lymph node groups include:
- parapharyngeal (retropharyngeal) nodes
- superior mediastinal nodes
- perifacial (buccinator) nodes
- para-tracheal lymph nodes
Examples of the non-lymphatic structures include:
The additional lymphatic or non-lymphatic structure(s), or both, should be identified.