The Effect of Lipoaspirate Processing Technique on Complications in Autologous Fat Grafting for Breast Reconstruction: A Propensity Score Analysis Study

Are We Speaking the Same Language? A Systematic Review on the Use of Consistent Language in Reporting Fat Necrosis in Autologous Fat Grafting of the Breast

BACKGROUND

Autologous fat grafting is a widely adopted approach to optimize outcomes in breast reconstruction and augmentation. Although fat necrosis is a well-known consequence of autologous fat grafting, it remains inconsistently defined in the literature. In late 2014, the Food and Drug Administration released a draft guidance to restrict future autologous fat grafting-a statement that was permissively modified in late 2017. In the context of evolving guidelines and autologous fat grafting outcome data, the language and descriptions of fat necrosis are inconsistent in the literature.

METHODS

Five databases were queried for studies reporting fat necrosis following autologous fat grafting for breast reconstruction or augmentation from inception to August 11, 2022. Studies were temporally stratified according to released FDA guidelines: pre-2015, 2015-2017, and 2018-2022.

RESULTS

Sixty-one articles met inclusion criteria. Prior to 2015, 6 of 21 studies (28.6%) offered clear definitions of fat necrosis. In contrast, the 2015-2017 period demonstrated an absence of clear fat necrosis definitions (0/13 studies, p = 0.03). Though the 2018-2022 period exhibited a rise in annual publications compared with the pre-2015 period (5.4 vs. 1.9, respectively, p = 0.04), this was not matched by a rise in clear fat necrosis reporting (14.8% studies, p = 0.45). Across all periods, only 16.4% of articles offered clear definitions, which exhibited wide heterogeneity.

CONCLUSION

Despite the increasing popularity of autologous fat grafting, fat necrosis remains inconsistently defined and described, especially in the context of changing FDA guidelines. This limits the reliable interpretation and application of the current literature reporting fat necrosis outcomes.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

In Vitro Characterization of Fat Grafts Processed Using the REVOLVE ENVI System versus Decantation

Background

This preclinical study evaluated benchtop/in vitro properties and fat viability and activity of grafts processed using the REVOLVE ENVI 600 system compared with decantation and evaluated properties of REVOLVE ENVI waste.

Methods

Lipoaspirate from six donors was processed using REVOLVE ENVI or decantation. The composition of each graft, hematocrit/red blood cell content, fat particle size/macrostructure, viable adipocyte count, and adipocyte activity were analyzed. Stromal vascular fraction was analyzed for viable progenitor cell count and colony-forming units.

Results

REVOLVE ENVI grafts had a higher mean (±SD) fat content at 85.6% ± 6.1% than decanted grafts at 72.1% ± 4.0% (P < 0.001), with negligible free oil (0.4% ± 1.1%) and cellular debris (<0.1%), whereas REVOLVE ENVI waste contained primarily aqueous fluid (91.0% ± 2.2%) with negligible viable fat. REVOLVE ENVI grafts had significantly lower hematocrit levels (P < 0.001) and contained significantly more large fat globules (P < 0.001) than decanted grafts or REVOLVE ENVI waste. The percentage of tissue particles of more than 1000 µm was highest for REVOLVE ENVI grafts at 61.6% ± 9.2% (decantation: 52.5% ± 13.4%; REVOLVE ENVI waste: 0.49% ± 1.50%), and the percentage of particles less than 200 µm was lowest for REVOLVE ENVI grafts at 15.7% ± 2.6% (decantation: 32.2% ± 8.9%; REVOLVE ENVI waste: 97.9% ± 4.5%). REVOLVE ENVI grafts contained 145.2% ± 36.0% more viable adipocytes, 145.7% ± 46.2% greater activity, 195.5% ± 104.2% more progenitors in SVF, and 363.5% ± 161.2% more SVF colony-forming units than decanted grafts.

Conclusion

Fat grafts processed using REVOLVE ENVI demonstrated greater viability and activity than decanted grafts in vitro.

Streamlining the Fat: A Systematic Review of Active Closed Wash and Filtration in Autologous Fat Grafting After Breast Reconstruction

Although fat grafting in breast reconstruction continues to grow in popularity, the optimal technique remains elusive and outcomes are varied. This systematic review of available controlled studies utilizing active closed wash and filtration (ACWF) systems sought to examine differences in fat processing efficiency, aesthetic outcomes, and revision rates. A literature search was performed from inception to February 2022 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) in Ovid MEDLINE (Wolters Kluwer, Alphen aan den Rijn, the Netherlands), Ovid Embase (Wolters Kluwer), and Cochrane Library (Wiley, Hoboken, NJ). Two independent reviewers screened the studies for eligibility with Covidence software. Bibliographies and citing references from selected articles were screened from Scopus (Elsevier, Amsterdam, the Netherlands). The search identified 3476 citations, with 6 studies included. Three studies demonstrated a significantly higher volume of graftable fat harvested in a significantly lower mean grafting time with ACWF than with their respective controls. With respect to adverse events, 3 studies reported significantly lower incidences of nodule or cyst formation with ACWF with respect to control. Two studies reported a significantly lower incidence of fat necrosis with ACWF vs control, with this trend upheld in 2 additional studies. Three studies reported significantly lower revision rates with ACWF with respect to control. No study reported inferiority with ACWF for any outcome of interest. These data suggest that ACWF systems yield higher fat volumes in less time than other common techniques, with decreased rates of suboptimal outcomes and revisions, thereby supporting active filtration as a safe and efficacious means of fat processing that may reduce operative times. Further large-scale, randomized trials are needed to definitively demonstrate the above trends.

LEVEL OF EVIDENCE: 4

Autologous Fat Grafting With CO2 Tissue Preparation (Carbo-pneumodissection): A Safe Method for Expanding and Enhancing Recipient Site Capacity and Aesthetic Outcomes

BACKGROUND

Autologous fat grafting (AFG) is commonly used as part of aesthetic and reconstruction procedures, but expanding and enhancing the recipient site capacity remains a major challenge.

OBJECTIVES

The aim of this study was to describe and assess an innovative intraoperative carbon dioxide (CO2) pneumodissection (CPD) recipient site preconditioning procedure intended to improve recipient site capacity and AFG outcomes.

METHODS

From June 2019 to August 2021, 53 patients after mastectomy or lumpectomy (76 breasts) underwent 96 AFG procedures as a separate stage immediately following tissue preconditioning with CPD.

RESULTS

There were no systemic or major local complications. The mean number of AFG procedures required to complete the reconstruction was 1.3 per breast. The vast majority of patients achieved a final satisfactory aesthetic outcome with either 1 or 2 procedures (77.6% and 18.4%, respectively). The volume of fat graft delivered into the recipient site per session following CPD was higher than previous literature reports for all study groups. Furthermore, the CPD procedure was associated with a reduced need for subsequent AFG to complete the reconstruction. The positive effect of CPD, in terms of AFG volume delivered, was even more prominent among scarred irradiated breasts. Despite the large fat graft volumes delivered in our study, only 5.3% of breasts experienced fat necrosis following the procedure.

CONCLUSIONS

CPD constitutes a safe, innovative, intraoperative method to expand and enhance recipient site capacity and fat grafting outcome. CPD allows cavernous expansion alongside preservation of the microcirculation. CPD works for both healthy and compromised tissues, in either reconstructive or aesthetic procedures.

LEVEL OF EVIDENCE: 4

“Achieving Optimal Clinical Outcomes in Autologous Fat Grafting: A Systematic Review of Processing Techniques”

BACKGROUND

Autologous fat grafting (AFG) is a versatile technique in reconstructive and cosmetic surgery. Graft processing is a key source of variability resulting in unreliable clinical outcomes, with no consensus on the optimal methodology. This systematic review identifies the evidence base supporting different processing paradigms.

METHODS

A systematic literature search was conducted using the PubMed, Scopus and The Cochrane Foundation databases. Studies comparing AFG processing methods and reporting long-term patient outcomes were identified.

RESULTS

Twenty-four studies (2413 patients) were identified. Processing techniques evaluated included centrifugation, decantation, washing, filtration, gauze rolling, as well as commercial devices and adipose-derived stem/stromal cell (ASC) enrichment methods. Objective volumetric and subjective patient-reported outcomes were discussed. There was a variable reporting of complications and volume retention rates. Complications were infrequent; palpable cysts (0-20%), surgical-site infections (0-8%) and fat necrosis (0-58.4%) were the most reported. No significant differences in long-term volume retention between techniques were found in AFG in the breast. In head and neck patients, greater volume retention was documented in ASC enrichment (64.8-95%) and commercial devices (41.2%) compared to centrifugation (31.8-76%).

CONCLUSIONS

Graft processing through washing and filtration, including when incorporated into commercial devices, results in superior long-term outcomes compared to centrifugation and decantation methods. ASC enrichment methods and commercial devices seem to have superior long-term volume retention in facial fat grafting.

Autologous Adipose-Derived Tissue Stromal Vascular Fraction (AD-tSVF) for Knee Osteoarthritis

Adipose tissue contains adult mesenchymal stem cells that may modulate the metabolism when applied to other tissues. Stromal vascular fraction (SVF) can be isolated from adipose tissue mechanically and/or enzymatically. SVF was recently used to decrease the pain and improve the function of knee osteoarthritis (OA) patients. Primary and/or secondary OA causes inflammation and degeneration in joints, and regenerative approaches that may modify the natural course of the disease are limited. SVF may modulate inflammation and initiate regeneration in joint tissues by initiating a paracrine effect. Chemokines released from SVF may slow down degeneration and stimulate regeneration in joints. In this review, we overviewed articular joint cartilage structures and functions, OA, and macro-, micro-, and nano-fat isolation techniques. Mechanic and enzymatic SVF processing techniques were summarized. Clinical outcomes of adipose tissue derived tissue SVF (AD-tSVF) were evaluated. Medical devices that can mechanically isolate AD-tSVF were listed, and publications referring to such devices were summarized. Recent review manuscripts were also systematically evaluated and included. Transferring adipose tissues and cells has its roots in plastic, reconstructive, and aesthetic surgery. Micro- and nano-fat is also transferred to other organs and tissues to stimulate regeneration as it contains regenerative cells. Minimal manipulation of the adipose tissue is recently preferred to isolate the regenerative cells without disrupting them from their natural environment. The number of patients in the follow-up studies are recently increasing. The duration of follow up is also increasing with favorable outcomes from the short- to mid-term. There are however variations for mean age and the severity of knee OA patients between studies. Positive outcomes are related to the higher number of cells in the AD-tSVF. Repetition of injections and concomitant treatments such as combining the AD-tSVF with platelet rich plasma or hyaluronan are not solidified. Good results were obtained when combined with arthroscopic debridement and micro- or nano-fracture techniques for small-sized cartilage defects. The optimum pressure applied to the tissues and cells during filtration and purification of the AD-tSVF is not specified yet. Quantitative monitoring of articular joint cartilage regeneration by ultrasound, MR, and synovial fluid analysis as well as with second-look arthroscopy could improve our current knowledge on AD-tSVF treatment in knee OA. AD-tSVF isolation techniques and technologies have the potential to improve knee OA treatment. The duration of centrifugation, filtration, washing, and purification should however be standardized. Using gravity-only for isolation and filtration could be a reasonable approach to avoid possible complications of other methodologies.