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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.

Volume 130, Number 1 Scalp as Donor Site for Thin Skin Grafts

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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.

Plastic and Reconstructive Surgery July 2012

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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]

REFERENCES

1. Mimoun M, Chaouat M, Picovski D, Serroussi D, Smarrito S.The scalp is an advantageous donor site for thin-skin grafts:A report on 945 harvested samples. Plast Reconstr Surg.2006;118:369373.

2. Sullivan T, Smith J, Kermode J, McIver E, Courtemanche DJ.Rating the burn scar. J Burn Care Rehabil. 1990;11:256260.

3. De Vries Reilingh TS, Bodegom ME, van Goor H, HartmanEH, van der Wilt GJ, Bleichrodt RP. Autologous tissue repairof large abdominal wall defects.Br J Surg. 2007;94:791803.

4. Tanabe HY, Aoyagi A, Tai T, Kiyokawa K, Inoue Y. Recon-struction for palmar skin defects of thedigits and hand usingplantar dermal grafting. Plast Reconstr Surg. 1998;101:992998.

5. Chen YR, Yeow VK. Cleft lip scar camouflage using dermalmicrografts. Plast Reconstr Surg. 1999;103:12501253.

6. Rubis BA, Danikas D, Neumeister M, Williams WG, Suchy H,Milner SM. The use of split-thickness dermal grafts to resur-face full thickness skin defects. Burns2002;28:752759.

7. Donati L, Klinger A, Montorsi W. Comparison of clinicalactivity of allo- and xeno-grafts of fresh and cryopreservedskin. Minerva Med. 1974;65:36543655.

8. Burke JF, Yannas IV, Quinby WC Jr, Bondoc CC, Jung WK. Suc-cessful use of a physiologically acceptable artificial skin in treat-ment of extensive burn injury. Ann Surg. 1981;194:413428.

9. Heimbach D, Luterman A, Burke J, et al.Artificial dermis formajor burns: A multi-center randomized clinical trial. AnnSurg.1988;208:313320.

10. Moiemen NS, Staiano JJ, Ojeh NO, et al. Reconstructivesurgery with a dermal regeneration template: Clinical and

histologic study. Plast Reconstr Surg. 2001;108:93103.


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11. Pandya AN, Woodward B, Parkhouse N. The use of culturedautologous keratinocytes with integra in the resurfacing ofacute burns. Plast Reconstr Surg. 1998;102:825828.

12. Haslik W, Kamolz LP, Nathschlager G, Andel H, Meissl G,Frey M. First experiences with the collagen-elastin matrixMatriderm as a dermal substitute in severe burn injuries ofthe hand. Burns2007;33:364368.

13. Fang P, Engrav LH, Gibran NS, et al. Dermatome setting forautografts to cover INTEGRA. J Burn Care Rehabil. 2002;23:327332.

14. Navsaria HA, Ojeh NO, Moiemen N, Griffiths MA, FrameJD. Reepitheliali zation of a full -thickness burn from stemcells of hair follicles micrografted into a tissue-engineered

dermal template (Integra). Plast Reconstr Surg. 2004;113:978981.

15. Lavker RM, Sun TT, Oshima H, et al. Hair follicle stem cells.J Invest Dermatol Symp Proc.2003;8:2838.

16. Ito M, Liu Y, Yang Z, et al. Stem cells in the hair follicle bulgecontribute to wound repair but not to homeostasis of theepidermis. Nat Med. 2005;11:13511354.

17. Levy V, Lindon C, Harfe BD, Morgan BA. Distinct stem cellpopulations regenerate the follicle and interfollicular epi-dermis. Dev Cell.2005;9:855861.

18. Levy V, Lindon C, Zheng Y, Harfe BD, Morgan BA. Epider-mal stem cells arise from the hair follicle after wounding.

FASEB J. 2007;21:13581356.


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