Introduction
In the early 1900s, George Crile recognized that cancer of the head and neck was primarily a locoregional disease and felt that patients could be cured if the cancer was completely excised. The cervical lymph nodes were recognized as the initial area of spread and so the best chance for cure was excision of the primary cancer sites in concert with the ipsilateral cervical soft tissue. He described and popularized radical neck dissections for the treatment of regionally metastatic head and neck cancer. Crile’s radical neck dissection remained the standard of care for cervical metastases for almost 70 years.
Modifications of the traditional radical neck dissection came after 1963, when Suarez demonstrated that the nonlymphatic structures (sternocleidomastoid muscle and internal jugular vein) were anatomically separated by fascia from the lymph nodes. Oncologic outcomes were found to be similar to radical neck dissections, and the functional and aesthetic outcomes of patients were clearly superior. In addition, particularly with the advent of radiation therapy, preservation of the sternocleidomastoid muscle was found to protect the carotid artery from subsequent damage and potential blowout.
Several classification schemes for a neck dissection were introduced, and in an effort to present a common language the Committee for Head and Neck Surgery and Oncology of the American Academy of Otolaryngology–Head and Neck Surgery introduced the most widely accepted classification system in 1991. A modified radical neck dissection was defined as “the excision of all lymph nodes routinely removed by the radical neck dissection, with preservation of one or more non-lymphatic structures.”
Key Operative Learning Points
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Modified radical neck dissection is strictly defined as the removal of lymph nodes from levels 1 to 5 while preserving one or more of the nonlymphatic structures (sternocleidomastoid muscle, spinal accessory nerve, internal jugular vein).
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Decisions to perform a modified radical neck dissection are often made intraoperatively, when those nonlymphatic structures are found to be involved with cancer.
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Preservation of the spinal accessory nerve maintains normal shoulder function.
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Neck dissections can be done safely when the surgeon has thorough knowledge of the anatomy.
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Soft tissue in level 4 should be clamped and ligated to prevent chyle leaks.
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Manipulation of the carotid artery can cause excessive stimulation of the carotid body reflex, resulting in bradycardia and hypotension. This can be resolved with injection of lidocaine directly into the carotid sinus.
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When approaching the carotid sheath, it is important to keep the plane of dissection over the jugular vein to prevent inadvertent damage to the sympathetic trunk, vagus nerve, or carotid artery.
Preoperative Period
History
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History of present illness
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Presentation at diagnosis
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Location of the primary cancer: The primary site will dictate which nodal levels are at risk for metastases and therefore will determine the extent of surgery. For example, cancer of the floor of the mouth rarely metastasizes to level V, and so if these nodes are not clinically or radiographically involved, level V nodes can be preserved, thereby obviating the need for a radical neck dissection.
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Symptoms related to the site of the primary
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Restriction in range of motion of the neck
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Shortness of breath: can be secondary to the primary lesion or medical comorbidities secondary to tobacco use; however, involvement of the phrenic nerve is possible. A chest radiograph will help to determine the integrity of the phrenic nerve.
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Numbness of the anterior tongue
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Dysgeusia
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Dysphagia
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Voice changes
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Weight loss: The patient’s nutritional status should be optimized before undergoing any surgical procedure because this will affect his or her wound healing. If a patient has had significant weight loss secondary to dysphagia or odynophagia, it may be beneficial to place a feeding tube and improve the patient’s nutritional status before intervention to prevent postoperative complications.
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Any neoadjuvant or definitive treatment
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Past medical/surgical history
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Medical illness: cardiovascular disease, stroke, carotid insufficiency
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Neck surgery: carotid endarterectomy, anterior approach to the cervical spine
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Family history of cancer
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Medications
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Antiplatelet drugs
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Vitamins/herbal products: i.e., vitamin E, Ginkgo biloba
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Opiates: Postoperative pain control in chronic pain patients is very different from opiate-naive patients. Consultation should be sought in those particularly complex cases (e.g., patients on suboxone or methadone).
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Social history
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Opiate abuse
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Drug rehabilitation programs
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Smoking
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Occupation
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Alcohol intake: Extent of alcohol intake is important in anticipating a patient’s postoperative needs and the risk for delirium tremens.
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Informed consent
Physical Examination
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Thorough examination of the head and neck with documentation of nodal levels involved as well as relevant surgical findings that may affect surgical decision making such as fixation to overlying structures (e.g., skin) or underlying structures (e.g., deep muscles of the neck)
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Fiberoptic nasopharyngoscopy
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Auscultation of the carotid for bruits
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Neurologic examination
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Invasion of major nerves
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Facial nerve: Observe symmetry with facial movement, with focus on the inferior division.
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Lingual nerve: difficult to examine, nerve injury often elicited through history
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Vagus nerve: ipsilateral vocal cord paresis and palate asymmetry
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Hypoglossal nerve: deviation of the tongue toward the injured side
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Spinal accessory nerve: winged scapula, sternocleidomastoid and atrophy of the trapezius
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Sympathetic trunk: ipsilateral Horner syndrome
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Phrenic nerve: History and imaging will help to determine phrenic nerve involvement.
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Brachial plexus: motor-sensory dysfunction in the ipsilateral arm
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Imaging
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Chest radiograph
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Metastases
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Synchronous primary cancer in the lung
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Pulmonary and cardiac status
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Computed tomography (CT) ( Fig. 65.1 )
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Adequate for radiographic staging when imaging of the chest is added
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May help to anticipate involvement of nonlymphatic structures
Fig. 65.1
A, Photograph and B and C axial computed tomography (CT) scans of the neck of a patient with massive cervical lymphadenopathy. The CT scans demonstrate encasement of the left carotid artery and suggest tumor invasion of the sternocleidomastoid muscle and the deep cervical muscles.
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Positron emission tomography (PET)-CT: In a multicenter prospective trial assessing the CT versus PET/CT for initial staging, PET/CT upstaged and changed management in almost 14% of patients. Studies like this have prompted the National Comprehensive Cancer Network to include recommendations for PET/CT in stage 3 or 4 cancer in the majority of subsites in the head and neck.
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Assesses local involvement
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Identifies distant metastases
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Second primary cancers
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Magnetic resonance imaging (MRI)
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Not required in many cases
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Helps to identify the presence of perineural invasion and the extent of the cancer
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Angiography
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Balloon occlusion testing helps anticipate the risk of stroke in patients with carotid involvement who may require carotid resection.
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Indications
Modified radical neck dissection is indicated when the spinal accessory nerve, internal jugular vein, or sternocleidomastoid muscle can be preserved without affecting oncologic outcomes and when a selective neck dissection would not adequately remove the volume of cancer in the neck. The decision to proceed with a modified radical neck dissection is often made intraoperatively, when the sternocleidomastoid muscle, spinal accessory nerve, or internal jugular vein are found to be involved with cancer.
For a neck dissection to be classified as a modified radical neck dissection, all lymph node levels must be dissected. Level 5 nodes are infrequently involved with noncutaneous head and neck squamous cell carcinoma. As demonstrated by Lindberg in 1972 and in many subsequent publications, nasopharyngeal primaries frequently metastasize to level 5 nodes; however, other head and neck sites rarely involve this level. Therefore, without palpable or radiographic evidence of metastases to level 5, dissections of level 5 is not indicated, with the exception of nasopharyngeal and some oropharyngeal primaries.
Contraindications
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N0 neck (see Selective Neck Dissection Chapter)
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Extensive metastasis
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Encasement of the carotid artery
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Invasion of the deep muscles of the neck
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Invasion of the skull base
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Distant metastases
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Comorbidities that prevent safe administration of general anesthesia
Preoperative Preparation
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Chlorhexidine wash: Despite the Centers for Disease Control and Prevention (CDC) recommending chlorhexidine washes preoperatively to decrease the bacterial load on the skin, there has been little to no evidence that it decreases the rate of soft tissue infections in head and neck surgery. For patients with a history of methicillin-resistant Staphylococcus aureus infections, a preoperative chlorhexidine wash may be of benefit.
Operative Period
Anesthesia
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General anesthesia
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Avoid paralysis: The anesthesia team should be aware of the need to monitor stimulation of particular muscles during the surgery; therefore paralysis should be avoided.
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Intubation: Technique varies depending on the site of the primary. Regardless, the otolaryngologist should be involved during the intubation to guide the anesthesiologist through the altered anatomy and to provide a surgical airway if necessary.
Positioning
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Supine, head extended with adequate shoulder support and turned to the nonoperative side to provide adequate exposure of the surgical site
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Table turned 90 degrees; 180 degrees if bilateral procedure is planned
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Shoulder roll or inflatable surgical pillow (e.g., surgical thyroid pillow) can be used for shoulder support and to provide neck extension.
Perioperative Antibiotic Prophylaxis
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There is no clear evidence that prophylactic perioperative antibiotics decrease the incidence of surgical site infections in clean neck dissections, although Carrau et al. did show a trend for a higher incidence of infections in untreated patients.
Monitoring
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Facial nerve monitor can be used to help with identification of the marginal mandibular nerve during dissection of level 1.
Instruments and Equipment to Have Available
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Head and neck set
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Bipolar and monopolar cautery
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2.0 and 3.0 silk reel
Key Anatomic Landmarks
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External landmarks:
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Angle of the jaw
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Mastoid tip
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Midline of the neck
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Anterior and posterior borders of the sternocleidomastoid muscle
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Clavicle
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Levels of the neck ( Fig. 65.2 ):
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Level Ia: submental triangle
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Boundaries: anterior belly of the digastric muscles and the hyoid bone
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Level Ib: submandibular triangle
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Boundaries: body of the mandible and the anterior and posterior belly of the digastric muscle
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Level II: upper jugular nodes
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Anterior boundary: border of the stylohyoid muscle
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Posterior: posterior border of the sternocleidomastoid muscle
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Superior: skull base
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Inferior: Level of the hyoid bone
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Further divided into level IIa and IIb by the spinal accessory nerve
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Level III: middle jugular nodes
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Anterior boundary: lateral border of the sternohyoid muscle
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Posterior: posterior border of the sternocleidomastoid muscle
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Superior: hyoid bone
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Inferior: omohyoid muscle or cricoid cartilage
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Level IV: lower jugular nodes
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Anterior boundary: lateral border of the sternohyoid muscle
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Posterior: posterior border of the sternocleidomastoid muscle
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Superior: omohyoid/cricoid
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Inferior: clavicle
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Level V: posterior triangle
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Anterior boundary: posterior border of the sternocleidomastoid muscle
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Posterior: anterior border of the trapezius muscle
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Inferior: clavicle
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Further divided into level Va and Vb by a horizontal extension at the level of the cricoid cartilage
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