Introduction
The nodal status of the neck remains one of the most important prognostic factors for overall survival in patients with cancer of the head and neck. The lymphatic drainage of the neck is organized into anatomic compartments ( Fig. 63.1 ). The type of neck dissection depends on the nodal levels removed and the extent of nonlymphatic structures preserved ( Table 63.1 ). Over the past century, the surgical approach to regional nodal metastases has continued to evolve in an effort to lessen morbidity while preserving locoregional control and survival rates. The radical neck dissection for a clinically positive neck was described by Crile more than 100 years ago and included removal of the sternocleidomastoid (SCM) muscle, spinal accessory nerve (SAN), internal jugular vein (IJV), submandibular gland, and sensory rootlets, in addition to the lymphatic bearing fibroadipose tissue. In the 1950s Suarez found success using an approach that preserved at least one of the nonlymphatic tissue-bearing structures that would come to be known as the modified radical neck dissection, which would be popular throughout the 1950s and 1960s. In both of these procedures, the lymph node levels I–V were removed, but the postoperative morbidity was decreased with the modified radical neck dissection. In the 1960s and 1970s, Ballantyne advocated for the removal of only the nodal compartments at highest risk while leaving some nodal stations undissected and preserving all nonlymphatic structures. This type of dissection would be known as the selective neck dissection and has many variations, including the supraomohyoid and the lateral neck dissection. The concept of selective neck dissections was further popularized by the work of Lindberg and then by Shah, which showed that regional spread occurs in an orderly and predictable fashion. Many studies have shown that selective neck dissection has decreased the morbidity with surgical treatment of the neck, while preserving oncologic safety in both the N0 and N+ neck.
| Radical neck dissection | Removal of nodal compartments I–V, IJV, SCM, and CN XI |
| Extended radical neck dissection | Removal of nodal compartments I–V, IJV, SCM, CNXI, and a nonlymphatic structure (nerve, vessel, muscle, skin, etc.) |
| Modified radical neck dissection | Removal of nodal compartments I–V and preservation of at one of the following: IJV, SCM, or CN XI |
| Selective neck dissection | Removal of lymphatic bearing tissue only, leaving at least 1 nodal compartment undissected |
| Superselective neck dissection | Removal of one or two contiguous nodal compartments and preserving all nonlymphatic tissue |
Recently there has been an interest in more precisely targeting nodal levels at risk and further minimizing potential complications by using the superselective neck dissection (SSND). This technique is defined by dissection of only one or two contiguous nodal stations and preservation of all nonlymphatic bearing tissue. In this chapter we will discuss the indications, technique, and rationale for SSND.
Key Operative Learning Points
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SSND is the removal of one or two contiguous neck levels while preserving all nonlymphatic structures.
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SSND is appropriate for N0 necks by examination and imaging, salvage neck dissections with a single concerning node, and indeterminate lateral nodes in papillary thyroid cancer (PTC).
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SSND performed for oral cavity primaries and N0 neck should include levels I and II.
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SSND performed for laryngeal primaries and N0 neck should include levels II and III.
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The goal of SSND is to minimize morbidity while maintaining regional control and survival rates.
Preoperative Period
History
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All patients with cancer of the head and neck should have a complete basic history regarding the mass in the neck, including onset, duration, location, pain, severity, and progression.
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All patients should be questioned about dyspnea, dysphagia, weight loss (how much over specific time period), hemoptysis, dysphonia, and otalgia.
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All patients should be asked about previous cancer of the head and neck. If yes, how were they treated? Surgery? Radiation? Chemotherapy? Combination of modalities?
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A full social history should be included regarding their occupation use of tobacco and alcohol, illicit drugs, and exposure to carcinogens or radiation.
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The patient should have a good social support system and be motivated to proceed with SSND. Reliability is an important factor as well, since close surveillance and follow-up are warranted.
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All patients should have a detailed family history performed with an emphasis on malignancies of the head and neck/thyroid.
Past Medical History
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The history regarding bleeding and coagulation disorders must include a history of bleeding or bruising easily. Ask about a family history of bleeding easily or a history of hemophilia or von Willebrand’s disease.
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Ask if there is a history of reactions to general anesthesia or malignant hyperthermia.
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Ask about a history of previous neck surgery (cervical spine fusion, thyroid surgery, previous neck dissection or open biopsies, carotid endarterectomy).
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Review the list of medications.
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Any anticoagulants other than aspirin should be held in the perioperative period.
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All herbal and over the counter (OTC) vitamins should be held perioperatively.
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Ask all patients about risk factors for poor wound healing (chronic steroid use, hypothyroidism, connective tissue disorders).
Physical Examination
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Overall appearance of the patient: Cachectic? Dehydrated? Well-nourished?
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Primary site: Note the location of the primary cancer and whether it extends to areas that include bilateral lymphatic drainage (midline lesions such as the base of the tongue, floor of the mouth, or supraglottis). It is important to estimate the thickness of the cancer, since this has been shown to correlate with occult cervical metastases.
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In patients who have been previously treated for the cancer, evaluate for complete response, and biopsy any suspicious areas (leukoplakia, erythema, or ulcerations).
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Evaluate all mucosal surfaces of the oral cavity, oropharynx, larynx, and hypopharynx to rule out synchronous lesions.
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Perform laryngoscopy to search for any mucosal lesions and vocal fold mobility.
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Neck: Palpate for any appreciable lymphadenopathy and note the level. Is the mass freely mobile or adherent to the skin or underlying structures?
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Evaluate mobility, including flexion and extension. Look for scars or evidence of previous surgery.
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In patients who have previously undergone radiotherapy to the neck, note the pliability and firmness of the tissue.
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It is important to note baseline function, especially in patients who have been previously treated.
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Shoulder mobility, normal protrusion of the tongue, facial nerve movement, and vocal fold mobility
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Imaging
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With an overall 30% rate of occult lymph node metastases in squamous cell carcinoma (SCCa) of the head and neck, physical examination of the neck should be augmented with imaging.
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The best imaging modality to detect nodal disease not appreciated on physical examination is controversial. While the sensitivity, specificity, and predictive values vary depending on the institution, we suggest that any of the modalities listed here are excellent options either in the pretreatment or posttreatment setting.
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Ultrasound
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Computed tomography (CT) scan with contrast
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Magnetic resonance imaging (MRI) with gadolinium
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Positron emission tomography – Computed tomography (PET-CT)
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Indications
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There are currently two clinical situations where SSND is considered:
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Patients whose primary cancer is in the larynx or oral cavity and an N0 neck by examination and imaging
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Patients who have been previously treated with either surgery or radiotherapy and have a persistent neck mass
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Another proposed indication is an SSND for pathologically indeterminate lateral neck nodes but clinically suspicious for patients with malignancy. These are typically patients who have nodes that are suspicious on ultrasound or CT, but the fine-needle biopsy was indeterminate or unable to be performed due to the location of the lymph node.
Contraindications
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Poor surgical candidate based on the patient’s medical status or comorbidities
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Patients with distant metastatic cancer
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In patients undergoing primary treatment, known cervical lymph node metastases are a contraindication to SSND. These patients will have a high risk of having nodal metastasis extending beyond one or two levels.
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Any evidence of extracapsular extension that would require sacrifice of nonlymphatic tissue
Preoperative Preparation
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All imaging should be reviewed prior to surgery. Any previous biopsies or pathology slides should be reviewed in house. We recommend a second review at the end of the case but before closing to ensure that no other suspicious areas were missed initially.
Operative Period
Anesthesia
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General endotracheal anesthesia with the endotracheal tube taped to the side opposite the neck dissection
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Paralysis should be avoided so that the surgeon can stimulate nerves once identified and be alerted by movement if dissecting near a nerve.
Positioning
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Supine with a shoulder roll or inflatable pillow for cervical extension. Exercise caution in patients with fusions or overextension in elderly patients.
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We prefer that the table be turned 180 degrees away to allow freedom of movement around the patient’s head and neck.
Preoperative Antibiotic
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The use of preoperative antibiotics in clean cases such as neck dissections is controversial. It is also important to note that many patients with cancer of the head and neck have risk factors for surgical site infections (age, poor nutrition, diabetes mellitus, tobacco and alcohol use, recent hospitalization, and previous treatment with radiation and chemotherapy).
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The World Health Organization advocates preoperative antibiotic prophylaxis in all cases.
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The American Society of Health System Pharmacists recommends against the routine use of antibiotics in clean cases without mucosal contamination.
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We routinely use a single dose of Ancef (cefazolin) before incision and discontinue it in the postoperative period, given the risk factors listed previously in patients with cancer of the head and neck and the low risk of a single preoperative antibiotic dose. Clindamycin is an alternative choice in patients with an allergy to beta-lactam antibiotics.
Monitoring
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Nerve monitoring is not used routinely. A handheld probe is used to confirm identification and function of nerves. The use of continuous neuromonitoring is controversial, but typically monitored nerves include the spinal accessory and marginal mandibular branch of the facial nerve. There is some predictive value of postoperative function to neuromonitoring CN XI based on amplitude and latency changes. However, these nerves should be at low risk during an SSND.
Instruments and Equipment to Have Available
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Standard neck dissection set
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Handheld nerve stimulator
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Many surgeons use energy devices to seal and cut vessels using ultrasonic or bipolar energy.
Key Anatomic Landmarks
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Platysma: This is the first muscle that is visualized after performing the initial incision on the neck. It is divided, and sub-platysmal flaps are elevated superiorly and inferiorly.
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External jugular vein (EJV): Located inferior to the great auricular nerve as it courses over the superior third of the SCM. EJV can have several communications to the facial, deep facial, and retromandibular veins.
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Great auricular nerve: Located just above the EJV and is the sensory nerve to the earlobe, and the skin around the inferior aspect of the auricle
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Marginal mandibular nerve: Branch of the facial nerve that innervates the depressor anguli oris, depressor labii inferiorus, and mentalis. It can be routinely identified coursing over the facial vessels at the mandibular notch or 1 cm anterior and 1 cm inferior to the angle of the mandible.
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The fibroadipose tissue containing lymphatic structures and nodes is located between the fascia of the SCM laterally, carotid sheath medially, and deep layer of the deep cervical fascia.
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Posterior belly of the digastric muscle: This separates level IB from IIA. It is safe to dissect on the inferior border of this muscle. The facial vein runs superficial to the digastric, so care must be taken not to damage this structure as it crosses. The spinal accessory and hypoglossal nerves run deep to the digastrics and should be safe while dissecting on the superficial surface of the muscle.
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Omohyoid: Strap muscle that originates from the scapula and inserts on the hyoid bone and depresses the larynx, and it defines the border of level III and IV. Dissecting on the superficial surface of this muscle protects the contents of the carotid sheath.
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Hyoid bone: Horseshoe-shaped structure in the upper neck that divides level II and III. Consists of the body, lesser cornu, and greater cornu.
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Hypoglossal nerve: Innervates the muscles of the tongue except for the palatoglossus. It can be found immediately anterior to the IJV in level IIA or inferior to the posterior belly of the digastric coursing under the ranine veins.
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SAN: Motor nerve to the SCM and trapezius muscles. It has a variable relationship to the IJV and can course over (96%), under (3%), or through (1%) the IJV. It can be found high in level IIA as it crosses the IJV, at its insertion in the SCM around the tendon, about 1 cm above Erb’s point or about two finger breadths above the lateral clavicle as it enters the trapezius. It divides level IIA from IIB.
Prerequisite Skills
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Experience with radical neck dissection, modified radical neck dissection, and selective neck dissection techniques
Operative Risks
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The risks of this procedure are similar to those in any neck dissection. The risks should be minimized due to the limited dissection area, but thorough anatomic knowledge of the neck is essential.
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Poor wound healing (especially radiated patients), hematoma, infection, scarring, shoulder dysfunction, chyle leak, marginal mandibular nerve weakness, damage to major vessels including stroke, voice problems and swallowing difficulty, phrenic nerve damage resulting in paralyzed diaphragm, numbness, and Horner’s syndrome
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Surgical Techniques
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This description provides a technique that can be applied to all levels of the neck that are indicated for SSND.
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For lesions that have bilateral lymphatic drainage (supraglottis, floor of the mouth), bilateral SSND should be performed.
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An incision should be planned in an existing transverse skin crease if possible. We recommend injection into the skin crease with 1% lidocaine and 1:100,000 parts epinephrine prior to incision. Given the limited dissection area, a smaller incision can be made.
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The incision is carried down through the subcutaneous tissue until the platysma is identified. It should be divided and subplatysmal flaps elevated circumferentially. Care should be exercised to elevate these flaps immediately deep to the platysma to avoid damaging superficial structures such as the marginal mandibular nerve superiorly over the mandible. This is especially true in thinner patients who have little fibroadipose tissue present.
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Identify and preserve the EJV and great auricular nerve when elevating subplatysmal flaps.
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For oral cavity primary SSCa, dissection of level I is necessary. The first maneuver should be to identify the marginal mandibular nerve. It can be found in a 1 × 1-cm area at the mandibular notch or approximately 1 cm and anterior and inferior to the angle of the mandible. The nerve must be dissected free and swept superiorly over the mandible to protect it during further dissection.
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Dissection then proceeds along the inferior aspect of the mandible to displace the submandibular gland and fibroadipose contents inferiorly. The facial artery and vein must be controlled and ligated at this step.
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Dissect inferiorly along the anterior and posterior belly of the digastric. The facial vein must again be identified and controlled along the posterior belly of the digastric.
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Begin by reflecting the fibroadipose tissue laterally off the mylohyoid. Here the nerve to the mylohyoid and submental vessels are encountered and can be ligated. The submental vessels can retract and cause bothersome bleeding, so pre-emptive control is important. Once the mylohyoid is free, retract it medially using an Army-Navy retractor.
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The loose areolar tissue around the submandibular gland can be pushed away with blunt dissection until the specimen is pedicled on the submandibular ganglion and submandibular duct. The facial artery can be ligated as it emerges from behind the posterior belly of the digastric.
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The submandibular ganglion is divided to preserve the lingual nerve, and the duct is ligated as close to the floor of mouth as possible, which mobilizes the specimen.
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Level IA can be quickly dissected off of the mylohyoid centrally between the two anterior bellies of the digastric.
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Dissect along the anterior border of the SCM while reflecting the muscle laterally and fibroadipose contents medially. The SAN should be identified and preserved as it enters the SCM. Care should be exercised in avoiding the branch of the SAN to the trapezius, as this branch can leave CN XI before it enters the SCM ( Fig. 63.2 ). The SAN should be traced in a superomedial direction until it intersects the IJV under the posterior belly of the digastric. Retraction of the posterior belly superiorly aids in this dissection. We do not routinely advocate the dissection of level IIB in N0 necks, given the low incidence of isolated disease in the absence of level IIA metastases. This also reduces potential injury to CN XI and postoperative morbidity.
