Neck Dissection Techniques

Neck Dissection Basics - Unraveling the Layers

Neck dissection (ND) is a surgical procedure to remove cervical lymph nodes, primarily for managing metastatic spread from head and neck cancers. Its goal is oncologic control.

• Types of Neck Dissection:
  • Radical Neck Dissection (RND):
    • Removes levels I-V, Sternocleidomastoid muscle (SCM), Internal Jugular Vein (IJV), Spinal Accessory Nerve (SAN).
  • Modified Radical Neck Dissection (MRND):
    • RND principles with preservation of ≥1 non-lymphatic structures (SAN, IJV, SCM).
    • Type I: Preserves SAN.
    • Type II: Preserves SAN, SCM.
    • Type III (Functional ND): Preserves SAN, SCM, IJV.
  • Selective Neck Dissection (SND):
    • Removes specific nodal groups at risk, preserving all major non-lymphatic structures.
    • E.g., Supraomohyoid ND (Levels I-III).

⭐ George Crile Sr. performed the first RND in 1906, standardizing the procedure for head and neck cancer treatment.

Nodal Levels & Anatomy - Landmarks & Landmines

• Level I (Submental IA, Submandibular IB):
  • IA: Ant. digastric bellies, hyoid. IB: Post. digastric, mandible.
  • ⚠️ Marginal mandibular n. (lip droop).
• Level II (Upper Jugular IIA/IIB): Skull base to hyoid.
  • SAN divides IIA (ant.) & IIB (post.).
  • ⚠️ SAN, IJV, Hypoglossal n. (deep).
• Level III (Middle Jugular): Hyoid to cricoid.
  • ⚠️ Vagus n., IJV.
• Level IV (Lower Jugular): Cricoid to clavicle.
  • ⚠️ Thoracic duct (L), Phrenic n. (on ant. scalene), Brachial plexus.
• Level V (Posterior Triangle VA/VB): SCM, Trapezius, Clavicle.
  • SAN divides VA (sup.) & VB (inf.). 📌 SAN vulnerable at Erb's point.
  • ⚠️ SAN, Brachial plexus.
• Level VI (Anterior/Central): Hyoid to suprasternal notch, b/w carotids.
  • Nodes: Pre/paratracheal, Precricoid (Delphian).
  • ⚠️ Recurrent Laryngeal Nerves.
• Level VII (Superior Mediastinal): Suprasternal notch to innominate a.

⭐ The Spinal Accessory Nerve (CN XI) is a key landmark, often at risk; injury causes shoulder droop/impaired abduction. Divides Level II (A/B) & V (A/B).

Indications & Choice - The Dissection Decision

• Therapeutic Neck Dissection (TND):
  • Indicated for clinically palpable nodes (cN+).
  • Goal: Remove existing metastases, achieve regional control.
• Elective Neck Dissection (END):
  • Indicated for clinically negative neck (cN0) with high risk (>15-20%) of occult metastases.
  • Risk factors: Primary tumor site (e.g., oral cavity, oropharynx), T-stage (esp. T2 or higher), depth of invasion (DOI >3-4 mm for oral SCC), perineural invasion (PNI), lymphovascular invasion (LVI).
• Choice of Dissection Type:
  • cN0 (END): Selective Neck Dissection (SND) tailored to primary site.
    • Oral Cavity: SND (Levels I-III).
    • Oropharynx, Hypopharynx, Larynx: SND (Levels II-IV).
  • cN+ (TND):
    • N1: Comprehensive SND or Modified Radical Neck Dissection (MRND).
    • N2-N3 / Extranodal Extension (ENE): MRND. Radical Neck Dissection (RND) is rarely performed.

⭐ For cN0 oral cavity squamous cell carcinoma, END (typically SND I-III) is indicated if DOI >4 mm or T-stage ≥T2, as risk of occult nodal metastasis often exceeds 20%.

Complications & Care - Navigating the Risks

• Intraoperative Risks:
  • Nerve Injury: Spinal Accessory (SAN) (most common in posterior triangle), Marginal Mandibular, Hypoglossal.
  • Vascular Injury: Carotid Artery, Internal Jugular Vein.
  • Chyle Leak (Left > Right): Thoracic duct injury.
• Postoperative Concerns & Management:
  • Hemorrhage, Hematoma, Seroma.
  • Wound Infection.
  • Nerve Palsies:
    • SAN: 📌 Shoulder drop, winging scapula. Early physiotherapy vital.
    • Marginal Mandibular: Lower lip weakness. Often transient.
  • Chyle Fistula (Persistent):
    • Initial: NPO, TPN, low-fat/Medium-Chain Triglyceride (MCT) diet, pressure dressing.

⭐ If chyle leak persists (>500-600 mL/day or >1-2 weeks despite conservative measures), escalate to octreotide or surgical intervention (e.g., duct ligation).

High‑Yield Points - ⚡ Biggest Takeaways

• Radical Neck Dissection (RND): Removes Sternocleidomastoid (SCM), Internal Jugular Vein (IJV), Spinal Accessory Nerve (SAN), and lymph nodes Levels I-V.
• Modified RND (MRND): Preserves one or more key structures, most commonly the SAN, followed by IJV and SCM.
• Selective Neck Dissection (SND): Removes specific at-risk nodal groups based on primary tumor site.
• Spinal Accessory Nerve (SAN) injury causes shoulder droop and impaired arm abduction; its preservation is crucial.
• Common complications include chyle leak (especially left-sided, thoracic duct injury) and nerve injuries (SAN, marginal mandibular).
• Levels I-V are standard dissection fields; Level VI (anterior compartment) is addressed for thyroid/laryngeal cancers.