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SKIN EPIDERMI S DERMIS.

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Presentation on theme: "SKIN EPIDERMI S DERMIS."— Presentation transcript:

1 SKIN EPIDERMI S DERMIS

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

3 Skin DERMIS Composed of two “sub- layers”: superficial papillary & deep reticular. The dermis contains collagen, capillaries, elastic fibers, fibroblasts, nerve endings, etc.

4 Definitions Graft A skin graft is a tissue of epidermis and varying amounts of dermis that is detached from its own blood supply and placed in a new area with a new blood supply. 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.

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

6 Classification of Grafts
Autografts – A tissue transferred from one part of the body to another. Homografts/Allograft – tissue transferred from a genetically different individual of the same species. Xenografts – a graft transferred from an individual of one species to an individual of another species.

7 Grafts are typically described in terms of thickness or depth.
Types of Grafts Grafts are typically described in terms of thickness or depth. Split Thickness: Contains 100% of the epidermis and a portion of the dermis. Split thickness grafts are further classified as thin or thick. Full Thickness: Contains 100% of the epidermis and dermis.

8 Advantages Disadvantages Thin Split Thickness Thick Split Thickness
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.

9 What factor determines the degree of primary contraction?
The amount of primary contraction is directly related to the thickness of dermis in the graft.

10 The Process of Take Phase 3 (day 3-5) – Neovascular Ingrowth
Phase 1 (0-48h) – Plasmatic Imbibition Diffusion of nutrition from the recipient bed. Phase 2 – Inosculation Vessels in graft connect with those in recipient bed. Phase 3 (day 3-5) – Neovascular Ingrowth Graft revascularized by ingrowth of new vessels into bed.

11 Requirements for Survival
Bed must be well vascularized. The contact between graft and recipient must be fully immobile. Low bacterial count at the site. No shearing. Fully Immobile.

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

13 Harvesting Tools Razor Blades
Grafting Knives (Blair, Ferris, Smith, Humbly, Goulian) Manual Drum Dermatomes (Padgett, Reese) **Electric/Air Powered Dermatomes (Brown, Padgett, Hall)

14 Padgett Dermatome

15 Goulian Blade

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17 What are unsuitable sites for grafting?
Bone Tendon Infected Wound Highly irradiated

18 Indications for Grafts
Extensive wounds. Burns. Specific surgeries that may require skin grafts for healing to occur. Areas of prior infection with extensive skin loss. Cosmetic reasons in reconstructive surgeries. Generally, skin grafting is used when, in the opinion of the reconstructive surgeon, other methods of reconstruction such as primary closure, second-intention healing, or local skin flaps are inappropriate, are unavailable, or would produce a suboptimal result.

19 Split Thickness Used when cosmetic appearance is not a primary issue or when the size of the wound is too large to use a full thickness graft. Chronic Ulcers Temporary coverage Correction of pigmentation disorders Burns

20 Full Thickness Indications for full thickness skin grafts include:
If adjacent tissue has premalignant or malignant lesions and precludes the use of a flap. Specific locations that lend themselves well to FTSGs include the nasal tip, helical rim, forehead, eyelids, medial canthus, concha, and digits.

21 Donor Sites The ideal donor site would provide skin that is identical to the skin surrounding the recipient area. Unfortunately, skin varies dramatically from one anatomic site to another in terms of: - Colour - Thickness - Hair - Texture

22 Flap A flap is a unit of tissue that is transferred from one site (donor site) to another (recipient site) while maintaining its own blood supply.

23 Flap Classification 1- method of transfer 2- type of tissue contained
3- blood supply

24 Flap Classification 1- Method of transfer
Local Flaps Advancement Rotation Transposition İnterpolation Distant Flaps Pedicled Free

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27 Transposition Flap

28 Bilobed Flap

29 Angles of Z-plasty Theoretical gain in length(%)
revise and redirect existing scars or provide additional length in the setting of scar Angles of Z-plasty Theoretical gain in length(%)

30 Flap Classification 2- Type of tissue
Skin Faciocutaneous Musculacutaneous Osteocutaneous

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34 Flap Classification 3- Blood supply
Random Axial (known blood supply-vessel)

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