Breast reconstruction using autologous tissue enables the reconstruction of a breast that resembles the softness and temperature of a natural breast. In many cases, a skin paddle is used to monitor the condition of the flap after breast reconstruction [14, 15]. In addition, skin paddles are required for immediate, delayed, and irradiated breast reconstruction when the skin envelope is not sufficiently expanded [13]. Revision surgery after breast reconstruction is partly at the patient's request. In examining the cosmetic aspects of the breast, the symmetry of the morphology is worked out at various facilities [25, 26]. While symmetry of form is important in the consideration of the shape, the color match of the skin paddle is also an important factor. However, there are no reports focusing on the color matching of skin paddles in breast reconstruction with a large population of Asian patients. In this paper, we summarize the color difference between the skin paddle and the native skin, and the postoperative changes of the skin paddle in breast reconstruction using the DIEP flap and the PAP flap more than a year after the surgery.
Several previous studies compared the degree of color match between the skin graft and the original skin in various head and neck reconstructive techniques, by analyzing digital photographs taken of patients, and calculating an objective biomedical measurement of color perception, namely, CIEDE2000 [27, 28]. In the study by Knott et al., on average, split-thickness skin grafts over de-epithelialized myogenous and adipofascial free tissue transfers resulted in a closer color match than the skin paddles of donor sites, with the exception of the radial forearm donor site [27]. Dermody et al. performed an objective analysis of color match in patients who had undergone free tissue reconstruction following surgery for head and neck cancer [28].
When analyzing the absolute values of CIEDE2000 scores, there are no direct comparisons available for assessing human skin color. Nevertheless, other industries have created standards to ensure consistent color quality control across different materials. In previous studies comparing skin color differences, the American Society of Testing and Materials lightfastness scale was utilized to evaluate color differences based on CIEDE2000 scores [28, 29]. Lightfastness I indicates excellent lightfastness, demonstrating a mean color change of less than four. Lightfastness II indicates very good lightfastness, with a mean color change of more than four but not more than eight. Lightfastness III indicates fair lightfastness, showing a mean color change of more than eight but not more than 16. Lightfastness Ⅳ indicates poor lightfastness, showing a mean color change of more than 16 but not more than 24. Lightfastness Ⅴ indicates very poor lightfastness, showing a mean color change of more than 24 (Table 4). Based on these standards, when evaluating the color match between the breast and the used flaps, the color difference between the DIEP flap and the breast was rated as very good, whereas the color difference between the PAP flap and the breast was rated as fair. From the perspective of color matching, it is advisable to use a tissue expander to stretch the breast skin when utilizing a PAP flap, to minimize the skin paddle. Furthermore, the PAP flap is not recommended for secondary reconstruction, in which a large amount of donor site skin is required.
Table 4
The evaluation of the color differences based on CIEDE2000 scores
Classification | CIEDE2000 | Perception |
Lightfastness I | < 4 | Excellent |
Lightfastness Ⅱ | 4 to 7.9 | Very good |
Lightfastness Ⅲ | 8 to 15.9 | Fair |
Lightfastness Ⅳ | 16 to 23.9 | Poor |
Lightfastness Ⅴ | 24≦ | Very poor |
Human skin varies in color tone from region to region [30]. Factors affecting color tone include melanocytes, blood vessels, telangiectasias, lentigines, hair follicles, ephelides, collagen density, and dermal thickness [31]. Optically, incident light on the skin is absorbed by pigments, such as melanin and hemoglobin in the skin, and diffuse reflected light enters the eye through scattering from the dermis and is recognized by the eye. Therefore, skin color is substantially affected by various factors, such as melanin, hemoglobin, and stratum corneum thickness [32]. Several studies have been published regarding standard CIELab values for various ethnic groups [33, 34]. Han et al. measured the skin color of 600 Korean volunteers using the same chroma meter as used in this study, to investigate which free-flap donor sites were colorimetrically appropriate for facial cutaneous reconstruction [33]. The CIELab values, including those for the breast, abdomen, and thigh in Korean subjects demonstrated a similar pattern to the CIELab values shown in our results.
The color difference between the skin paddle and its surroundings was larger for the PAP flap than for the DIEP flap in color matching after reconstruction using different free flaps. Using CIEDE2000, Mahrhofer et al. evaluated the skin color difference between the DIEP flap and the TMG flap in 60 Caucasian patients who had undergone unilateral secondary breast reconstruction [35]. A comparison between the DIEP flap and the TMG flap more than a year postoperatively demonstrated that the DIEP flap showed a preferable color match compared to the TMG flap (CIEDE2000 scores, 2.8 vs. 4.0, p = 0.009). In studies with different races, breast reconstruction using the DIEP flap showed a better color match, as in the present study. In addition, comparing the color match reconstructed by using the PAP flaps of Asian patients in our study and the TMG flaps of Caucasian patients in the previous research, there was a clear difference in coloration in the Asian patients (CIEDE2000 scores, 8.69 vs. 4.0). This result shows that color matching is significant in breast reconstruction using PAP flaps in Asian patients.
An interesting finding of our present study was that skin paddle coloration changes postoperatively. Regardless of the type of flap, there was an increase in L* and decrease in a* in the skin paddle and donor site. Yamamoto et al. evaluated the skin color of the transferred flap and the donor region by means of a chroma meter in nine patients who underwent head and neck reconstruction, and three patients who underwent breast reconstruction [34]. A comparison between the transferred flaps and the donor sites demonstrated that the L* and a* values of the flaps used for facial reconstruction were noticeably different from those of the donor regions. In the three patients who underwent breast reconstruction using the transverse rectus abdominis myocutaneous (TRAM) flap, the color tone of the skin paddle was compared with that of the donor area. Although the number of cases was small, the study also showed an increase in L* and a decrease in a* in patients who underwent breast reconstruction using the TRAM flap. Reasons may include the breast region being strongly stretched by the surrounding skin.
Our study has some limitations. First, the study was performed using a group of patients of a single race, and hence the possibility that the results may vary by race cannot be ruled out. Second, the color data of the donor area in this study were obtained at the time of the postoperative outpatient clinic appointment, and are not preoperative data. However, the abdomen and inner thighs are nonexposed areas and are considered to be minimally affected by ultraviolet light, so we believe that the use of this data as preoperative color of the donor area did not greatly affect our results.
To summarize, our study's results demonstrated a clear difference in color matching when comparing the skin of the abdomen and thighs to the breast, and that the DIEP flap has a less noticeable postoperative color difference with the breast compared with the PAP flap.