Definition and Overview
A neck dissection is a surgery performed to remove lymph nodes in the neck where cancer has spread to. Malignancies of the head and neck can metastasise to lymph nodes in the neck (cervical lymph nodes), decreasing survival rate up to 50%. It is for this reason that one of the major aspects in the treatment of head and neck cancers is the management and control of neck node metastasis.
The lymph nodes in the neck are divided into 6 regions, known as levels, namely:
- Level 1 - Submandibular and submental nodes
- Levels 2, 3 and 4 - The upper, middle, and lower jugular nodes, respectively
- Level 5 - Nodes in the posterior triangle
- Level 6 - Lymph nodes in the anterior compartment near the midline
There are several kinds of neck dissections, depending on the extent of resection involved. A radical neck dissection removes all the lymph nodes in the neck on one side, as well as the sternocleidomastoid muscle (SCM), the internal jugular vein (IJV), and cranial nerve XI or the spinal accessory nerve. Lesser resections are involved in modified radical neck dissection and selective neck dissection.
Who Should Undergo and Expected Results
Upon work-up, patients with involved lymph nodes noted on their clinical or radiologic assessment may have to be subjected to radical neck dissection. Primary sites of malignancies that metastasise to neck nodes include the thyroid and salivary glands and parts of the aerodigestive tract, such as the oral cavity, the tongue and the larynx. Cancer of the scalp and the skin on the face may also spread to the cervical nodes, requiring neck dissection.
Radical neck dissection is usually performed as part of curative cancer surgery, together with the resection of the primary site of malignancy.
In the past, radical neck dissection was performed for any extent of cervical lymph node involvement, from microscopic nodal involvement to bulky disease. However, advancements in the understanding of head and neck malignancies and lymphatic spread of the disease have resulted in modifications in neck dissection surgery that limit morbidity while ensuring adequate lymphatic control. In many cases, modified or selective neck dissections have shown similar success rates with the radical form. Thus, although radical neck dissection remains to be the standard surgical procedure for cervical lymph node removal, its performance of radical neck dissection has become limited to:
- Head and neck cancer patients with advanced nodal disease, or those with gross involvement of extralymphatic structures (SCM, IJV or spinal accessory nerve)
- Some patients with multiple positive nodes found near the spinal accessory nerve
- Patients with recurrence or persistence of the disease after being subjected to chemotherapy, radiotherapy, or both
- Patients with recurrence of the disease after lesser neck dissections have been performed
How is the Procedure Performed?
For the procedure, the patient is placed in a supine position with the neck extended. The usual incision for a radical neck dissection is known as a hockey stick incision. The platysma muscle is flapped, and the dissection proceeds in the subplatysmal plane. The order of dissection of lymph nodes depends on the surgeon, but is usually completed per level before proceeding to the next zone.
The fatty tissues in between the superficial fascia and the deep fascia of the neck, which contain the lymphatics, are removed using electrocautery or a harmonic scalpel. The SCM muscle and the IJV are identified and isolated. These structures are transected right above the clavicle (inferior border) and near the posterior digastric belly (superior border). The dissection involves sacrificing the spinal accessory nerve.
Several important structures must be identified and preserved such as the carotid artery, the vagus nerve, the phrenic nerve, and the brachial plexus. The dissection of lymph nodes in levels 2-4 may proceed from inferior to superior, or vice versa.
Possible Risks and Complications
Classical radical neck dissection may be associated with a number of potential complications, which include:
- Bleeding or haemorrhage
- Injuries to the IJV and the adjacent carotid artery. In these cases, repair of the carotid artery should be performed during the operation.
- Sensory loss on the face and neck
- Shoulder drop due to the resection of the spinal accessory nerve leading to limited movement of the shoulder and arm. This can be improved by physical therapy and rehabilitation.
- Oedema of the face
- Swelling of one side of the face and neck
- Facial or cerebral oedema (for patients who undergo bilateral radical neck dissection)
- Neurologic defects
- Skin flap necrosis
- Salivary fistula (particularly in patients with history of radiation)
- Chylous fistula
Rupture of the carotid artery
Civantos FJ, Moffat FL, Goodwin WJ. Lymphatic mapping and sentinel lymphadenectomy for 106 head and neck lesions: contrasts between oral cavity and cutaneous malignancy. Laryngoscope. 2006 Mar. 112(3 Pt 2 Suppl 109):1-15.
Sebbesen L, Bilde A, Therkildsen M, Mortensen J, Specht L, von Buchwald C. 3 years follow-up of sentinel node negative patients with early oral cavity squamous cell carcinoma. Head Neck. 2013 Jun 26.