Morning Report Senin, 2 Februari 2015

Skin functionsProtective barrier, against:TraumaRadiationTemperature changesInfectionContThermoregulation, through:Vasoconstriction & VasodilatationInsensible fluid loss controlSkin anatomySkin varies in thickness depending on:Anatomic location:thickest in the palm & sole of the feetthinnest in the eyelids & postauricular region.Sex / male thicker than female.Age / children have thin skinSkin layers1. EpidermisStratified squamous epithelium / Keratinocytes.No blood vesselsNutrients from dermis by diffusion through basement membrane.

Cont2. Dermis:Papillary dermisThinnerLoose connective tissue, containing:CapillariesElastic fibersReticular fibersSome collagenContReticular dermis:Thicker layerDense connective tissue, containing:Larger blood vesselsClosely interlaced elastic fibersCoarse, branching collagen fibers arranged in layers parallel to the surface.FibroblastsMast cellsNerve endingsLymphaticsSome epidermal appendagesEpithelial cell sourceEpithelial cells re-epithelialize when the overlying epithelium is removed or destroyed by:Partial thickness burnAbrasionsSTSG harvesting.ContSource, intradermal structures (epithelial appendages):Sebaceous glandsSweat glandsApocrine glandsHair folliclesWhats skin graft?Is transplantation of the skin from one part to another part (removed from its blood supply).TypesAccording to the origin:Autograft / from the same individualAllograft / from different individual (of the same species)Xenograft / from different species (gene pig)ContAccording to the dermal thickness:STSG (epidermis + variable thickness dermis)Thin (0.005 0.012 inches)Intermediate (0.012 0.018)Thick (0.018 0.030)Could be;MeshedSheetFTSG (epidermis + entire dermis)Contains adnexal structures (sweat glands,sebaceous glands, hair follicles & capillaries).THICK GRAFTS ???!!!ADVANTAGES:The thicker the dermal component, the more the characteristics of normal skin are maintained following grafting, because:Greater collagen contentLarger no. of dermal vascular plexusesLarger no. of epithelial appendagesDISADVANTAGES :More favorable conditions for survivalgreater amount of tissue requiringrevascularization.CHOICE BETWEEN FULL- ANDSPLIT-THICKNESS SG.Depends on the wounds :ConditionLocationSizeAesthetic concernsFULL THICKNESS SKIN GRAFTSAdvantagesIdeal for the face / where local flap is inaccessible or not indicated.Retain more characteristics of normal skin, including;ColorTextureThicknessLess secondary contractionIn children grow with the individualGreater sensory return (greater availability of neurilemaal sheet)ContDisadvantagesMore primary contracturesMore hair follicles transferredMore precarious survival (well vascularized bed)Limited range of applications, for;Small woundsUncontaminated woundsWell vascularized woundsPRIMARY CONTRACTURE: immediate recoil of a freshly harvested graft due to the ELASTIN in the dermis (the more dermis the graft has, the more primary contracture).FTSG DONOR SITESClosed :PrimarilySTSG / from another site.FTSG ProcedurePlanning ( measuring, pattern made, donor site infiltration LA +/- Epinephrine)Harvesting scalpelDonor site closed primarily.Graft placed.STSGADVANTAGES:Less ideal conditions for survival, broader range of application.Less hair follicles transferredUsed to resurface :Large woundsLine cavitiesMucosal defectsFlap donor sitesMuscle flapDonor site heals by epidermal appendages cells immigration & proliferation.ContDisadvantages;More fragileCan not withstand subsequent radiation therapyMore secondary contractureDo not grow with the individualSmoother & shiner than normal skinAbnormal pigmentation tendency (pale/ white/hyperpigmented)Donor site more painful than the recipient siteSECONDARY CONTRACTURE: contraction of a healed scar due to MYOFIBROBLAST activity (the thinner the STSG, the greater the secondary contracture).STSG is more functional than cosmeticSkin graft survival (TAKE)Depends on the grafts ability to;Receive nutrients & vascular ingrowth from the bed (in 3 phases, 4 theories)Close contact & immobilization (skin graft adherence, in 2 phases)Skin graft revascularizationPhases;Serum imbibition;Lasts 24 48 hrFibrin layer forms (adhere the graft to the bed.Nutrient absorption into the graft (from the bed by capillary action).Inosculation;Recipient & donor end capillaries aligned.Kissing capillaries;Graft revascularized through kissing capillaries.

Graft revascularization theoriesNeovascularization (invade graft)Communication (between graft & bed vessels)Neovascularization + communicationGraft vasculature made up primarily from its Original vessels before transfer.How to optimize TAKE?Well vascular bed, seldom take in exposed;Bone without periosteum (despite orbit or temporal bone)Cartilage without perichondriumTendon without paratenonClose contact (between graft & bed);HematomasSeromasThese 2 immobilize & compromise graft take.Skin graft adherence phases First phase:Begins with placement of the graft on the bed.Graft adhered by fibrin deposition.Lasts 72 hr.Second phase:Growth of fibrous tissue & vessels into the graft.ContSheet graftDefinition/ Is a continuous, uninterrupted graft.Advantages/Superior aesthetic resultDisadvantages/Not allowing blood or serum to drain.ContMeshed graftDefinition/ Is a sheet graft after multiple mechanical incisions.Advantages/Allowing immediate graft expansion.Cover larger area per cm2Allows blood & serum drainage.Disadvantages/Pebbled appearance (aesthetically not acceptable).What will happen if a woundheals without skin graft?Granulating wounds heal secondarily demonstrate the greatest degree of contraction & are most prone to hypertrophic scarring.EPITHELIAL APPENDAGES INTHE SKIN GRAFTTheir no. depends on the dermal thickness.Graft sweats / depend on:Sweat glands no. transferredSympathetic reinnervation of these glands from the recipient site.Skin graft reinnervated from:Nerve fiber ingrowth from the recipient site.From the periphry.Donor siteEpidermisRegenerate from epidermal appendages cells immigration, left in the dermis.DermisNever regenerates.STSGOriginal donor site can be used for subsequent harvest(dependant on donor dermis thickness).HealingBy re-epithelialization from epidermal appendages within nearly 7 days according to its thickness.Enhanced by moist dressing & protection from;Mechanical traumaDesiccationDonor site selectionConsiderColorTextureThicknessVascularityDonor site morbiditySitesAny whereFace:Supracalvicular areaUpper eyelid (small amount, very thin)Common sites (for STSG):ThighButtocksAbdominal wallSG postoperative careGraft failure, causes;HematomaSerromaRaising the graft, prevent revascularization. Infection ( > 105 organism 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 dressingDefinition/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 immunosuppressed as in large burns, rejection take longer).AmnionXenograft (pig skin), rejected before becoming vascularized (take).Synthetic skin substitutes/SiliconePolymersComposed membranesHuman 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.

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