Scars, Grafts & Flaps

Question 1

What is the reconstructive ladder?

Answer 1

Question 2

What are skin grafts?

Answer 2

• Healthy skin removed from unaffected area of body and used to cover lost/damaged skin
• Transfer of tissue without blood supply
• Survival relies upon revascularisation
• Can be: split-thickness OR full-thickness

Question 3

What are split-thickness skin grafts?

Answer 3

• Involving epidermis and a variable amount of dermis
• Thin layer of skin, thin as tissue
• Taken from area that heals well eg. thigh, calf, buttocks
• Donor area heals 2-3wks, pink for wks and may leave faint scar
• Excised with a dermatome / Watson kife
• Good for larger defects; can be meshed

Question 4

What are full-thickness grafts?

Answer 4

• Epidermal and full-thickness of dermis
• Excised as an elipse with a scalpel
• Sites include upper neck, behind ear, upper arm, groin
• Thicker graft → revascularisation difficult
• Dressing left in place for 5-7days for recipient site
• Donor area takes 5-10 days to heal (closed with stitches)
• Excellent for small defects on the face

Question 5

What are composite grafts?

Answer 5

• Used to treat wounds with complex shape/contour
• Such as following removal of skin cancer from nose
• Graft comprises of all layers of skin, fat and sometimes underlying cartilage from donor site

Question 6

What stages occur in the process for the graft to ‘take’?

Answer 6

• Skin graft’s survival relies on process of ‘take’
• Initally graft adheres by fibrin
• After 2-4d, fibrin breaks down + revascularisation begins
• 1 - Adherence → fibrin bonds form immediately upon application of graft
• 2 - Imbibition → graft swells for first 2-4d; fluid supplies nutrients to tissue
• 3 - Revascularisation → 4th day onwards: blood vessel ingrowth into skin graft
• 4 - Remodelling → histological architechture of graft ⇒ ‘normal’

Question 7

Why might skin grafts fail?

Answer 7

• Reasons for failure must be explained to pt + measures taken to prevent them
• Skin grafts will also fail if placed upside down
• Causes:
  
  • Infection
  • Shear forces
  • Haematoma / Seroma
  • Poor bed vascularity

Question 8

What is tissue expansion?

Answer 8

• Encourages body to “grow” extra skin by stretching surrounding tissue
• Extra skin can then be used to help reconstruct nearby area
• Used for breast reconstruction + repairing large wounds
• Under GA, expander inserted under skin, filled w/ salt water
• If large skin area affected, can take 3-4 months for skin to grow enough
• This technique ensures similar skin colour and texture to surrounding area
• Lower chance of failure as blood supply to skin remains connected

Question 9

What is flap surgery and the 3 types?

Answer 9

• In contrast to graft, flap contains within its substance a network of blood vessels which nourish the tissue
• Because they carry blood supply, can be used to repair more complex defects
• Three main types: local, regional and distant

Question 10

What are features of a local flap?

Answer 10

• Flap may be raised as a local flap, in the immediate vicinity of defect eg. rhomboid flap (facial reconstruction)
• Uses a piece of skin and underlying tissue that lie near the wound
• Flap remains attached at one end so that it continues to be nourished by original blood supply and is repositioned over wounded area

Question 11

What are features of a regional flap?

Answer 11

• Eg. pec major flap (chest reconstruction)
• Uses section of tissue attached by specific blood vessel
• When flap is lifted, it needs only a very narrow attachment to original site to receive nourishing blood supply form artery + vein

Question 12

What are features of a distant (free) flap?

Answer 12

• Eg. Free ALT flap (limb reconstruction)
• Involves transfer of living tissue from one part of body to another, along with the blood vessel that keeps it alive
• Further modification of flap transfer where flap is entirely disconnected from original blood supply then reconnected using microsurgery in recipient site

Question 13

What is a hypertrophic scar?

Answer 13

• Scar elevated but within borders of the original scar
• More common than keloid (5-15% of scars)
• Nodules present, randomly arranged fibrils + parallel fibres
• May go on to develop contractures
• Common in areas of tension, flexor surfaces

Question 14

What is a keloid scar?

Answer 14

• Derived from greek for ‘crabs claw’
• Grow outside original wound borders, tumour-like lesions
• Often itchy
• No nodules, can occur from trivial injury, can recur
• Common sites → Extensor surfaces, ears, face, chest, neck, and shoulders
• More prevalent in dark-skinned populations + in young adults

Question 15

What is the treatment for keloid scars?

Answer 15

• Early keloids → treat w/ intra-lesional steroids eg. triamcinolone
• Excision is sometimes required