Role of nanofat injection in treating post-traumatic scars

INTRODUCTION

Scars represent a fibrous tissue that replaces normal tissue following wounds, injuries, and some diseases. Scars are mostly benign in nature; however, they are able to cause major esthetic, functional, and social problems.¹

Numerous modalities have been tried for treatment of scars, yet most of them were unsatisfactory. The quest for a safe and effective approach for treatment with good esthetic outcome is still a major concern.²

Neuber first described autologous fat grafting (AFG) in 1893 and it was further recognized by Coleman.In addition to its known filling effect, AFG is considered a potential mechanism for treating scars owing to the presence of adipose tissue derived stem cells (ADSCs) which have a high regenerative ability and can repair injured tissues.^{3, 4}

PATIENTS AND METHODS

This is a prospective study that was conducted at Dermatology Department, Al-Azhar University. The study was approved by the Ethical Committee of Al-Azhar Faculty of Medicine.

The study included 19 patients with post-traumatic scars. Patients were recruited from the dermatology outpatient clinics of the university hospitals. Informed written consents were signed by all participants of this study after explaining the nature of the study to them.

Inclusion criterion: all patients with post-traumatic scars including accidental and surgical traumas.

Exclusion criteria: age50 years, recent scar injuries (

Scars were evaluated clinically by the Vancouver scar scale (VSS). The VSS score ranges between 0 – 14 evaluating vascularity, height, pliability, and pigmentation.⁵

We followed Coleman’s⁶ technique for AFG. Klein’s⁷ solution was used for tumescent anesthesia, then harvesting of fat (mostly from the abdomen) was done by negative pressure through a multi-port blunt tipped harvesting cannula attached to 10 ml syringe. Centrifugation of fat at 3000 rpm for 3 minutes was done to separate it from remnants of tumescent anesthesia and blood. Mechanical emulsification was then done via 30 passes using 1 mm connector mounted between two syringes. Fat was then passed through 400 μm filter to obtain the nanofat. Under complete aseptic conditions, intradermal nanofat injections were performed by 1 ml insulin syringes. Follow up was done one week after the procedure and then after 6 months.

Biopsy was taken (using a 2-mm punch) before the procedure and another biopsy was taken after 6 months to evaluate the response. Multiple stains were used including hematoxylin and eosin (H&E), Masson trichrome, orcein, CD-31, and S100. Objective evaluation was done by Leica Q500 MC image analyzing system from 5 random fields.

Statistical analysis was done using Statistical Package for Social Science (SPSS), Version 24.0.

RESULTS

Nineteen patients were included, 10 (52.6%) females and 9 (47.4%) males. The age ranged between 19 - 40 years (mean ± SD = 30.05 ± 6.42). The duration of scars ranged from 2 to 11 years (4.53 ± 2.55).

Face was the site of injury in 18 patients (94.7%) and 1 patient (5.3%) was affected in the abdomen.

Total VSS score showed a high statistical significant difference before and after treatment due to the high statistical significant difference in height, and the statistical significant difference in pigmentation (Figs. 1-3) (Table 1).

Fig. 1: Male patient 26 years old with post-traumatic scar of 9 years duration in the forehead. (A) Before treatment. (B) Six months after nanofat injection, marked improvement in height and pliability was seen and felt.

Fig. 2: Female patient 22 years old with post-traumatic scar of 6 years duration in the left zygomatic and temporal area. (A) Before treatment. (B) Six months after nanofat injection, improvement in height and pigmentation was noted with improved pliability.

Fig. 3: Female patient 29 years old with post-surgical abdominal scar of 2 years duration. (A) Before treatment. (B) Six months after nanofat injection, marked improvement in color and texture was seen.

X2: Chi-square test; MW: Mann-Whitney test; NS: p-value > 0.05 is considered non-significant; S: p-value < 0.05 is considered significant; HS: p-value < 0.001 is considered highly significant.

Table 1: Comparison of VSS before and after nanofat injection:

Pathological assessment showed high statistical significant improvement of epidermal thickness, collagen and elastic fibers thickness, and new blood vessels formation. Despite melanocytes exhibited normalized distribution in some patients, no statistical significant difference was recorded (Fig. 4-5) (Table 2).

Fig. 4: (A) Before treatment (H&E x100); nearly flattened epidermis. (B) Six months after nanofat, revealing increased epidermal thickness, rete-ridges elongation with undulating dermoepidermal junction (H&E x100). (C) Before treatment (Masson trichrome x100); random distribution of collagen fibers with increased inter-fibrillar spaces. (D) Six months after nanofat, revealing increased collagen density, decreased interfibrillar spaces (Masson trichrome x100).

Fig. 5: (A) Before treatment (orcein x100); decreased density of elastic fibers. (B) Six months after nanofat, showing increased density of elastic fibers (orcein x100). (C) Before treatment (CD-31 x100); randomly distributed vascular spaces. (D) Six months after nanofat, showing increased angiogenesis (CD-31 x100).

IQR: Interquartile Range; T: Independent sample T test.

Table 2: Comparison of pathological findings before and after nanofat injection.

Regarding procedural pain, 13 patients (68.4%) reported mild pain, 4 patients (21.1%) reported moderate pain. Bruising occurred in 4 patients (21.1%), erythema in 2 patients (10.5%), edema in 1 patient (5.3%), and hyperpigmentation in 1 patient (5.3%), while 11 patients (57.9%) experienced no complications.

One patient (5.3%) reported slight improvement, 2 patients (10.5%) reported moderate improvement, 6 patients (31.6%) reported significant improvement and 10 patients (52.6%) reported marked improvement after evaluating patients’ satisfaction.