Concepts of Skin Grafts and Skin Substitutes

Question 1

Split-thickness skingrafts, whencompared with full-thickness
skin grafts may experience more pigment changes,
be more susceptible to trauma, and have a lower metabolic
demand of the recipient site wound bed

Answer 1

T

Question 2

Skin grafts heal by a process of imbibition and revascularization through angiogenesis.

Answer 2

T

Question 3

eventual reepithelialization over a
span of about 8 weeks.

Answer 3

F 4 WEEK

Question 4

15% of total
adult body weigh is skin

Answer 4

T

Question 5

the dominant cell
type in the dermis dendrocytes
and mast cells

Answer 5

F fibroblasts are the dominant cell
type in the dermis

Question 6

the pilosebaceous units and sweat glands present in papilary derms

Answer 6

F reticular dermis

Question 7

secondary contraction is a myofibroblast-mediated process

Answer 7

T

Question 8

both
split-thickness and full-thickness grafts are vulnerable to shear forces
during the healing process

Answer 8

T

Question 9

grafts with less dermal
element are less fragile to subsequent trauma

Answer 9

F grafts with a larger dermal
element are less fragile to subsequent trauma

Question 10

Thicker skin
grafts place greater metabolic demands on the wound bed during
healing

Answer 10

T

Question 11

split-thickness skin grafts
also generally do not contain intact accessory skin structures such as
hair follicles and sweat glands.

Answer 11

T

Question 12

Skin graft take has historically been broken down into three
classic phases

Answer 12

imbibition (0-48 hours)
inosculation (48-72 hours)
revascularization (>96 hours)

Question 13

graft survival has been shown
to be dependent on the vascularity of the recipient site site

Answer 13

F graft survival has been shown
to be dependent on the vascularity of the donor site (with grafts harvested from a highly vascular area healing better than a graft from a
poorly perfused area

Question 14

Freshly harvested grafts have also been shown
to attract blood vessel ingrowth more rapidly than grafts that have
been frozen and subsequently thawed

Answer 14

T

Question 15

Freshly harvested grafts less tolerant
of the ischemic period because of increased metabolic activity

Answer 15

T

Question 16

The first stage of skin graft healing is an ischemic phase known as plasmatic or serum imbibition

Answer 16

T

Question 17

lmbibition it is alaways last for 28 hours

Answer 17

F tlasts approximately 24 hours in a proliferative wound
48 hours in a fresh wound
several days in a poorly perfused wound bed

Question 18

As the
grafts absorb serum, they become edematous and gain as much as
40% of their initial weight in the first 28 hours

Answer 18

F in the first 24 hours

Question 19

starting to decrease
in weight after 24hours

Answer 19

F starting to decrease
in weight after 96 hours

Question 20

During imbibition, metabolism within the graft becomes anaerobic

Answer 20

T

Question 21

inosculation phase is no longer vaible idea

Answer 21

T

Question 22

connections between the wound bed vessels and graft vasculature do
occur with angiogenesis and new vessel
ingrowth in a unidirectional fashion from the wound bed into the
graft

Answer 22

T

Question 23

new vascular connections do not necessarily
occur at the wound interface with the graft

Answer 23

T

Question 24

A peak in vessel density is seen at
postgraft day 7

Answer 24

T

Question 25

With the vascular density at the interface increasing
2.5-fold between post-graft days 3 and 7 before returning to levels near
those of post-graft day 3 by day 10.

Answer 25

T

Question 26

After 96 hours, both the wound
bed and the skin graft demonstratedincreased capillary diameter and
functional capillary density

Answer 26

T

Question 27

By 10 days after grafting (240 hours), the skin graft was fully
revascularized,

Answer 27

T

Question 28

At 120 hours(5 days), capillary diameter and functional capillary density
within the wound bed began to decrease, while still increasing within
the graft

Answer 28

T

Question 29

angiogenesis is the primary factor in skin graft revascularization, beginning as early
as 24 hours after grafting

Answer 29

T

Question 30

native microcirculation start within the graft in 48 to 72 hours

Answer 30

T

Question 31

graft vessels demonstrate an angiogenic response to
reperfusion between 3 and 8 days post grafting

Answer 31

T

Question 32

Matrix metalloproteinases MTl-MMP and MMP-2 are associated
with the initiation of angiogenesis

Answer 32

T

Question 33

Preexisting vascular
channels in the periphery of the skin graft were 100% replaced by
vessel ingrowth from the wound bed by day 10, whereas those in the
center ofthe graft were replaced to a much lesser extent (50%-60%)

Answer 33

T

Question 34

During the first 10 days after grafting, the epidermis of the graft doubles in thickness

Answer 34

F During the first 4 days after grafting, the epidermis of the graft doubles in thickness

Question 35

This increased cellular turnover
does not return to baseline until 2weeks after grafting

Answer 35

F 4 week

Question 36

It is generally
accepted that fibroblasts within the dermis ofa healing skin graft are
not native graft fibroblasts

Answer 36

T

Question 37

Collagen turnover in the
the dermis, peaking at 2 to 3 weeks after grafting at three to four times faster than the collagen turnover rate for normal skin

Answer 37

T

Question 38

Approximately, 85% ofthe original collagen in a skin graft is replaced within 5 months of grafting

Answer 38

T

Question 39

split-thickness grafts replace mor than their original collagen compared with full-thickness grafts ofthe same size

Answer 39

F split-thickness grafts replace only half as much of their original collagen compared with full-thickness grafts ofthe same size

Question 40

Elastin
within the graft is also replaced, with degeneration from postgraft day 3,
and regeneration starting 4 to 6 weeks after grafting.

Answer 40

T

Question 41

A full-thickness graft loses approximately 40% of its surface area after harvest whereas a split-thickness graft loses
10% to 20% ofits area

Answer 41

T

Question 42

Secondary contraction is increase with increasing the amount of dermis in the graft

Answer 42

F inversely proportional to the amount of dermis in the graft

Question 43

Graft with collagen
matrix, in fact behaves much like full-thickness skin grafts in terms
of inhibiting wound contraction

Answer 43

T

Question 44

Once wound contraction is complete, full-thickness grafts &split thickness graft are able to grow with the surrounding tissue,

Answer 44

F Once wound contraction is complete, full-thickness grafts are able to grow with the surrounding tissue, whereas split-thickness grafts remain fixed

Question 45

skin
grafts take approximately 2 weeks longer to heal in diabetic patients
than in nondiabetic patients

Answer 45

T

Question 46

Gauze
dressings had the highest infection rates

Answer 46

T

Question 47

Time to complete reepithelialization was 7 days (30%) shorter when hydrocolloid
dressings were used

Answer 47

T

Question 48

it is generally accepted
that the dressing should maintain a moist wound environment for
at least 3 days

Answer 48

F it is generally accepted
that the dressing should maintain a moist wound environment for
at least 1 week.

Question 49

cultured autografts and cultured allografts epidermal grafts can be used

Answer 49

T

Question 50

Epicel is……

Answer 50

cultured epidermal autografts

Question 51

Limitation of use Epicel

Answer 51

variable graft take rate, limited mechanical resistance, hyperkeratosis, scar
contracture, ulceration, and blister formation because of reactions
to foreign fibroblasts in feeder media, as well as the lengthy culture
time (3-4 weeks) required and the high cost

Question 52

keratinocyte activation, growth factor secretion, and reepithelialization from the wound edge, more akin to cultured keratinocytes than
full- or split-thickness grafts

Answer 52

T

Question 53

Dermal-epidermal grafting llows expansion by a factor of 1:100 (instead of the typical
1:5 expansion of a full-thickness skin graft and 1:9 expansion of a
meshed split-thickness skin graft)

Answer 53

T

Question 54

Micrografts need to
retain their dermal orientation,

Answer 54

F Micrografts also do not need to
retain their dermal orientation,

Question 55

Micro grafting take place
under local anesthetic in an outpatient setting

Answer 55

T

Question 56

Fractional skin harvesting is done by harvesting split-thickness skin tissue

Answer 56

F Full thickness skin tissue

Question 57

The high
antigenicity of skin allografts, in particular, the epidermal layer

Answer 57

T

Question 58

Dermagraft IS …..

Answer 58

is created by seeding neonatal foreskin fibroblasts onto a biodegradable polyglycolic acid mesh

Question 59

In integra New blood vessels can be seen in the deep portion of the matrix by
day 12 and reach the superficial surface by day 28

Answer 59

T

Question 60

Wen we can put skin graft after the integra?

Answer 60

After1 week

Question 61

Integra can also be used without the silicone layer as a
filler for contour deformities

Answer 61

T

Question 62

Integra without the silicone layer can lead to from eccessive granulation tissue

Answer 62

T

Question 63

myofibroblasts start migrating into the matrix and start producing collagen by the beginning of week 3. The silicone epidermal
layer has usually sloughed or been removed by this point in time with integra

Answer 63

T

Question 64

Integra can also be used without the silicone layer as a
filler for contour deformities, although this does require a lengthier
period of neovascularization for vessel ingrowth through a thicker
matrix

Answer 64

T

Question 65

use of this
product, especially in combination with other modalities such as negative-pressure wound therapy, can often generate granulation tissue
even over challenging surfaces, such as bone, tendon, and hardware

Answer 65

T