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Flashcards in 80.Skin grafts Deck (31):
1

difference btwn skin flaps and skin grafts

flaps--vascular, living tissue at the time of implantationgrafts--separated from all vascular and nervous supply when implanted

2

classification of skin grafts

SOURCE1. autografts (same animal)2. allograft (same species)3. xenografts (different species)4. isografts (identical twins)THICKNESS1. full (epidermis and full dermis)2. split thickness (epidermis and partial variable dermis)SIZE OF COVERAGE1. island or seed grafts (rely on keratinocytes)2. sheet grafts

3

3 most common causes of graft failure

1. separation of the graft from bed2. infection3. movement

4

how does infection contribute to graft failure

exudate accumulation (may separate graft from bed)bacT enzymes (plasmin, proteolytic enzymes, elastase) break down fibrin attachments Beta hemolytic Strep and Pseudomonas

5

process of engraftment ("graft take")

for a graft to survive regenerative must exceed degeneration by the 7-8th post op day1. adherence(fibrin strands link btwn collagen and elastin)2. plasmatic imbibition (nutrient exchange and fluid buildup)3. inosculation (connecting of native blood flow)4. revascularization (ingrowth of new vessels)

6

rate of new capillary ingrowth into graft

0.5 mm/daycytokine control---vascular endothelial growth factors

7

T/Fsplit thickness grafts are not recommended in cats

TRUEbecause the skin of cats is so thin, split thickness grafts are not indicated

8

types of graft knives

1. weck graft knife2. humby and watson graft knives3. dermatomes (power drive--Brown dermatome)(or just do it free hand with scalpel)

9

ideal thickness for partial thickness skin grafts in dogs

0.35-0.38 mm

10

if overlapping graft to recipient bed, how much should they overlap

1-2 cm

11

bandage post op graft placement

to immobilizenonadherent dressingsmay use triple Ab on graft edges or 0.1% gentamicin sulfate+/- VACbandage change 48 hr (the longer the better)

12

advantages of partial or split thickness grafts

--better viability (89% vs 58% for full thickness)--greater capillary density (more vessels available)--less distance for ingrowing vessels, nutrients to travel --result in greater expansion after healing

13

disadvantages of split thickness grafts

---less durable--more subject to trauma--less hair growth--scaly appearance, lack sebaceous glands--expensive equipment (dermatomes, knives)

14

full thickness mesh grafts

slits--parallel staggered rowsprovides: drainage, flexibility, conformity, expansion

15

3 indications for mesh graft

1. to allow drainage2. to cover large skin defects3. reconstruct irregular surfaces

16

preparation of a mesh graft

must be free of all SQ FATkeep moistslits are 1-2 cm long 0.5-2 cm aparttrim 2-3 mm margin before suture placement into bed

17

in horses, hyperbaric oxygen therapy following graft placement showed....

less GT productionless edemaMORE inflammationLOWER % viabilitynot recommended at this time

18

viability of mesh grafts

90-100%

19

possible disadvantage of mesh graft

excessive GT may protrude from slits and overtop of the graft

20

indications for full thickness Unmeshed graft

1. prevention of post graft contraction

21

T/Ffull thickness unmeshed grafts are NOT sutured in the central portion of the wound bed

TRUE in order to avoid hemorrhage and consequent hematoma formation(may need a drain placed)

22

advantages of full thickness unmeshed grafts

1. pliable2. movable3. resist trauma4. cosmetic5. minimal post op contraction

23

disadvantage of full thickness Unmeshed graft

DO NOT SURVIVE AS WELL AS SPLIT THICKNESS grafts89% split thickness58% full thickness

24

types of island or seed grafts

pinchpunchstrip (5 mm wide)stamp (square

25

pinch/punch graft harvesting

DO not include SQ!

26

pinch/punch graft placement into donor bed

smaller recipient holes are made in bed (vs larger hole at donor site

27

advantages of island/seed grafts

simplerequire no special equipmentengraftment takes easilyeasily harvestedallow drainagewithstand infection wellfits irregular defects

28

disadvantages of island/seed graft

excessive bleedingpoor cosmosestime consuming

29

where are mucosal grafts harvested from

buccal or sublingual mucosa

30

advantages of mucosal grafts

--revascularize and heal quickly (bc thin)--good lining for conjunctiva, nasal passage, preputial surfaces

31

disadvantage of mucosal grafts

difficult to handle because very thincan damage easily during handlinguse stay sutures

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