- Email: [email protected]
Minced skin grafting for promoting epithelialization of the donor site after split-thickness skin grafting
JBUR 5104 No. of Pages 5
burns xxx (2016) xxx –xxx
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/burns
Minced skin grafting for promoting epithelialization of the donor site after split-thickness skin grafting Toru Miyanaga * , Yasuo Haseda, Akihiko Sakagami Department of Plastic Surgery, Kouseiren Takaoka Hospital, Toyama, Japan
article info
abstract
Article history:
It is important to minimize time to healing in the donor site after split-thickness skin grafting
Accepted 18 October 2016
(STSG). It has been shown that minced skin grafting improves the appearance of the STSG
Available online xxx
donor site. The objective of this study was to investigate whether mincing the leftover harvested skin and grafting it back onto the donor site during minced grafting (MG) reduces
Keywords: Minced skin grafting Epithelialization Donor Split-thickness skin grafting Leftover
healing time of the donor site. Normal healing time of the donor site after STSG is 10–20 days; therefore, healing time more than a month is abnormal. Out of the 96 patients (MG: controls=48:48) initially selected for this study, 7 patients (1 in the MG group and 6 in the control group) with abnormal wound healing (healing time >1 month) were excluded because their healing times were too long (from 1.5 to 6 months). All donor sites were on the lateral thigh. A part of the skin was minced and uniformly spread on the entire surface of the donor site. A calcium alginate dressing was applied and covered with a protective gauze dressing. Patients in the control group were treated identically, except that MG was not performed. MG of the STSG donor site reduced the average time to healing by approximately 4days (9.1 vs. 13.2). This effect was independent from the size of the donor site and MG/STSG mass ratio. This procedure, which makes use of skin leftovers after skin grafting, should be performed prior to applying wound covering material as a means of reducing time to healing and level of patient’s discomfort. © 2016 Elsevier Ltd and ISBI. All rights reserved.
1.
Introduction
Split-thickness skin grafting (STSG) is an important medical treatment in plastic and skin surgery. The ideal treatment for the donor site after STSG should minimize time to healing and patient discomfort, and provide a satisfactory cosmetic outcome. Reducing the healing time also reduces financial and mental burdens and accelerates the patient’s return to a normal social life. Shimizu et al. demonstrated that recruited minced skin grafting improves the appearance of the donor
site skin after STSG [1] . However, the effect of minced grafting (MG) on re-epithelialization has not been described. We investigated whether this method reduces the healing time of the donor site.
2.
Methods
We performed a retrospective review of data from the clinical database of the Kouseiren Takaoka Hospital, Japan. Patients who had undergone STSG between January 2010 and March
* Corresponding author at: Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku, Ishikawa 920-0293, Japan. Fax: +81 76 286 8915. E-mail address: [email protected] (T. Miyanaga). http://dx.doi.org/10.1016/j.burns.2016.10.011 0305-4179/© 2016 Elsevier Ltd and ISBI. All rights reserved.
Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011
JBUR 5104 No. of Pages 5
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2014 were identified, and their medical records were carefully analyzed. During the review, the principles outlined in the Declaration of Helsinki were followed. Individuals with incomplete data were excluded. A total of 96 patients were included in this retrospective study, of which 48 patients (MG group) were treated with minced grafting between July 2012 and March 2014, and 48 patients (control group) were treated with other methods between January 2010 and June 2012. This study was approved by the institutional ethics board. Before the surgery, we informed the patient regarding alternative donor sites and possible complications, including contamination from recipient site, discoloring, and hypertrophic scar at the donor site. All patients provided informed consent.
2.1.
Surgical procedure
All STSGs were taken from the lateral thigh with an electric 1 dermatome (Zimmer Air, Warsaw, IN) at a depth of 0.25– 0.30 mm, including the entire epidermis and a part of the dermis. Hemostasis was achieved by covering the donor site with gauze soaked in physiological saline solution. Splitthickness skin left after grafting was washed with saline and used for MG. This skin was minced with scissors into tiny particles on the flat side of a disposable carrier for a skin graft mesher or the bottom side of a Petri dish until it was pasty. Based on macroscopic evaluation, the approximate particle diameter was <0.5mm. The small pasty graft mass composed of a large number of minced graft particles and a small amount of saline solution was uniformly spread on the entire surface of the donor site with Adson forceps or small dressing forceps (Fig. 1). At this time, the mass should be as 1 flat as possible. A calcium alginate dressing (Kaltostat , ConvaTec Ltd.) was applied on the donor site and covered with a secondary protective gauze dressing. Patients in the control group were treated in the same way, except that MG was not performed. The gauze dressing was exchanged daily, whereas the alginate dressing was not removed until complete healing was achieved, unless there was evidence of leakage, bleeding, infection, or pain. The alginate dressing could be removed
easily once epithelialization was completed. Full epithelialization was defined as continuous coverage with epidermis.
2.2.
Evaluation
Healing times were compared between the MG and control groups. To evaluate the dependence of time to healing on the size of harvested STSG, the MG and control groups were each divided into 4 subgroups with different STSG areas: <25cm2, 25–100cm2, 100–200cm2, and >200cm2. Healing times were compared between corresponding subgroups of the MG and control groups. To evaluate the dependence of time to healing on mass ratio of MG to total harvested STSG, 28 patients from the MG group treated between May 2011 and May 2012 were divided into 2 subgroups according to the ratio of MG to total harvested STSG (<20% and >20%) by measuring the mass of harvested STSG and MG. Healing times were compared between these 2 groups.
2.3.
Statistical analysis
Statistical analysis was performed using SPSS (IBM, USA, 2011). Statistical evaluation was performed with the t-test. Significance was defined as P<0.05. All authors conducted the evaluation and the corresponding author conducted the analysis.
3.
Results
3.1.
Patient characteristics
The characteristics of the patients are shown in Table 1. There was no difference in patient characteristics between the 2 groups regarding the patient’s age, gender, etiology, and other medical history. Normal healing time of the donor site after STSG is 10–20days [2]; therefore, healing time more than a month is abnormal. There were 7 patients with abnormal wound healing (healing time >1 month), and the difference in the abnormal healing rate between the 2 groups was statistically significant (P<0.05). All excluded individuals had hypoalbuminemia, and 6 of them also had diabetes mellitus. Out of the 96 patients initially selected for this study, 7 patients (1 in the MG group and 6 in the control group) with abnormal wound healing were excluded because their healing times were too long (from 1.5 to 6 months). The data of the 89 remaining patients were used for analysis. All the MGs survived, and all the donor sites healed without any postoperative complications including contamination from recipient site, discoloring, and hypertrophic scar.
3.2. Comparison of healing times between the MG and control groups
Fig. 1 – Minced skin grafting. Some of the skin left after split-thickness grafting was minced into tiny particles with scissors until it was pasty. This small, pasty graft mass was uniformly distributed in a flat layer over the entire surface of the donor site.
There were 47 patients in the MG group and 42 in the control group. The median time to complete healing of the donor sites in the MG group was 9 days, with an average value of 9.1 2.3days (range, 6–17 days), whereas in the control group the corresponding values were 13days (median), 13.12.4days (average), and 9–19days (range). The difference in the healing
Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011
JBUR 5104 No. of Pages 5
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Table 1 – Patient characteristics. Characteristic N =96 Sex, n (%) Male Female
MG 48
34 (71) 14 (29)
Control
P
Area (cm2)
48
30 (63) 18 (37)
Table 2 – The dependence of time to healing on the size of harvested STSGs.
0.37
<25 25–100 100–200 >200
MG (days)
Control (days)
P value
8.4 1.8 9.2 2.6 10.1 3 9.25 1.3
13 2.4 13 2.7 12.7 2.0 13.6 2.6
<0.01 <0.01 <0.05 <0.01
MG: minced grafting.
Age Mean (SD) Median Range
64 (22) 67 1–94
61.9 (20) 66 1–96
0.62
Cause, n Skin ulcer Skin tumor Burn Hidradenitis suppurativa
17 13 12 6
20 16 9 3
0.53 0.5 0.46 0.29
Underlying disease, n Diabetes Hypoalbuminemia Hypertension Angina pectoris Peripheral artery disease
14 14 13 4 3
14 11 11 5 3
1 0.49 0.64 0.73 1
6 (13) 42 (87)
0.049
Healing time more than a month, n (%) 1 (2) Yes 47 (98) No
Bold value indicates a statistically significant with a p-value less than 0.05.
time between the 2 groups was statistically significant (P<0.01).
3.3. The dependence of time to healing on the size of harvested STSGs There were 13 (graft area <25cm2), 21 (25–100cm2), 9 (100– 200cm2), and 4 (>200cm2) patients in the subgroups of the MG group selected according to STSG areas. In the control group, the corresponding numbers were 6 (<25cm2), 15 (25–100cm2), 10 (100–200cm2), and 11 (>200cm2). The times to complete healing of the donor sites in the MG subgroups were 8.4 1.8days (<25cm2), 9.22.6days (25–100cm2), 10.13.0days (100–200cm2), and 9.31.3days (>200cm2). The corresponding times in the control group were 13.02.4days (<25cm2), 13.0 2.7days (25–100cm2), 12.72.0days (100–200cm2), and 13.6 2.6days (>200cm2). The differences in the healing times between the corresponding subgroups of the MG and control groups were statistically significant, with P values of <0.01 (25– 100cm2), <0.01 (25–100cm2), <0.05 (100–200cm2), and <0.01 (>200cm2) (Table 2).
3.4. The dependence of the time to healing on the mass ratio of MG to total harvested STSG There were 11 patients in the <20% subgroup and 17 in the >20% subgroup. The time to complete healing of the donor site in the <20% subgroup was 10.003.19 days, whereas in the >20% subgroup it was 8.351.37 days. The difference in the healing
times between the 2 subgroups was not statistically significant (P=0.13). The differences in the healing times between each of the <20% and >20% subgroups and the control group were statistically significant (P=0.011 and P<0.01, respectively).
4.
Selected case reports
4.1.
Case 1
A 64-year-old man presented with a skin defect of the lower leg caused by trauma. STSG (0.30mm) was performed after debridement. The total mass of the harvested STSG was 0.61g, and the mass of the MG was 0.19g (MG/harvested STSG ratio: 0.31, >20%). The eschars of the MG were left on the donor site. The time to complete healing of the donor site was 8 days. The donor site around the grafting area became pink and developed a thicker epithelium (Fig. 2a). The eschars separated spontaneously a week later. The appearance of the donor site was satisfactory 11 months after the MG (Fig. 2b).
4.2.
Case 2
A 75-year-old man presented with Bowen’s disease. STSG (0.25mm) was performed after the tumor was excised. The total mass of the harvested STSG was 0.56g, and the mass of the MG was 0.10g (MG/harvested STSG ratio: 0.19, <20%). The time to complete healing of the donor site was 8days (Fig. 3a). The eschars separated spontaneously 2 weeks later. The site of grafting had the same pigmentation as the normal lateral thigh skin, and the appearance was relatively satisfactory (Fig. 3b). The appearance of the donor site was about the same as that of normal skin 6 months after the MG (Fig. 3c).
5.
Discussion
Several types of wound covering material have been reported that can reduce the healing time to 10–20days in the donor site after split-thickness skin grafting (STSG), provided that appropriate wound care is present [2]. According to the results of the present study, MG of the STSG donor site reduced the average time to healing by approximately 4days (9.1days with MG and alginate dressing vs. 13.1days with alginate dressing only). This effect was independent from the size of the donor site and MG/STSG mass ratio. In addition, there were fewer cases of abnormal healing (healing time >1 month) in the MG group than in the control group. The healing process of the donor site consists of activation, migration, and proliferation of keratinocytes across the wound
Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011
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Fig. 2 – Minced skin grafting (MG) was performed using 31% of the skin (by mass) of the total harvested split-thickness skin graft. (A) The time to complete healing of the donor site was 8 days, and the eschars of the MG were left on the donor site. The donor site around the grafting became pink and developed a thicker epithelium. The eschars separated spontaneously a week later. (B) Appearance of the donor site 11 months after the MG procedure.
surface from both the basal layer of the surrounding epidermis and the adnexal structures in the dermal layer, such as sebaceous glands and hair follicles [3,4]. A split-thickness graft (0.25–0.3mm) contains the dermis, adnexal structures, and basal layer of the epidermis. Thus, in addition to keratinocytes, it also includes stem cells located in the adnexal structures [5]. We suggest that MG accelerates wound healing via delivering keratinocytes and stem cells to the wound. Therefore, the small pasty graft mass of the MG should be distributed uniformly to achieve an even distribution of keratinocytes and made as flat as possible to increase the contact between the graft and the wound, facilitating the survival of the graft. In addition, it was reported that minced skin grafting accelerated
re-epithelialization of skin wounds in pigs [6] and chronic wounds in humans [7] by means of selective release of cytokines, chemokines and growth factors by the minced skin in vivo [8]. Although these minced grafts were derived from fullthickness skin, MGs derived from split-thickness skin may also accelerate healing of the donor site via a similar mechanism. Simizu et al. reported that MG improves the appearance of the donor site [1]. Although we did not compare the appearance of the donor sites in the MG and control groups, we noticed that the appearance in the MG group improved promptly after the treatment. The shape of the wound varies in clinical practice, and it is difficult to harvest an STSG with exactly the same shape.
Fig. 3 – Minced skin grafting (MG) was performed using 19% of the skin (by mass) of the total harvested split-thickness skin graft. (A) The time to complete healing of the donor site was 8 days. (B) The eschars separated spontaneously 2 weeks later. The site of grafting had the same pigmentation as normal lateral thigh skin. (C) Appearance of the donor site was similar to that of normal skin 6 months after MG. Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011
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Therefore, a small part of the graft is usually left after the grafting procedure, and the leftover graft is generally thrown away. The action is ‘Mottainai’, which is a Japanese term conveying a sense of regret concerning waste. The main advantage of MG is the reutilization of this graft tissue to reduce the healing time (as demonstrated in this study) and improve the appearance of the donor site [1]. The potential advantage is to prevent prolongation of donor healing. MG is a useful and safe procedure compatible with various types of dressings. Therefore, the procedure should be done if there is graft tissue left after STSG. A potential disadvantage of this approach is the possibility of donor site contamination from the recipient site. Therefore, the graft tissue left after STSG should be thoroughly washed with saline solution before performing MG. This study is limited by its retrospective design. Prospective, randomized, and blind or half-side studies should be conducted in the future to precisely evaluate the efficacy of our technique.
6.
Conclusions
MG substantially reduces the healing time of the donor site after STSG. This procedure, which makes use of skin leftovers after skin grafting, should be performed before wound covering material is applied as a way of reducing time to healing and level of patient’s discomfort.
Conflict of interest
5
REFERENCES
[1] Simizu R, Kishi K, Okabe K, Uchikawa Y, Sakamoto Y, Hattori N, et al. Recruited minced skin grafting for improving the skin appearance of the donor site of a split-thickness skin graft. Dermatol Surg 2012;38:654–60. [2] Assadian O, Arnoldo B, Purdue G, Burris A, Skrinjar E, Duschek N. A prospective, randomised study of a novel transforming methacrylate dressing compared with a silver-containing sodium carboxymethylcellulose dressing on partial-thickness skin graft donor sites in burn patients. Int Wound J 2015; 12(3):351–6. [3] Ito M, Liu Y, Yang Z, Nguyen J, Liang F, Morris RJ, et al. Stem cells in the hair follicle bulge contribute to wound repair but not to homeostasis of the epidermis. Nat Med 2005; 11:1351–4. [4] Levy V, Lindon C, Zheng Y, Harfe BD, Morgan BA. Epidermal stem cells arise from the hair follicle after wounding. FASEB J 2007;21:1358–66. [5] Zakine G, Mimoun M, Pham J, Chaouat M. Reepithelialization from stem cells of hair follicles of dermal graft of the scalp in acute treatment of third-degree burns: first clinical and histologic study. Plast Reconstr Surg 2012;130:42–50e. [6] Svensjö T, Pomahac B, Yao F, Slama J, Wasif N, Eriksson E. Autologous skin transplantation: comparison of minced skin to other techniques. J Surg Res 2002;103:19–29. [7] Boggio P, Tiberio R, Gattoni M, Colombo E, Leigheb G. Is there an easier way to autograft skin in chronic leg ulcers? ‘Minced micrografts’, a new technique. J Eur Acad Dermatol Venereol 2008;22:1168–72. [8] Pertusi G, Tiberio R, Graziola F, Boggio P, Colombo E, Bozzo C. Selective release of cytokines, chemokines, and growth factors by minced skin in vitro supports the effectiveness of autologous minced micrografts technique for chronic ulcer repair. Wound Rep Regener 2012;20:178–84.
All authors declare that there is no conflict of interest that could inappropriately influence this work.
Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011
burns xxx (2016) xxx –xxx
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/burns
Minced skin grafting for promoting epithelialization of the donor site after split-thickness skin grafting Toru Miyanaga * , Yasuo Haseda, Akihiko Sakagami Department of Plastic Surgery, Kouseiren Takaoka Hospital, Toyama, Japan
article info
abstract
Article history:
It is important to minimize time to healing in the donor site after split-thickness skin grafting
Accepted 18 October 2016
(STSG). It has been shown that minced skin grafting improves the appearance of the STSG
Available online xxx
donor site. The objective of this study was to investigate whether mincing the leftover harvested skin and grafting it back onto the donor site during minced grafting (MG) reduces
Keywords: Minced skin grafting Epithelialization Donor Split-thickness skin grafting Leftover
healing time of the donor site. Normal healing time of the donor site after STSG is 10–20 days; therefore, healing time more than a month is abnormal. Out of the 96 patients (MG: controls=48:48) initially selected for this study, 7 patients (1 in the MG group and 6 in the control group) with abnormal wound healing (healing time >1 month) were excluded because their healing times were too long (from 1.5 to 6 months). All donor sites were on the lateral thigh. A part of the skin was minced and uniformly spread on the entire surface of the donor site. A calcium alginate dressing was applied and covered with a protective gauze dressing. Patients in the control group were treated identically, except that MG was not performed. MG of the STSG donor site reduced the average time to healing by approximately 4days (9.1 vs. 13.2). This effect was independent from the size of the donor site and MG/STSG mass ratio. This procedure, which makes use of skin leftovers after skin grafting, should be performed prior to applying wound covering material as a means of reducing time to healing and level of patient’s discomfort. © 2016 Elsevier Ltd and ISBI. All rights reserved.
1.
Introduction
Split-thickness skin grafting (STSG) is an important medical treatment in plastic and skin surgery. The ideal treatment for the donor site after STSG should minimize time to healing and patient discomfort, and provide a satisfactory cosmetic outcome. Reducing the healing time also reduces financial and mental burdens and accelerates the patient’s return to a normal social life. Shimizu et al. demonstrated that recruited minced skin grafting improves the appearance of the donor
site skin after STSG [1] . However, the effect of minced grafting (MG) on re-epithelialization has not been described. We investigated whether this method reduces the healing time of the donor site.
2.
Methods
We performed a retrospective review of data from the clinical database of the Kouseiren Takaoka Hospital, Japan. Patients who had undergone STSG between January 2010 and March
* Corresponding author at: Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku, Ishikawa 920-0293, Japan. Fax: +81 76 286 8915. E-mail address: [email protected] (T. Miyanaga). http://dx.doi.org/10.1016/j.burns.2016.10.011 0305-4179/© 2016 Elsevier Ltd and ISBI. All rights reserved.
Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011
JBUR 5104 No. of Pages 5
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2014 were identified, and their medical records were carefully analyzed. During the review, the principles outlined in the Declaration of Helsinki were followed. Individuals with incomplete data were excluded. A total of 96 patients were included in this retrospective study, of which 48 patients (MG group) were treated with minced grafting between July 2012 and March 2014, and 48 patients (control group) were treated with other methods between January 2010 and June 2012. This study was approved by the institutional ethics board. Before the surgery, we informed the patient regarding alternative donor sites and possible complications, including contamination from recipient site, discoloring, and hypertrophic scar at the donor site. All patients provided informed consent.
2.1.
Surgical procedure
All STSGs were taken from the lateral thigh with an electric 1 dermatome (Zimmer Air, Warsaw, IN) at a depth of 0.25– 0.30 mm, including the entire epidermis and a part of the dermis. Hemostasis was achieved by covering the donor site with gauze soaked in physiological saline solution. Splitthickness skin left after grafting was washed with saline and used for MG. This skin was minced with scissors into tiny particles on the flat side of a disposable carrier for a skin graft mesher or the bottom side of a Petri dish until it was pasty. Based on macroscopic evaluation, the approximate particle diameter was <0.5mm. The small pasty graft mass composed of a large number of minced graft particles and a small amount of saline solution was uniformly spread on the entire surface of the donor site with Adson forceps or small dressing forceps (Fig. 1). At this time, the mass should be as 1 flat as possible. A calcium alginate dressing (Kaltostat , ConvaTec Ltd.) was applied on the donor site and covered with a secondary protective gauze dressing. Patients in the control group were treated in the same way, except that MG was not performed. The gauze dressing was exchanged daily, whereas the alginate dressing was not removed until complete healing was achieved, unless there was evidence of leakage, bleeding, infection, or pain. The alginate dressing could be removed
easily once epithelialization was completed. Full epithelialization was defined as continuous coverage with epidermis.
2.2.
Evaluation
Healing times were compared between the MG and control groups. To evaluate the dependence of time to healing on the size of harvested STSG, the MG and control groups were each divided into 4 subgroups with different STSG areas: <25cm2, 25–100cm2, 100–200cm2, and >200cm2. Healing times were compared between corresponding subgroups of the MG and control groups. To evaluate the dependence of time to healing on mass ratio of MG to total harvested STSG, 28 patients from the MG group treated between May 2011 and May 2012 were divided into 2 subgroups according to the ratio of MG to total harvested STSG (<20% and >20%) by measuring the mass of harvested STSG and MG. Healing times were compared between these 2 groups.
2.3.
Statistical analysis
Statistical analysis was performed using SPSS (IBM, USA, 2011). Statistical evaluation was performed with the t-test. Significance was defined as P<0.05. All authors conducted the evaluation and the corresponding author conducted the analysis.
3.
Results
3.1.
Patient characteristics
The characteristics of the patients are shown in Table 1. There was no difference in patient characteristics between the 2 groups regarding the patient’s age, gender, etiology, and other medical history. Normal healing time of the donor site after STSG is 10–20days [2]; therefore, healing time more than a month is abnormal. There were 7 patients with abnormal wound healing (healing time >1 month), and the difference in the abnormal healing rate between the 2 groups was statistically significant (P<0.05). All excluded individuals had hypoalbuminemia, and 6 of them also had diabetes mellitus. Out of the 96 patients initially selected for this study, 7 patients (1 in the MG group and 6 in the control group) with abnormal wound healing were excluded because their healing times were too long (from 1.5 to 6 months). The data of the 89 remaining patients were used for analysis. All the MGs survived, and all the donor sites healed without any postoperative complications including contamination from recipient site, discoloring, and hypertrophic scar.
3.2. Comparison of healing times between the MG and control groups
Fig. 1 – Minced skin grafting. Some of the skin left after split-thickness grafting was minced into tiny particles with scissors until it was pasty. This small, pasty graft mass was uniformly distributed in a flat layer over the entire surface of the donor site.
There were 47 patients in the MG group and 42 in the control group. The median time to complete healing of the donor sites in the MG group was 9 days, with an average value of 9.1 2.3days (range, 6–17 days), whereas in the control group the corresponding values were 13days (median), 13.12.4days (average), and 9–19days (range). The difference in the healing
Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011
JBUR 5104 No. of Pages 5
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Table 1 – Patient characteristics. Characteristic N =96 Sex, n (%) Male Female
MG 48
34 (71) 14 (29)
Control
P
Area (cm2)
48
30 (63) 18 (37)
Table 2 – The dependence of time to healing on the size of harvested STSGs.
0.37
<25 25–100 100–200 >200
MG (days)
Control (days)
P value
8.4 1.8 9.2 2.6 10.1 3 9.25 1.3
13 2.4 13 2.7 12.7 2.0 13.6 2.6
<0.01 <0.01 <0.05 <0.01
MG: minced grafting.
Age Mean (SD) Median Range
64 (22) 67 1–94
61.9 (20) 66 1–96
0.62
Cause, n Skin ulcer Skin tumor Burn Hidradenitis suppurativa
17 13 12 6
20 16 9 3
0.53 0.5 0.46 0.29
Underlying disease, n Diabetes Hypoalbuminemia Hypertension Angina pectoris Peripheral artery disease
14 14 13 4 3
14 11 11 5 3
1 0.49 0.64 0.73 1
6 (13) 42 (87)
0.049
Healing time more than a month, n (%) 1 (2) Yes 47 (98) No
Bold value indicates a statistically significant with a p-value less than 0.05.
time between the 2 groups was statistically significant (P<0.01).
3.3. The dependence of time to healing on the size of harvested STSGs There were 13 (graft area <25cm2), 21 (25–100cm2), 9 (100– 200cm2), and 4 (>200cm2) patients in the subgroups of the MG group selected according to STSG areas. In the control group, the corresponding numbers were 6 (<25cm2), 15 (25–100cm2), 10 (100–200cm2), and 11 (>200cm2). The times to complete healing of the donor sites in the MG subgroups were 8.4 1.8days (<25cm2), 9.22.6days (25–100cm2), 10.13.0days (100–200cm2), and 9.31.3days (>200cm2). The corresponding times in the control group were 13.02.4days (<25cm2), 13.0 2.7days (25–100cm2), 12.72.0days (100–200cm2), and 13.6 2.6days (>200cm2). The differences in the healing times between the corresponding subgroups of the MG and control groups were statistically significant, with P values of <0.01 (25– 100cm2), <0.01 (25–100cm2), <0.05 (100–200cm2), and <0.01 (>200cm2) (Table 2).
3.4. The dependence of the time to healing on the mass ratio of MG to total harvested STSG There were 11 patients in the <20% subgroup and 17 in the >20% subgroup. The time to complete healing of the donor site in the <20% subgroup was 10.003.19 days, whereas in the >20% subgroup it was 8.351.37 days. The difference in the healing
times between the 2 subgroups was not statistically significant (P=0.13). The differences in the healing times between each of the <20% and >20% subgroups and the control group were statistically significant (P=0.011 and P<0.01, respectively).
4.
Selected case reports
4.1.
Case 1
A 64-year-old man presented with a skin defect of the lower leg caused by trauma. STSG (0.30mm) was performed after debridement. The total mass of the harvested STSG was 0.61g, and the mass of the MG was 0.19g (MG/harvested STSG ratio: 0.31, >20%). The eschars of the MG were left on the donor site. The time to complete healing of the donor site was 8 days. The donor site around the grafting area became pink and developed a thicker epithelium (Fig. 2a). The eschars separated spontaneously a week later. The appearance of the donor site was satisfactory 11 months after the MG (Fig. 2b).
4.2.
Case 2
A 75-year-old man presented with Bowen’s disease. STSG (0.25mm) was performed after the tumor was excised. The total mass of the harvested STSG was 0.56g, and the mass of the MG was 0.10g (MG/harvested STSG ratio: 0.19, <20%). The time to complete healing of the donor site was 8days (Fig. 3a). The eschars separated spontaneously 2 weeks later. The site of grafting had the same pigmentation as the normal lateral thigh skin, and the appearance was relatively satisfactory (Fig. 3b). The appearance of the donor site was about the same as that of normal skin 6 months after the MG (Fig. 3c).
5.
Discussion
Several types of wound covering material have been reported that can reduce the healing time to 10–20days in the donor site after split-thickness skin grafting (STSG), provided that appropriate wound care is present [2]. According to the results of the present study, MG of the STSG donor site reduced the average time to healing by approximately 4days (9.1days with MG and alginate dressing vs. 13.1days with alginate dressing only). This effect was independent from the size of the donor site and MG/STSG mass ratio. In addition, there were fewer cases of abnormal healing (healing time >1 month) in the MG group than in the control group. The healing process of the donor site consists of activation, migration, and proliferation of keratinocytes across the wound
Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011
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Fig. 2 – Minced skin grafting (MG) was performed using 31% of the skin (by mass) of the total harvested split-thickness skin graft. (A) The time to complete healing of the donor site was 8 days, and the eschars of the MG were left on the donor site. The donor site around the grafting became pink and developed a thicker epithelium. The eschars separated spontaneously a week later. (B) Appearance of the donor site 11 months after the MG procedure.
surface from both the basal layer of the surrounding epidermis and the adnexal structures in the dermal layer, such as sebaceous glands and hair follicles [3,4]. A split-thickness graft (0.25–0.3mm) contains the dermis, adnexal structures, and basal layer of the epidermis. Thus, in addition to keratinocytes, it also includes stem cells located in the adnexal structures [5]. We suggest that MG accelerates wound healing via delivering keratinocytes and stem cells to the wound. Therefore, the small pasty graft mass of the MG should be distributed uniformly to achieve an even distribution of keratinocytes and made as flat as possible to increase the contact between the graft and the wound, facilitating the survival of the graft. In addition, it was reported that minced skin grafting accelerated
re-epithelialization of skin wounds in pigs [6] and chronic wounds in humans [7] by means of selective release of cytokines, chemokines and growth factors by the minced skin in vivo [8]. Although these minced grafts were derived from fullthickness skin, MGs derived from split-thickness skin may also accelerate healing of the donor site via a similar mechanism. Simizu et al. reported that MG improves the appearance of the donor site [1]. Although we did not compare the appearance of the donor sites in the MG and control groups, we noticed that the appearance in the MG group improved promptly after the treatment. The shape of the wound varies in clinical practice, and it is difficult to harvest an STSG with exactly the same shape.
Fig. 3 – Minced skin grafting (MG) was performed using 19% of the skin (by mass) of the total harvested split-thickness skin graft. (A) The time to complete healing of the donor site was 8 days. (B) The eschars separated spontaneously 2 weeks later. The site of grafting had the same pigmentation as normal lateral thigh skin. (C) Appearance of the donor site was similar to that of normal skin 6 months after MG. Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011
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Therefore, a small part of the graft is usually left after the grafting procedure, and the leftover graft is generally thrown away. The action is ‘Mottainai’, which is a Japanese term conveying a sense of regret concerning waste. The main advantage of MG is the reutilization of this graft tissue to reduce the healing time (as demonstrated in this study) and improve the appearance of the donor site [1]. The potential advantage is to prevent prolongation of donor healing. MG is a useful and safe procedure compatible with various types of dressings. Therefore, the procedure should be done if there is graft tissue left after STSG. A potential disadvantage of this approach is the possibility of donor site contamination from the recipient site. Therefore, the graft tissue left after STSG should be thoroughly washed with saline solution before performing MG. This study is limited by its retrospective design. Prospective, randomized, and blind or half-side studies should be conducted in the future to precisely evaluate the efficacy of our technique.
6.
Conclusions
MG substantially reduces the healing time of the donor site after STSG. This procedure, which makes use of skin leftovers after skin grafting, should be performed before wound covering material is applied as a way of reducing time to healing and level of patient’s discomfort.
Conflict of interest
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REFERENCES
[1] Simizu R, Kishi K, Okabe K, Uchikawa Y, Sakamoto Y, Hattori N, et al. Recruited minced skin grafting for improving the skin appearance of the donor site of a split-thickness skin graft. Dermatol Surg 2012;38:654–60. [2] Assadian O, Arnoldo B, Purdue G, Burris A, Skrinjar E, Duschek N. A prospective, randomised study of a novel transforming methacrylate dressing compared with a silver-containing sodium carboxymethylcellulose dressing on partial-thickness skin graft donor sites in burn patients. Int Wound J 2015; 12(3):351–6. [3] Ito M, Liu Y, Yang Z, Nguyen J, Liang F, Morris RJ, et al. Stem cells in the hair follicle bulge contribute to wound repair but not to homeostasis of the epidermis. Nat Med 2005; 11:1351–4. [4] Levy V, Lindon C, Zheng Y, Harfe BD, Morgan BA. Epidermal stem cells arise from the hair follicle after wounding. FASEB J 2007;21:1358–66. [5] Zakine G, Mimoun M, Pham J, Chaouat M. Reepithelialization from stem cells of hair follicles of dermal graft of the scalp in acute treatment of third-degree burns: first clinical and histologic study. Plast Reconstr Surg 2012;130:42–50e. [6] Svensjö T, Pomahac B, Yao F, Slama J, Wasif N, Eriksson E. Autologous skin transplantation: comparison of minced skin to other techniques. J Surg Res 2002;103:19–29. [7] Boggio P, Tiberio R, Gattoni M, Colombo E, Leigheb G. Is there an easier way to autograft skin in chronic leg ulcers? ‘Minced micrografts’, a new technique. J Eur Acad Dermatol Venereol 2008;22:1168–72. [8] Pertusi G, Tiberio R, Graziola F, Boggio P, Colombo E, Bozzo C. Selective release of cytokines, chemokines, and growth factors by minced skin in vitro supports the effectiveness of autologous minced micrografts technique for chronic ulcer repair. Wound Rep Regener 2012;20:178–84.
All authors declare that there is no conflict of interest that could inappropriately influence this work.
Please cite this article in press as: T. Miyanaga, et al., Minced skin grafting for promoting epithelialization of the donor site after splitthickness skin grafting, Burns (2016), http://dx.doi.org/10.1016/j.burns.2016.10.011