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SCC Right Lateral Border of Tongue + Wide Local Excision + Neck Dissection

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PART 1 — THE DIAGNOSIS

What Is It?

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Clinical Findings — What You Will See / Have Seen

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Aetiology & Risk Factors

• Tobacco (smoking + smokeless) + alcohol (synergistic)
• Poor oral hygiene, chronic dental trauma/irritation
• Immunosuppression
• Increasing incidence in young patients with no identifiable risk factors — postulated genetic susceptibility
• HPV-negative oral tongue SCC — TP53 (83%) and CDKN2A (57%) mutations dominate (unlike HPV+ oropharyngeal SCC which is TP53 wild-type)

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Investigations

• Incisional biopsy of the lesion (most tongue lesions are biopsy-able in the office/OPD)

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AJCC 8th Edition TNM Staging (Oral Cavity — Know This Cold)

• N1: Single ipsilateral node ≤3 cm, no ENE
• N2a: Single ipsilateral node 3–6 cm, no ENE
• N2b: Multiple ipsilateral nodes ≤6 cm, no ENE
• N2c: Bilateral/contralateral nodes ≤6 cm, no ENE
• N3b: Any node with clinical ENE

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Histopathological Prognostic Factors (What the Path Report Will Say)

• DOI — most important for staging and nodal risk
• Tumour grade — well (G1), moderate (G2), poorly differentiated (G3); poorly differentiated = more aggressive
• Pattern of invasion — cohesive vs. non-cohesive advancing front; non-cohesive = worse
• Perineural invasion (PNI) — independent risk factor for cervical metastasis, local recurrence
• Lymphovascular invasion (LVI)
• Bone invasion — cortical erosion alone ≠ T4; medullary invasion = T4a
• Resection margins — clear (>5 mm), close (1–5 mm), involved (<1 mm). Close/involved margins → adjuvant RT

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Consultant's Questions — Be Ready For These

1. What is the most common site for SCC within the tongue? → Lateral border
2. Why does lateral border tongue SCC carry a poor prognosis? → Rich lymphatic drainage, early occult nodal spread, proximity to deep muscles and floor of mouth
3. What is DOI and why does it matter? → Depth of invasion from basement membrane of adjacent normal mucosa to deepest tumour point; >4 mm → risk of nodal mets doubles; determines T stage in 8th AJCC
4. What is the incidence of occult nodal metastasis in clinically N0 oral tongue SCC? → 20–25%; justifies elective neck dissection
5. What is a skip metastasis? → Direct spread to level III or IV bypassing levels I and II — more common with oral tongue
6. Which neck levels drain the oral tongue? → Levels I, II, III (level IV also at risk for tongue SCC — skip metastasis)
7. What is the significance of ENE? → Extranodal extension — breach of lymph node capsule; independent predictor of disease-specific survival; now upstages N disease in AJCC 8th
8. What are indications for postoperative radiotherapy? → Involved/close margins, PNI, LVI, bone invasion, ENE, ≥2 positive nodes, N2–N3 disease
9. What is erythroplakia? → Red velvety mucosal lesion with highest malignant transformation rate (~50%) — more dangerous than leukoplakia
10. What is the management of mandibular involvement? → Periosteal invasion → marginal mandibulectomy; medullary invasion → segmental resection

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PART 2 — THE PROCEDURES

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PROCEDURE A: Wide Local Excision of the Right Lateral Border of Tongue (Partial Glossectomy)

Anatomy of the Tongue

• Anterior 2/3, separated from base (posterior 1/3) by the circumvallate papillae
• Lateral border = where most SCCs arise

• Superior longitudinal, inferior longitudinal, transverse, vertical

• Sensation, anterior 2/3: Lingual nerve (branch of V3)
• Taste, anterior 2/3: Chorda tympani (CN VII) via lingual nerve
• Sensation + taste, posterior 1/3: CN IX (glossopharyngeal)
• Motor (all muscles except palatoglossus): CN XII (hypoglossal)

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Instruments for Wide Local Excision

• Blade 15 / 10 scalpel
• Mouth gag (Dingman or Boyle Davis) for exposure
• Self-retaining tongue sutures (2-0 silk stay sutures in tongue tip)
• Needle holders, tissue forceps, scissors
• Bipolar or monopolar cautery
• Diathermy loop / CO₂ laser (in some centres)
• Vessel loops / Lahey swabs
• Measuring rule (for margin marking)
• Specimen orientation suture/marking inks

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Wide Local Excision — Step by Step

• General anaesthesia — nasoendotracheal intubation (keeps mouth free)
• Patient supine, head ring, shoulder roll for neck extension
• Mouth gag inserted for exposure

1. Mark the tumour margins — minimum 1 cm clear margin marked around the visible/palpable tumour edges with a marking pen. Frozen section margin control is performed intraoperatively.
2. Stay sutures — 2-0 silk sutures placed through the tongue tip and lateral tongue to provide traction and improve visualisation.
3. Incision — Full-thickness elliptical incision through mucosa, submucosa, and underlying muscle using blade 15 or electrocautery. The cut is made in continuity, not piecemeal.
4. Deep margin — Resection extends down through intrinsic and, if needed, extrinsic tongue muscle (hyoglossus). The lingual artery lies deep — careful haemostasis required. Suture ligation of the lingual vessels if they are encountered.
5. Orientation of specimen — Suture/ink specimen immediately (e.g., long stitch = superior, short = anterior). Send for frozen section (margins) and formal histopathology (DOI, grade, PNI, LVI).
6. Hemostasis — Bipolar cautery / suture ligation. The tongue is highly vascular.
7. Reconstruction / closure:
   • Small defects (<1/3 tongue): Primary closure with absorbable sutures (3-0 Vicryl) — best functional outcome
   • Moderate defects: Secondary intention (floor of mouth) or split-thickness skin graft
   • Large defects (>1/2 tongue): Radial forearm free flap (RFFF) or anterolateral thigh (ALT) flap

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PROCEDURE B: Neck Dissection

Anatomy of the Neck Levels (AHNS Classification)

Key Structures to Protect

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Neck Dissection Types — Know the Classification

• Radical ND (RND): Removes levels I–V + SCM + IJV + CN XI → rarely done now
• Modified Radical ND (MRND): Levels I–V, preserves one or more of (SCM, IJV, CN XI) — Type I: preserves CN XI; Type II: preserves CN XI + IJV; Type III: all three preserved
• Selective ND (SND): Only at-risk levels. For oral tongue: Supraomohyoid ND = Levels I–III (add IV for tongue)
• Extended ND: Standard + additional structures (e.g. parotid, retropharyngeal nodes)

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Neck Dissection — Step by Step (Supraomohyoid / Selective I–IV for Tongue SCC)

• Supine, head ring, shoulder roll
• Head turned contralateral to dissection side
• Prep and drape neck

• Modified apron incision (MacFee/hockey-stick) — 2 cm below mandible, extending posteriorly toward mastoid tip
• Skin flaps raised in subplatysmal plane — preserve greater auricular nerve and external jugular vein posteriorly

1. Raise subplatysmal flaps — superiorly to mandible, inferiorly to clavicle (if extended). Identify and protect the marginal mandibular nerve in the superficial layer of deep cervical fascia over the submandibular gland.
2. Open investing fascia at anterior border of SCM. Dissect fibrofatty contents away from SCM medially.
3. Identify CN XI (SAN) — enters SCM posteriorly; dissect free from skull base to SCM entry. This delineates the superior border of Level IIB.
4. Level II dissection — Triangular packet bounded by posterior belly of digastric (superior), SAN (posterior), and SCM (lateral). Pass tissue packet under the SAN to protect it.
5. Levels III and IV — Sweep fibrofatty tissue inferiorly. The phrenic nerve lies on the anterior scalene (deep to prevertebral fascia — do not breach). The sensory branches of cervical plexus can be preserved in SND (not Level V dissection).
6. Level I dissection (submandibular triangle):
   • Skeletonise the inferior border of the mandible
   • Identify and ligate the facial artery and vein (retromandibular)
   • Identify lingual nerve and CN XII entering submandibular region
   • Excise submandibular gland if indicated (or separate it from the nodal specimen)
   • Protect the marginal mandibular branch throughout
7. Medial sweep — All fibrofatty tissue swept medially over the carotid sheath. IJV is exposed and preserved. The omohyoid muscle is skeletonised at the hyoid and used as the inferior boundary marker.
8. Specimen removed en bloc — Oriented and sent to histopathology. All levels should be separately marked.
9. Haemostasis + closure:
   • Suction drains (Redivac/Blake) × 1–2 placed
   • Platysma closed (2-0 Vicryl)
   • Skin closed (3-0 Prolene or staples)

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Postoperative Considerations

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Post-op Oncological Decision Points

• pN0 (no nodes) + clear margins → Surveillance
• pN+ single node, no ENE → consider post-op RT
• Multiple nodes or ENE → Post-op chemoradiation (platinum-based)
• Positive/close margins → Post-op RT ± chemotherapy
• DOI >4 mm in clinically N0 tongue → Elective neck dissection (levels I–IV) justified

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Incisions for Modified Neck Dissection

The Guiding Principle

• Give adequate exposure of all levels being dissected
• Avoid trifurcate points (three-way junctions = poor blood supply = necrosis risk)
• Keep the carotid artery covered by a broad skin flap at all times
• Lie in a skin crease where possible (cosmesis)
• Avoid prior radiation ports when possible

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1. MacFee Incision (Two Parallel Transverse Incisions) — MOST COMMONLY USED

• Upper limb: 2 fingerbreadths below mandible, from mastoid tip to midline/submental region
• Lower limb: Just above the clavicle (supraclavicular), extending laterally

• Best blood supply to the intervening skin bridge — the central skin flap between the two incisions receives perforators from both sides
• Best choice in irradiated necks — lowest wound dehiscence rate (0% in one study vs. 11% for triradiate)
• Cosmetically excellent — lies in skin creases (Langer's lines)
• No trifurcate point

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2. Modified Apron (Schobinger) Incision — Most Common for Levels I–III

• Can be extended into a lip-split for oral cavity access (pull-through technique)
• Bilateral apron: Extends across the midline to the other side — for bilateral SND
• Boomerang incision: For bilateral ND when lip-splitting is also required

• Ideal for combined wide local excision + neck dissection — the upper limb can be extended to access the oral cavity via pull-through or lip split
• Excellent Level I and II exposure
• Single incision = simpler and cosmetically reasonable

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3. Hockey Stick Incision

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4. Triradiate (Y / T-shaped) Incision — Now Largely Abandoned

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Summary Table

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For Today's Case (Tongue SCC + Right MRND)

1. Access to Levels I–V on the right
2. Can be connected to the oral cavity via pull-through or lip-split for the tongue wide local excision
3. The incision is placed in a skin crease, 2 cm below the mandible