Plastic surgery Skin graft and flaps

Skin functions X Protective barrier against: 1.Trauma 2.Radiation 3. Temperature changes 4. Infection

Cont. Thermoregulation through: 1.Vasoconstriction&Vasodilatation 2. Insensible fluid loss control

Skin anatomy . Skin varies in thickness depending on: Anatomic location thickest in the palm & sole of the feet, thinnest in the eyelids & postauricular region. Sex male thicker than female. Age / children have thin skin

Skin layers Epidermis Stratified squamous epithelium /Keratinocytes. No blood vessels /Nutrients From dermis by diffusion through basement membrane

Dermis Papillary dermis Thinner Loose connective tissue, containing: Capillaries. Elastic fibers. Reticular fibers Some collagen

Reticular dermis Thicker layer Dense connective tissue, containing: Larger blood vessels Closely interlaced elastic fibers Coarse, branching collagen fibers arranged inlayers parallel to the surface. Fibroblasts Mast cells Nerve endings Lymphatics Some epidermal appendages

Epithelial cell source Epithelial cells re-epithelialize when the overlying epithelium is removed or destroyed by; Partial thickness burn Abrasions STSG harvesting

Source intradermal structures(epithelial appendages): Sebaceous glands Sweat glands Apocrine glands Hair follicles

What’s skin graft? Is transplantation of the skin from one part to another part(removed from its blood supply)

Types   According to the origin: Autograft/ from the same individual Iso-graft :identical twin Allograft/ from different individual (of the same species) Xenograft / from different species (gene pig)

Types, cont. According to the dermal thickness: STSG( split thickness skin graft) (epidermis +variable thickness dermis) Thin (0.005 – 0.012 inches) Intermediate (0.012 – 0.018) Thick (0.018 – 0.030) Could be; Meshed Sheet  FTSG (full thickness skin graft ) (epidermis +Entire dermis)Contains adnexal structures (sweat glands ,sebaceous glands, hair follicles & capillaries)

Advantages Disadvantages Type of Graft Advantages Disadvantages Thin Split Thickness Best Survival Heals Rapidly Least resembles original skin. Least resistance to trauma. Poor Sensation Maximal Secondary Contraction Thick Split Thickness More qualities of normal skin. Less Contraction Looks better Fair Sensation Lower graft survival Slower healing. Full Thickness Most resembles normal skin. Minimal Secondary contraction Resistant to trauma Good Sensation Aesthetically pleasing Poorest survival. Donor site must be closed surgically. Donor sites are limited.

CHOICE BETWEEN FULL- AND SPLIT-THICKNESS SG.SPLIT-THICKNESS SG. Depends on the wound’s Condition Location Size Aesthetic concern

FTSG DONOR SITES Closed : Primarily STSG/ from another site

Skin graft survival (TAKE) Depends on the graft’s ability to; Receive nutrients& vascular in growth from the bed (in 3 phases, 4 theories) Close contact & immobilization(skin graft adherence, in 2 phases )

Skin graft revascularization Phases Serum imbibition Lasts 24 – 48 hr Fibrin layer forms (adhere the graft tothe bed. Nutrient absorption into the graft (fromthe bed by capillary action)

Inosculation Recipient & donor end capillaries aligned. Kissing capillaries Graft revascularized through kissing capillaries

How to optimize TAKE? Well vascular bed, seldom take in exposed; Bone without periosteum (despite orbit or temporal bone) Cartilage without perichondrium Tendon without paratenon Close contact(between graft & bed); Hematomas Seromas These 2 immobilize & compromise graft take

Other Factors that Contribute to Graft Failure Systemic Factors Malnutrition Sepsis Medical Conditions (Diabetes) Medications Steroids Antineoplastic agents Vasonconstrictors (e.g. nicotine)

Sheet graft Definition / Is a continuous, uninterrupted graft. Advantages / Superior aesthetic result Disadvantages / Not allowing blood or serum to drain.

Meshed graft Definition / Is a sheet graft after multiple mechanical incisions. Advantages / Allowing immediate graft expansion. Cover larger area per cm Allows blood & serum drainage. Disadvantages / Pebbled appearance (aesthetically not acceptable).

What will happen if a wound heals without skin graft What will happen if a wound heals without skin graft? heals without skin graft? Granulating wounds heal secondarily demonstrate the greatest degree of contraction& are most prone to hypertrophic scarring

Donor site selection Consider Color Texture Thickness Vascularity Donor site morbidity Sites Any where Face: Supra-calvicular area Upper eyelid (small amount, very thin) Common sites (for STSG): Thigh Buttocks Abdominal wall

Harvesting Tools Razor Blades Grafting Knives (Blair, Ferris, Smith, Humbly, Goulian) Manual Drum Dermatomes (Padgett, Reese) **Electric/Air Powered Dermatomes (Brown, Padgett, Hall) Electric & Air Powered tools are most commonly used.

SG postoperative care Graft failure causes; Hematoma Serroma Raising the graft, prevent revascularization. Infection( > 10organism per gram of tissue) Minimized by careful bed preparation & early graft inspection after applying to a contaminated bed. Infection at the graft donor site can converts partial thickness dermal loss into complete thickness dermal loss. . Mobilization Interrupt revascularization, prevented by tie-over bolster dressing on the face & trunk, splinting on the extremities

Biologic dressing Definition /Temporary wound coverage, eg. Large burns, necrotizing facsiitis. Advantage /Protect the recipient bed from desiccation & further trauma until definitive closure. Biologic skin substitutes / Human allograft (take, rejected after 10 days, unless the recipient immuno-suppressed as in large burns, rejection take longer). Amnion Xenograft (pig skin), rejected before becoming vascularized (take). Synthetic skin substitutes / Silicone Polymers Composed membrane

Human epidermis (in vitro) Human epidermis cultured in vitro to yield sheet of cultured epithelium that will provide coverage , albeit fragile (due to lack of epidermis), for Large wounds

Flap Flap Any tissue used for reconstruction or wound closure that retains all or part of its original blood supply after the tissue has been moved to the recipient location.

Graft vs. Flap Graft Does not maintain original blood supply. Flap Maintains original blood supply.

CLASSIFICATION Tissue to be transferred Location of donor site Blood supply

Tissue to be transferred Single component Skin flap — i.e. Parascapular flap. Muscle flap — i.e. Rectus muscle flap or latissimus dorsi muscle fla Bone flap — i.e. Fibula flap Fascia flap — i.e. Serratus fascia flap Multiple components Fasciocutaneous — Radial forearm flap or anterolateral thigh flap Myocutaneous — Transverse rectus abdominis muscle flap osseocutaneous — Fibula with a skin paddle

Location of donor site Flaps can be described by the proximity to the primary defect that needs to be reconstructed. The harvest leaves a secondary defect that needs to be closed Local Regional Distant

Local flaps — Local flaps are raised from the tissue adjacent to the primary defect. Its movement into the defect can be described as rotation, transposition, and interpolation. Advancement flaps include single pedicle, bipedicle, and V-Y flaps. e.g. lip may be repaired by a flap from the adjacent cheek.

Plantar rotation flap transposition flap

Regional When the skin flap is not from the adjacent area, but is from the same region of the body. e.g. the tip of nose might be repaired with a flap from the forehead.

Distant — moving tissue (skin, fascia, muscle, bone, or some combination) from one part of the body, to another part, where it is needed. A distant flap is required when there is no healthy soft tissue adjacent to an open wound with which to provide adequate coverage. may be either pedicled (transferred while still attached to their original blood supply) or free.

Pedicled flaps remain attached to the body at the harvest site Pedicled flaps remain attached to the body at the harvest site. The pedicle is the base that remains attached and includes the blood supply. It is transferred to the defect with its vascular pedicle acting as a leash. Usually via a musculocutaneous or fasciocutaneous fashion. Free flaps are detached at the vascular pedicle and transferred from the donor site to the recipient site. They require re-anastamosis of the artery and vein to recipient vessels at the recipient site.

Groin Pedicle Flap

pedicled groin flap

Blood supply Random (no named blood vessel) the blood supply is not derived from a recognized artery but, rather, comes from many little unnamed vessels rely on blood flow through dermal and subdermal plexus limited in length and width e.g. advancement flap, rotation advancement flap, rhomboid flap.

Axial (named blood vessel) Axial pattern flaps are designed with a specific named vascular system that enters the base and runs along longitudinal flap axis runs in subcutaneous tissue superficial to muscle Flap blood supply secure for at least length of blood vessels e.g: lateral forehead flap - superficial temporal i. Blood supply by direct artery and accompanying vein ii. Greater length possible than with random flap iii. Can be free flap iv. Peninsular — skin and vessel intact in pedicle v. Island — vessels intact, but no skin over pedicle

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