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CLASSIFICATION AND FLAPS IN HEAD & NECK SURGERY

Comprehensive Answer for 50 Marks (RGUHS Standard)

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INTRODUCTION

╔═══════════════════════════════════════════════════════╗
║            THE RECONSTRUCTIVE LADDER                  ║
║  SIMPLE ─────────────────────────────── COMPLEX      ║
║                                                       ║
║  1. Secondary intention healing                       ║
║  2. Primary closure                                   ║
║  3. Skin graft (STSG / FTSG)                         ║
║  4. Local flap                                        ║
║  5. Regional pedicled flap                            ║
║  6. Distant pedicled flap                             ║
║  7. Free microvascular tissue transfer               ║
╚═══════════════════════════════════════════════════════╝

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CLASSIFICATION OF FLAPS

A. Based on Blood Supply (Mathes & Nahai, 1997)

┌─────────────────────────────────────────────────────────────┐
│              CLASSIFICATION BY BLOOD SUPPLY                  │
├─────────────────────┬───────────────────────────────────────┤
│  RANDOM PATTERN     │        AXIAL PATTERN                   │
│  (subdermal plexus) │    (named vessel in pedicle)           │
├─────────────────────┼───────────────────────────────────────┤
│ • Rhomboid flap     │ • Forehead flap (supratrochlear a.)   │
│ • Z-plasty          │ • Nasolabial (facial/angular a.)       │
│ • Rotation flap     │ • PMMC (thoracoacromial a.)            │
│ • Advancement flap  │ • Deltopectoral (int. mammary perfs.) │
│ • Bilobed flap      │ • RFFF (radial artery)                 │
│                     │ • ALT (LCFA descending branch)         │
│                     │ • Fibula (peroneal artery)             │
└─────────────────────┴───────────────────────────────────────┘

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B. Based on Tissue Composition

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C. Based on Location

LOCAL → Immediately adjacent to defect (nasolabial, forehead, bilobed)
    ↓
REGIONAL → Same anatomical region (PMMC, deltopectoral, SCM, trapezius)
    ↓
DISTANT → Remote site with intact pedicle (latissimus dorsi pedicled)
    ↓
FREE → Completely detached; microsurgical anastomosis (RFFF, ALT, fibula)

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D. Based on Method of Transfer (KEY FOR EXAMS)

┌────────────────────────────────────────────────────────────────┐
│                    METHOD OF MOVEMENT                           │
├──────────────┬─────────────────────────────────────────────────┤
│ ADVANCEMENT  │ Tissue moved forward in straight line            │
│              │ e.g., V-Y plasty, Rintala flap, H-flap          │
├──────────────┼─────────────────────────────────────────────────┤
│ ROTATION     │ Pivots in an arc around a fixed pivot point      │
│              │ e.g., Cervicofacial rotation, scalp rotation     │
├──────────────┼─────────────────────────────────────────────────┤
│TRANSPOSITION │ Jumps laterally over intervening intact skin     │
│              │ e.g., Rhomboid (Limberg), Z-plasty, bilobed      │
├──────────────┼─────────────────────────────────────────────────┤
│INTERPOLATION │ Crosses intact skin on a pedicle; 2-stage        │
│              │ e.g., Forehead flap, nasolabial interpolation    │
└──────────────┴─────────────────────────────────────────────────┘

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E. Mathes & Nahai Classification of Muscle Flaps (1981)

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FLAP SELECTION FLOWCHART

              HEAD & NECK DEFECT REQUIRING RECONSTRUCTION
                               │
          ┌────────────────────┼───────────────────┐
          ▼                    ▼                   ▼
     SMALL (<2cm)        MEDIUM (2-6cm)      LARGE / COMPLEX
     Superficial         Moderate depth      Deep or composite
          │                    │                   │
    Primary closure       Local flap          ┌────┴─────┐
    or FTSG/STSG      (advancement,       REGIONAL   FREE FLAP
                      rotation,            PEDICLED
                      transposition,      (PMMC, DP,
                      interpolation)      Trapezius,
                                          SAI flap)
                                               │
                                    Previous surgery / RT?
                                    YES → FREE FLAP preferred
                                    NO → Pedicled acceptable

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I. LOCAL FLAPS IN HEAD & NECK

1. Advancement Flaps

• Island of tissue advanced forward; V-shaped incision closed as Y
• Flap designed ~2x defect size
• Uses: nasal tip, columella, cheek, periorbital defects

• Midline vertical advancement from nasion to hairline
• Used for nasal dorsum defects up to 2 cm
• (Scott-Brown's block 12, line 4160)

• Large skin mobilized from cheek and neck
• Used for lower eyelid and malar defects
• Extended with Z-plasty / back-cut for better reach

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2. Rotation Flaps

• Skin from cheek-neck rotated superiorly
• Based on facial artery perforators
• Uses: large cheek, malar, lower eyelid defects
• Danger: facial nerve branches in the flap

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3. Transposition Flaps

• Two equilateral triangular flaps transposed across central limb
• 60° angles give 75% scar lengthening
• Uses: scar revision, contracture release, lengthening oral commissure

• Parallelogram-shaped transposition flap
• Four possible flap orientations for any rhomboid defect
• Uses: cheek, temple, lateral nose, postauricular, scalp

• Two lobes: first fills primary defect, second fills first donor
• Each lobe at 45° arc (Zitelli); originally 90° (McGregor)
• Uses: nasal tip, alar reconstruction - preferred for defects <1.5 cm alar
• (Scott-Brown's block 11)

• Long, narrow flap transposed 90-180°
• Used for small nasal, eyelid defects

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4. Interpolation Flaps

• Based on supratrochlear artery (axial pattern)
• Oldest flap in surgery - described by Susruta, 600 BC
• Oblique or vertical design across forehead
• Two-stage procedure: Stage 1 - flap raised, tip inset; Stage 2 at 3 weeks - pedicle divided
• Optional Stage 3 for nasal tip thinning and refinement
• Donor: primary closure if width <2.5 cm; STSG or secondary healing if wider
• Primary indication: nasal reconstruction (subtotal and total nasal defects)
• (Scott-Brown's ORL H&N Surgery, block 12, line 4172-4175)

• Superiorly based: angular artery (branch of facial artery)
• Inferiorly based: labial vessels
• Rich blood supply; one of the most reliable local flaps
• Can be folded on itself for through-and-through defects
• Uses: alar reconstruction, floor of mouth, buccal mucosa, palate
• Pedicle divided at 3 weeks
• (Scott-Brown's block 11, line 8174)

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II. REGIONAL PEDICLED FLAPS

1. Deltopectoral (DP) Flap

• Described by Bakamjian (1965) - first major axial skin flap described
• Based on 2nd, 3rd, 4th perforators of internal mammary artery
• Fasciocutaneous; extends from sternum across chest to deltoid
• Dimensions: ~20 x 9 cm
• Two-stage: flap raised and inset → pedicle divided at 3 weeks
• Uses: pharyngeal reconstruction, cervical esophagus, neck skin cover, salvage after PMMC failure
• Disadvantage: hair-bearing in men; limited arc of rotation; donor site requires STSG

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2. Pectoralis Major Myocutaneous Flap (PMMC)

• Described by Ariyan (1979) - transformed H&N reconstruction
• Blood supply: Pectoral branch of thoracoacromial artery (dominant) + lateral thoracic artery
• Mathes & Nahai Type V muscle
• Pivot point: below medial clavicle
• Skin paddle designed over lower pectoralis muscle, overlying 4th-6th ribs
• Can include a segment of rib (composite flap)

PMMC FLAP ANATOMY:
                    ┌──────────────────────────┐
  Thoracoacromial ──►   PECTORALIS MAJOR        │
  artery                   MUSCLE               │
  (pectoral branch)        │                    │
                           │   [SKIN PADDLE]     │
                           │  (over lower 1/3)  │
                    └──────────────────────────┘
                                  │
                          TUNNELLED UNDER
                          SKIN OF CHEST/NECK
                                  │
                             DEFECT SITE
                             (oral cavity /
                              pharynx / neck)

• Reliable blood supply
• Large volume of tissue
• Single-stage, same operative field
• Can protect carotid artery (muscle-only)
• Can include rib for composite reconstruction

• Bulky (especially obese, large-breasted patients)
• Hair-bearing in males
• Limited reach to skull base
• Poor colour/texture match for face
• Shoulder weakness in some patients

• Total/subtotal glossectomy
• Hypopharyngeal defects
• Skin cover post-neck dissection
• Carotid blowout protection
• Salvage after free flap failure

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3. Sternocleidomastoid (SCM) Flap

• Blood supply: occipital artery (superior third), superior thyroid artery (middle), transverse cervical artery (inferior)
• Used as muscle-only or myocutaneous flap
• Superior-based SCM flap: parotid region, lower face
• Inferior-based SCM flap: hypopharynx, tracheostoma reconstruction
• Critical limitation: NOT reliable after radical neck dissection (Type III) - accessory nerve divided; SCM devascularized
• Uses: small pharyngeal defects, parotidectomy cover, orocutaneous fistula closure

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4. Trapezius Flap

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5. Latissimus Dorsi Flap

• Thoracodorsal artery (branch of subscapular system)
• Mathes & Nahai Type V
• Can provide up to 25 x 15 cm skin paddle + large muscle volume
• Can be used as pedicled (posterior neck, scalp) or free flap
• Uses: scalp reconstruction (entire scalp), posterior neck, large trunk defects

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6. Temporalis Muscle Flap

• Deep temporal artery (branch of internal maxillary artery)
• Rotation through infratemporal fossa (coronoid removed for access)
• Provides thin, pliable musculofascial tissue
• Uses: orbital exenteration lining, palate reconstruction, maxillary defects, facial nerve reanimation
• Disadvantage: temporal hollowing at donor site

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7. Supraclavicular Artery Island (SAI) Flap

• Described by Lamberty (1979), systematized by Pallua
• Based on branch of transverse cervical artery
• Pedicle origin within the triangle: posterior border SCM (anterior), external jugular vein (posterior), clavicle (inferior)
• Dimensions: up to 30 cm length, 12 cm width
• Fasciocutaneous flap from shoulder and supraclavicular area

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III. FREE FLAPS (MICROVASCULAR TISSUE TRANSFER)

FREE FLAP SELECTION FLOWCHART:

            COMPLEX H&N DEFECT REQUIRING FREE FLAP
                           │
       ┌───────────────────┼──────────────────┐
       ▼                   ▼                  ▼
  SOFT TISSUE           BONY DEFECT      VISCERAL TUBE
  DEFECT ONLY           (+/- soft tissue) (pharynx/esophagus)
       │                   │                  │
  ┌────┴────┐         ┌────┴────┐        ┌────┴────┐
  │  THIN   │         │MANDIBLE │        │Jejunum  │
  │→ RFFF   │         │→ Fibula │        │OR tubed │
  │  or     │         │  free   │        │RFFF/ALT │
  │Scapular │         │  flap   │        └─────────┘
  └────┬────┘         │MAXILLA  │
       │              │→ Fibula │
  ┌────┴────┐         │ Scapula │
  │  BULKY  │         │ Iliac   │
  │→ ALT or │         └─────────┘
  │  TRAM/  │
  │  DIEP   │
  └─────────┘

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1. Radial Forearm Free Flap (RFFF / "Chinese Flap")

• Described by Yang et al. (1981)
• Based on radial artery + paired venae comitantes + cephalic vein
• Fasciocutaneous; thin and pliable
• Dimensions: up to 10 x 35 cm
• Allen test mandatory before harvest (confirm ulnar collateral adequacy)
• Donor site requires STSG for defects >4 cm

• Thin, pliable - ideal for mucosal lining
• Long pedicle (up to 20 cm)
• Reliable, consistent anatomy
• Can be made sensate (medial/lateral cutaneous nerve of forearm)
• Can be tubed for pharyngeal/cervical esophageal reconstruction

• Sacrifice of radial artery
• Donor site morbidity (cold intolerance, STSG cosmesis)
• Not suitable for large volumetric defects

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2. Anterolateral Thigh Flap (ALT Flap)

• Described by Song et al. (1984)
• Based on descending branch of lateral circumflex femoral artery (LCFA)
• Perforators run through or between vastus lateralis and rectus femoris
• Can be raised as fasciocutaneous, myocutaneous (with vastus lateralis), or chimeric
• Dimensions: up to 25 x 15 cm
• Now the most commonly used free flap for H&N reconstruction worldwide

• Large, adjustable skin paddle
• Minimal donor morbidity (primary closure if <8 cm width)
• Can include fascia lata as sling, or include motor nerve to VL
• Chimeric options (multiple paddles, muscle component)
• Can be thinned for mucosal lining
• Simultaneous two-team surgery possible

• Variable perforator anatomy (5-10% may need to abandon ALT)
• Thick in obese patients (may need thinning/defatting)

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3. Fibula Free Flap (Osteocutaneous Fibula)

• Described by Hidalgo (1989)
• Based on peroneal artery (septocutaneous or musculocutaneous perforators to skin paddle)
• Provides up to 25 cm of bicortical bone (most donatable bone in the body)
• Gold standard for mandibular reconstruction (Cummings, block 16; Molteni et al. 2023 systematic review [PMID 37269408])
• Preoperative CTA or Duplex to confirm 3-vessel flow and perforator location
• Multiple osteotomies possible (periosteum preserved between cuts)
• Adequate bone stock for dental implants

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4. Rectus Abdominis Free Flap (TRAM / DIEP)

• TRAM: Transverse Rectus Abdominis Myocutaneous - based on deep inferior epigastric artery
• DIEP: pure perforator flap (skin + fat only, muscle spared) - less donor morbidity
• Large skin paddle with substantial soft tissue volume
• Uses in H&N: total glossectomy, skull base, massive scalp reconstruction, laryngectomy defects
• Disadvantage: bulky; abdominal hernia risk with TRAM; longer OR time

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5. Jejunal Free Flap

• Segment of jejunum on superior mesenteric vessels
• Used for circumferential pharyngeal/esophageal reconstruction
• Provides mucosa-lined tube resembling native esophagus
• Requires laparotomy (bowel harvest + intestinal anastomosis)
• Being increasingly replaced by tubed RFFF or tubed ALT in experienced centres
• Disadvantages: laparotomy morbidity; "wet" pharyngeal voice; poor radiation tolerance; monitoring difficult

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6. Scapular / Parascapular Free Flap

• Based on circumflex scapular artery (branch of subscapular system)
• Thin fasciocutaneous; skin paddle up to 14 x 10 cm
• Can be combined as chimeric subscapular system flap (with LD muscle and/or scapular bone)
• Uses: oral cavity, neck skin, scalp, composite midface
• Recent meta-analysis (McGregor et al. 2024, [PMID 39045822]): acceptable donor site morbidity, but shoulder abduction and flexion limited; physiotherapy is essential postoperatively

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7. Temporoparietal Fascia (TPF) Flap

• Based on superficial temporal artery and vein
• Can be used as regional pedicled or free flap
• Thin vascularized fascial sheet (2-3 mm) - excellent for covering cartilage frameworks
• Uses: auricular reconstruction, tracheal reconstruction, orbital reconstruction, facial contouring
• Systematic review (Horen et al. 2021, [PMID 34387574]): highly reliable for complex 3D defects

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IV. FLAP PHYSIOLOGY AND SURVIVAL

• Preliminary surgery 2-3 weeks before definitive transfer
• Causes adrenergic desensitization → choke vessel vasodilation
• Converts random zones to axial pattern → increases survival 30-40%

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V. FREE FLAP MONITORING

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VI. COMPREHENSIVE NAMED FLAP SUMMARY TABLE

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VII. RECENT ADVANCES

1. Perforator Flaps - Pure fasciocutaneous flaps (DIEP, ALT, PAP) that spare underlying muscle; reduce donor site functional morbidity significantly compared to myocutaneous flaps.
2. Chimeric / Conjoined Free Flaps - Multiple tissue components harvested on a single vascular axis (e.g., subscapular system: scapula bone + LD muscle + parascapular skin) for complex composite 3D defects in a single-stage free flap.
3. Virtual Surgical Planning (VSP) + CAD/CAM Cutting Guides - Computer-planned osteotomies with pre-bent titanium plates and cutting guides for fibula mandibular reconstruction; now standard of care at major centres; improves symmetry and accuracy.
4. Pre-fabricated and Pre-laminated Flaps - Cartilage or bone frameworks implanted at donor site weeks before transfer; used for total nasal and auricular reconstruction.
5. Supermicrosurgery - Anastomosis of vessels <0.8 mm; enables perforator-to-perforator anastomoses; valuable in irradiated fields with limited conventional recipient vessels.
6. Robotic / Video-assisted Flap Harvest - Minimally invasive latissimus dorsi harvest; smaller scars, faster recovery.
7. Impact of Adjuvant Radiotherapy on Free Flaps - Meta-analysis (Pfister et al. 2024, [PMID 38401274]): adjuvant radiochemotherapy causes significant free flap volume reduction over time; counselling needed regarding long-term functional outcomes.
8. Mandibular Reconstruction - Systematic review (Molteni et al. 2023, [PMID 37269408]): fibula free flap confirmed gold standard; scapula preferred for composite midface; VSP improves outcomes.
9. Scapula Free Flap Morbidity - Meta-analysis (McGregor et al. 2024, [PMID 39045822]): scapular donor site shoulder abduction and flexion limitations; early physiotherapy is mandatory.
10. Postoperative ICU vs. Non-ICU Care for Free Flaps - Meta-analysis (Mashrah et al. 2022, [PMID 34992114]): non-ICU monitored settings with dedicated nursing protocols show comparable flap survival to ICU; enables resource optimization.

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COMPLETE SUMMARY FLOWCHART

╔══════════════════════════════════════════════════════════════════╗
║                   CLASSIFICATION OF FLAPS                        ║
╠══════════════════════════════════════════════════════════════════╣
║                           │                                      ║
║    ┌──────────────────────┼──────────────────────┐              ║
║    ▼                      ▼                      ▼              ║
║ BY BLOOD            BY TISSUE TYPE          BY MOVEMENT         ║
║ SUPPLY              ────────────────        ────────────        ║
║ ─────────           Cutaneous               Advancement         ║
║ Random pattern      Fasciocutaneous         Rotation            ║
║ Axial pattern       Myocutaneous            Transposition       ║
║                     Osseocutaneous          Interpolation       ║
║                     Visceral                                     ║
║                     Chimeric/Composite                          ║
║                                                                  ║
║         ┌────────────────┼───────────────────┐                 ║
║         ▼                ▼                   ▼                 ║
║     LOCAL FLAPS    REGIONAL FLAPS       FREE FLAPS             ║
║     ──────────     ──────────────       ──────────             ║
║   Advancement      Deltopectoral        RFFF                   ║
║   Rotation         PMMC                 ALT                    ║
║   Transposition    SCM                  Fibula                 ║
║   Interpolation    Trapezius            Jejunum                ║
║   Forehead         Latissimus dorsi     TRAM/DIEP              ║
║   Nasolabial       Temporalis           Scapular               ║
║   Rhomboid         SAI flap             TPF                    ║
║   Bilobed                                                       ║
╚══════════════════════════════════════════════════════════════════╝

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REFERENCES

1. Scott-Brown's Otorhinolaryngology Head & Neck Surgery (8th Ed, Gleeson) - Chapters 85, 91, 92: Local flaps, nasal reconstruction, supraclavicular flap
2. Cummings Otolaryngology Head and Neck Surgery (7th Ed, Flint) - Chapters 77-78: Skin flap physiology, free tissue transfer, osteocutaneous flaps
3. Ariyan S. The pectoralis major myocutaneous flap. Plast Reconstr Surg 1979; 63:73-81
4. Bakamjian VY. A two-stage method for pharyngoesophageal reconstruction. Plast Reconstr Surg 1965; 36:173
5. Hidalgo DA. Fibula free flap: a new method of mandible reconstruction. Plast Reconstr Surg 1989; 84:71-79
6. Song YG et al. The free thigh flap: a new free flap concept based on the septocutaneous artery. Br J Plast Surg 1984
7. Mathes SJ, Nahai F. Classification of the vascular anatomy of muscles. Plast Reconstr Surg 1981; 67:177-187
8. Molteni G et al. Mandibular reconstruction in HNC: which is the gold standard? Eur Arch Otorhinolaryngol 2023 (PMID 37269408)
9. Pfister P et al. Impact of adjuvant radiochemotherapy on free flap volume in H&N reconstruction. J Plast Reconstr Aesthet Surg 2024 (PMID 38401274)
10. McGregor S et al. Donor site morbidity after scapula free flap in H&N reconstruction. Head Neck 2024 (PMID 39045822)
11. Mashrah MA et al. Postoperative care after head and neck free-flap surgery. BMJ Open 2022 (PMID 34992114)
12. Horen SR et al. Temporoparietal Fascial Free Flap: A Systematic Review. Ann Plast Surg 2021 (PMID 34387574)
13. Dhingra PL & Dhingra S - Diseases of ENT Head and Neck Surgery (6th Ed)
14. Hazarika P - Textbook of ENT and Head & Neck Surgery (clinical integration)

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RGUHS Exam Tip: This is a standard 50-mark question. Cover all four main sections: Classification (10 marks) → Local flaps with diagrams (10 marks) → Regional pedicled flaps - PMMC and DP in particular detail (15 marks) → Free flaps - RFFF, ALT, Fibula (10 marks) → Flap failure + monitoring + recent advances (5 marks). The Reconstructive Ladder, classification flowchart, PMMC anatomy diagram, and bilobed flap diagram are mandatory for full marks.