Radical neck dissection is described and illustrated. Radical neck dissection refers to the removal of all ipsilateral cervical lymph node groups extending from the inferior border of the mandible superiorly to the clavicle inferiorly and from the lateral border of the sternohyoid muscle, hyoid bone, and contralateral anterior belly of the digastric muscle anteriorly to the anterior border of the trapezius muscle posteriorly. Today most surgeons employ a modified radical neck dissection or functional neck dissection.
Modified radical neck dissection is defined as the excision of all lymph nodes routinely removed in a radical neck dissection with preservation of one or more nonlymphatic structures (spinal accesory nerve, internal jugular vein, and strenocleidomastoid muscle).
The surgeon stands on the side of the proposed dissection. Many types of incision have been used. The incision illustrated allows maximum anatomic visualization, whereas many surgeons prefer two nearly parallel, oblique incisions with an intervening skin bridge that is broadly based at both ends. The most useful incision is a modification of the double trifurcate incision (Figure 1), in which the angles of the skin flaps are obtuse and connected by a short vertical incision. Some prefer to make only the upper transverse incision with a single vertical extension that proceeds to the sternocleidomastoid muscle edge and then takes a lazy-S posterior course to the clavicle, as shown by the dashed line in Figure 1. The upper arm of the double Y extends from the mastoid process to just below the midline of the mandible. The lower arm extends from the trapezius in a gentle curve to the midline of the neck. This incision allows the greatest exposure of the neck area while producing a good cosmetic result. Creation of the skin flaps includes the platysma muscle (Figure 2). In most instances, if the skin flaps are developed without inclusion of the platysma muscle, poor wound healing and uncomfortable scarring with fixation of the skin to the deep neck structures will result. The two lateral skin flaps are turned back, the posterior flap is extended as far as the anterior edge of the trapezius muscle, and the anterolateral flap is extended to expose the strap muscles covering the thyroid gland. In developing the superior skin flap, care must be taken to preserve the mandibular marginal branch of the facial nerve (Figure 2). This branch of the facial nerve innervates the lower lip. In the majority of cases the nerve can be identified as it crosses over the external maxillary artery and the anterior facial vein beneath the platysma muscle. Usually, it lies parallel to the lower border of the mandible. Occasionally, the nerve will lie much higher, and it may not be visualized during the neck dissection. As suggested by others, a useful maneuver to preserve this nerve is to identify the external maxillary artery and the anterior facial vein at least 1 cm below the lower border of the mandible (Figure 2). After identification, the nerve is retracted and covered by securing the upper end of the vascular stump to the platysma muscle. If obvious or strongly suspected tumor is present in this area, the branches of this nerve are sacrificed voluntarily. The inferior skin flap should be reflected down to expose the superior aspect of the clavicle.