Split thickness skin grafting presentation.pptx

Split thickness skin grafting ppt

1. STSG

2. Introduction Skin graft is a tissue of epidermis and varying amount of dermis that is detached from its own blood supply and placed in a new area with a new blood supply. It doesn’t maintain its original blood supply.

3. Historical prepective Grafting of skin originated among the tile maker caste in India approx. 3000yr ago. Reverdin, a Swedish medical student studying in Paris, placed 2- to 3-mm epidermal grafts onto a granulating wound in 1869 that skin autotransplantation was born. Louis Ollier, a French surgeon, described the first intermediate thickness skin graft and was using grafts as large as 8 cm2 in 1872.

4. Carl Thiersch, a prominent German surgeon, erroneously thought that thin epidermal grafts were required for successful donor site healing, he was the first surgeon to recognize the importance of preparing the recipient bed. In 1874,Thiersch described removing granulation tissue from the wound before applying his graft, which dramatically improved graft "take."

5. Blair and Brown differentiated between full-thickness, intermediate-thickness, and epidermal (Thiersch) grafts. They identified the advantages and disadvantages of each. In 1875, John Reissberg Wolfe (I824-I904), of Glasgow, reported the successful repair of a defect about the lower eyelid with a free whole-thickness graft

6. Skin structure The skin consists of two distinct layers, an epidermis and dermis 1. EPIDERMIS : The outermost layer, is essentially avascular. Stratified squamous epithelium. Composed primarily of keratinocytes. Relies on diffusion from underlying tissues. Separated from the dermis by a basement membrane.

7. 2. DERMIS Composed of 2 sub layers : Superficial papillary layer Deep reticular layer Contains collagen, capillaries, elastic fibers, fibroblasts, nerve endings

8. Types 1. STSG - split thickness skin graft - consist of epidermis and a variable portion of dermis . They are further divided on the basis of thickness of dermis. 2. FTSG - full thickness skin graft

9. Classification of STSG Based on thickness- Thin - 0.15–0.3 mm, Thiersch–Ollier Intermediate - 0.3–0.45 mm, Blair–Brown Thick - 0.45– 0.6 mm, Padgett. Skin grafts thicker than 0.6 mm usually correspond to full-thickness skin grafts and are called Wolfe– Krause grafts .

10. Based on size and technique- 1. PINCH GRAFT - These are ‘small deep ‘grafts’. The procedure involves lifting the skin with a needle and a 0.5 cm fragment is cut to obtain a graft which is thicker in the center and tapering towards the edges.

11. The resulting wounds can be closed primarily. The grafts are transferred to the wound at regular intervals, distance between them being about 5 mm. This method is now of historical importance due to extremely ugly scarring of the donor site.

12. 2. Stamp grafts – These are split thickness grafts which, after harvesting, are cut as square or rectangular pieces of skin of different sizes. Applied to the wound and held in place with occlusive dressings. The intervening areas between the stamps heal by epithelialization from the margins of the graft causing hypertrophy and unsightly scars. May be of use in case of very extensive raw areas.

13. 3.Sheet grafting – It is the most widely used at present. Harvested with the help of the latest modified Humby skin grafting knife or dermatome. Large sheets about 10 cm wide or more can be procured easily covering large raw areas. This gives good aesthetic results especially on the face. These sheets can be meshed to increase their size to cover larger areas.

14. 4. Meek grafting– It is being used lately. This was described in 1958 by an American surgeon, CP Meek. It involved the use of a ‘Meek-Wall ’ dermatome to obtain postage stamp autografts which are expanded using double pleated gauzes. This produced a regular distribution of autograft islands with a ninefold expansion. This technique was redesigned, and a special spray called ‘meek adhesive’ was developed and the prefolded gauzes were manufactured with expansion ratios of 1:3, 1:4, 1:6 and 1:9. Required very small donor areas and the graft islands were evenly placed in a regular pattern. The epithelialization and hospitalization time is reported to be shorter, compared to the mesh graft method. Preferred in extensive burns where the donor areas are very limited.

15. Graft bed Capable of providing the necessary initial fibrin anchorage. Rich blood supply to vascularise the graft.

16. Healing- 1. Imbibition Initial 24- 48 hrs Graft depends on the plasma which leaks out from the recipient venules, arterioles and capillaries and fills up the space between the graft and host bed. Plasma is absorbed by the graft passively and is the source of its nourishment. The graft increases in weight and volume during this stage

17. 2. Inosculation 48 to 72 hrs Process of capillaries joining between the skin graft and recipient bed

18. 3. Revascularisation 4 - 7 days By 4th POD blood inflow through the graft from the host bed is established. The graft now appears pink and blanches on pressure. This flow continues to increase till venous outflow from the graft back to the host bed is also started and by 1 month after grafting, the vascularization phase is completed. Thus, it is important to evacuate any hematoma or collection under the graft before 72 hours or on 1st check dress.

19. 4. Graft maturation: The process of maturation takes about 6-12 months. During this phase of maturation both the wound and the graft appear to undergo contraction. This process of graft contraction is actually a manifestation of the wound bed contraction mediated by the myofibroblasts.This process is called ‘ Secondary Contraction ’ of a skin graft. A FTSG has minimal secondary contraction compared to a STSG. The reason for this appears to be the thickness of dermis which inhibits myofibroblasts differentiation. PRIMARY CONTRACTION- Occurs at the time of graft harvest Due to recoil of elastin More in FTSG than STSG

20. Reinnervation of Graft The new nerve fibers invade the graft at 40 days along the empty Schwann sheaths or along the blood vessels. At 2-3 months , gradually the sensation returns in the graft- Pain is the first sensation to return followed by touch, temperature and tactile discrimination, although the sensation does not match that of the normal skin. Sweating starts 2-3 months post grafting. Till such time, the graft remains dry and scaly and needs to be protected by moisturizing creams. Once the sweat glands are reinnervated, their behavior is similar to that of the recipient bed and not the donor site. Hair growth is rarely seen in thin SSG because of damage to majority of the hair follicles. But in a thick SSG and FTG, hair growth resumes and resembles that of the donor area.

21. Indications 1. Skin loss- Post traumatic Post surgical burns Scar contracture release Pathological - eg : venous ulcers 2. Mucosal loss- In oral cavity- after excision of leukoplakic patch Vaginal agenesis

22. Contraindications Absolute Relative 1. Avascular recipient area- 1. Pressure sore Cortical bone without periosteum 2. Wound due to irradiation Cartilage without perichondrium. 3. Wound due to vascuilitis Tendon without paratenon. 4. Wounds in cosmetically sensitive area 5. Malnutrition 2. Infection- beta–hemolytic Streptococcus pyogenes

23. Essential Criteria for Skin Grafting 1. Grafting of post burn raw areas should be done as soon as the granulation tissue is healthy. If delayed for long, the granulating areas become fibrotic and graft ‘take’ is less than satisfactory. 2. The granulation tissue should have healthy red appearance i.e. it should be a well vascularized bed. 3. The wound bed should be free from infection. Wound cultures should always be done prior to grafting.

24. 4. The general condition of the patient should be stable. Hemoglobin should be a minimum of 10 gm%. The patient should be built up nutritionally. 5. Quantitative culture of the wound - Counts of >10 *5 organisms /gm of tissue should be first treated using systemic and topical antimicrobial therapy and frequent change of dressing till the colony count decreases. 6. Complete hemostasis should be achieved in the wound bed prior to graft application especially if the granulations have been scraped. 7. Immobilization of the part without shearing between the graft and bed is very essential. 8. Closest possible contact with the bed

25. Equipment The first device built specifically for harvesting of skin grafts was a simple instrument developed by Humby in 1936.

26. Electric dermatome James Barrett Brown introduced the first power-driven dermatome.

27. Donor sites The ideal donor site would provide skin that is identical to the skin surrounding the donor area. Common sites- inner thigh, upper arm, forearm, buttock

28. Technique of Harvesting Split Skin Graft Once the donor site has been selected, the graft can be harvested under general anesthesia, regional nerve blocks or even local anesthesia. Infiltration of local anesthesia with adrenaline reduces the amount of blood loss from the donor area apart from prolonging the duration of the effect of the local anesthesia. The area is lubricated with Vaseline or paraffin and saline. An assistant gives traction to the skin from one end of the donor site while the operating surgeon gives traction from the opposite side. Wooden / metallic Gabbroo graft boards are frequently used for applying the traction and counter traction. The knife is placed parallel to the surface of skin and then moved ‘to and fro’ with moderate pressure and gradually moved ahead with moderate speed till a long sheet is removed. The width of the graft harvested can be adjusted according to the area available.

29. In case of dermatome, it is kept on the skin surface at an angle of 30-45° and the throttle is pressed and the dermatome advanced flat to the skin with gentle downward pressure. Once the sheet of graft is harvested, the dermatome is angled upwards and lifted off the donor site cutting the graft.

30. Meshing of graft Meshing of a skin graft is an old technique first described by Lanz of Amsterdam in 1907 when it was done manually. It was re-introduced by Tanner, Vandeput and Olley(1964) with a new instrument. The principle behind meshing a graft is to gain expansion by making incisions parallel to the longitudinal axis of the graft and the maximum advantage of meshing is gained when the long axis of the meshes parallel the stress lines of the area to be grafted.

31. Earlier Padgetts roller graft mesher was used. The latest is the Zimmer’s mesher in which the carrier with the graft can be pulled through the mesher with the help of a handle or lever. By adjusting the lengths of the cuts, the resulting size of the graft can be changed and expansion of 1.5 to 9 times the original size can be gained.

32. Advantages- 1. It expands the graft. 2. Discharge can escape through the gaps in the graft so that the accumulated discharge does not lift the graft off the wound surface. 3. The meshing gives a larger edge for production of new epithelial cells than the stamp grafts or strip grafts. 4. The raw areas seen within the mesh heals by the epithelisation from the slit margins and this takes only a few days as the raw areas within the mesh are always less than 5 mm wide. 5. Easily placed in close proximity to the wound in case of uneven or convoluted surfaces. 6. It is easier to express out a hematoma or seroma.

33. Disadvantages 1. The checkered board pattern or cobblestone appearance can be displeasing especially in aesthetically important areas like face. 2. The secondary epithelium in the meshed area is not of the same quality as the grafted skin and this is visible for rest of life.

34. APPLICATION OF GRAFT Before the application of the graft to the wound bed proper haemostasis should achieved.

35. Storage of skin The graft is wrapped in gauze moistened with saline and placed in a sterile , sealed container . At 4 degree Celsius , it may survive up to 21 days.

36. Complications 1. The main complication of skin grafting is the failure of graft to ‘take’. a. Infection : Infection is the most common reason for graft failure especially with beta-hemolytic Streptococcus. b. Hematoma : Hematoma under the graft prevents the graft from getting vascularized. c. Ineffective immobilization : Therefore, it is important to avoid shearing between the graft and the wound bed. d. Poorly vascularized bed : It is not able to sustain a graft and leads to graft failure.

37. 2. Blister formation and breakdown in graft occurs in the extremities especially weight bearing lower limbs in which the increased hydrostatic pressure causes venous congestion in graft. This is also seen as purple discoloration of the graft. 3. Itching is a persistent problem of grafted patient. It is due to drying of the graft. 4. Repeated scaling in the graft is seen because of absence/ diminished number of sweat and sebaceous glands in the graft. Hence, they require lubrication for rest of the life. 5. Contractures result from failure to splint and apply pressure over the graft which allows secondary contraction of the bed and graft. This process lasts for 1-2 years.

38. Post operative Dressing of the graft All postburn raw areas are potentially contaminated wounds. Therefore, it is of utmost importance to change the first dressing by 48-72 hours post grafting. They are only dabbed with saline gauze to remove all the exudate and express out any seromas through the mesh or by giving a slit in the graft.

39. The second dressing be done at POD 5 and dried up graft overlapping the normal skin can then be debrided and dressing can be changed to a less bulky dressing. Sutures or staples, can be removed on the third dressing. Immobilization of joints can be discontinued after 7 days, once the grafts have taken up. Proper physiotherapy with full range of movements should be resumed only after all dressings are removed and healing is complete.

40. Post operative care of graft 1.Once the wounds have completely healed, the grafts have to be kept lubricated with some oil massage and require a continuous pressure using pressure garments or crepe bandage- prevent inter-graft hypertrophy and venous congestion. In lower limbs, the pressure support is essential for 3 to 6 months. They have to be worn throughout the day and night especially during ambulation. 2. Weight bearing in grafted lower limbs can be started only after 2 weeks and gradually by 3 weeks walking can be resumed but only with protection of a pressure garment or crepe bandage.

41. The grafted area can be left exposed if there is no loss by 10 days. By 14 days patient can be allowed to have a bath. By 3 weeks the graft is usually strong enough to withstand reasonable wear and tear.

42. Healing of the donor site Epithelisation occurs from cut portions of pilosebaceous apparatus and Sweat glands in the donor area until the area is resurfaced with the skin. The donor site of thin graft, with its full complement of cut pilosebaceous follicles, heals in approx 7-9 days. Thick graft- depending virtually entirely on sweat gland remnants, heal more slowly approx 14 days or more.

43. Dressing of the graft

44. Exposed grafting