Neck dissection | |
Specialty: | oncology |
The neck dissection is a surgical procedure for control of neck lymph node metastasis from squamous cell carcinoma (SCC) of the head and neck.[1] The aim of the procedure is to remove lymph nodes from one side of the neck into which cancer cells may have migrated. Metastasis of squamous cell carcinoma into the lymph nodes of the neck reduce survival and is the most important factor in the spread of the disease. The metastases may originate from SCC of the upper aerodigestive tract, including the oral cavity, tongue, nasopharynx, oropharynx, hypopharynx, and larynx, as well as the thyroid, parotid and posterior scalp.
To describe the lymph nodes of the neck for neck dissection, the neck is divided into 6 areas called Levels. The levels are identified by Roman numeral, increasing towards the chest. A further Level VII to denote lymph node groups in the superior mediastinum is no longer used. Instead, lymph nodes in other non-neck regions are referred to by the name of their specific nodal groups.
The submental triangle (sublevel IA) is bounded by the anterior belly of the digastric muscles (laterally) and the hyoid (inferiorly). The submandibular triangle (sublevel IB) is bounded by the body of the mandible (superiorly), the stylohyoid (posteriorly), and the anterior belly of the digastric (anteriorly).
Level II is bounded by the inferior border of the hyoid (inferiorly), the base of skull (superiorly), the stylohyoid muscle (anteriorly) and the posterior border of the SCM (posteriorly). Sublevel IIA nodes lie anterior to the SAN. Sublevel IIB nodes lie posterior to the SAN.
This level is bounded by the inferior border of the hyoid (superiorly) and the inferior border of the cricoid (inferiorly), the posterior border of the sternohyoid (anteriorly) and the posterior border of the SCM (posteriorly).
This level is bounded by the inferior border of the cricoid (superiorly), the clavicle / sternal notch (inferiorly), the posterior border of the sternohyoid (anteriorly) and the posterior border of the SCM (posteriorly).
This compartment is bounded by the clavicle (inferiorly), the anterior border of the trapezius (posteriorly), the posterior border of the SCM (anteriorly). It is divided into sublevels VA (lying above a transverse plane marking the inferior border of the anterior cricoid arch) and VB (below the aforementioned plane).
This compartment is bounded by the common carotid arteries (laterally), the hyoid (superiorly), the suprasternal notch (inferiorly).
The 2001 revisions proposed by the American Head and Neck Society (AHNS) and the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) are as follows.