Head and neck cancer is the sixth most common cancer worldwide. The single most important factor affecting prognosis for squamous cell carcinoma is the status of the cervical lymph nodes. Metastasis to the regional lymph nodes reduces the 5-year survival rate by 50% compared with that of patients with early-stage disease. The American Cancer Society reports that 40% of patients with squamous carcinoma of the oral cavity and pharynx present with regional metastases. Therefore, management of cervical lymph nodes is a vital component in the overall treatment plan for patients with squamous cell carcinoma of the head and neck.
The classification of cervical lymph nodes is according to the system developed at Memorial Sloan-Kettering Cancer Center in the 1930s. This system divides the lymph nodes in the lateral aspect of the neck into five nodal levels, I through V as described below. The lymph nodes in the central compartment are in category level VI, and those in the superior anterior mediastinum are level VII. The clinical and surgical landmarks for neck node levels are:
1. Level I (submental and submandibular triangles) borders are:
2. Level II (upper jugular lymph nodes) borders are:
3. Level III (middle jugular lymph nodes) borders are:
4. Level IV (lower jugular lymph nodes) borders are:
5. Level V (posterior triangle of the neck) borders are:
6. Level VI: (central compartment of the neck) borders are:
7. Level VII: (superior mediastinal lymph nodes) borders are:
Before understanding the indications of neck dissection, it is essential to revise the brief background, history, and types of neck dissection. The credit for neck dissection as a curative procedure for cervical metastases belongs to George Washington Crile from the Cleveland Clinic. In 1900, he performed different types of neck dissections and subsequently described the classic operation of RND in his seminal article of 1905 published in the Transactions of the Southern Surgical and Gynecological Association. This operation is considered being the basic neck dissection, and all other procedures are considered being its modifications. Hayes Martin from Memorial Sloan-Kettering Cancer Center, who described the stepwise procedure of RND in his classic article in 1951 popularized this operation. However, this operative procedure is not without morbidity, as it results in a cosmetic deformity and dysfunction of shoulder movement. Argentinian Oswaldo Suarez was the first to describe functional neck dissection in 1963, now called modified radical neck dissection (MRND). He described the removal of all five lymph node levels in the neck while preserving the spinal accessory nerve, sternocleidomastoid muscle, and internal jugular vein to limit any functional disability in the shoulder. The types and indications of various types of neck dissection are as follows:
1. Radical neck dissection (RND): Lymph nodes from level I-V, ipsilateral sternocleidomastoid muscle (SCM), internal jugular vein (IJV), and spinal accessory nerve (SAN) undergo removal. RND is indicated when N+ the neck for squamous cell carcinoma (SCC) where SAN involved and/or extensive soft tissue disease with the invasion of SCM and IJV.
2. Modified radical neck dissection type I (MRND-I): Lymph nodes from level I-V, ipsilateral sternocleidomastoid muscle, and internal jugular vein get removed, with preservation of the spinal accessory nerve. Indications for MRND-I is in N+ the neck for SCC where SAN is free of disease.
3. Modified radical neck dissection type II (MRND-II): Removal of lymph nodes from level I-V and ipsilateral sternocleidomastoid muscle, with preservation of IJV and SAN. The N+ neck for SCC or thyroid cancer where IJV involved but SAN is free of disease.
4. Modified radical neck dissection type II (MRND-III): Lymph nodes from level I-V undergo removal, with preservation of SCM, IJV, and SCM. MRND-III is indicated in metastatic differentiated thyroid carcinoma.
The severe comorbidities related to the removal of SCM, IJV, and SAN led to the numerous modifications of the procedure with selective removal of lymph nodes. They are:
1. Supraomohyoid neck dissection (SOHD): Lymph nodes removed are Levels I–III, with sparing of IJV, SCM, and SAN. SOHD is indicated in N0 neck for SCC of oral cavity and oropharynx (include level 4) and N0 neck malignant melanoma where primary site is anterior to ear (include parotidectomy for face and scalp).
2. Extended supraomohyoid neck dissection (Ex SOHD): Removal of lymph nodes in levels I–IV, with sparing of IJV, SCM, and SAN. The procedure is indicated in N0 neck for SCC of the lateral tongue.
3. Lateral neck dissection: Removal of lymph nodes from level II-IV with sparing of IJV, SCM, and SAN. Indications for this procedure are in N0 neck for SCC of larynx and hypopharynx.
4. Postero-lateral neck dissection: Removal of levels II–V, suboccipital, retro-auricular nodes with sparing of IJV, SCM, and SAN. Indications for this procedure is in N0 neck malignant melanoma where the primary site is posterior to ear.
5. Modified lateral neck dissection: Removal of levels II to V lymph nodes with relative sparing of SCM, IJV, SAN, and submaxillary gland. This procedure has an indication of therapeutic neck dissection for thyroid cancer with lateral neck nodes.
The list of the basic set of types of equipment that are required and I use in my clinical practice is:
Mosquito hemostats, curved Allis forceps, Kelly hemostats, Pean forceps, thyroid tenacula, Babcock forceps, right angle clamps, assorted needle holders, towel clamps, tonsil suction tubes, Trousseau tracheal dilator, rake retractors, army-navy retractors, Richardson retractors, vein retractors, skin hooks, single and double Gelpi retractor, knife handles, no. 10 and no. 15 blades, tracheal hook, Mayo scissors, straight and curved Metzenbaum scissors, scissors, small, curved, sharp and blunt, tissue forceps, Adson tissue forceps, Brown-Adson tissue forceps, periosteal elevators, Freer elevators, bayonet forceps, Brown or Stryker dermatome (if there is anticipation of a skin graft), needle magnet or counter graduate bulb syringes, dissectors (peanut), umbilical tapes, vessel loops, nerve stimulator (locator), suction drainage unit, lap sponges, 4x4 cotton-gauze sponges.
The surgical team comprises:
An operating surgeon, A resident assistant, scrub nurse, circulating nurse, and the anesthetist.
There are no specific preoperative preparatory requirements for patients undergoing neck dissection other than planning of the incisions for neck dissection, particularly if the primary tumor isundergoing resection simultaneously. Also, preparation of the neck dissection incisions must take into consideration any reconstructive effort required to repair the surgical defectcreated after excision of the primary tumor. General endotracheal anesthesia with muscle relaxation is essential for performing a neck dissection. The patient placement is in the supine position with the head elevated to 30 degrees. The neck is hyper-extended and rotated to the opposite side.
Incision: A single trifurcate neck incision was the most frequently used incision in the past. However, it is now these operations are carried out effectively with a single skin crease incision in the mid-neck of sufficient length. The named incisions that a reader should know are Latyshevsky and Freund, Mac Fee, Crile, Kocher, Schobinger, and Hockey stick incision.
Raising skin flaps: The skin incision is deepened through the subcutaneous tissue and then through the platysma muscle. The posterior flap is then raised in the subplatysmal plane by applying traction to the flap with skin hooks and counter-traction of the deeper soft tissues. The flap is elevated up to the anterior border of the trapezius muscle. (Figure I).
Identifying Marginal mandibular nerve: Careful identification of the marginal branch of the facial nerve is crucial. Posteriorly the greater auricular nerve and the external jugular vein overlying the sternocleidomastoid muscle come into view as the elevation of the flap continues. The greater auricular nerve and the external jugular vein should be identified carefully and preserved. We advise the use of the scalpel or scissors to dissect around the mandibular branch rather than electrocautery as it may cause temporary damage to the nerve. This nerve lies just anterior to the submandibular fascia and superficial to the posterior facial vein. The vein is ligated, and its upper stump retracted cephalad, protecting the marginal branch of the facial nerve. The pre-vascular facial lymph nodes are exposed and dissected out (Hayes Martin maneuver).
Superior Dissection: The fibrous fatty tissue of the submental triangle is dissected off the anterior bellies of the digastric muscles and the mylohyoid. The fascia is then dissected off the anterior belly of the digastric muscle, and the specimen is retracted posteriorly, removing the fibrous fatty tissue containing lymph nodes lateral to the mylohyoid muscle. When the dissection reaches the posterior border of the mylohyoid, this is retracted anteriorly, exposing the lingual nerve and the submandibular gland duct are divided. Finally, the facial artery is ligated as it crosses forward, under the posterior belly of the digastric muscle. The tail of the parotid gland is transected, and the sternocleidomastoid muscle is then incised close to its insertion in the mastoid process. The fibro-fatty tissue medial to the muscle is incised, exposing the splenius capitis and the levator scapulae muscles. Otherwise, incising the fascia below the digastric muscle and gentle inferior traction of the specimen allows identification of the hypoglossal nerve, the upper end of the internal jugular vein, and the spinal accessory nerve. At this point in the dissection, the internal jugular vein and the spinal accessory nerve are divided if the location and extent of the tumor permit it.
Inferior dissection: The dissection is continued posteriorly and inferiorly along the anterior border of the trapezius muscle. The spinal accessory nerve and the transverse cervical vessels are divided as they cross the anterior the border of the trapezius muscle. During this step of the operation, it is important to preserve the branches of the cervical plexus that innervate the levator scapulae muscle, unless the extent of the disease in the neck precludes it. The sternocleidomastoid muscle and the superficial layer of the deep cervical fascia are incised above the superior border of the clavicle. The external jugular vein and the omohyoid muscle are divided. The fibro-fatty tissue in this region is then gently pushed in an upward direction, exposing the brachial plexus, the scalenus anticus muscle, and the phrenic nerve (Fig. 1-6). Posteriorly, the dissection is continued to join the previous dissection along the anterior border of the trapezius.
Medial dissection: The dissection is continued medially to expose the vagus nerve, the common carotid artery, and the internal jugular vein. Inferiorly, the phrenic nerve is identified and protected. The surgeon must remain very vigilant on the left side to be able to identify thoracic duct, which arches downward and forward from behind the common carotid to open into the internal jugular vein, the subclavian vein, or the angle formed by the junction of these two vessels. The duct is located anterior or superficial to the anterior scalene muscle and the phrenic nerve. To prevent a chyle leak, the surgeon must also remember that the thoracic duct may have multiple connections at its upper end and that at the base of the neck it usually receives a jugular, a subclavian, and perhaps other minor lymphatic trunks, which must be individually ligated or clipped.
The internal jugular vein can be divided either superiorly or inferiorly, depending on the location of the disease in the neck. If the tumor mass is located low in the jugulodigastric region or the mid-jugular region, the internal jugular vein is first ligated and divided superiorly. The dissection then continues in an inferior direction, separating the specimen from the vagus nerve, the carotid artery, and the superior thyroid vessels. If instead, the disease is located high in the jugulodigastric region, the internal jugular vein is dividedinferiorly, and the dissection continues in a superior direction along the common carotid artery; this is especially useful when the tumor is extensive and may require removal of the external carotid artery or the hypoglossal nerve. Mobilization of the surgical specimen from below allows easier dissection from the internal carotid artery and, if possible, the external carotid and the hypoglossal nerve.Closure: Incision closure is in two layers: the first layer approximates the platysma anteriorly and the subcutaneous tissue laterally, and the second layer approximates the skin. One or two suction drains should remain in place. The drain(s) should not rest immediately over the carotid artery or in the area of the thoracic duct.
1. Infection.2. Air leak.3. Postoperative bleeding.4. Chylous fistula. The reported incidence varies between 1% and 2.5%. Management depends on the time of onset of the fistula, on the amount of chyle drainage in 24 hours, and the presence or absence of accumulation of chyle under the skin flaps. When the daily output of chyle exceeds 600 mL in a day or 200 to 300 mL per day for 3 days, especially when the chyle fistula becomes apparent immediately after surgery, conservative closed wound management is unlikely to succeed; these are indications for surgical exploration.5. Synchronous bilateral radical neck dissections, in which both internal jugular veins undergo ligation, can result in the development of facial edema, cerebral edema, or both; blindness; and hypoxia.6. Carotid artery rupture. The most feared and often lethal complication after neck surgery is exposure and rupture of the carotid artery. Therefore, every effort must be made to prevent it. If the skin incisions have proper design, the carotid seldom becomes exposed in the absence of a salivary fistula. If the carotid becomes exposed, it should be covered promptly with well-vascularized tissue.
7. The most notable sequelae observed in patients who have undergone a radical neck dissection are related to removal of the spinal accessory nerve. The resulting denervation of the trapezius muscle causes destabilization of the scapula with progressive flaring at the vertebral border, drooping, and lateral and anterior rotation. The loss of trapezius function decreases the patient’s ability to abduct the shoulder above 90 degrees at the shoulder. These physical changes result in a syndrome of pain, weakness, and deformity of the shoulder girdle commonly associated with the radical neck dissection.
Currently, head and neck surgeons throughout the world use a variety of different cervical lymph node dissections for the surgical treatment of the neck in patients with cancer of the head and neck region. In contrast to the measured pace of refinements to the technique of neck dissection, the role of neck dissection in the management of regional disease across the entire gamut of histologies, from squamous cell carcinoma to cutaneous melanoma, to papillary thyroid carcinoma, is evolving rapidly. As chemoradiotherapy (CRT) has become the cornerstone of the primary treatment of squamous cell carcinoma of the head and neck, there has been considerable debate as to the appropriate treatment of advanced nodal disease (stage N2 or N3) in these patients.
1. The residency and fellowship programs in head and neck surgery should possess the tools and skill set needed to manage such a challenging disease.
2. Multidisciplinary head and neck cancer teams with the education and experience should propagate high- quality care based on the principles of maximizing survival and functional preservation.
3. The strategic priorities should be in place to take part in national initiatives to improve the quality of cancer care through the development of quality measures that are disease-specific and based on the best evidence available.
4. The patients with head and neck cancer care should be under the care of regional and tertiary care facilities with the infrastructure to care for them, as this will reduce costs and improve the quality of care.