16 Neck Dissection

Question 1

According to the AJCC, what constitutes the Level I nodal group?

Answer 1

According to the AJCC, what constitutes the Level I nodal group?

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

Question 2

What constitutes the Level II nodal group?

Answer 2

What constitutes the Level II nodal group?

Level II includes the uppermost jugular nodes and is divided into Level IIa (nodes anterior to the spinal accessory nerve: cranial nerve XI) and Level IIb (nodes posterior to CN XI). Anatomically, 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)

Question 3

What constitutes the Level III nodal group?

Answer 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 (see Figure 16-1).

Question 4

What constitutes the Level IV nodal group?

Answer 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 (see Figure 16-1).

Question 5

What constitutes the Level V nodal group?

Answer 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 inferiorly. It includes Level Va (spinal accessory nodes) and Vb (supraclavicular and transverse cervical nodes) (see Figure 16-1).

Question 6

What constitutes the Level VI nodal group?

Answer 6

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 the pretracheal, paratracheal, and Delphian (precricoid) nodes. Perithyroidal nodes and nodes occurring along the recurrent laryngeal nerves are also in Level VI (see Figure 16-1).

Question 7

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

Answer 7

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

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

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

Level II: This nodal basin drains most of the primary SCCHN sites including the oral cavity, nasal cavity, nasopharynx, oropharynx, hypopharynx, larynx, parotid gland

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

Level IV: Hypopharynx, thyroid, larynx, cervical esophagus

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

Level VI: Thyroid, larynx (glottic and subglottic), cervical esophagus, apex of piriform sinus (see Figure 16-1)

Question 8

What is the AJCC staging for nodal disease for head and neck tumors (excluding nasopharynx and thyroid)?

Answer 8

What is the AJCC staging for nodal disease for head and neck tumors (excluding nasopharynx and thyroid)?

see image

Question 9

What is the AJCC staging for nodal for nasopharyngeal tumors?

Answer 9

What is the AJCC staging for nodal for nasopharyngeal tumors?

see image

Question 10

What is the AJCC staging for nodal for thyroid tumors?

Answer 10

What is the AJCC staging for nodal for thyroid tumors?

see image

Question 11

What is a radical neck dissection (RND)?

Answer 11

What is a radical neck dissection (RND)?

This neck dissection, first popularized by George Crile in the early twentieth century and later by Hayes Martin in the 1950s, espoused the concept of radical en bloc resection of cervical lymph nodes for cancers of the head and neck. RND included removal of lymph node Levels I through V, along with the SCM, IJV, and spinal accessory nerve (CN XI). Morbidities resulting from RND include shoulder dysfunction due to sacrifice of CN XI (winged scapula, inability to raise the arm above 90 degrees, shoulder pain), and limited bilateral surgery due to IJV sacrifice.

Question 12

What are the indications for an RND?

Answer 12

What are the indications for an RND?

RND is indicated for patients whose cervical node metastasis has extended beyond the capsule of the lymph node to invade the SCM, the spinal accessory nerve, or IJV.

Question 13

What is a modified radical neck dissection (MRND)?

Answer 13

What is a modified radical neck dissection (MRND)?

In an MRND, lymph node Levels I through V are removed, but one or more of the nonlymphatic structures (spinal accessory nerve, SCM, or IJV) are spared. This significantly reduces the morbidity associated with a RND.

Question 14

What are the indications for a MRND?

Answer 14

What are the indications for a MRND?

Unless there is fixation or infiltration of the nonlymphatic structures by tumor, the SCM, IJV, and spinal accessory nerve are preserved. Given that hypoglossal and lingual nerves are routinely preserved in neck dissection, sacrificing an uninvolved spinal accessory nerve in an en bloc resection of the neck cannot be justified. In bilateral neck dissections, removal of both internal jugular veins can result in significant venous edema and chronic lymphedema of the face and can be fatal in 10% of patients when performed simultaneously. At least one IJV should be preserved in bilateral procedures. If both IJVs are involved by disease, a staged neck dissection separated by at least 2 weeks should be performed to allow for collateral circulations to develop.

Question 15

What is a selective neck dissection (SND)?

Answer 15

What is a selective neck dissection (SND)?

In an SND, an en bloc resection of one or more nodal groups is performed while preserving nonlymphatic structures. Only the nodal groups determined to be at highest risk for metastasis are removed, thus preserving functional and cosmetic structures within the neck.

Question 16

What are the indications for an SND?

Answer 16

What are the indications for an SND?

In previously untreated patients with SCCHN, the level of nodal metastasis occurs in a predictable pattern. This allows for the identification of highest-risk first-echelon lymph nodes for a variety of primary tumor sites (see Question 7). SND can be used for treatment in conjunction with resection of tumors with limited neck disease, for surgical staging of the neck in the clinically N0 neck, or to direct further adjuvant therapy if multiple nodes or the presence of extracapsular spread is found.

Question 17

What is the extent of SND in these primary SCCHN sites?

Answer 17

What is the extent of SND in these primary SCCHN sites?

• Oral cavity: Levels I, II, III (supraomohyoid neck dissection)
• Oropharynx, hypopharynx, larynx: Levels II-IV (lateral neck dissection)
• Posterior scalp: Levels II-V, retroauricular, and suboccipital nodes (posterolateral neck dissection)
• Preauricular, anterior scalp: Levels II-Va, parotid and facial nodes
• Anterior and lateral face: Levels I-III, parotid and facial nodes
• Thyroid, esophagus, advanced laryngeal tumor: Level VI (anterior or central neck dissection). Additional levels may also be dissected with advanced tumors.

Question 18

What is the role of lymphoscintigraphy in neck dissection?

Answer 18

What is the role of lymphoscintigraphy in neck dissection?

The use of lymphoscintigraphy and sentinel lymph node biopsy (SNLB) in head and neck melanoma is well established and is a good predictor of disease-free survival with low false negative rates. In head and neck mucosal malignancies, SNLB can be used to (1) stage neck disease in clinically NO necks; (2) identify lymphatic flows into atypical nodal basins that would not be addressed in classic SNDs; (3) determine lymphatic flow changes as a result of surgery and radiation that are at risk for metastasis from recurrent or residual disease. SNLB as a method for avoiding neck dissection is considered investigational and not widely accepted as standard of care.

Question 19

What are some complications after a neck dissection?

Answer 19

What are some complications after a neck dissection?

Chyle leak: Most commonly associated with a Level IV dissection. Occurs in 1% to 2% of neck dissections. Injury to the thoracic duct occurs as it enters the IJV laterally just superior to the junction of the IJV and subclavian vein. Daily output greater than 500 ml will require surgical exploration and ligation of the duct. Output of less than 500 ml may be managed conservatively with pressure dressing, low-fat diet, and wound drainage. Total parenteral nutrition may be considered in high-output leaks.

Facial and cerebral edema: Associated with bilateral ligation of IJV and in patients with previous radiation therapy. This can be avoided by staged neck dissections and by preserving one or more external jugular veins. Cerebral edema resulting from IJV ligation can cause inappropriate secretions of antidiurectic hormone (SIADH). Intravenous fluids should be carefully administered in bilateral neck dissections where the IJV is ligated and serum and urine osmolarity carefully monitored perioperatively.

Carotid rupture/blowout: This catastrophic complication is associated with salivary fistula, flap breakdown due to previous radiation, malnutrition, infection, and diabetes. Poorly placed and designed flap incisions can expose the carotid and increase risk of rupture. Placement of vascularized tissue over the carotid is indicated in cases of large salivary fistulas or carotid exposure.

Question 20

What is the difference between a salvage neck dissection and a planned neck dissection?

Answer 20

What is the difference between a salvage neck dissection and a planned neck dissection?

Salvage neck dissection is neck dissection that occurs in the setting of an incomplete response to organ preservation treatment (radiation or chemoradiation). Salvage neck dissection can occur immediately after chemoradiation or late for recurrent disease.

Planned neck dissection refers to neck dissection that occurs early after chemoradiation as part of a planned treatment plan for large volume nodal disease (bulky N2b or N3 disease) regardless of the response to chemoradiation. The rationale behind planned neck dissection is that large pretreatment nodes may contain nests of viable SCC cells that can become the focus of recurrent disease.

Question 21

Types of neck dissection after chemoradiation or radiation therapy.

Answer 21

Types of neck dissection after chemoradiation or radiation therapy.

Neck dissection after chemoradiation falls into one of three categories:

1. Failure at the primary site: Neck dissection is performed at the same time as salvage surgery for the primary site. Usually done regardless of nodal status at completion of treatment.
2. Salvage neck dissection: Neck dissection is performed only if there is persistent nodal disease after treatment. Assessment of nodal disease is performed 8 to 10 weeks post-treatment using PET scan or CT and MRI.
3. Planned neck dissection: Some surgeons will recommend a planned neck dissection for high volume nodal disease (N3) regardless of response to therapy. In low volume nodal disease (N1 or N2), surgery is performed only if there is persistent nodal disease at post-treatment assessment at 8 to 10 weeks.

Question 22

Fine needle aspiration (FNA) versus open biopsy (excisional or incisional) of suspected cervical lymph nodes.

Answer 22

Fine needle aspiration (FNA) versus open biopsy (excisional or incisional) of suspected cervical lymph nodes. Controversial

An open biopsy may not increase rates of local recurrence, complications, and distant metastasis as previously believed, as long as adequate treatment is started in a timely fashion. But with FNA approaching 99% in sensitivity and specificity for SCC, the need for an open biopsy should be limited to those nodes suspected of having lymphoma. Neck dissection in a field that has been violated by an open biopsy may require resection of structures that normally would have been spared in SND, resulting in greater functional and cosmetic deficits to the patient. For this reason alone, an open biopsy should never be used as a first-line diagnostic procedure in SCC of the head and neck.

Question 23

Surgical treatment of the clinically negative (N0) neck.

Answer 23

Surgical treatment of the clinically negative (N0) neck. Controversial

The rationale for operating on the NO neck includes: (1) decreasing locoregional recurrence; (2) decreasing risk of distant metastasis; (3) improved overall survival benefit; and (4) pathologic staging of regional lymph nodes. While most trials have not supported any overall survival benefits of electively treating the NO neck over close clinical observation, many institutions continue to support elective treatment when the risk of occult metastasis is greater than 15%. SND encompassing the highest risk nodal basins is favored over MRND in elective treatment of the N0 neck.

Question 24

Should a carotid artery involved by tumor be sacrificed in neck dissection?

Answer 24

Should a carotid artery involved by tumor be sacrificed in neck dissection? Controversial

This is one of the most controversial issues in neck dissection. Opponents point to the relatively high rates of mortality (30%) and CNS complication (45%) with carotid resection with only 15% of patients alive and free of disease at 1 year despite carotid sacrifice. Proponents argue that with improved methods for assessing collateral circulation through the circle of Willis (endovascular balloon occlusion testing, xenon inhalation CT scan, intraarterial xenon, PET scan), a planned ligation and reconstruction of the carotid artery can result in acceptable CNS complications (12%) and improved 1-year disease-free survival rates (45%). Others have demonstrated a 22% 2-year disease-free survival. Some surgeons advocate peeling gross residual tumor off of the carotid artery as a compromise between these two approaches. A frank discussion with the patient as well as thorough preoperative testing should be performed in any cases where carotid artery resection is contemplated.

Question 25

Are MRND and SND comparable in controlling locoregional disease?

Answer 25

Are MRND and SND comparable in controlling locoregional disease? Controversial

Most studies to date support SND for both N0 and N+ neck disease in selected patients. The locoregional control rates for SND are comparable to MRND for N0 (5% recurrence) and N+ (10% recurrence) disease, especially when postoperative radiotherapy is added to groups with multiple positive nodes or nodes with extracapsular spread (ECS). Regional control rates of more than 94% are seen in large multi-institutional studies looking at the efficacy of SND in clinically N+ disease in SCCHN.

Question 26

Should SND or MRND be performed after chemoradiation?

Answer 26

Should SND or MRND be performed after chemoradiation? Controversial

In the past, most surgeons advocated MRND after radiation or chemoradiation in order to encompass all five nodal levels in salvage or planned surgery. Current data, however, suggest that for some N1 and even N2 disease, SND may be as effective as MRND in locoregional control after therapy. Even in those patients with bulky N2 or N3 disease before treatment, very few had recurrences outside of Levels II to IV, suggesting that Level V dissection may be unnecessary in a majority of salvage neck dissections. One notable exception is the posterior scalp in which Level V is a first echelon lymph node basin. For most other primary head and neck sites, SND is likely more than adequate for salvage neck dissection unless there is fixation or infiltration of surrounding tissue by nodal metastasis.