Introduction
Skin defects on the hands are common injuries that may result in discomfort or disability
if not treated appropriately.[1]
[2] Split-thickness skin grafts (STSGs) are conventionally used for treating skin defects.[3] However, they can result in complications, such as delayed healing, contracture
formation, and abnormal scarring at both recipient and donor sites.[4]
[5] Harvesting skin grafts activates dermal pain receptors and causes significant pain
at the donor sites.[6]
To overcome these complications, new surgical techniques, such as micrografting systems,
fractional skin harvesting, and de-epithelialized skin grafts have been developed
over the years in previous studies.[7]
[8] This study describes a technique by which a thin epithelial layer with only the
proximal part still attached to the hypothenar area is harvested, followed by harvesting
a partial-thickness skin flap composed of epidermal and dermal layers. The elevated
epithelial layer at the donor site was covered back to the donor site and regrafted
as if the swing door had closed.
The aim of this study is to compare the outcomes of “Swing-door” technique and conventional
method of STSG with respect to donor site outcomes such as pain, scar, and healing
time, as well as recipient site outcomes such as graft take rate, scar, and healing
time.
Methods
Patients
From August 2019 to February 2023, a retrospective review was conducted on patients
with hand skin defects who received “Swing-door” or conventional STSG. The study included
patients with skin defects greater than 1.0 × 1.0 cm, who underwent STSG using the
hypothenar area ([Fig. 1]). Data including patient demographics, underlying medical conditions, such as hypertension
and diabetes mellitus, smoking history, and defect size were evaluated.
Fig. 1 Images demonstrating (A) normal skin layers of hypothenar area and skin layers of hypothenar area during
“Swing-door” harvest technique. (B) “Swing-door” STSG. (C) Conventional STSG technique in donor and recipient sites. STSG, split-thickness
skin graft.
Surgical Techniques
All surgeries were performed using a brachial plexus block. The necrotic tissue at
the recipient site was completely removed. Meticulous hemostasis was achieved using
an electric bipolar coagulator to prevent hematoma formation. The size of the defect
was measured using a metric ruler and the skin graft was harvested from the hypothenar
area. The design was made out of gentian violet and Vaseline was applied to the hypothenar
surface to create a smooth and even surface. An extremely thin epithelial flap was
then elevated using a razor blade with a freehand technique, taking care to elevate
only the outermost epithelial layer as thinly as possible, to the extent that the
letters on the razor blade could be seen through the flap. The proximal side of the
flap was left attached to the donor site in a form of “Swing-door.” The skin graft,
composed of epidermis and dermis, was harvested from the same area under the epithelial
flap using a razor blade ([Fig. 2]). During the harvest process, a mark was made with gentian violet to differentiate
between the upper and lower layers and prevent reversal during grafting.
Fig. 2 (A) Epithelial flap elevation technique. It is elevated as thinly as possible with proximal
side attached. (B) Harvesting of STSG beneath epithelial flap. (C) Direct donor coverage by replacing the epithelial flap like a “Swing-door.” (D) Harvested STSG (area marked with purple circle: epithelial flap; area marked with
purple cross sign: STSG). STSG, split-thickness skin graft.
The skin graft was tailored to fit the size and shape of the recipient site. The graft
was fixed to the recipient site by using Chromic 6–0 (AILEE Co., Busan, Korea). A
tie-over dressing was applied to the skin graft after fixation, and the skin graft
was evaluated after 5 days by removing the tie-over dressing. The elevated epithelial
flap was placed over the recipient site. The donor site dressing was performed using
Mepitel (Mölnlycke, Sweden), a wound contact layer with a silicone adhesion dressing,
to maintain appropriate moisture and prevent damage to the recovery of the epithelial
flap and the surrounding skin ([Video 1]).
Video 1 Complimentary video showing the process of “Swing-door” skin graft technique: Graft
harvesting, Skin grafting and Donor closure.
Patients who underwent conventional skin graft showed surgical differences in skin
graft harvest and donor site management. After designing from the hypothenar area
to match the size of the defect, an STSG was elevated using a razor blade. The skin
graft was fixed at the donor site using Chromic 6–0. Tie-over dressing was used to
fix the skin graft for 5 days. The donor site was covered with Mepitel dressing material.
Assessment
At the recipient site, the graft take percentage was assessed on postoperative day
10. Take was evaluated based on the graft color, capillary refill time, and absence
of fluid collection. Graft quality was measured using the Vancouver Scar Scale (VSS),
considering vascularity, pigmentation, pliability, and height. Healing time at the
recipient site was also evaluated.
At the donor site, pain levels were scored using a Visual Analog Scale (VAS) between
0 (no pain) and 10 (most painful) on postoperative day 10. Patients were followed
up for at least 1 month postoperatively to evaluate the scar tissue using the VSS.
Healing time at the donor site was also measured.
Two physicians scored the graft take percentage and VSS, considering donor site skin
elasticity, height from the normal skin, vascularization, and pigmentation.[9] The final VSS score was calculated as the mean of both scores. The days to epithelialization
were compared between the groups, with a p
-value of less than 0.05 considered statistically significant.
Statistical Analysis
Statistical significance between the continuous variables of the two skin graft types
was analyzed using the Mann–Whitney test. Discrete variables were analyzed using Fisher's
exact test. Statistical significance was set at p-value < 0.05. The statistical analyses were performed using the IBM SPSS Statistics
(version 26.0).
Results
Nineteen patients who underwent the “Swing-door” technique and 20 patients who underwent
the conventional technique were included. In terms of wound characteristics, the mean
defect size was smaller in the “Swing-door” group (1.6 cm × 1.4 cm) compared to that
of the conventional group (1.8 cm × 1.5 cm). There were no statistically significant
differences in incidence of complications, including infection, hematoma, and partial
skin graft loss between the two groups. No patients in either group experienced total
skin graft loss ([Table 1]).
Table 1
Patient demographic data
|
Conventional group (n = 20)
|
“Swing-door” group (n = 19)
|
p-Value
|
|
Number of patients
|
|
|
|
|
Males
|
18
|
17
|
–
|
|
Females
|
2
|
2
|
–
|
|
Age, mean (y)
|
47.8 ± 15.2
|
46.1 ± 13.8
|
0.125
|
|
Underlying diseases
|
|
|
|
|
Hypertension, n (%)
|
4 (20.0%)
|
3 (15.8%)
|
1.000
|
|
DM, n (%)
|
2 (10.0%)
|
2 (10.5%)
|
1.000
|
|
Smoking, n (%)
|
4 (20.0%)
|
3 (15.8%)
|
1.000
|
|
Mean defect size (cm)
|
1.8 × 1.5
|
1.6 × 1.4
|
0.291
|
Abbreviation: DM, diabetes mellitus.
At the recipient site, the percentage of graft take was higher in the conventional
group on day 10 (95.3 vs. 96.5%, p-value = 0.218). However, no statistically significant correlations were observed.
The “Swing-door” group showed lower VSS scores than the conventional group (4.1 ± 1.4
vs. 5.1 ± 1.6, p-value = 0.026). However, the time required to achieve full epithelialization was
longer in the “Swing-door” group (15.1 vs. 11.7 d, p-value = 0.001; [Table 2]).
Table 2
Comparison of complications and postoperative outcomes between “Swing-door” and conventional
groups in the recipient sites
|
Conventional group (n = 20)
|
“Swing-door” group (n = 19)
|
p-Value
|
|
Recipient
|
|
|
|
|
Percentage of graft take at day 10
|
96.5
|
95.3
|
0.218
|
|
VSS (mean, range)
|
5.1 ± 1.6
|
4.1 ± 1.4
|
0.026[a]
|
|
Time taken to full epithelialization (mean, d)
|
11.7
|
15.1
|
0.001[a]
|
|
Complication
|
|
|
|
|
Infection, n (%)
|
0
|
1 (5.3)
|
0.401
|
|
Hematoma, n (%)
|
2 (10.0)
|
0
|
0.130
|
|
Partial skin graft loss, n (%)
|
2 (10.0)
|
2 (10.5)
|
1.000
|
|
Total skin graft loss, n (%)
|
0
|
0
|
|
Abbreviation: VSS, Vancouver Scar Scale.
Note: p-Values were computed using Fisher's exact test to analyze the differences of each
complication between the two groups.
a
p-value <0.05 indicates statistical significance.
In the donor site, the “Swing-door” group reported significantly lower pain scores
than the conventional group at postoperative days 5 and 7, with mean pain scores of
1.7 ± 0.6 versus 7.3 ± 0.2 at day 5 (p-value = 0.041) and 1.5 ± 0.2 versus 6.8 ± 0.3 at day 7 (p-value = 0.030). However, there was no statistically significant difference in the
VAS scores between the two groups with mean pain scores of 1.3 ± 0.3 versus 5.0 ± 0.6
at day 10 (p-value = 0.369). In addition, the “Swing-door” group showed significantly lower VSS
scores than the conventional group (2.4 ± 0.2 vs. 3.5 ± 0.8, p-value = 0.048). The time taken for full epithelialization in donor site was significantly
shorter in the “Swing-door” group (8.3 d) compared to the conventional group (13.5
d; [Table 3]; [Figs. 3] and [4]).
Table 3
Comparison of postoperative outcomes between “Swing-door” and conventional groups
in the donor sites
|
Conventional group (n = 20)
|
“Swing-door” group (n = 19)
|
p-Value
|
|
Donor
|
|
|
|
|
VAS at day 5 (mean, range)
|
7.3 ± 0.2
|
1.7 ± 0.6
|
0.041[a]
|
|
VAS at day 7 (mean, range)
|
6.8 ± 0.3
|
1.5 ± 0.2
|
0.030[a]
|
|
VAS at day 10 (mean, range)
|
5.0 ± 0.6
|
1.3 ± 0.3
|
0.369
|
|
VSS (mean, range)
|
3.5 ± 0.8
|
2.4 ± 0.2
|
0.048[a]
|
|
Time taken to full epithelialization (mean, d)
|
13.5
|
8.3
|
0.005[a]
|
Abbreviations: VAS, visual analog scale; VSS, Vancouver Scar Scale.
a
p-value <0.05 indicates statistical significance.
Fig. 3 A case of conventional STSG. (A) Preoperative photograph. (B) Recipient site at postoperative 6 months. (C) Donor site at postoperative 5 days. (D) Recipient site at postoperative 6 months. STSG, split-thickness skin graft.
Fig. 4 A case of “Swing-door” STSG. (A) Preoperative photograph. (B) Recipient site at postoperative 6 months. (C) Donor site at postoperative 5 days. (D) Recipient site at postoperative 6 months. STSG, split-thickness skin graft.
Discussion
The STSG is a useful reconstructive option for skin defects.[10] However, patients often experience complications, such as pain, pruritus, hypertrophic
scarring, color mismatch, dryness, and contracture.[11]
[12] Modified surgical techniques, like the “Swing-door” method, have been developed
to overcome these complications. Our comparative study suggests that the “Swing-door”
technique has several advantages over the conventional method.
At the recipient sites, the “Swing-door” group showed better outcomes on the VSS.
The VSS score assesses scars based on various parameters, such as pigmentation, pliability,
and thickness, with higher scores indicating worse outcomes. The lower VSS score in
the “Swing-door” group indicates that this technique resulted in better cosmetic outcomes
compared to the conventional technique at the recipient sites. In order to interpret
this result, specimens from the epithelial flap and “Swing-door” skin graft were collected
for histological evaluation. According to the results, when harvested using the “Swing-door”
technique, the epithelium on the surface of the skin graft was partially removed,
leaving the epidermis in the form of epithelial islands on the dermis ([Fig. 5B]). The partially remaining epithelial islands are hypothesized to undergo reepithelialization
and healing through cellular multiplication and migration toward the peripheral boundaries.[13] This process is believed to result in less color mismatch and step differences compared
to conventional skin grafting.
Fig. 5 Histological comparison between “Swing-door” and conventional STSG. (A) Epithelial flap mostly consisted of keratinized layer of stratum corneum (black
star) and partial epidermal layers including stratum granulosum and spinosum. (B) Keratinized layer of stratum corneum (black star) was mostly removed from “Swing-door”
skin graft. Epidermal layer including stratum basale (black circle) and dermis (black
square) were preserved (H&E, ×100). STSG, split-thickness skin graft.
The scar quality appears to be associated with the keratin layer. According to a previous
study, increased expression of keratin K2e in the upper spinous and granular layers
of the interfollicular epidermis, such as in keloid scars, is highly associated with
scar formation, such as keloid scars.[14] There appears to be a relationship between the number of keratin layers and scar
quality. Histological studies indicate that the keratin layer of the “Swing-door”
skin graft is mostly removed, which may be the reason for the superior pliability
measured by the VSS in the “Swing-door” group.
The “Swing-door” group showed slower healing time and lower take rate in the recipient
site. Wound healing is thought to occur simultaneously in the two different areas.
While the skin graft enters the wound bed on the inner side, the de-epithelialized
skin graft on the outer side requires reepithelialization to occur simultaneously.
However, the most critical part of skin graft take is known to be revascularization
in recipient bed which requires factors such as VEGF and HIF-1a that are known to
be responsible for the neoangiogenesis process.[15] The graft take is heavily dependent on the recipient site. Therefore, the slower
healing time and lower take rate of the “Swing-door” group in the recipient site may
not be caused by technical difference between “Swing-door” and conventional methods,
but rather due to differences in conditions of the recipient sites.
Hematoma is one of the main complications associated with graft failure, as it acts
as a barrier between the wound bed and skin grafts, which ultimately leads to skin
graft failure.[10] The hematoma that occurred in this study was discovered after the removal of the
tie-over dressing. After creating a hole with an 18-gauge needle for hematoma removal,
they were resolved without any graft loss. Skin grafts can also be lost due to infections
that occur during the tie-over period or in the early weeks postoperation, even after
a successful graft take.[16] One case of infection that occurred in our study showed sign of infection with partial
melting down of the graft at the time of removal of tie-over dressing. This led to
partial skin graft loss, but naturally underwent full reepithelialization without
the need for additional surgery. The incidence of complications, including hematoma
and infection, was similar in both groups at the recipient site and did not result
in detrimental outcome which may have caused additional surgery, indicating that the
“Swing-door” technique does not significantly increase the incidence and severity
of complications compared to the conventional method.
In the “Swing-door” group, histologic study has shown that the epithelial flap contains
some epithelial cells on the inner side ([Fig. 5A]). By replacing the epithelial flap with the donor site, the flap functioned similarly
to a very thin graft. This epithelial regraft, which was previously described as a
tissue with independent reepithelialization potential,[17] assists in the healing process. Simultaneously, it acts as a partial biological
dressing, which appears to enable faster epithelialization at the donor site. In the
donor site, the healing time was faster in the “Swing-door” group. A previous study
reported that the use of occlusive or semiocclusive dressings that maintain a moist
environment results in earlier completion of epithelialization compared to dry and
open dressings.[18] Furthermore, they offer optimal protection against wound dehydration, contamination,
and mechanical trauma, thereby promoting rapid healing.[19]
Donor site pain is one of the most burdensome concerns for patients. The “Swing-door”
technique was associated with significantly less pain and discomfort around the donor
site during the early postoperative period, as reflected by the lower VAS score at
postoperative days 5 and 7. At the donor site of an STSG, the injured nerve endings
exposed to external stimuli cause heightened pain compared to the recipient site.
The use of an occlusive environment reduces pain by protecting nerve endings from
oxygen exposure and decreasing the concentration of macrophage-derived arachidonic
acid metabolites that can exacerbate pain.[20] Since the epithelial flap is instantly replaced back to its donor site intraoperatively,
the time nerve endings are exposed to outer environment is significantly decreased
in “Swing-door” technique, thus leading to less pain for the patients. This finding
is particularly important for improving patient satisfaction and compliance with postoperative
care, as pain and discomfort can significantly affect the quality of life and recovery
process.[21]
The “Swing-door” technique also showed superior cosmetic outcomes compared to the
conventional technique, as evidenced by the lower VSS score in the donor site. According
to the histological study by Thompson,[22] regrafting of the donor site of STSG promotes advanced regeneration of elastic tissue,
thus resulting in less hypertrophic scarring and improved cosmetic results. This was
confirmed in the present study. In the “Swing-door” technique, it is believed that
the thin epithelial flap acted as a regraft by being directly folded back onto the
donor site and contributed to less hypertrophic scar.
The potential advantage of the “Swing-door” technique includes cost savings in postoperative
management. Since the epithelial flap is directly replaced at the donor site, it partially
acts as a biological dressing, thus promoting wound healing without the need for additional
dressing material. This technique is expected to reduce expenses associated with donor
site dressing materials.
One limitation of our study is the potential variation in the thickness of the skin
graft harvested when using the freehand technique, as the dermatomes were not used.
This could have affected the results, as studies have reported that thicker skin grafts
can affect the take and healing.[23] To minimize this variability, our study was conducted using cases performed by only
one surgeon. However, the use of more standardized operative tools or dermatome devices
could overcome this limitation.
Another limitation is that this technique is only applicable to the hypothenar and
plantar areas, where the keratin layers are thicker than those in other parts of the
body. The hypothenar region is one of the most glabrous and thick areas of the human
body. Studies have shown that keratinocytes within the palm and sole epidermis possess
exceptionally large amounts of keratin filaments in their cytoplasm, unlike other
parts of the body with thin skin.[24] This may be due to the expression of palmoplantar-specific keratin in the hypothenar
and plantar arch areas.[25] Therefore, there is a difficulty in that the size of the skin defect is limited
to the size of the skin graft that can be harvested from the hypothenar area. Furthermore,
since hypothenar skin has less melanin-containing pigment cells and compact connective
tissues, it serves as an optimal candidate for the coverage of skin defects in hands.[26] Therefore, the “Swing-door” technique has a limitation in that it can mainly be
used for small skin defects on the hand.
Moreover, since the percentage of skin graft take and VSS were subjectively determined
by the observers, biases may have been introduced. To address this issue, two different
physicians evaluated the outcomes. However, the development of more objective evaluation
tools in the future could overcome this limitation.
It is important to note that both the “Swing-door” group and the conventional group
had relatively low case numbers in this study. The limited sample size may have influenced
the statistical power of our analysis. Therefore, our results should be interpreted
with caution. Future studies with larger sample sizes may provide further insight
into the differences between these techniques.
The “Swing-door” technique for split-thickness skin grafting in the treatment of skin
defects of the hands showed satisfiable results. This technique offers advantages
over conventional techniques in terms of pain, faster wound healing, improved cosmetic
outcomes at the donor site, and comparable outcomes at the recipient site.
