Radical neck dissection

General endotracheal anesthesia with adequate muscle relaxation is essential. The patient typically is in the supine position, with the head and chest elevated to 30°. The neck is hyperextended and turned to the contralateral side. Although the skin incision will be affected by the planned resection of the primary tumor and subsequent reconstruction, adequate exposure and preservation of cutaneous vascular supply must be achieved. Most commonly, a single trifurcate incision is used (Figure 2), extending from the ipsilateral mastoid tip along an upper neck skin crease up to the midline at the level of the thyrohyoid membrane, approximately 2 fingerbreadths below the mandible. The descending limb of the incision begins at the posterior border of the ipsilateral sternocleidomastoid muscle and travels in a curvilinear fashion to the midclavicular point. The skin incision is made with a scalpel and the dissection proceeds thereafter with electrocautery. At the beginning of the procedure, only the posterior half of the transverse incision and the descending limb are incised; the remaining incision is made after the posterior triangle dissection has been completed.

The posterior skin flap is elevated initially, in the subplatysmal plane, up to the anterior border of the trapezius muscle, which should be exposed from the mastoid to the clavicle, and represents the posterior limit of dissection. If the platysma is invaded by metastasis, it is resected, and dissection therefore proceeds superficial to the platysma in a subcutaneous plane. Countertraction is applied and the soft tissue is divided from the anterior border of the trapezius muscle and elevated off of the floor of the posterior triangle of the neck, with sequential exposure of the splenius capitis, levator scapulae and scalene muscles. During this dissection the peripheral cutaneous branches of the cervical plexus and the spinal accessory nerve are divided. The transverse cervical artery and vein are identified, divided between clamps and ligated inferiorly. Care is taken to identify the brachial plexus between the middle and anterior scalene muscles, and the phrenic nerve on the surface of the anterior scalene muscle (Figure 3). This is facilitated by division of the posterior belly of the omohyoid and its retraction medially. Cutaneous cervical nerve branches are identified coming off of the cervical roots as dissection proceeds cephalad. The cutaneous branches are divided, carefully preserving the motor branches to the posterior compartment muscles and the phrenic nerve. The cutaneous roots are ligated along with their accompanying small blood vessels. The superior attachment of the sternocleidomastoid muscle to the mastoid tip is divided and the specimen is allowed to rest in situ.

The remaining transverse skin incision is then completed and attention is turned anteriorly. The anterior flap is elevated in the subplatysmal plane until the sternal and clavicular attachments of the sternocleidomastoid muscle are exposed and divided. Retraction of this detached muscle superiorly allows identification of the carotid sheath. Meticulous sharp and blunt dissection exposes the common carotid artery and the vagus nerve, which are preserved, and the internal jugular vein, which is divided at its lower end and doubly ligated (Figure 4). Care is taken to identify and ligate lymphatic vessels on either side of the neck, with particular attention to controlling the thoracic duct on the left side of the neck. The proximal stumps of the transverse cervical artery and vein are divided and ligated.

Dissection continues cephalad within the carotid sheath, with division of the middle thyroid vein and identification of the hypoglossal nerve after the carotid bifurcation where it may loop around the occipital branch of the external carotid artery. The descendens hypoglossi to the strap muscles is often a good guide, leading up to the hypoglossal nerve. The common facial vein and several pharyngeal veins crossing the digastric muscle are divided to expose the posterior belly and tendon of the digastric up to the hyoid bone (Figure 5). The anterior belly of the omohyoid muscle is the anterior limit of the dissection. It is divided near the hyoid bone. The superior thyroid artery is preserved while the superior thyroid vein is divided and ligated. Once the lower border of the digastric muscle is exposed completely, the specimen is allowed to rest in the surgical field.

Attention is then turned to the superior flap, which is also elevated in the subplatysmal plane with care taken to identify and preserve the marginal mandibular branch of the facial nerve as it crosses the facial artery and vein (Figure 6). Retraction of the superior stumps of these vessels after their division further protects the nerve (Figure 7). Dissection continues anteriorly along the border of the mandible. The superomedial limit of dissection is the anterior belly of the contralateral digastric muscle. After the mylohyoid muscle is exposed and its neurovascular bundle divided and ligated (Figure 8), its lateral edge is retracted medially with a loop retractor and the submandibular gland is mobilized. The lingual nerve is identified, and its postganglionic secretomotor fibers are divided, as is Wharton’s duct (Figure 9). As the gland is elevated posteriorly, the proximal portion of the facial artery is identified, divided and ligated (Figure 10). Any remaining veins of the pharyngeal venous plexus accompanying the hypoglossal nerve must be divided between claps and ligated. After the posterior belly of the digastric is exposed and retracted superiorly, which may require transection of the tail of the parotid gland, the internal jugular vein is identified and skeletonized circumferentially. The spinal accessory nerve is identified and divided at the skull base (Figure 11), and the internal jugular vein is divided between clamps and doubly ligated, allowing delivery of the specimen.

Meticulous hemostasis is achieved, and the wound is closed over 2 suction drains. One drain is tacked posteriorly along the trapezius muscle with a loop of catgut suture. The anterior drain lies along the strap muscles. These drains are brought out through separate stab incisions inferiorly (Figure 12). The platysma is closed with 3-0 chromic catgut interrupted sutures and the skin with 5-0 nylon. Care is taken to achieve an airtight closure and to initiate suction on the drains during closure to prevent clots from forming within the drains. Postoperatively, the drains are removed when there is minimal serous drainage.

Complications unique to radical neck dissection are related to the sacrifice of the sternocleidomastoid muscle and the spinal accessory nerve. This “shoulder syndrome” can be debilitating and requires diligent physical therapy (Figure 13). Bilateral radical neck dissection can result in significant facial lymphedema, which dissipates only slowly. If combined with laryngectomy, simultaneous bilateral resection of the internal jugular veins can result in acute obstruction to both intra- and extracranial venous drainage and massive venous edema (Figure 14). The extent of resection of soft tissue in a radical neck dissection can leave the carotid artery relatively exposed, and subsequent radiation therapy increases the risk of hemorrhage. A locoregional musculocutaneous flap can provide some protection from this. Current indications for radical neck dissection are such that only patients with extensive disease, or disease that has failed prior treatment, undergo the procedure. Thus, their postoperative risks, both of complication and recurrence, are significant.