SKIN GRAFTS AND SKIN FLAPS

SKIN GRAFTS AND SKIN FLAPSDr. Ridhika Munjal

SkinSkin is largest organ of human body and is composed of two layers, i.e.,EpidermisDermis

SkinEpidermis: Stratified squamous epithelium composed primarily of keratinocytes. No blood vessels. Relies on diffusion from underlying tissues. Separated from the dermis by a basement membrane

SkinDermis:Composed of two sub-layers: (a)superficial papillary (b)deep reticular.The dermis contains collagen, capillaries, elastic fibers, fibroblasts, nerve endings, etc.

Skin Grafting:Definitions: Graft: It is transfer of tissue from one area to other without its blood supply or nerve supply. Autograft: It is tissue transfer from one location to another on the same patient. Isograft: Tissue transfer between two genetically identical individuals, eg, twins. Allograft (Homograft): Tissue transfer between two genetically different members, eg, kidney transplant. Xenograft (Heterograft): Tissue transfer from a donor of one species to a recipient of another species.

Types Of Skin GraftPartial Thickness GraftFull Thickness Graft

Partial Thickness GraftAlso called as split thickness graft/ Thiersch graft.It is removal of full epidermis plus part of dermis from the donor area.

Advantages:It is technically easier.Graft take up is better.Donor area heals on its own. Disadvantages:1. Infection2. Contracture.3. Loss of hair growth.Seroma and haematoma formation will prevent graft take up.Contraindicated in skin grafting over bone, tendon, cartilage and joint.Cant be done in group A beta haemolytic streptococcci infection.

Full Thickness GraftAlso called as Wolfe graft.It includes both epidermis + full dermis. Advantages:Colour match is good.No contracture.Sensation and function of sebaceous gland, hair follicles retained better.

Disadvantages:Used only for small areas.Wider donor area has to be covered with SSG .

IndicationsWell granulated ulcer.Clean wound.After surgery to cover and close the defect created.

Stages Of Graft IntakeStage of Plasmic Imbibition: During 1st 48 hours nourishment of the graft occurs from plasma exudate from host bed capillaries.Inosculation of blood: After 48 hours graft and host vessels form anastomosis.Fibroblast Maturation: Capillary ingrowth completes the healing by fibroblast maturation.The grafts are securely adhered to bed by 10-14 days.

TechniqueKnife used: Humbys KnifeBlade: Eschmann blade, Downs blade.Donor Area:SSG: Commonly used site: Thigh. Other sites: Arm, leg, forearm. Dressing is opened after 10 days.Full Thickness Graft: Post-auricular area. Supraclavicular area. Groin crease area.

Recepient Area: Area is scraped well and graft is placed after making window cuts in graft to prevent development of seroma. Graft is fixed and dressing is placed. Dressing is opened on 5th post-operative day. Merchurochrome is applied over the recepient margin to promote epithelialisation.

Humbys Knife

Technique Of SSGDonor Site

Skin FlapsIt is transfer of donor tissue with its blood supply to the recipient area.Parts of flap:BasePedicleTip

Anatomy and blood supply of skin flap

IndicationsTo cover wider and deeper defects.To cover bone, tendon and cartilage.If skin graft repeatedly fails.

Classification of Flapsl. Due to blood supply: i) Random pattern flapii) Axial pattern flap

2. Due to site of flap: i) Local flap ii)Distant flap

Flaps according to blood supplyi)Random Flaps:These flaps consist of three sides of a rectangle, bearing no specific relationship to where the blood supply enters.The length to breadth ratio is no more than 1.5:1.

ii) Axial Flaps:These are much longer flaps, based on known blood vessels.

Types of Flaps according to siteLocal flaps:It is raised next to tissue defect.Types of local flaps:Transposition Flap: It is squarely designed which moves laterally to close the defect creating a larger are on its original place, which is covered with SSG.

Transposition Flap

Types of Local Flapsii) Z Plasty: It involves transposition of two inter-digitating triangular flaps.There is change in direction as well as gain in length of the common limb of Z.Most important factors are angle size and length of the limb. Used in contracture release like Dupuytrens contracture and pilonidal sinus.

Types of Local Flapsiii)Rotation Flap: Semicircular flaps of skin and subcutaneous tissue that resolve in arc around a pivot point to shift tissue in a circle.Eg: Gluteal region.iv) Advancement Flap: It moves directly forward and rely on skin elasticity to stretch and fill a defect. May need triangle excision at the base to make it work (Burrows Triangle) Eg: Flexor surfaces.

Rotation Flap

Advancement Flap

Types Of Local Flapsv) V-Y advancement flap: Advance skin on each side of a V- shaped incision to close the wound a Y- shaped closure. Eg: Cut finger tip.

vi) Y-V advancement flap: Used to release multiple band scars over joints.

V-Y advancement Flap

Y-V advancement flap

Types of Local Flapsvii) Bilobed Flap:It uses a flap to close a convex defect and a second smaller flap to close the donor site.Eg: nasal defects.

viii) Rhomboid Flap:It relies on the looseness of adjacent skin to transfer a rhomboid shape flap into a defect that has been converted into similar rhomboid shape.Eg: cheek, temple, back and flat surface defects.

Bilobed Flap

Rhomboid Flap

Local FlapsAdvantages :Best local cosmetic tissue match.Often a simple procedure.Local or regional anesthesia option.

Disadvantages :Possible local tissue shortage.Scarring may exacerbate the condition.

Types Of Flaps(b) Distant Flaps: To repair defects in which local tissue is inadequate, distant flaps can be moved on long pedicles that contain blood supply. The pedicle may be buried beneath the skin to create an island flap or left above the skin and formed into tube.

Distant FlapsTypes of distant flaps: i) Forehead flap: It is based on anterior branch of superficial temporal artery.

ii) Deltopectoral flap (Bakamijan Flap): It is based on three perforating branches of internal mammary artery.

Forehead flap

Deltopectoral Flap

Distant Flapsiii) Groin flap: It is based on superficial circumflex iliac artery.

iv) Latissimus Dorsi muscle flap: It is based on thoracodorsal artery.

v) Pectoralis major flap:It is based on pectoral branches of thoracoacromial artery.

Groin Flap

Pectoralis major flap

Distant Flapsvi) Gastrocnemius muscle flap

vii) Transverse rectus abdominis muscle flap (TRAM flap): Superior pedicle is based on superior epigastric vessels. Inferior pedicle is based on inferior epigastric vessels.

TRAM flap

Distant FlapsAdvantages:Good blood supply and good take up.Gives bulk, texture and colour to the area.

Diasadvantages:Long term hospitalization.Infection.Kinking, rotation and flap necrosis.Staged procedure.

Saltatory FlapIt is mobilizing the flaps in stages from distant donor area towards recipient area.Waltzing: It is a technique wherein flap is moved from donor area and attached adjacent to recipient defect area. Later, in 2nd stage, it is moved towards the defect formally. It reduces the tension on flap and increases success rate.

Waltzing of Flap

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