Pan-xi Yu， Wen-qi Diao， Zuo-liang Qi*， and Jing-long Cai*

1Department No. 16， Plastic Surgery Hospital， Chinese Academy of Medical Sciences & Peking Union Medical College， Beijing 100144， China

2Department of Respiratory Medicine， Peking University Third

Hospital， Beijing 100191， China

3Department of Dermatology， Peking Xiang-Yun Dermatological Hospital， Beijing 100068， China

?

Effect of Dermabrasion and ReCell?on Large Superficial Facial Scars Caused by Burn，Trauma and Acnes△

Pan-xi Yu1， Wen-qi Diao2， Zuo-liang Qi*， and Jing-long Cai3*

1Department No. 16， Plastic Surgery Hospital， Chinese Academy of Medical Sciences & Peking Union Medical College， Beijing 100144， China

2Department of Respiratory Medicine， Peking University Third

Hospital， Beijing 100191， China

3Department of Dermatology， Peking Xiang-Yun Dermatological Hospital， Beijing 100068， China

dermabrasion； ReCell?； scars； Patient and Observer Scar Assessment Scale

Objective To explore the effects of dermabrasion combined with ReCell?on large superficial facial scars caused by burn， trauma and acnes.

Methods Nineteen patients with large superficial facial scars were treated by the same surgeon with dermabrasion combined with ReCell?. According to the etiology， patients were classified into post-burning group （n=5）， post-traumatic group （n=7） and post-acne group （n=7）. Fifteen patients completed the follow-ups， 5 patients in each group. Healing time， complication rate， the preoperative and 18-month-post-operative assessments using Patient Satisfaction Score （PSS）， Vancouver Scar Scale （VSS）， and Patient and Observer Scar Assessment Scale （POSAS） of each group were analyzed to compare the effect of the combined therapy on outcomes.

Results The healing time of post-burning group （19.6±4.0 days）， post-traumatic group （15.8±2.6 days）， and post-acne group （11.4±3.1 days） varied remarkably （F=7.701， P=0.007）. The complication rates were 60%， 20%， and 0 respectively. The post-operative POSAS improved significantly in all groups （P＜0.05），where the most significant improvement was shown in the post-acne group （P＜0.05）. The post-operative PSS and VSS improved only in the post-traumatic group and post-acne group （all P＜0.05）， where the more significant improvement was also shown in the post-acne group （P＜0.05）.

Conclusions The combined treatment of dermabrasion and ReCell?has remarkable effect on acne scars， moderate effect on traumatic scars and is not suggested for burn scars. POSAS should be applied to assess the therapeutic effects of treatments for large irregular scars.

Chin Med Sci J 2016； 31（3）：173-179

S KIN injuries such as burning， laceration and acne infection represent a major health care burden and inevitably heal with some extend of scars. Unaesthetic scarring is associated with physical and psychosocial consequences， and nowhere is this truer than large ones in the face. Revision of large facial scars is difficult， yet the superficial ones might be relatively more curable since their therapeutic goal is basically to improve the appearance instead of function.

Dermabrasion is widely used to reduce skin lesion， and has been increasingly applied with skin grafts or biomaterials to cover the post-braded defects.1，2However， they are not appropriate to cover large defects. ReCell?has been repeatedly reported to facilitate epithelialization of large skin defects.3-5The combination of ReCell?and dermabrasion were used in the treatments of scars or nevus.6，7With the increasing popularity of ReCell?application， clinical indications of the combined therapy should be well addressed， especially when it comes to the treatment of large scars in face. To our knowledge this is the first study to attest and compare the effect of dermabrasion combined with ReCell?on the treatment of different types of large superficial facial scars.

PATIENTS AND METHODS

Patients’ selection

Since January 2012 to December 2012， patients who came to Plastic Surgery Hospital， Chinese Academy of Medical Sciences and Peking Union Medical College for scar revision were recruited in the study based on the predetermined inclusion and exclusion criteria. The inclusion criteria were：（1） the Han nationality people at the age of 15-30. （2）Superficial scars that were defined as those with the height or depth less than 2 mm from the surrounding normal skin depending on the clinician's experience. （3） Stable scars that occurred more than 12 months， without progressive tendency and sensation of pain and itches. （4） Facial scars with size ≥8 cm in length or ≥25 cm2in area. （5） Scars caused by burning， trauma or acnes. The exclusion criteria were： （1） Patients unable to take care of wounds themselves.（2） Patients unable to give informed consent. （3） Patients unavailable for follow-up. （4） Patients with a history of hypertrophic scar or keloid or any other past history that might affect the treatment directly or delay wound healing.

This study was approval by the Institutional Ethics Board of Plastic Surgery Hospital， Chinese Academy of Medical Sciences and Peking Union Medical College. Informed consent was signed before treatment. Photographs in the paper were released with the permission of the patients.

Pre-operative assessment

Three types of assessment scales were used， including Patient Satisfaction Score （PSS）， Vancouver Scar Scale（VSS， Table 1）， and Patient and Observer Scar Assessment Scale （POSAS， Fig. 1）. POSAS consists of Patient Scar Assessment Scale （PSAS） and Observer Scar Assessment Scale （OSAS）.8Each patient was trained to evaluate PSS and PSAS before operation. Three trained clinicians assessed VSS and OSAS blindly to the grouping. The average score of VSS and OSAS was taken for further statistical analysis.

Operation

For each patient， the operation was conducted by the same plastic surgeon. After general anesthesia， scars were gently abraded by mechanical dermabrasion （Medtronic Inc.， MN，USA） until pinpoint bleeding was observed. Hemostasis of the abraded area was achieved with topical application of 1% lidocaine and epinephrine. A thin split-thickness cutaneous biopsy （0.2-0.3 mm） was performed at post-auricular area and the tissue specimen was used to produce cellular suspension through ReCell?devices （Avita， Australia）. The harvested ReCell?suspension was sprayed directly onto the post-dermabraded area. Non-adherent dressings were then placed on the operated area.

Table 1. Numerical scale of Vancouver Scar Scale

Post-operation

Dressings were not completely removed until the formation of a newborn epidermis. Patients were informed to protect the wounds from sunlight， and were advised to keep using the same moisturizing cream and sunscreen for at least 6 months.

Outcome measures

Both the recipient and donor sites underwent daily observation. Complications were carefully observed and managed. Wound healing time， which was defined as the time for 90% of the wound to re-epithelialize， was recorded. Post-operative follow-ups consisted of four visits at months 1， 6， 12 and 18 after the operation. Post-operative assessments，including PSS， VSS and POSAS were performed at each follow-up without knowing the prior results to minimize the influence of them. The assessment scores of the last followup visit （the 18-month follow-up） were taken as the final post-operative scores for statistical analysis. The postoperative improvement was represented by the difference of score between the pre-operative score and the post-operative score.

Statistical analysis

Data of healing time， complication rate， and post-operative improvement of POSAS， PSS and VSS were analyzed statistically. All statistical analyses were performed using SPSS 20 （SPSS Inc. Chicago， IL， USA）.

For healing time， POSAS， PSS and VSS， Shapiro-Wilk test and Levene's test were used respectively to check the normal distribution and homogeneity of variance of all the assessment data， because the sample size was less than 50. Then a series of statistic methods were applied to check the significance of the among-group difference （difference among the three treatment groups） and that of the between-group difference （difference between each pair of groups）. The statistic flow diagram is shown in Fig. 2. A two-tailed P value ＜0.05 was deemed statistically significant.

RESULTS

Nineteen patients with large superficial facial scars caused by burning， trauma or acnes were recruited and were divided into post-burning group （n=5）， posttraumatic group （n=7） and post-acne group （n=7）. At the 18th post-operative month， 3 patients lost to follow-up，and 1 patient refused to be involved in the study. So there were 5 patients left in each group. The healing time， complication， pre-operative and post-operative assessment scorings are recorded in Table 2.

Figure 2. Statistic flow diagram. 1. Statistic analyses for among- and between-group significance， 2. Statistic analyses for within-group significance， 3. If 3 groups are all normally distributed （P＞0.1）， 4. If any group is abnormally distributed （P≤0.1）， 5. If homogeneity of variance is indicated （P＞0.1）， 6. If homogeneity of variance is not indicated （P≤0.1）， 7 and 8. If among-group significance is indicated （P≤0.05）， 9. If normally distributed （P＞0.1）， 10. If abnormally distributed （P≤0.1）.

Table 2. Results of assessment indexes of each patient in the study

Except PSS post-operative improvement in the group of PBG （P=0.000）， of all the other assessment data of the indexes were normal distributed and homogeneity （all P＞0.1）.

The healing time of the post-burning group （19.6±4.0 days）， post-traumatic group （15.8±2.6 days） and postacne group （11.4±3.1 days） differed significantly （F=7.701，P=0.007）. In advanced between-group comparison， the healing time of the post-acne group was found to be significantly shorter than that of the post-burning group（P＜0.05）.

Generally the complication rate was 60% in the postburning group， 20% in the post-traumatic group， and 0 in the post-acne group. Three out of five post-burning patients reported post-operative complications. One of them suffered from patchy hypopigmentation scattered over the recipientsite. One reported dyspigmentation on the face after a slow wound healing （21 days）. The third patient （Fig. 3）had scars on the right forehead and the cheek. The frontal wound did not show any signs of healing and the jugal wound was covered by only 70% re-epithelialization on the 26th post-operative day. A skin graft from the anteromedial thigh was applied to cover the frontal wound， whereas the jugal wound was left to heal spontaneously. Only one post-traumatic （Fig. 4） was noticed with a 1 cm×3 cm scar at the post-auricular donor site at the 1st follow-up. The scar was excised directly and left a trivial longitudinal 3 cm surgical trace. For the post-acne patients （Fig. 5）， no complication was observed during follow-up.

The improvement of PSS of the three groups differed remarkably （post-traumatic group 2.2±1.1， post-acne group 4.4±1.7， post-burning group 0.4±0.9， P=0.007， Kruskal- Wallis test）. However， only the improvement of the post-acne group significantly outstripped that of the post-burning group （P=0.005， Nemenyi test）. Additionally， the PSS after the operation was significantly improved in the posttraumatic group （P=0.011 student's t test） and in the post-acne group （P=0.004 student's t test）， but improvement of PSS in the post-burning group was not significant（P=0.317， Wilcoxon test）.

Figure 3. Oblique views of a patient （No. 2） in the postburning group： pre-operation （A） and 18-monthpost-operation （B）.

Figure 4. Frontal views of a patient （No. 9） in the post-traumatic group： pre-operation （A） and 18-month-post-operation （B）.

Figure 5. Lateral views of a patient （No. 13） in the post-acne group： pre-operative （A） and 18-month-post-operation （B） .

The improvement of VSS score varied significantly among the three groups （post-traumatic group 3.2±2.4，post-acne group 8.8±1.9， post-burning group 1.8±1.1，F(xiàn)=16.629， P=0.000）， but a further Student-Newman-Keuls test indicated only the post-acne improvement surpassed post-burning improvement significantly. Similar to the PSS， the improvement of VSS was notable in the post-traumatic group （P=0.040） and post-acne group（P=0.001）， but not significant in the post-burning group（P=0.052）.

The improvement of POSAS was statistically significant in the post-burning group （PSAS score 6.0±3.8， P=0.016，OSAS score 6.0±3.3， P=0.024）， post-traumatic group（PSAS score 9.4±3.5， P=0.011， OSAS score 11.0±5.4，P=0.004） and post-acne group （PSAS score 33.0±4.1，P=0.001， OSAS score 21.4±5.1， P=0.000）. There was a significant difference of PSAS and OSAS among the three groups when compared with each other， （PSAS： F=13.859，P=0.001； OSAS： F=74.915， P=0.000）， and the improvement of the post-acne group was more significant than that of other groups （all P＜0.05）.

DISCUSSION

Large facial lesions caused by burn， trauma and acnes could develop into physically and psychosocially devastating scars. The clinical choice among miscellaneous treatments for large facial scars remains an important therapeutic consideration. Although dermabrasion has been widely applied to treat superficial lesions，1，9it is a painful procedure and leaves an open wound to heal for a considerable period of time. Intense pain and complications during healing are also concerns. The speed-up effect of skin grafting on post-dermabraded wound has been reported，1，2，10but its application is restricted due to disadvantages such as hair growth， texture mismatch， as well as size limitation and complications of donor sites.11

ReCell?has been cumulatively reported to facilitate epithelialization， enhance appropriate pigmentation， and repair superficial skin defect and scars.3-7It provides keratinocytes that serve as the backbone of epidermis，melanocytes that promote skin pigmentation， and fibroblasts that communicate epidermis and dermis.12Besides its advantages such as convenience， timesaving， and diversity of skin cells， ReCell?uses 1 cm2of donor site to repair 80 cm2of recipient site， which make it feasible to be applied in the treatment of large defects.

In this study， patients in post-acne group benefited most from the combined therapy of dermabrasion and ReCell?： the shortest healing time， zero complication， and the most significant amelioration in PSS， VSS and POSAS，while the post-burning patients seemed gain no benefit from the treatment in terms of PSS and VSS. The following aspects may explain the distinctive curative effects.

Foremost， the underlying pathological damage of scars caused by burning， trauma， and acnes contributed to the curative difference. The physiological basis of healing rests upon skin's capacity to regenerate epidermal cover by epithelialization through skin appendages. Trauma brings mechanical injuries onto skin directly， scarcely involving surrounding appendages. Acnes can cause topical infection，but usually confined to the involved pilosebaceous unit.13While thermal damage diffuses to surrounding tissues and destroy massive skin appendages， leading to impaired skin's capacity to re-epithelialize， delayed wound healing and higher risk of complications. Thermal force not only leads to coagulative necrosis of burned tissue， but also triggers microvascular reactions of underlying dermis and subcutaneous tissues， where progressive vasoconstriction and thrombosis may occur.14Blood supply is essential for skin repairing. The broad range of vascular damage and tissue debility makes the post-burning wound intractable. Moreover， burning gives rise to pronounced acute inflammatory processes. The overflow of inflammatory factors are involved to generate a hypertrophic scar as an undesired consequence of skin repairing and reconstruction.14

In the second place， according to the depth of thermal injury， superficial burns usually heal without scarring， while deep-partial-thickness and the deeper burns always repair with scars.15Therefore， post-burning scars are at least the products of deep-partial-thickness burns， which affect deep dermis beneath the papillary layer. That is to say， no matter how a burn scar appears or is defined as superficial，its underlying structural disorganization involves at least the dermal papillary layer. The depth of the underlying damage of burn scars makes them incompetent candidates for dermabrasion and ReCell?.

It has been well accepted that skin coloration is mainly controlled by melanin. Hypopigmentation is caused by decreased synthesis and impaired transfer of melanin；hyperpigmentation is resulted from over-activity of melanocytes and ultra neovasculature.16Although normal melanocytes can be supplemented by ReCell?， the widespread impact of burning could generate a vascular chaos and destroy the tissue homeostasis which is essential for the vitality of melanocytes and melanin transfer. This might explain the high incidence of dyspigmentation in postburning group.

Delayed healing was also observed in a post-burning patient （Fig. 3）. According to the previous findings that wounds not expected to heal by 25 days should be excised or skin-grafted，17，18a skin graft was applied to cover the frontal wound. The jugal wound healed without surgical intervention ended with a scar. Re-epithelialization occurs secondary to epithelial lining of skin appendages. Since skin appendages were extensively damaged in postburning patients， more time was required for healing， thus higher risk of complications arose.

Our study indicated the important value of POSAS in the scar assessment. PSS and VSS have been commonly used in the scar assessment for patients and clinicians.19，20Nonetheless， PSS is a subjective index and intuitive to provide significant guidance， while VSS has been reported to have an unacceptable low reliability and is insufficient for large irregular scars as well as scars not caused by burn.21，22POSAS is a double numeric scoring system including PSAS and OSAS， which have been suggested to replace PSS and VSS.23The correlation between PSAS and OSAS has been statistically proved.8In this study， the PSS and VSS of post-burning group did not show significant improvement after operation， whereas the amelioration of POSAS was statistically significant. In addition， the PSAS revealed a significant better improvement in post-acne group than that in post-traumatic group， while no statistical difference of PSS was indicated between the two groups. Our result suggested that compared with PSS and VSS， POSAS might be more sensitive to reflect scar amelioration and the therapeutic effect for scars.

The absence of negative control groups and the small sample size were the limitations of this study. In clinical setting， a large post-dermabraded wound is usually accompanied with a considerable complication， thus for the benefits of patient， we did not perform the treatment of dermabrasion for large facial scars as the control group. However， this study points out the direction for the clinical application of the dermabrasion combined with ReCell?as a therapy for large facial scars.

In conclusion， this study evaluates and compares the therapeutic effect of dermabrasion combined with ReCell?on large superficial facial scars of different causes. The combination of dermabrasion and ReCell?has remarkable effect on acne scars， moderate effect on traumatic scars，and is not suggested for burn scars. In addition， this study supported the application POSAS in the assessment of the therapeutic effects of large irregular scars.

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for publication December 22， 2015.

*Corresponding authors Zuo-liang Qi Tel： 86-10-88964826， E-mail： qizuolianglh@163.com， Jing-long Cai Tel： 86-10-56309999， E-mail： caijinglong@126.com

△Supported by National Natural Science Foundation of China （81372063）.