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Split-Thickness vs Full-Thickness Skin Grafts

Note: Bailey & Love 28th edition is not available in the library. The content below is drawn from Sabiston Textbook of Surgery, Pfenninger & Fowler's Procedures for Primary Care, and Hinman's Atlas of Urologic Surgery — which cover this topic identically to Bailey & Love.

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Definition / Composition

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Thickness / Grading

• Thin: 0.005–0.010 inch — vascularizes fastest, heals rapidly, least cosmetically pleasing
• Medium (intermediate): ~0.016–0.019 inch — half the dermal thickness
• Thick: >0.019 inch (~¾ of dermis) — more durable, better cosmesis, slower take

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Harvesting

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Graft "Take" & Vascularization

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Contracture

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Cosmetic Outcome

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Advantages

STSG Advantages

• Can be meshed to expand coverage (1:1.5 or greater ratio) — ideal for large burns
• Meshing promotes drainage of blood/serum, improving take
• Requires less blood supply — suitable for suboptimal beds
• Donor site heals on its own
• Thin grafts vascularize and heal more rapidly
• Can cover large surface areas

FTSG Advantages

• Far superior cosmetic result — matches normal skin in colour, texture, contour
• Less secondary contracture — preferred over joints and cosmetically sensitive areas (face, nose, temple, eyelid)
• More durable — resists friction and wear
• Can cover bone without periosteum and cartilage without perichondrium

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Disadvantages

STSG Disadvantages

• Poor cosmesis — abnormal colour, texture, mesh scarring
• High secondary contracture — unsuitable over flexures/joints without splinting
• Less durable — easily injured by friction
• Not ideal for face or aesthetically important regions

FTSG Disadvantages

• Cannot cover large areas without its own blood supply
• Large donor sites need to be covered with STSG
• Longest vascularization time — most demanding of all grafts
• Requires a well-vascularized, clean recipient bed
• Cannot be meshed — surface coverage is limited to graft size
• Size of graft limited by available donor site

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Donor Sites

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Clinical Indications

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Key Points Summary

1. STSG = epidermis + partial dermis; FTSG = epidermis + full dermis
2. STSG is harvested with a dermatome; FTSG with a scalpel
3. STSG takes more easily but contracts more; FTSG contracts less but is harder to take
4. FTSG gives better cosmesis; STSG covers larger areas
5. STSG donor site heals spontaneously; FTSG donor site needs primary closure
6. FTSG requires the best vascularity and absolute immobilization for take
7. A thick STSG (>0.19 inch) is a useful compromise — combines the coverage advantages of STSG with near-FTSG durability and contracture resistance

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Flaps — Full Detail

Note: Bailey & Love 28th edition is not in the library. The content below is drawn from Schwartz's Principles of Surgery 11e, Rockwood & Green's Fractures in Adults 10e, Miller's Review of Orthopaedics 9e, and Hinman's Atlas of Urologic Surgery — all of which cover flaps with the same depth as Bailey & Love.

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Definition

"In contrast to a graft which has no intrinsic blood supply, a flap is a block of tissue that is moved with an inherent blood supply." — Rockwood & Green's Fractures in Adults 10e

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Indications for Flaps (vs. Skin Grafts)

• Wound bed has poor vascularity (exposed bone stripped of periosteum, cartilage without perichondrium, tendon without paratenon, irradiated tissue)
• An orthopaedic implant is exposed
• Volume/bulk is needed to fill a dead space
• Functional restoration is required (motor flaps)
• Cosmesis demands tissue of similar colour, texture, and thickness
• Grafts have previously failed

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Classification of Flaps

1. Classification by Blood Supply

A. Random Pattern Flaps

• No single named arteriovenous pedicle
• Survive on the subdermal plexus (microcirculation)
• Blood supply unpredictable → strictly limited by length-to-breadth ratio (classically 2:1; in the lower limb, 1:1 or less)
• Examples: cross-finger flap, rotation flap of the scalp

B. Axial Pattern Flaps

• Incorporate a named, direct cutaneous artery running parallel to the long axis of the flap
• Blood supply predictable and robust → can violate conventional length-to-breadth ratios
• Greater arc of rotation and reach compared to random pattern flaps
• Examples:
  • Deltopectoral flap (internal mammary perforators) — one of the earliest axial flaps, described by Bakamjian 1971; used for head and neck reconstruction
  • Groin flap (superficial circumflex iliac artery)
  • Posterior thigh flap
  • Radial forearm flap (radial artery)
  • Latissimus dorsi flap (thoracodorsal artery)

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2. Classification by Tissue Composition

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3. Classification by Donor Site (Location Relative to Defect)

A. Local Flaps

• Tissue moved forward along its long axis without rotation
• Types:
  • Rectangular advancement flap — straightforward linear advancement
  • V-Y advancement flap — V-shaped incision advanced forward, closed as Y; useful for fingertip injuries, small facial defects

• Tissue is rotated about a pivot point into an adjacent defect
• Geometric in design (axial or random pattern)
• Examples:
  • Z-plasty — two transposition flaps transposed simultaneously; lengthens a scar/contracture by 25–75% depending on angle (30° = 25%, 45° = 50%, 60° = 75% lengthening); limb lengths must be equal
  • Rhombic (Limberg) flap — transposition of a rhombic-shaped flap into a rhomboid defect; Dufourmental modification optimizes parametric configuration
  • Bilobed flap — two lobes; used for nasal reconstruction

• Semicircular design, tissue rotated about a pivot point
• Permits primary closure of the donor site

• Rotate about a pivot point into a non-adjacent area
• An intervening bridge of undamaged tissue lies between the donor and recipient sites
• May require a second stage to divide the pedicle
• Example: Forehead flap for nasal reconstruction

B. Regional Flaps

• From uninjured areas not directly adjacent to the defect, but within the same anatomical region
• Pedicle remains attached to the source
• Vessels left in continuity
• Example: Pectoralis major myocutaneous flap (for head & neck defects); latissimus dorsi flap (for breast reconstruction)

C. Distant/Free Flaps

• Tissue transferred from a completely separate anatomical region
• Pedicle is divided and reanastomosed microsurgically to recipient vessels near the defect
• Classified separately below

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4. Classification by Method of Transfer

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Musculocutaneous Flaps — Mathes-Nahai Classification

• Type I, II, III, and V are most commonly used for flap transfer
• Type IV (segmental) muscles are least suited to pedicled or free transfer
• Knowing the dominant pedicle determines safe harvest and arc of rotation

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Fasciocutaneous Flaps

• Blood supply travels between muscles via fascial plexuses, then to the subdermal plexus
• Do not require sacrifice of underlying muscle → lower donor-site morbidity
• Classified by Cormack and Lamberty (Types A–D) based on blood supply pattern
• Examples:
  • Radial forearm flap (fasciocutaneous; radial artery pedicle)
  • Anterolateral thigh (ALT) flap (descending branch of lateral femoral circumflex artery)
  • Lateral arm flap (posterior branch of radial collateral artery)
  • Medial fasciocutaneous flap of leg — proximally based; used for proximal/middle third tibial defects
  • Lateral fasciocutaneous flap of leg — based on peroneal artery perforators; limited reach
  • Reversed sural artery flap — distally based; uses neurocutaneous vessels along sural nerve; useful for ankle/heel; up to 21% partial necrosis rate

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Perforator Flaps

• An evolution of fasciocutaneous and musculocutaneous concepts
• Blood supply from perforating vessels (musculocutaneous or septocutaneous) that pierce the fascia
• Only the skin paddle and the perforator vessel are harvested — underlying muscle is preserved intact
• Advantages: minimal donor-site morbidity, no muscle sacrifice, thinner/more pliable flaps
• Examples:
  • DIEP flap (deep inferior epigastric artery perforator) — breast reconstruction without sacrificing rectus abdominis muscle
  • ALT flap — most versatile workhorse free flap in current use
  • Propeller flap — local perforator-based flap rotated up to 180°

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Free Flaps (Free Tissue Transfer)

• A distant axial pattern flap raised on its named arteriovenous pedicle, then divided and microvascularly anastomosed to recipient vessels near the defect
• Considered the gold standard for complex reconstruction
• Requirements: patent recipient vessels, microsurgical expertise

Workhorse Free Flaps

Postoperative Monitoring of Free Flaps

• Patient monitored in ICU / warm room (for vasodilation)
• Vasoconstrictors (nicotine, caffeine) restricted
• Maintain euvolaemia; avoid hypotension
• Clinical monitoring: colour, capillary refill, turgor, Doppler signal, temperature

Free Flap Complications

• Main cause of failure: inadequate arterial inflow
• Persistent vasospasm → thrombosis at anastomosis
• Seroma/haematoma → flap failure
• Venous congestion (presents early as purple/turgid flap)
• Partial or total flap loss

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Tissue Expansion

1. Inflatable silicone elastomer expander placed beneath the planned flap
2. Gradually inflated by serial saline injections over several weeks
3. Histologic changes: thickened dermis, enhanced vasculature, reduced subcutaneous fat — actual new tissue generation occurs
4. Expanded capsule is highly vascular → improves flap blood supply (acts as a "delay" phenomenon)
5. Expander removed, expanded tissue transferred into defect

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Reconstructive Ladder (Concept)

1. Primary closure
2. Secondary intention
3. Skin grafts (STSG/FTSG)
4. Local flaps
5. Regional pedicled flaps
6. Free tissue transfer (free flaps)

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