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Neck Dissection


Key Points

  • 1.

    The presence of cervical lymphadenopathy is a significant negative prognostic indicator in head and neck squamous cell carcinoma.

  • 2.

    Knowledge and identification of first echelon nodes for various primary head and neck tumor sites allows for selective neck dissection of nodes at greatest risk for metastatic disease.

  • 3.

    A thorough knowledge of key anatomic relationships allows the surgeon to preserve important anatomic structures while proceeding efficiently with an oncologic neck dissection.

  • 4.

    In certain contexts, controversies remain in the approach and extent of surgical management of neck disease where evidence that weighs the risks and morbidity of the procedure versus the procedure’s impact on survival is not yet available.

Pearls

  • 1.

    Plan the neck incision appropriately. Consider the lymph node basins to be dissected, be at least two finger breadths below the mandible to protect the marginal mandibular nerve and for improved cosmesis, and avoid incisions with trifurcations, especially a trifurcation over the carotid. Also consider the need for cervicofacial advancement flaps, supraclavicular artery island flaps, submental flaps, and other reconstructive options.

  • 2.

    Raise superior and inferior neck skin flaps in the subplatysmal plane to preserve the vascular supply and viability of the skin flaps. The superior limit is the inferior border of the mandible and the inferior limit is the clavicle.

  • 3.

    The digastric muscle is often referred to as the “resident’s friend” because it is lateral to many of the most important structures of the neck, including the internal jugular vein (IJV), carotid artery, and the hypoglossal nerve. Dissecting systematically along the digastric muscle prevents injury to these structures.

  • 4.

    Cranial nerve (CN) XI is located at the junction of the upper one-third and lower two-thirds of the sternocleidomastoid muscle and is typically accompanied by a vessel that is encountered first. The relationship of CNXI and the IJV is variable. CNXI is most commonly superficial to the vein but can also be posterior to or travel between the IJV. In Level V, CNXI is identified deep to Erb’s point and travels obliquely to the trapezius muscle. It is important not to confuse CNXI with superficial branches of the cervical plexus.

  • 5.

    It is important that the fibrofatty tissue of Level IIb be passed underneath CNXI to be removed en bloc with the rest of the neck dissection specimen.

  • 6.

    The floor of the neck dissection is formed by the fascia overlying the splenius capitis and levator scapulae muscles superiorly, the deep cervical rootlets in the mid-portion, and the scalene muscles (anterior, middle, posterior) inferiorly.

  • 7.

    The phrenic nerve can be preserved by not violating the vertebral layer (or deep layer) of the deep cervical fascia at the level of the scalene muscles.

  • 8.

    The deep branches of the cervical plexus should be preserved as well as the transverse cervical artery and vein.

  • 9.

    A dissection too far medial along the deep muscles of the neck may result in injury to the sympathetic chain, which runs posterior to the carotid artery and should be preserved.

  • 10.

    The best way to prevent a chyle leak is to dissect laterally from the IJV as you dissect below the omohyoid muscle (i.e., Level IV). Lymphatic vessels must be handled and ligated carefully when identified. Dissecting and ligating the Level IV tissues in segments may aid in capturing crossing lymphatic vessels. Increasing the intrathoracic pressure via Valsalva maneuver during surgery can test for and identify the source of a chyle leak.

Questions

1

According to the American Joint Committee on Cancer (AJCC), what constitutes the Level I nodal group?

Level I includes both submental (Ia) and submandibular (Ib) lymph node basins. Anatomically, Ia includes the triangle formed by the anterior bellies of the digastric muscle bilaterally and the hyoid bone, and the mylohyoid muscle forms the floor. Level Ib is bound by the posterior belly of the digastric muscle and the mandible and includes lymph nodes around the facial artery and vein ( Fig. 17.1 ).

Fig. 17.1, The six levels of the neck for describing the location of lymph nodes.

2

What constitutes the Level II nodal group?

Level II includes the uppermost jugular nodes and is divided into Level IIa (nodes anteromedial to the spinal accessory nerve/cranial nerve XI) and Level IIb (nodes posterior lateral to CNXI). This includes all nodes adjacent to the great vessels from the skull base to the carotid bifurcation and from the sternohyoid muscle to the posterior border of the sternocleidomastoid muscle (SCM) ( Fig. 17.1 ).

3

What constitutes the Level III nodal group?

Level III includes the mid-jugular nodes extending from the carotid bifurcation to the omohyoid muscle and from the sternohyoid muscle to the posterior border of the SCM ( Fig. 17.1 ).

4

What constitutes the Level IV nodal group?

Level IV includes the inferior-most jugular nodes extending from the omohyoid muscle to the clavicle and from the sternohyoid muscle to the posterior border of the SCM ( Fig. 17.1 ).

5

What constitutes the Level V nodal group?

Level V includes the posterior triangle bounded by the posterior border of the SCM, the anterior edge of the trapezius muscle, and the clavicle. Level V is divided into two subgroups by a horizontal plane at the level of the cricoid: Level Va (spinal accessory nodes) and level Vb (supraclavicular and transverse cervical nodes) ( Fig. 17.1 ).

6

What serves as the boundary between Levels II to IV and Level V?

The plane delineated by the cervical plexus rootlets serves as the deep boundary of Levels II to IV and the corresponding superficial boundary of level V.

7

What constitutes the Level VI nodal group?

Level VI includes the central compartment nodes extending from the hyoid bone to the suprasternal notch and laterally by the carotid arteries. These include pretracheal, paratracheal, and Delphian (precricoid) nodes. Perithyroidal nodes and nodes occurring along the recurrent laryngeal nerves are also in Level VI ( Fig. 17.1 ).

8

Which primary sites are most likely to metastasize to these nodal groups?

  • 1.

    Level Ia: Anterior oral tongue, floor of mouth, lower alveolar ridge/gingiva, lower lip

  • 2.

    Level Ib: Oral cavity (including tongue, lateral floor of mouth, buccal mucosa), anterior nasal cavity, maxillary sinus, submandibular gland

  • 3.

    Level II: Most primary head and neck sites including oral cavity, nasal cavity, nasopharynx, oropharynx, hypopharynx, larynx, parotid gland

  • 4.

    Level III: Oral cavity, oropharynx, nasopharynx, hypopharynx, larynx

  • 5.

    Level IV: Hypopharynx, thyroid, larynx, cervical esophagus

  • 6.

    Level V: Cutaneous malignancies of posterior scalp and neck, nasopharynx, oropharynx

  • 7.

    Level VI: Thyroid, larynx (glottic and subglottic), cervical esophagus, apex of piriform sinus ( Fig. 17.1 )

9

What is the AJCC eighth edition clinical staging for nodal disease for head and neck tumors (excluding human papillomavirus (HPV)-positive oropharynx, nasopharynx, and thyroid)? How does it differ from pathologic staging?

Regional Lymph Nodes (N), Clinical N (cN)

  • NX Regional lymph nodes cannot be assessed

  • N0 No regional lymph node metastasis

  • N1 Metastasis in a single ipsilateral lymph node, 3 centimeters or smaller in greatest dimension, extranodal extension (ENE)(−)

  • N2 Metastasis in a single ipsilateral node, 3 to 6 centimeters in greatest dimension, ENE(−); or metastases in multiple ipsilateral lymph nodes, none larger than 6 centimeters in greatest dimension, and ENE(−); or in bilateral or contralateral lymph nodes, none larger than 6 centimeters in greatest dimension, and ENE(−)

    • N2a Metastasis in a single ipsilateral lymph node, 3 to 6 centimeters in greatest dimension and ENE(−)

    • N2b Metastases in multiple ipsilateral lymph nodes, none larger than 6 centimeters in greatest dimension, and ENE(−)

    • N2c Metastases in bilateral or contralateral lymph nodes, none larger than 6 centimeters in greatest dimension, and ENE(−)

  • N3 Metastasis in a lymph node larger than 6 centimeters in greatest dimension and ENE(−); or metastasis in any node(s) and clinically overt ENE(+)

    • N3a Metastasis in a lymph node larger than 6 centimeters in greatest dimension and ENE(−)

    • N3b Metastasis in any node(s) and clinically overt ENE(+)

pN2 and pN3 pathologic staging differs as outlined below. pNX, pN0, and pN1 is the same as clinical staging.

  • pN2 Metastasis in a single ipsilateral node, 3 centimeters or smaller in greatest dimension, and ENE(+); or 3 to 6 centimeters in greatest dimension and ENE(−); or metastases in multiple ipsilateral lymph nodes, none larger than 6 centimeters in greatest dimension, and ENE(−); or in bilateral or contralateral lymph node(s), none larger than 6 centimeters in greatest dimension, and ENE(−)

    • pN2a Metastasis in a single ipsilateral node, 3 centimeters or smaller in greatest dimension, and ENE(+); or a single ipsilateral node, 3 to 6 centimeters in greatest dimension, and ENE(−)

    • pN2b Metastases in multiple ipsilateral lymph nodes, none larger than 6 centimeters in greatest dimension, and ENE(−)

    • pN2c Metastases in bilateral or contralateral lymph nodes, none larger than 6 centimeters in greatest dimension, and ENE(−)

  • pN3 Metastasis in a lymph node larger than 6 centimeters in greatest dimension and ENE(−); or metastasis in a single ipsilateral node larger than 3 centimeters in greatest dimension and ENE(+); or multiple ipsilateral, contralateral, or bilateral nodes any with ENE(+); or a single contralateral node of any size and ENE(+)

    • pN3a Metastasis in a lymph node larger than 6 centimeters in greatest dimension and ENE(−)

    • pN3b Metastasis in a single ipsilateral node larger than 3 centimeters in greatest dimension and ENE(+); or multiple ipsilateral, contralateral, or bilateral nodes any with ENE(+); or a single contralateral, node of any size and ENE(+)

10

What is the AJCC eighth edition clinical nodal staging for nasopharyngeal tumors?

Regional Lymph Nodes (N)

  • NX Regional lymph nodes cannot be assessed

  • N0 No regional lymph node metastasis

  • N1 Unilateral metastasis in cervical lymph node(s) and/or unilateral or bilateral metastasis in retropharyngeal lymph node(s), 6 centimeters or smaller in greatest dimension, above the caudal border of cricoid cartilage

  • N2 Bilateral metastasis in cervical lymph node(s), 6 centimeters or smaller in greatest dimension, above the caudal border of cricoid cartilage

  • N3 Unilateral or bilateral metastasis in cervical lymph node(s), larger than 6 centimeters in greatest dimension, and/or extension below the caudal border of cricoid cartilage

11

What is the AJCC eighth edition clinical nodal staging for HPV+ oropharyngeal tumors? How does it differ from pathologic staging?

Regional Lymph Nodes (N), Clinical N (cN)

  • NX Regional lymph nodes cannot be assessed

  • N0 No regional lymph node metastasis

  • N1 One or more ipsilateral lymph nodes, none larger than 6 centimeters

  • N2 Contralateral or bilateral lymph nodes, none larger than 6 centimeters

  • N3 Lymph node(s) larger than 6 centimeters

Regional Lymph Nodes (N), Pathologic N (pN)

  • NX Regional lymph nodes cannot be assessed

  • pN0 No regional lymph node metastasis

  • pN1 Metastasis in four or fewer lymph nodes

  • pN2 Metastasis in more than four lymph nodes

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