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C H A P T E R 2 | Oncologic Components of Lymphadenectomy

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Anterior and inferior nodes Internal jugular vein Carotid bifurcation

Middle scalene muscle

Vagus nerve

Subclavian vein Anterior scalene muscle Phrenic nerve Brachial plexus

Thoracic duct Transverse cervical artery Common carotid artery

FIGURE 2-10  En bloc dissection of internal jugular vein lymph nodes and exposure of the floor of the neck.

The lateral compartment can be dissected in either a medial to lateral (starting at the carotid sheath) or lateral to medial (starting posterior to the SCM) fashion as well as inferior to superior (starting at the clavicle) or superior to inferior (starting at the posterior belly of the digastric) manner. A medial to lateral/inferior to supe- rior approach is described here. Whichever approach is chosen, the dissection should be comprehensive and progressive. The dissection may be initiated superior to the clavicle (level IV) by incising the fascia over the carotid artery and IJV to expose the contents of the carotid sheath. Particular care should be taken to include the soft tissue posterior to the IJV to avoid missing lymph node metastases (Fig. 2-10). At this point during a left neck dissection, the surgeon may encounter the thoracic duct where it enters the confluence of the IJV and the subclavian vein. If either the tho- racic duct or smaller lymphatic channels are disturbed during dissection, they should be ligated to avoid development of a postoperative chyle leak. As the lymph node bundle is dissected, the phrenic nerve, which runs craniocaudally along the anterior scalene muscle, should be identified. Care should be taken to avoid dissection of the fascia overlying the anterior scalene muscle, thereby avoiding injury to the phrenic nerve, as well as the fascia overlying the brachial plexus located between anterior and middle scalene muscles. As the dissection proceeds in a caudal to cranial fashion and level II is exposed, the surgeon should appreciate the course of the hypoglossal nerve in relationship to the superior-medial aspect of the dissection (Fig. 2-11). The facial vein may need to be ligated to expose fully the level II lymph nodes and to avoid injury to the hypoglossal nerve. Superior laterally and emerging under the posterior belly of