1. Skin Substitutes in Reconstruction of Burns
RECENT ADVANCES
Skin Substitutes in Reconstruction of Burns
Dr. S.M. Tahir.
Associate Professor
Burn Surgery.
LUMHS

2. Epi In USA, 450,000 pts require medical treatment annually.
RECENT ADVANCES
In USA, 450,000 pts require medical treatment annually.
45,000 admissions to hospitals
3500 deaths.
Impact is much greater in developing countries.
In India (population over 1 billion) 700,000 cases of burns are hospitalized every year.

3. Epi: East Mediterranean Region
RECENT ADVANCES
Systemic review by Kendrick in year 2010.
Incidence is 315/100,000.
(remarkably in contrast to USA 19/100,000)
50% are young patients.
25% are between age 0-5 years.
Hospital mortality is % .

4. Classification ACELLULAR SKIN SUBSTITUTES
RECENT ADVANCES6
Classification
ACELLULAR SKIN SUBSTITUTES
Biobrane®
Integra®
Alloderm®
CELLULAR ALLOGENIC SKIN SUBSTITUTES
Transcyte®
Dermagraft®
Apligraf® (Graftskin®)
CELLULAR AUTOLOGOUS SKIN SUBSTITUTES
Cultured Epidermal Autograft (CEA)
Cultured /Engineered Skin Substitutes (CSS/ESS)

5. ACELLULAR SKIN SUBSTITUTES Biobrane®
RECENT ADVANCES
Started in 1970.
Now most widely used SS.
Made of nylon mesh, which acts as a “dermis” and a silicon membrane which acts as an “epidermis”. Both are embedded in pig collagen.
It is mainly used as a temporary coverage for
Superficial/mid-dermal burns.
Wound.
Donor site.

6. Advantages: Readily availability, low pain,
RECENT ADVANCES
Advantages:
Readily availability,
low pain,
Shorten hospital admission time,
Accelerated wound healing, and
Useful adjuvant to Buy time until skin graft material is available.

7. RECENT ADVANCES
Disadvantages:
Exudates collected beneath biobrane makes patient prone to infection.
Few reported cases of toxic shock.
Uses Pig collagen and therefore not accepted in our country .

8. Biobrane®
RECENT ADVANCES

9. Management of superficial partial thickness burns with Biobrane.
(a) An extensively blistered burn wound . (b)meticulously cleaned
(c) Biobrane glove has been applied (d) excellent healing occurs by day 9.

10. Area to be grafted got Reduced
Graft reduction; the superficial burn components heal with Biobrane while the deeper area demarcates allowing accurate grafting with minimal sacrifice of viable tissue.

11. Elderly Patients
Salvage in the elderly; initially appearing superficial, this burn in a 78-year-old struggled to heal spontaneously but resulted in the best outcome.

12. Temporizing Measure
(a) 80% TBSA burn. (b & C )Receives Biobrane initially as a temporizing dressing
(d) meshed graft and cultured cell suspension are hold by Biobrane(d) resulting in healing (e).

13. Acellular skin substitutes Integra®
RECENT ADVANCES
Pioneered by Yannas and Burke.
It is a bi-layered skin , impermeable to water .
Epidermal layer is a silicone membrane.
The dermal part is made of bovine collagen and shark chondroitin-6-sulphate glycosaminoglycan.
After coverage, the wound becomes revascularized within 2-3 weeks. At this stage, the superficial silicone layer is removed and replaced by a very thin split skin graft applied onto the neo-dermis bed.

14. Advantages: Disadvantages : Immediate availability,
RECENT ADVANCES
Advantages:
Immediate availability,
Allowing time for the neo-dermis formation, and
Good aesthetic results.
Disadvantages :
Two-step.
Expensive, and
Infection (exudate collection underneath).

15. Application of Integra®
Integra is supplied with outer Tyvek pouch.
Aluminum foil pouch is opened.
INTEGRA® is packaged between 2 polyethylene sheets and an attached center tab.
By holding tab, gently peel off one of the polyethylene sheets

16. Gently peel off the other polyethylene sheet
By holding tab, placed into a basin containing the sterile saline solution and carefully remove INTEGRA® from the tab.
Rinse INTEGRA®  for 1-2 minutes
Integra Can be meshed to 1:1, with non crushing mesher without using instruments.

17.  INTEGRA® Dermal Regeneration Template is scooped from from the holding basin with gloved hands and place directly onto the wound.
The silicone side is facing up and the Collagen-GAG matrix is against the wound bed. The black thread identifies the silicone side.

18. Alloderm®
RECENT ADVANCES
This is formed from acellular matrix derived from a cadaveric dermis.
The allodermis is processed by salt to remove the epidermis and then extracted with a solution to remove any cellular material.
Freeze-dried to render it inert immunologically.
 AlloDerm supports tissue regeneration by allowing rapid revascularization, white cell migration and cell population - ultimately being transformed into host tissue for a strong, natural repair.

19. Basement membrane remains intact but It has no epidermal layer.
RECENT ADVANCES
Basement membrane remains intact but It has no epidermal layer.
Yet this acellular matrix provides a good natural medium for fibroblast and endothelial cells to regenerate from the neo­dermis.
Widely used in breast Reconstruction and dental surgery.

20. Alloderm is usually used as sling to support implant and cover the anterior surface of the implant.
The Alloderm is sutured to the body wall posterior to the implant.

23. CELLULAR ALLOGENIC SKIN SUBSTITUTES Transcyte®
RECENT ADVANCES
The Transcyte® tissue engineered skin substitute is made from a nylon mesh and a silastic semi permissible layer.
Allogenic fibroblasts from neonatal foreskin are embedded in the mesh and allowed to grow for 3-6 weeks to produce a cellular matrix of collagen and growth factors which may enhance wound healing.
 It is left in place until either spontaneous separation occurs which indicates wound bed healing or the wound is dealt with surgically.
It has been licensed by the FDA for use in burns.

24. TransCyte is a temporary cover made from artificial skin, which promotes faster healing in burn patients without the pain and complexity involved in current treatment programs.

28. Dermagraft®
RECENT ADVANCES
The Dermagraft® skin substitute is similar to Transcyte® but
It lacks the silicone layer and
Contains viable fibroblasts.
It is produced by mixing living neonatal foreskin fibroblasts with a polyglycolic acid mesh (Dexon or Vicryl).

29. The polyglycolic acid mesh is absorbed within 3-4 weeks.
RECENT ADVANCES
The fibroblasts are cryopreserved at -80°C to maintain viability and when implanted to the wound, start to proliferate and produce a variety of growth factors and extracellular collagen matrix components.
 The polyglycolic acid mesh is absorbed within 3-4 weeks.
It has been used effectively in Diabetic foot

30. Diagnosis: DFU of 6 months duration Ulcer healed in 8 weeks after adding 8 applications of Dermagraft to conventional therapy
RECENT ADVANCES

31. Apligraf®(Graftskin®)
RECENT ADVANCES
The FDA approved it for clinical use in for the treatment of venous ulcers or neuropathic diabetic ulcers.
It has both living dermis and epidermis and therefore example of “skin equivalent’ or “organo-typical skin substitute” .

32. Apligraf
RECENT ADVANCES
It is prepared by mixing living fibroblasts from neonatal foreskin with bovine collagen type I and left for 2 weeks to allow formation of new collagen and matrix resulting in dense fibrous network.
A suspension of living neonatal foreskin keratinocytes (from the same or different neonatal donor) is seeded on the surface of the dermal fibrous matrix and left for 4 days to proliferate and differentiate.

33. Apligraf Licensed indication are (not responding to other measures)
RECENT ADVANCES
Licensed indication are (not responding to other measures)
Diabetic and
Venous ulcer
It is also used to manage wounds in
Epidermolysis bullosa,
Donor sites,
Surgical excision of skin cancer and
Burns.

34. Apligraft as supplied
Apligraft is being Remove from package

35. PERFORATING APLIGRAFT
FENESTRATE
MESH

36. Apligraft is being applied to the wound

37. Apligraft can be fixed to wound by using any of the following
Staple
Steri Strip
Skin glue.

38. CELLULAR AUTOLOGOUS SKIN SUBSTITUTES Cultured Epidermal Autograft (CEA)
RECENT ADVANCES
The technique of cells culture was originally developed by Rheinwald and Green
The use of these substitutes is useful when we need permanent skin coverage by cultured autologous keratinocytes.

39. Cultured Epidermal Autograft (CEA) EPICEL
RECENT ADVANCES
Skin biopsy is taken from the patient.
Dermis and subcutaneous tissue are removed.
The remaining epidermis is minced with mice fibroblast which is already lethally irradiated using 3T3.
Allow to grow 4-5 weeks using culture medium containing essential elements including epidermal growth factors

40. RECENT ADVANCES
Cultured keratinocytes are difficult to handle and therefore they need a delivery system or a supporting dressing.
Commercially available CEA vary in delivery system and supporting dressing.

41. Application of Cultured Epidermal Autografts
Cultured Epidermal Autografts Applied to the Hand and Arm

42. RECENT ADVANCES
Clinically problem associated with use of Keratinocytes are due to poorly developed dermoepidemal junction and include.
Blisters formation following small amounts of friction since the dermal epidermal junction is not completely developed.
Scarring,
contracture and
Hyperkeratosis. 

43. However it is unpredictable ranges from 0% to 100%.
RECENT ADVANCES
Take rate is usually 30-80%.
However it is unpredictable ranges from 0% to 100%.
CEA is susceptible to digestion by collagenase enzymes present in the wound bed.

44. Cultured Skin Substitutes (CSS) Engineered Skin Substitutes(ESS)
It has both epidermal and dermal components.
It is an autologous graft so there is minimal risk of infection transmission.
It provides permanent coverage.
Several types were developed recently with different dermal biosynthetic scaffolds.
The most commonly used type is a hyaluronic acid derived substitute.

45. RECENT ADVANCES
Hyaluronic acid (Hyaluronan) is a naturally occurring polymer within the skin and it has been found to be pro-angiogenic thus stimulating blood vessel growth.
It was found first in the vitreous humor of the eye in 1934 and subsequently synthesized in vitro in 1964.

46. Hyaluronic acid facilitates the
RECENT ADVANCES
Hyaluronic acid facilitates the
Growth and movement of fibroblasts,
Controls matrix hydration and
Osmoregulation.
It is also a free radical scavenger and an inflammatory regulator.

47. Flow Chart for ESS
RECENT ADVANCES

48. Selective Culture of Skin

50. Example Case

53. Thank You