Grafts & flaps

A presentation
a. The anatomy of the skin
b. The types of skin grafts
c. Indications of a skin graft
d. Mechanism of a graft take
e. Causes of graft failure
f. How to perform skin grafting

1. GRAFTS & FLAPS

2. Skin Grafts Skin grafting (or Skin transplant ) is a technique for the transfer of cutaneous tissue from one site of the body to another, often to cover large defects. Originated 3000 years ago in India. Introduced into Western medicine in the 19 th Century In 1817, Sir Astley Cooper reconstructed an amputated thumb with FTSG. Reverdin - harvesting skin islands with the scalpel tip for web space reconstruction. James Carlton Tanner – Mesh skin grafts Harvesting instruments – pinch grafts, harvesting knife, shave blade, dermatomes

3. Anatomy of Skin Largest Organ in weight and surface area Surface area - 1.2 – 2.2m 2 Thickness - 0.5–4.0 mm Functions of the skin Protection Containment Thermoregulation Sensation Metabolic function

4. Epidermis

5. Dermis

6. Skin Appendages

7. Subcutaneous Tissue Compartmentalised Adipose tissue. Deeper parts of the hair follicles, apocrine and eccrine glands. Composite grafts

8. Classifications of Grafts Source of graft Autograft – same subject Homograft – same species but different subject Isograft – same species but different subject with same genetic background Xenografts – different species

9. Classifications of Grafts Split thickness skin graft Epidermis and a variable dermis. Thin STSG and Thick STSG Indications Debrided burn wounds Chronic wounds with less vascularized wound beds Exposed flap areas Acute well-vascularized wounds

10. Split Thickness Skin Graft A STSG consists of epidermis and a variable amount of superficial to profound (papillary) dermis. Thin (0.005-0.012 in) Intermediate (0.012-0.018 in) Thick (0.018-0.030 in) The dermis is responsible for the visco -elastic properties of the skin The dermis is responsible for stability of the future skin. Body areas with high mechanical friction need thicker STSG

11. Donor Site Main sites - trunk and thighs. Graft can be taken from any other part of the body where healthy skin is limited e.g. – Burns Face and hands are preferentially spared from skin harvest. Does not include full length of appendages

12. Thin STSG Thin STSGs include the epidermis and a thin layer of the dermis Advantages Reduced morbidity of the donor site Multiple skin graft harvests Good graft take Disadvantages Poor graft stability Unviable hair appendages Secondary graft contraction Aesthetically less pleasant

13. Thick STSG Areas of high mechanical friction - joints, plantar soles, and the palm Advantages Less secondary graft contraction Aesthetically better Possible hair growth Better sensory function Disadvantages Slower healing Poor graft take

14. Thick STSG

15. Meshed STSG Meshing of STSG is done to enlarge the size.

16. Meshed Skin Graft Can be done with a blade or a mesher. Mesher has different templates for the spacing dimension (1 : 1 to 1 : 9). Smaller wounds (1 : 1.5) Large wounds – (1 : 3 and 1 : 6)

17. Meshed STSG Indications To cover large wounds (limited donor sites) To cover irregular geometric surfaces eg . Joints. Contraindications Avoided in important aesthetic or functional areas e.g face, neck and hands Contractures and Cobblestone appearance

18. Full Thickness Skin Grafts FTSG - epidermis and the whole dermis excellent function and sensitivity after engraftment. Indications Reconstruction of aesthetically dominant area e.g. face or scalp Reconstruction of functionally dominant area e.g. hand.

19. Full Thickness Skin Grafts Areas of loose skin Donor site requires primary closure. Donor Sites Gluteal folds, infra-abdominal fold Hypothenar eminence Post-auricular region Upper eyelids and above the eyebrow Wrist and Elbow crease Foreskin

20. Preparing a FTSG

21. Full Thickness Skin Grafts Advantages Minimal to no secondary graft contraction Excellent skin quality and stability Hair regrowth and skin appendage function Disadvantages Limited availability Risk of graft failure is higher

22. Composite Graft Components - Epidermis, Dermis and Subcutaneous tissue Donor sites is the same as for FTSG Poor graft take due to the poorly vascularized adipose tissues Can be used in children Applications Reconstruction of the nasal tip, the alar Reconstruction of columella in cleft lip

23. Final Points on Skin Grafts. The aesthetics of a skin graft is rarely the same as the normal skin. Patient should be thoroughly counselled before the procedure.

24. Recipient Site Consideration Wound bed preparation Sharp excision of wound margins Low bacterial load on graft bed (< 10 5 ) Debridement of Necrotic tissues Excision, standard dressing, water jets, Ultrasound Haemostasis of graft bed Soft tissue adaptation to cover exposed tendons and bones without peritendons and periosteum respectively.

25. Recipient Site Consideration Functional Consideration the size of graft needed the degree of wound contraction expected color and texture of the skin required, Need for adnexal glands Aesthetic Consideration Tissue from a similar or adjacent site will give the best color match. Face– supraclavicular, posterior auricular, upper eyelid or scalp skin grafts Glabrous skin (palms and soles of feet) – Hypothenar eminence.

26. Donor Site Consideration Consideration of the obligatory scarring or discoloration at donor site Common Sites - thigh, trunk, and buttocks, Regions frequently covered by clothing. Facial defects – FTSG from among the scalp, neck, and supraclavicular area. Eyelid defects – contralateral eyelid skin. Nasal skin – FTSG from nasolabial folds, supraclavicular or anterior auricular area. Regrafting of degloved skin in trauma patients Requires extensive defatting Primary regrafting or stored for later use.

27. Donor Site Consideration Full-thickness donor sites in Head and Neck Pre- and postauricular regions Nasolabial crease, Neck. Supraclavicular region, Eyelids Other common regions Inguinal crease - often used for large defects. Nipple–areola reconstruction – graft from contralateral region + FTSG from the groin. Donor sites of FTSG often require primary closure. Some donor site require a STGF

28. Donor Site Dressing The donor site of an STSG generally heals (re-epithelializes) in 7–21 days. size and depth of the graft harvested The age of the patient. A myriad of donor site dressings. Vaseline gauze is placed over the donor site.

29. Storage of Graft Skin grafts can be stored on a moist gauze at 4°C for up to 2 weeks. Although the viability decreases over time

30. Skin Fixation and Dressing Open wound technique Requires intensive monitoring Suturing or stapling and overlying compressive dressings (bolster dressing) Scattered sutured can be used for larger skin graft. Bolster dressing that stabilizes the graft and allows fluid exit into it Staples are more convenient to use. Compression dressing should be continued until 5–10 days after grafting. In some areas dressing is taken off on POD 3 to predict graft take.

31. Bolster Dressing

32. Skin Fixation and Dressing Splint or casts High risk of wound contraction Chin scar release or Joint and web space release of the hand Vacuum assisted pressure dressing Elegant for larger and uneven areas e.g. joints. Useful if fast mobilization is desired. joint regions or the lower extremities Ensure fluid removal and stabilization of the graft.

33. Skin Fixation and Dressing . Sealant e.g. Fibrin glue Applied to the dermis of graft Acts as provisional extracellular matrix under the graft.

34. How to perform a skin graft Prepare the wound bed for grafting (debridement and hemostasis) Estimate the needed skin graft size Clean the donor site from any residual disinfection (i.e. Betadine) Apply paraffin on the donor site Set the dermatome at 0.2 mm thickness Stretch the donor site skin Apply the dermatome at a 45° angle and apply light pressure Slide the dermatome along the skin while an assistant is lifting the skin graft with two forceps Lift the dermatome upwards when the desired size of graft is obtained Dress the donor site with Vaseline gauze, dry gauze and bandages

35. How to perform a skin graft Fix the bandage generously to the skin (e.g. thigh) to avoid sliding down of the dressing Spread evenly the graft (dermal site of the graft upwards) on a dermal carrier (rough surface of the carrier upwards) of the desired size (1 : 1.5, 1 : 3, etc ). Pass the graft through the graft mesher paying attention that it does not detach from the dermal carrier Apply the graft on the recipient site by sutures, surgical staples or fibrin glue When indicated apply a bolster dressing by placing Vaseline gauze on the skin graft, followed by a cotton sponge impregnated with Betadine or saline solution and tight sutures (4/0 nylon or polypropylene) from the opposite wound margins together at the center of the defect. First dressing change should be around 5–7 days post-op

36. Mechanism of Graft Take Fibrin Adhesion Plasma Imbibition Vascularization Remodelling

37. Complications Recipient Site Haematoma Seroma Infections Nontake (Graft Failure) Wound Contraction Instability Cosmetic Issues Donor Site Infection Hypertrophic scars and Keloids Itching Hypersensitivity to changes in temperature