Table 1.
Summary of design, SVF/ADSC isolation procedures, populations, interventions, clinical and microscopic outcomes of selected studies.
| Reference | Study Design (Level of Evidence) | SVF/ADSC Isolation Technique | No. of Patients (Scars) | Scar Types | Treatment (Study Groups) | Clinical/Macroscopic Outcomes | Microscopic Findings |
|---|---|---|---|---|---|---|---|
| Wu et al. 2013 [51] | Case report (V) | SVF: Gravitational decanting -> Coleman’s procedure -> spectroscopy | 1 | cicatrix scar after lipoma excision on the back | PALF with SVF-enriched autologous fat transfer in conjunction with collagenase and hyaluronic acid serum with trichloroacetic acid peeling | Resolution of scar adherence against the muscle, reduced swelling, quicker epithelialization, improvement in clinical (texture, color, size) and ultrasonographic examination, and pain resolution * | None were examined due to patient’s lack of consent. |
| Gentile et al. 2014 [52] | Case-control (III) | SVF: Enzymatic isolation with a commercially available system | 30 | burn or post-traumatic scars | 1. Coleman’s fat graft (control) 2. SVF-enriched autologous fat graft 3. Coleman’s fat graft + PRP |
Contour restoring and volume maintenance improvement (39%—control, 63%—SVF, 69%—PRP)†, lower fat reabsorption in facial scars in study groups vs. control *. Patients’ satisfaction with texture, softness and contour in all groups *. |
None were examined. |
| Carstens et al. 2015 [53] | Case report (V) | SVF: Enzymatic digestion -> centrifugation | 1 | fibrosis of the right hand as late sequelae of a burn scar | Local injections of isolated SVF into 4 MCP joints and SVF-enriched lipofilling of the dorsum of the hand | Range of motion restoration in MCP, PIP and DIP joints, full opposition of the thumb after 6 weeks. Improvement of skin color and elasticity. Increased vascularization * | None were examined. |
| Elkahky et al. 2016 [54] | Low-quality randomized controlled trial (II) | SVF: Enzymatic digestion -> centrifugation -> filtering | 20 | atrophic rolling facial post-acne scars | 1. Intradermal injection of SVF 2. Intradermal injection of PRP underneath the scars on the entire face |
Total scar surface area reduction after 1 month (no difference between groups) and 3 months (66.49 ± 12.82—SVF vs. 80.2 ± 8.9 in the PRP group †). Patients reported high satisfaction rates and good treatment tolerance *. | At 3 month follow-up, increased epidermal thickness, number and density of collagen and elastic fibers †, redevelopment of rete processes, acanthosis, spongiosis |
| Zhou et al. 2016 [55] | Prospective cohort study (II) | ADSC-CM: Enzymatic digestion -> centrifugation -> filtering -> centrifugation -> cell culture -> conditioning in hypoxia -> medium collection | 13 | Facial atrophic acne scars | Split-face study: 1. 3 × FxCR + topical DMEM (control) 2. 3 × FxCR + topical ADSC-CM |
Higher patients’ satisfaction (2.35 ± 0.69 vs. 2.08 ± 0.76) and clinical improvement in the study group, measured with ECCA score (32.69 ± 18.1 vs. 26.15 ± 19.16) †. Lower melanin index and TEWL; higher elasticity and hydration in ADSC-CM-treated group †. | Semi-quantitative analysis showed increased collagen (49.9 ± 0.6% vs. 36.1 ± 0.6%) and elastin (37.6 ± 0.8 vs. 26.1 ± 0.4%) density†, more orderly alignment of fibers in ADSC-CM treated sample *. |
| Gentile et al. 2017 [56] | Low-quality randomized controlled trial (II) | Nanofat: 1. Mechanical dissociation -> filtering 2. Mechanical isolation of SVF with commercially available system + nanofat 3. Centrifugation -> mechanical fat dissociation 4. Low-speed centrifugation -> mechanical fat dissociation |
43 | burn or post-traumatic scars | Intradermal injections: 1. Nanofat (control) 2. Supercharged nanofat (SVF-enriched nanofat) 3. Centrifuged nanofat 4. Evo nanofat |
Scoring of pigmentation, vascularization, pliability, thickness, itching and pain by the patients and operator showed that supercharged (means 25.6; 25.7) > evo (means 25.3; 25.2) > centrifuged (means 24; 23.8) > classic nanofat (means 22.6; 22) †. | Significant improvement of epidermal and dermal thickness in all studied groups after 6 months with no difference between them†. New collagen and vessels formation in a representative sample from the supercharged group *. |
| Tenna et al. 2017 [57] | Low-quality randomized controlled trial (II) | Nanofat: Coleman’s procedure -> mechanical emulsification | 30 | Chronic acne scars | Two treatments (6 months interval) with either (subcutaneous injections): 1. Nanofat + PRP (control) or 2. Nanofat + PRP +FxCR |
Significant improvement of skin thickness 3 months after the 2nd treatment in group 2 (0.74 cm vs. 1.37 cm) †, but not in control (0.53 cm vs. 1.2 cm), compared with baseline. No difference in skin thickness increase between the groups. | None were examined. |
| Ghareeb et al. 2017 [58] | Case series (IV) | Nanofat: Coleman’s procedure -> mechanical emulsification | 30 | Facial scars—various etiology—26 were atrophic | Subcutaneous nanofat injections | Significant improvement in scar vascularity, pigmentation, pliability and pruritus as per VSS score †. Satisfaction in 76% of the patients. | None were examined. |
| Carstens et al. 2017 [59] | Case series (IV) | SVF: Washing -> enzymatic digestion -> centrifugation | 5 (35 treatment zones) | Burn scars | Subcutaneous nanofat injections | Significant improvements in VSS score, scar hardness (durometer), elasticity (cutometer) † and patients’ satisfaction *. | None were examined |
| Bhooshan et al. 2018 [60] | Case series (IV) | Classic nanofat | 34 | Post-traumatic, burn or post-inflammatory scars | Nanofat injected intralesionally | Significant improvement in POSAS—mean 27.4 ± 7.5 vs. 14 ± 14.4 (patient’s assessment) and mean 31 ± 8.5 vs. 18 ± 6.8 (observer’s assessment). Significantly better results in younger scars (<5 years) † | None were examined. |
| Gu et al. 2018 [61] | Case series (IV) | Nanofat: Coleman’s procedure -> mechanical emulsification -> centrifugation (3000 RPM × 3min) | 20 (25) | Atrophic facial scars (post-surgical, burn, post-traumatic and post-acne) | Condensed nanofat intradermal injection. One scar required additional subcutaneous lipofilling. | Significant clinical improvement both in patient’s (28.8 ± 1.02 vs. 12.2 ± 0.8) and physician’s (18 ± 0.71 vs. 9.2 ± 0.37) assessment, measured with a POSAS score†. | 6 months post-op: increased melanin density (0.671 vs. 0.844) †. Sebaceous and sweat glands visualized with CK14 and CK19 staining. |
| Lee et al. 2018 (two studies) [62] | Case series (IV)/Case-control (III) | SVF: Centrifugation -> enzymatic digestion -> multiple centrifugations | Study 1: 17 (19) Study 2: 15 |
Various; restricted to face in study 2. | Study 1: SVF injection (s.c./i.d.) alone or in the course of other procedures. Study 2: Scar revision with or without SVF injection (s.c./i.d.) (2 groups) |
Study 1: Improvement of OSAS (vascularity, pigmentation, hardness, flexibility), SBSES (only in overall score), VSS (vascularity, pigmentation, pliability) and VAS median scores 6 months post-op vs. baseline† Study 2: Improvement of OSAS, VSS and VAS overall median scores, as well as height and pliability in the SVF-treated group vs. control after 6 months †. |
None were examined. |
| Uyulmaz et al. 2018 [63] | Case series (IV) | Classic nanofat | 40 | Various | Nanofat injection into scars or i.d. (twice in 4 cases) | Softer and less prominent scars. Good or satisfactory clinical outcome in most cases. Improved patients’ satisfaction * | None were examined. |
| Abou Eitta et al. 2019 [64] | Prospective cohort study (II) | SVF: Washing -> enzymatic digestion -> centrifugation | 10 | post-acne scars | Split-face study: 1st half—intradermal SVF injection 2nd half—3 × FxCR |
At 3 month follow-up, significant reduction in scar severity and area percentage compared to baseline. TEWL, hydration, patients’ satisfaction, skin texture and homogeneity improved. No differences between the groups. | None were examined. |
| Malik et al. 2019 [65] | Low-quality randomized controlled trial (II) | SVF: Gravitational decanting -> enzymatic digestion -> centrifugation | 10 | amputation stump scars | Injection into scarred stump: 1. Fat grafting (control) 2. SVF-enriched fat graft |
After 6 months, POSAS overall score (mean sum of 77 vs. 40.4 in cases and 79.2 vs. 42,4 in controls) and all its individual parameters improved over time in both groups †. Fat accumulation over stump increased in SVF-treated (mean fat area 17.9 vs. 26.8) patients †, but not in control (24.1 vs. 28.8). | None were examined. |
| Jan et al. 2019 [66] | Case series (IV) | Classic nanofat | 48 | Post-burn facial scars | Nanofat injection (subcutaneous or intradermal) | After 6 months, improvement of POSAS score in all patient-measured parameters + pigmentation and pliability, measured by observer (overall observer’s mean 7.5 ± 0.77 vs. 4.33 ± 0.48) † | None were examined. |
| Shalaby et al. 2020 [67] | Prospective cohort study (II) | Nanofat: Coleman’s procedure -> mechanical emulsification (90×) | 60 | Atrophic scars | Intradermal and subcutaneous injections of either: 1. Nanofat (control) 2. Nanofat + PRP |
After 3 months—significant improvement in scar pliability, height and total VSS score (4.6 ± 1.7 vs. 2.4 ± 1.3 in nanofat + PRP; 5.2 ± 1.8 vs. 1.9 ± 1.4 in nanofat group), but no differences between the groups †. | None were examined |
| Pallua et al. 2020 [68] | Case reports (V) | Nanofat: Centrifugation -> mechanical emulsification -> cenrifugtion | 2 | Post-traumatic or post-acne facial scars | Subcutaneous microfat injection + s.c./intradermal nanofat injection ± PRP | Improvement in skin and scar quality, improved flexibility and decreased irritation. 6 months–1 year follow-up * | None were examined |
SVF—stromal vascular fraction, ADSC—adipose-derived stem cells, PALF—percutaneous aponeurotic lipofilling, Coleman’s fat graft—as described in Figure 2, PRP—platelet-rich plasma, MCP—metacarpophalangeal, PIP—proximal interphalangeal, DIP—distal interphalangeal, FxCR—fractional carbon dioxide resurfacing, DMEM—Dulbecco’s modified eagle medium, ADSC-CM—adipose-derived stem cells-conditioned medium, ECCA—échelle d’évaluation clinique des cicatrices d’acné, TEWL—transepidermal water loss, POSAS—patient and observer scar assessment score, OSAS—observer scar assessment score, VAS—visual analog scale, VSS—Vancouver scar scale, mVSS—modified Vancouver scar scale, s.c.—subcutaneous, i.d.—intradermal. * no statistical analysis. † statistically significant outcome (p < 0.05).