Overview
Definition:
Neck dissection is a surgical procedure involving the removal of lymph nodes and surrounding tissues from the neck
It is primarily performed for staging and treatment of head and neck cancers, particularly squamous cell carcinomas originating in the oral cavity, oropharynx, larynx, and hypopharynx
The classification into levels I-V provides a systematic approach to anatomical understanding and surgical strategy, ensuring thoroughness while minimizing morbidity.
Epidemiology:
Head and neck cancers represent a significant global health burden, with squamous cell carcinoma being the most common histological subtype
Lymph node metastasis is a critical prognostic factor, making neck dissection a cornerstone of management
The incidence varies by geographic region and risk factors such as tobacco and alcohol use, and HPV infection.
Clinical Significance:
Accurate knowledge of neck dissection levels is paramount for surgeons to achieve oncologic control, prevent recurrence, and preserve important neurovascular structures
It guides the extent of resection, helping to tailor the procedure to the specific tumor site and extent of nodal involvement, thereby optimizing patient outcomes and quality of life.
Neck Anatomy Levels
Level I:
Boundaries: Inferiorly by the anterior belly of the digastric muscle
superiorly by the mandible
anteriorly by the midline of the neck
posteriorly by the posterior belly of the digastric muscle and stylohyoid muscle
Contents: Submental and submandibular lymph nodes
submandibular salivary gland
facial artery and vein.
Level Ii:
Boundaries: Superiorly by the hyoid bone
inferiorly by the cricothyroid membrane
anteriorly by the posterior border of the sternocleidomastoid muscle
posteriorly by the anterior border of the sternocleidomastoid muscle
Contents: Upper deep cervical lymph nodes
jugular chain
spinal accessory nerve (CN XI)
internal jugular vein (IJV)
carotid sheath structures.
Level Iii:
Boundaries: Superiorly by the hyoid bone
inferiorly by the cricoid cartilage
anteriorly by the anterior border of the sternocleidomastoid muscle
posteriorly by the posterior border of the sternocleidomastoid muscle
Contents: Middle deep cervical lymph nodes
jugular chain
recurrent laryngeal nerve (RLN) can be at risk posteromedially.
Level Iv:
Boundaries: Superiorly by the cricoid cartilage
inferiorly by the clavicle
anteriorly by the anterior border of the sternocleidomastoid muscle
posteriorly by the posterior border of the sternocleidomastoid muscle
Contents: Lower deep cervical lymph nodes
jugular chain
subclavian vein and artery are in close proximity.
Level V:
Boundaries: Posterior triangle of the neck
Superiorly by the apex of the posterior triangle (union of sternocleidomastoid and trapezius muscles)
inferiorly by the clavicle
anteriorly by the posterior border of the sternocleidomastoid muscle
Contents: Lymph nodes in the supraclavicular and posterior triangle regions
spinal accessory nerve (CN XI)
transverse cervical artery and vein.
Indications And Contraindications
Indications:
Clinical or radiologically suspicious lymph nodes
pathologically confirmed nodal metastasis from primary head and neck malignancy
elective neck dissection in high-risk squamous cell carcinomas (e.g., T3/T4 tumors, multiple positive nodes, extranodal extension)
post-operative management of known nodal disease.
Contraindications:
Distant metastatic disease
unresectable primary tumor
extensive bilateral nodal involvement with fixed nodes precluding resection
patient comorbidities that make extensive surgery unsafe.
Surgical Technique
Preoperative Preparation:
Detailed imaging (CT, MRI, PET-CT) to assess nodal involvement
multidisciplinary tumor board discussion
informed consent regarding risks and benefits
appropriate antibiotic prophylaxis
positioning of the patient
surgical marking.
Procedure Steps:
Incision design based on tumor location and extent of dissection (e.g., transverse, curvilinear, or trapezius flap incisions)
identification and preservation of key structures (e.g., IJV, carotid artery, vagus nerve, CN XI, RLN, phrenic nerve)
meticulous dissection of lymph node-bearing compartments corresponding to the levels requiring clearance
identification and ligation of feeding vessels
specimen retrieval for histopathological analysis.
Types Of Neck Dissection:
Radical Neck Dissection (RND): Removal of all lymph nodes levels I-V, along with sternocleidomastoid muscle, IJV, and CN XI
Modified Neck Dissection (MND): Preserves one or more of these structures
Selective Neck Dissection (SLND): Removes specific lymph node levels based on primary tumor site and risk of metastasis (e.g., supraomohyoid, lateral neck dissection).
Complications
Early Complications:
Bleeding and hematoma formation
chyle leak (especially with thoracic duct injury)
seroma
wound infection
nerve injury (e.g., phrenic nerve palsy leading to diaphragmatic dysfunction, CN XI palsy causing shoulder dysfunction, hypoglossal nerve injury causing tongue deviation).
Late Complications:
Chronic pain
lymphedema of the head, neck, or arm
scar contractures
cosmetic deformity
phrenic nerve or CN XI palsy with long-term sequelae
fistula formation.
Prevention Strategies:
Meticulous surgical technique
careful identification and preservation of vital structures
adequate hemostasis
use of drains
proper wound closure
judicious use of muscle flaps for reconstruction if needed
patient education on postoperative care and rehabilitation exercises.
Key Points
Exam Focus:
Understanding the boundaries and contents of each neck dissection level is crucial for DNB/NEET SS
Differentiate between radical, modified, and selective neck dissections and their indications
Recognize the common neurovascular structures at risk in each level.
Clinical Pearls:
Always consider the primary tumor location when deciding which levels to dissect
Preservation of the spinal accessory nerve (CN XI) is a key difference in modified versus radical neck dissection
Chyle leak typically occurs on the left side due to the thoracic duct.
Common Mistakes:
Inadequate nodal clearance leading to recurrence
inadvertent injury to vital structures (IJV, carotid artery, nerves)
failure to identify and manage complications like chyle leak or nerve palsy
performing an overly aggressive dissection when a selective approach would suffice, leading to increased morbidity.