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RECONSTRUCTIVE
Reepithelialization from Stem Cells of HairFollicles of Dermal
Graft of the Scalp in Acute
Treatment of Third-Degree Burns: First Clinicaland Histologic
StudyGilbert Zakine, M.D., Ph.D.
Maurice Mimoun, M.D.Julien Pham, M.D.
Marc Chaouat, M.D., Ph.D.
Tours and Paris, France
Background: The scalp, an excellent donor site for thin skin
grafts, presents alimited surface but is rich in keratinocyte stem
cells. The purpose of this study
was to double scalp harvesting in one procedure and to evaluate
the capacity ofthe dermal layer to spontaneously reepithelialize
from hair follicle stem cells.Methods: Two layers of 0.2-mm
split-thickness skin graft, a dermoepidermalgraft and a dermal
graft, were harvested from scalp during the same procedure.Fifteen
burn patients were included in this study. Healing of the scalp
donor siteand percentage of graft taken were evaluated. The
Vancouver Scar Scale was
used at 3 months and 1 year. Histologic studies were performed
at day 0 and 3months on grafts, and on the scalp at day 28.Results:
Nine patients were treated on the limbs with meshed dermal graft.
Six
were treated on the hands with unmeshed dermal graft. Graft take
was good forboth types of grafts. The mean time for scalp healing
was 9.3 days. Histologicstudy confirmed that the second layer was a
dermal graft with numerous annexesand that, at 3 months, the dermis
had normal thickness but with rarer andsmaller epidermal crests
than dermal graft. The difference between the mean
Vancouver Scar Scale score of dermal graft and dermoepidermal
graft was notsignificant.Conclusion: The authors study shows the
efficacy of dermal graft from the scalpand good scalp healing.
(Plast. Reconstr. Surg. 130: 42e, 2012.)
CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.
The scalp is an excellent donor site for thinskin grafts.1 Its
rapid healing is attributableto the number of hair follicles, which
are rich
in epithelial stem cells. The absence of visible scar-ring is
also a great advantage for this donor site.However, its surface is
limited to no more than 3or 4 percent of the total body surface
area. Theaim of this study was to double the scalp donorsurface by
harvesting a split-thickness dermal graft
immediately after a classic split-thickness dermoepi-dermal
graft. The hypothesis was that the dermalgraft contains numerous
epithelial stem cells thatenable complete healing of the recipient
site. In thisstudy, we verified the quality of recipient-site
healing
after a dermal graft and scalp healing after doublegraft harvest
in burn patients.
PATIENTS AND METHODSFifteen burn patients hospitalized in the
burn
unit were included in this study. Patients withalopecia, burned
or too thin scalp, and elderlypatients (older than 70 years) were
excluded.Patients of African or Caribbean origin, becauseof a
higher risk of hypertrophic or keloid scarand the shallowness of
follicular bulbs, were alsoexcluded.
Surgical TechniqueThe entire scalp was harvested in two layers
of
0.2 mm (0.008 inch). All patients had had theirHopital
Trousseau, Centre Hospitalier Regional et Univer-sitaire de Tours;
and Hpital Saint Louis, AP-HP, UFRMdecine Paris 7 Denis
Diderot.Received for publication September 23, 2011; accepted
Jan-uary 20, 2012.Copyright 2012 by the American Society of Plastic
Surgeons
DOI: 10.1097/PRS.0b013e318254fa21
Disclosure:The authors have no financial interestto declare in
relation to the content of this article. Nooutside was funding was
received.
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scalps shaved and were under general anesthesia.After
infiltration of the scalp with adrenalized saline(to decrease
bleeding),1 two thin grafts, 0.2 mmthick, were harvested with an
electric dermatome onthe scalp (Fig. 1). The grafts, stapled to the
excisedburn area (fixed to the wound edges with staples(Ethicon,
Inc., Somerville, N.J.), were meshed three-fold for limbs or
unmeshed for hands. Tiny perfo-rations were made in the unmeshed
skin to preventthe accumulation of fluid. Some areas were
treatedwith superficial layer grafts and some were treatedwith deep
layer grafts (placed on either side).
After the procedure, a paraffin gauze dressingwas applied on the
recipient site, changed on thethird day, and then changed every
day. A calciumalginate (Algosteril; Smith & Nephew,
London,United Kingdom) was applied on the scalp donorsite and
changed every 3 days until complete
cicatrization.Clinical evaluation was performed and photo-
graphs of the recipient site were obtained on days0, 3, 5, 7, 9,
21, and 28. Evaluation of the percent-age of taken graft was
performed on day 9 and theresults were compared between the
superficialand the deep graft area; thus, the patient was hisor her
own control. Clinical evaluation of scalphealing was also
performed.
Histologic study was performed on superficialand deep skin
grafts undermined from the scalp.Punch biopsies of the scalp
(diameter of 3 mm),
from which two layers were taken, were performedon day 28. Punch
biopsies were also performed onboth types of grafts at 3 months
postoperatively.
The Vancouver Scar Scale2 was chosen to com-plete the clinical
evaluation of the grafted areas at 3and 12 months. This score (from
0 for normal skin
to 13) used four parameters: vascularity (related tothe analysis
of redness), skin pigmentation, pliability(based on elastic texture
of the scar), and skin thick-ness (quantifying hypertrophy).
Possible aftereffects were evaluated at months1, 2, and 3.
Length of follow-up was 2 years.
RESULTS
Clinical ResultsFifteen patients were treated according to
our
protocol, nine men and six women, with a meanage of 46.2 years
(range, 25 to 79 years) and amean unit burn surface score of 56.5
(Table 1).Mean total body surface area burned was 24.93percent.
Mean excised grafted area was 13 percentof the total body surface
area.
Six patients were treated with an unmeshed
dermal graft to cover one hand; for five of them,the other hand
was treated with a dermoepidermalgraft. Nine patients were treated
with a meshed der-mal graft to cover the limbs compared with a
der-moepidermal graft. Thus, each patient was hisor herown
control.
Mean surface covered by the meshed dermalgraft was 4.67 percent
total body surface area and1.67 percent total body surface area for
unmesheddermal graft. The dermal graft was pink on day 0(Fig. 2),
whitish or transparent on day 3, and redsince day 5 or 6, and
clinical epithelialization was
well seen at day 9 (Fig. 3).On day 3, the whitish color of the
deep dermal
graft made the evaluation of viability difficult. Heal-ing
evaluation on day 9 revealed that the mean per-centage of
successful unmeshed grafts (Fig. 4) was89.16 9.75 percent for
dermal grafts and 90 per-cent 10.48 for dermoepidermal grafts. The
meanpercentage of successful meshed grafts on day 9 was92.226.28
percent for dermal grafts and945.38percent for dermoepidermal
grafts.
On day 21, total healing was observed in all ofthe patients. A
reddish color on the dermal grafts
(Fig. 5) was noted during the first 2 months andprogressively
disappeared (Fig. 6).Vancouver Scar Scale (scores over 13) at
the
third month were 6.0 1.3 for the unmesheddermal graft, 5.2 1.8
for the unmeshed der-moepidermal graft, 6.33 1.58 for the
mesheddermal graft, and 5.3 1.8 for the meshed der-moepidermal
graft. At 1 year (Fig. 7), dermalgrafts had no reddish color but
did have goodelasticity. The Vancouver Scar Scale score at 12months
was 2.5 0.8 for the unmeshed dermalgraft, 2.2 1.1 for the unmeshed
dermoepider-
mal graft, 3
1.65 for the meshed dermal graft,
Fig. 1. The two layers of skin grafts harvested from the
scalp.
(Left) Dermoepidermal graft and (right) dermal graft, which
can
be placed on either side because of the absence of
epidermis.
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and 2.8 1.7 for the meshed dermoepidermalgraft. The differences
between the mean Vancou-ver Scar Scale score for dermal graft and
der-moepidermal graft were not significant for the
meshed and the unmeshed grafts.In the present series, there was
a patient trans-ferred from a North African country 3 weeks
afterburn injury who presented a burn with 35 percentof the total
body surface area unhealed and wastreated with unmeshed dermal
graft on the lefthand and with unmeshed dermoepidermal grafton the
right hand. On day 9, the results werecompared, with a good result
for both hands, butthe unmeshed dermal graft was subsequently
par-tially deepithelialized because of mycotic infec-tion. Finally,
the left hand healed spontaneously,
but with a poor quality.
Table 1. Patient Data
CaseAge(yr)
BurnArea(% of
TBSA)
DeepBurnArea(% ofTBSA)
DG Surface
(% of TBSA)
Percentage of SuccessfulGraft at Day 9
ScalpHealing(Days)Unmeshed Meshed
DGUnmeshed
DGMeshed
DEGUnmeshed
DEGMeshed
1 35 35 32 4.5 80 100 72 25 30 12 6.5 100 80 113 58 35 5 2.5 95
90 84 79 22 13 5 90 95 95 78 11 8 4 85 95 96 41 16 12 5.5 95 95 107
55 20 11 4.5 95 95 88 63 28 22 5 100 100 129 51 32 26 5.5 90 95
8
10 33 56 9 2.5 95 100 911 52 12 2 2 70 70 1112 29 25 7 1.5 85 90
1013 42 22 18 2.5 95 95 814 24 26 14 2 90 95 1015 28 4 4 1 100 95
9
Mean 46.2 24.93 13 1.67 4.67 89.16 9.75 92.22 6.28 90 10.48 94
5.38 9.26 1.33
TBSA, total body surface area; DG, dermal graft; DEG,
dermoepidermal graft.
Fig. 2. Unmesheddermal graft at day 0 after excision of a
third-
degree burn of the right hand of a 28-year-old man.
Fig. 3. (Above) Unmeshed dermal graft at day 9 of the hand
of
the previous patient. (Below) Unmeshed dermal graft at day 9
at
5
magnification.
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Fig. 4. (Left) Left hand covered by unmeshed dermal graft and
(right) the right hand covered by unmeshed dermoepidermal
graft on (above) day 0 and (below) day 9.
Fig.5.
At1month,theanteriorpartofthethightreatedwithmesheddermalgraft(left)andthe
posterior part of thethigh (right) treated with
mesheddermoepidermal graft after excision of a
third-degree burn of a 35-year-old man are shown.
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two groups, modification with destruction of thecollagen network
in the superficial dermis (pap-illary dermis) and a small degree of
remodeling inthe deep part of the dermis (reticular dermis)were
noted.
Biopsies of the scalp were performed at day 28.The thickness of
the new epidermis and the archi-tecture of the dermis were similar
to normal scalp.
DISCUSSIONScalp is the best donor site for thin skin grafts
because of rapid healing and the absence of visiblescarring.1
Thick dermal graft, taken from total skin
harvested from the abdominal area, has been used
for abdominal repair3; dermal grafts have beentaken from the
plantar surface of the foot forresurfacing a volar hand defect4;
and dermal graftshave been used for camouflaging lip scars5
butnever for skin coverage. In a pig model,6 split-thickness,
superficial, and deep dermal grafts haveshown their ability to
resurface full-thickness skindefects.
Dermal autografts have never been used inburn treatment. In
extensive deep burns, porcineskin and preserved cadaver skin7 are
used for tem-porary wound coverage; however, 1 to 2 weeksafter
grafting, these tissues undergo immune-me-
diated rejection.
Fig. 8. Healing of a double harvested scalp at day 9 (left) and
at day 21 (right).
Fig. 9. Sample taken from the scalp (hematoxylin-eosin-saffron;
original magnification,100). (Left)
Dermoepidermal graft with epidermis and papillary dermis.
(Right) Dermal graft with superficial part
of reticular dermis including adnexal structures rich in
keratinocytes and stem cells.
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Several dermal substitutes have been developedfor burn
treatment. Integra (Integra LifeSciencesCorp., Plainsboro, N.J.)
dermal regeneration tem-plate, which is a biodegradable template of
bovinecollagen introduced8 in 1981, has been used ex-tensively for
years and has been evaluated by nu-merous authors.9,10 Dermal
matrix must be coveredby a split-thickness graft or by cultured
autologouskeratinocytes11 secondarily after 2 to 4 weeks for
themajority of dermal substitutes and immediately for
some of the new dermal substitutes.12 Dermoepider-mal graft or
epidermal graft obtained from autolo-gous keratinocyte culture must
be placed on thedermis because the dermal layer never heals
spon-taneously without the association of an epidermallayer. Dermal
graft from the scalp does not need tobe covered by an epidermal
graft.
Clinical results have shown that the mean Van-couver Scar Scale
scores obtained were higher inthe dermal graft at 3 months and
comparable tothe control areas at 12 months. This is the
con-sequence of the reddish color caused by vascular-
ization in some patients in the dermal graft groupat 3
months.Histologic study confirmed that classic thin
split-thickness graft (0.2 mm) contains dermis, thedermal
papillae, and the basal layer of the epider-mis. In a thin
split-thickness graft, the mean thick-ness is 0.05 mm for the
epidermis and 0.15 mm forthe dermis.13 Histologic study also showed
that thedermal graft contains a great number of adnexaand probably
follicular bulges, which could ex-plain its capacity to
reepithelialize spontaneously.
The adnexal structures are very rich in kera-
tinocytes and stem cells, particularly around the
hair follicles.14 Hair follicle stem cells play a rolein
regulating the hair cycle but also in sebaceousgland and epidermis
reparation during woundhealing.15 At the start of each hair cycle,
bulgestem cells migrate downward to regenerate thebulk of the hair
follicle and produce a new hair(anagen phase). Stem cells resident
in the follic-ular bulge contribute to wound repair but not
tohomeostasis of the epidermis16 because they arenot the source of
the stem cells of the epidermis
in the absence of trauma.17In the present study, it was probably
the fol-
licular stem cell contained around the follicle andin the bulge
that allowed healing and not the stemcell contained in the bulb,
which is not harvestedin the graft. When the epidermis is damaged,
ker-atinocytes from the epidermis and follicles sur-rounding the
wound are mobilized to regeneratean epidermal barrier.18
Keratinocytes invade thewound surface and generate a thickened and
hy-perproliferative epithelium that gradually revertsto a more
normally organized stratified epidermis.
During normal development, the epidermis andhair follicle are
distinct lineage compartmentsmaintained by independent stem cell
populations.Both epidermal and follicular keratinocytes
arerecruited to participate in epidermal repair in re-sponse to
injury. However, it is generally thoughtthat follicular cells
contribute to the wound epider-mis only transiently and are
ultimately replaced bythe progeny of stem cells derived from the
originalepidermal compartment before wounding.
The dermal graft presented in our clinical ex-perience is not
conceivable on localizations other
than the scalp. The stem cells contained around
Fig. 10. Punch biopsy specimens at 3 months
(hematoxylin-eosin-saffron; original magnification, 250).
(Left)
Dermoepidermal graft and (right) dermalgraft.The dermalgraft
presenteda normal thicknessbut with rarer and
smaller epidermal crests compared with the dermoepidermal
graft.
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and in the follicular bulge allowed rapid healingof the donor
site (less rapidly obviously after hav-ing harvested two layers)
and at the same timeallowed epithelialization of the graft. This
studyhas shown that it is possible to double the area ofscalp
grafts in one operation.
Clinical evaluation showed that the quality ofthe new epidermis
was good and histology showedthat the thickness of the epidermis
was normal. At3 months, there was no dyschromia of the deepdermal
graft.
After taking two layers of skin graft, the scalphealed slowly.
Mean healing time was 9.8 days fora scalp from which two layers
were taken, whereasit was 6.2 days for single-layer donor sites.1
Noalopecia was noted. After the healing period, theaspect and the
quality of the scalp scar was thesame as for classic single
harvesting (Fig. 8).
If the hair is not abundant enough, scalp graftsmust not be
taken, especially if two layers are re-quired, which corresponds to
harvesting of 0.4mm. In this case, the risk of alopecia or of
delayedhealing exists. This technique can be performedwith an
electric dermatome, which can harvest athin skin graft of 0.2 mm
when performed by anexperienced operator. Strict adherence to
theseconditions is very important for avoiding alopeciaor delayed
healing of the scalp.
Because of the absence of epidermis in dermalgraft, these grafts
can be placed on either side.
Both the superficial and deep surfaces of thesegrafts have the
same reddish aspect. With macro-photography, one can see that the
epithelializa-tion comes from the adnexa, with the appearanceof
multiple tiny reddish spots (Fig. 3). Dermalgraft take was adequate
but slightly inferior todermoepidermal graft take.
Concerning the patient who contracted my-cotic infection that
partially deepithelialized thedermal graft, we think that in the
first weeks, neo-epidermis from the deep layer graft was
perhapsless resistant or more sensitive to local or general
infection, probably because of longer epithelialmaturation. It
was the only case of secondarydeepithelialization, and the quality
of dermal graftof the other patients was the same as for
classicgrafts.
Doubling the area of skin harvested from thescalp can minimize
scarring and avoid a secondoperation. This is illustrated by one
case of a 24-year-old man with burns of the right hand andforearm
that were totally grafted with only the skinof his scalp, taking in
two layers during one op-eration and avoiding visible scar of limb
harvest-
ing. The deep layer was used unmeshed for the
hand (Fig. 3 and Fig. 6) and the superficial layerwas used
meshed for forearm. The patient wastreated in a single operation
and had no visibledonor-site scar (Fig. 8).
CONCLUSIONS
This clinical study shows the capacity of der-mal graft from the
scalp to reepithelialize from thehair follicle stem cell included
in the graft. Heal-ing was total and there were no significant
differ-ences between the mean percentage of successfulgraft from
the dermal graft group and the der-moepidermal graft group. The
Vancouver ScarScale scores at 1 year were equivalent. The
scalphealed in a relatively short time. After exclusion ofalopecic,
insufficiently hairy, or elderly patients,this method can be chosen
when donor sites arerare or to decrease the number of procedures
and
scarring; however, it requires a surgeon with goodtraining in
scalp skin graft harvesting and ade-quate equipment.
Gilbert Zakine, M.D., Ph.D.
Department of Plastic, Reconstructive, and AestheticSurgery,
Burn UnitHopital Trousseau
Centre Hospitalier Regional et Universitaire de ToursAvenue de
la Republique a Chambray-Les Tours
Tours, 37 044 Cedex 9, [email protected]
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