Avoiding a Systematic Error in Assessing Fat Graft Survival in the Breast with Repeated Magnetic Resonance Imaging

Fat Grafting With Expanded Adipose-Derived Stromal Cells for Breast Augmentation: A Randomized Controlled Trial

BACKGROUND

The main challenge with fat grafting is loss of some of the graft to postsurgery resorption. Previous studies suggest that adipose-derived stromal cells (ASCs) can improve the volume retention of fat grafts but there is a lack of randomized trials to support the use of ASCs in clinical practice.

OBJECTIVES

This trial aimed to investigate whether ASCs improve fat graft volume retention in patients undergoing breast augmentation with lipofilling.

METHODS

This was a double-blind, randomized controlled trial of breast augmentation with ASC-enriched fat grafting. Healthy women aged 30 to 45 years were enrolled. First, the participants underwent liposuction to obtain fat for culture expansion of ASCs. Then, the participants were randomly assigned to undergo a 300- to 350-mL breast augmentation with ASC-enriched fat grafting (10 × 106 ASCs/mL fat graft) to 1 of their breasts and placebo-enriched fat grafting of identical volume to the contralateral breast. The primary outcome was fat graft volume retention after a 1-year follow-up measured with MRI. The trial is registered at www.clinicaltrialsregister.eu (EudraCT-2014-000510-59).

RESULTS

Ten participants were included in the trial; all completed the treatment and follow-up. No serious adverse events occurred. Fat graft volume retention after 1 year was 54.0% (95% CI, 30.4%-77.6%) in the breasts treated with ASC-enriched fat grafting (n = 10) and 55.9% (95% CI, 28.9%-82.9%) in the contralateral breasts treated with placebo-enriched fat grafting (n = 10) (P = 0.566).

CONCLUSIONS

The findings of this trial do not support that ASC-enriched fat grafting is superior to standard fat grafting for breast augmentation.

LEVEL OF EVIDENCE: 2

Review of Quantitative Imaging for Objective Assessment of Fat Grafting Outcomes in Breast Surgery

This article presents a comprehensive review of the use of quantitative measurements based on breast images to assess fat retention, breast aesthetics, and fat necrosis after autologous fat grafting. Breast volume measured from MRI and 3-dimensional surface images is widely used as a measure of fat retention. Breast aesthetics are assessed from a combination of anthropometric (distance and contour) measurements on breast surface images. Examination of radiologic images (ultrasonography, mammography, and MRI) is utilized to assess fat necrosis. The article discusses implementation guidelines for objective outcome assessment to support robust quantification and enable investigations of fat grafting efficacy. Level of Evidence: 4.

New Validated Method for Measuring Fat Graft Retention in the Breast with MRI

In this study, we present a new method for measuring fat graft volume retention in the breast based on magnetic resonance imaging scans and a validation study to assess its accuracy and precision. The method was validated by 4 observers using the magnetic resonance imaging scans of 14 patients undergoing breast augmentation with fat grafting. The method was translated into software and was used to measure the change in breast volume from a preoperative scan to a postoperative scan recorded within 3 hours after the surgery, which was compared with the injected fat graft volume. The new method measured the injected fat graft volumes with an average systematic overestimation of 6.3% (SD, 10.5). The median interobserver variation was <7%. We propose that this new method can be a good alternative to previous techniques for clinical research purposes. The software can be made available upon request free of charge for use on the MeVisLab platform.

[Long-term evaluation after autologous fat transplantation for breast augmentation]

Background The transplantation of autologous fat is an increasingly common but not standardized procedure in aesthetic and reconstructive surgery. Until now only studies about the short-term results after transplantation with autologous fat have been published. In this publication we present our results of a long-term study after fat transplantation.Patients/Material and Methods 14 patients underwent an MRI investigation which was done before and 5-9 years (mean 6 years) years after aesthetic breast lipofilling according to BEAULI-protocol. The difference in volume was calculated with the open source software OsiriX. Two groups were analyzed separately to calculate the influence of body weight changes in final volume gain. In the first group patients with a stable BMI (increase of less than 1 kg/m²⁾ were included. The second group includes patients with a BMI gain exceeding more than 1 kg/m². The mean increase in BMI was 1,6 kg/m² (minimum 0 - maximum 3,9). None of the patients lost weight.Results Depending on the desired amount of breast augmentation the patients underwent between one to four operations. An average of 176 ml fat was transplanted per breast and surgery. In the first group a mean volume survival of 74 % (IQR 58 % - 92 %) was observed. In the second group an increase of 135 % (IQR 105 % - 318 %) of the volume of transplanted fat was observed. After an intermediate weight loss one of the patients regained her initial weight.Conclusion In this study the transplantation of autologous fat renders good long-term results. There is a significant correlation between change of weight and fat transplant volume survival over the years. This also explains the very high increase in breast volume in some patients. Autologous fat transplantation seems to be a safe and efficient method for breast augmentation. For further statements studies with larger number of cases are necessary.

Complications after Breast Augmentation with Fat Grafting: A Systematic Review

BACKGROUND

Breast augmentation with fat grafting is used as an alternative to breast implants. However, a systematic evaluation of the complication rates after fat grafting using only studies with consecutive patients has not previously been performed. In this study, the authors compiled studies reporting complication rates and radiologic changes in consecutive patients undergoing cosmetic breast augmentation with fat grafting.

METHODS

Studies reporting on consecutive patients undergoing breast augmentation with fat grafting were included. Complication rates, radiologic changes, Breast Imaging Reporting and Data System assessments, and the number of patients undergoing revision surgery were extracted. Mean complication rates and radiologic changes were calculated with meta-analytical methods.

RESULTS

Twenty-two studies with 2073 patients were included. The rates of major complications were low (hematoma, 0.5 percent; infection, 0.6 percent; and seroma, 0.1 percent). None of these patients needed revision surgery. The most frequent minor complication was palpable cysts in 2.0 percent of the patients; 67 percent of these were treated with aspiration. The radiologic changes in the patients after fat grafting were as follows: oil cysts, 6.5 percent; calcifications, 4.5 percent; and fat necrosis, 1.2 percent. The risk of being referred for additional radiologic imaging (e.g., to exclude malignant changes) was 16.4 percent, and the risk of being referred for biopsy was 3.2 percent.

CONCLUSIONS

The complication rates after breast augmentation with fat grafting are low and support fat grafting as an alternative to breast augmentation with implants. The rates of radiologic changes are high after fat grafting, but the changes do not seem to have any therapeutic consequences for the patients.

Methods used for evaluation of volume retention rate in autologous fat grafting for breast augmentation: a systematic review

BACKGROUND

Autologous fat grafting has gained popularity in breast augmentation. Various methods can be used to estimate the volume retention rate. This systematic review aimed to establish whether the type of method used for measuring breast volume is a factor that influences the reported volume retention rate.

METHODS

Studies were identified using the electronic databases PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science from inception of the database up to February 2019. Articles describing autologous fat grafting for breast augmentation were selected based on pre-determined inclusion and exclusion criteria. The characteristics of the included studies were summarized, and the reported volume retention rate from the studies was compared. A quality assessment of all included articles was performed using the methodological index for non-randomized studies criteria.

RESULTS

A total of 618 articles were identified, of which 12 studies, with a total of 1337 cases, were eligible. The retention rate of injected adipose tissue varied when the method of fat grafting and volume analysis used were both the same, as well as when the method of fat grafting was the same but the method of volumetric evaluation used was different.

CONCLUSIONS

Currently, the tools available for estimating the volume retention rate come with limitations. In order to objectively evaluate the percentage of graft retention, a standard protocol that applies to the different methods should be established in the future.

Identification of the Optimal Recipient Layer for Transplanted Fat: A Prospective Study on Breast Lipoaugmentation

BACKGROUND

Fat grafting has become a popular procedure in aesthetic and reconstructive surgeries due to its safety, minimal invasiveness, and favorable visual outcomes, although the volume retention rate is unpredictable.

OBJECTIVES

A prospective clinical study on lipoaugmentation of the breast was conducted to compare fat retention rates in the pectoralis muscle and the periglandular area.

METHODS

This prospective study included 20 breasts from 11 patients who underwent primary lipoaugmentation. Volume retention rate and percentage augmentation among different recipient layers, as well as complications and patient satisfaction, were evaluated. Magnetic resonance imaging was performed preoperatively and at 1 day and 3 months postoperatively. Complications were recorded, and patient satisfaction was appraised through the use of the Breast-Q questionnaire.

RESULTS

Breasts were injected with 207 ± 29 mL of fat, achieving overall volume retention rates of 56.63% ± 16.40%. The overall augmentation was 21.53% ± 10.27%. Volume retention rate was significantly higher (59.00% ± 13.84%) in the periglandular area than in the pectoralis muscle (47.21% ± 22.41%) (P = 0.04). Augmentation was significantly higher (32.13% ± 12.96%) in the periglandular area than in the pectoralis muscle (4.95% ± 4.23%) (P = 0.00). Pain and numbness were the only reported complications. The Breast-Q score increased significantly for the measures "satisfaction with breasts," "psychosocial well-being," and "sexual well-being."

CONCLUSIONS

Fat transfer is a safe and acceptable method for aesthetic and reconstructive breast surgery. The periglandular area was a better recipient site than muscle for transferred fat.

LEVEL OF EVIDENCE: 4

The current gold standard breast volumetry technique seems to overestimate fat graft volume retention in the breast: A validation study

BACKGROUND

MRI is generally considered as the gold standard for measuring breast volume because of its high accuracy of the modality. Many techniques used to measure total breast volume have been validated, but none of these techniques have been validated for their ability to measure the volume retention of fat grafts in the breast. In this study, the authors investigated the accuracy of the most common MRI technique used to measure fat graft retention in the breast by measuring the volume changes after breast augmentation.

METHODS

Patients undergoing breast augmentation with either breast implants or fat grafting underwent MRI scans before and after surgery. Blinded observers measured the change in breast volume from the MRI scans. The difference between the measured change in breast volume and the volume of the breast augmentation was used to determine the accuracy of the MRI technique.

RESULTS

Twenty-eight patients with a total of 56 breasts were included. In total, 168 measurements of change in breast volume were performed by the observers. The MRI measurements of change in breast volume overestimated the true volumes of the breast augmentations by an average of 50.8%, and only 8 of the 168 individual measurements had measurement errors below 50 mL.

CONCLUSION

The MRI technique, which is considered as the gold standard for the quantification of fat graft volume retention, was associated with a significant measurement error. These findings have potential implications for the interpretation of previously published results of studies based on this technique.

Evaluation of Retropectoral Fat Grafting in Breast Reduction by Magnetic Resonance Imaging: A Pilot Study

BACKGROUND

One of the challenges in breast reduction is to maintain breast projection with 45% of its volume in the upper pole and 55% in the lower pole. Although widely used in breast surgeries, the behavior of fat grafts is still not completely understood.

OBJECTIVES

To evaluate by magnetic resonance imaging (MRI) the survival of fat transferred to the retropectoral plane in patients undergoing breast reduction, in the search for an oncologically safe procedure with high predictability and reproducibility.

METHODS

This pilot study was conducted with 7 patients who underwent breast reduction combined with fat grafting in the submuscular plane. Aspirated fat was processed by sedimentation. MRI of the breasts was performed preoperatively and at 1 and 6 months postoperatively. Fat survival was calculated as the difference between the volumes of fat measured preoperatively and postoperatively by MRI divided by the volume of grafted fat.

RESULTS

Fourteen breasts were operated on and received on average 119.6 mL of autologous fat in the submuscular plane. Fat survival rate was 43.9% at 1 month after surgery, decreasing to 23.4% in the late postoperative period. The mean anteroposterior projection of the grafted tissue was 1.51 cm at 1 month postoperatively, decreasing to 1.07 cm in the late postoperative period.

CONCLUSIONS

Retropectoral fat grafting may contribute to maintaining the fullness of the upper pole of the breasts. This is an innovative experimental model for future studies on fat harvesting, preparation, and grafting techniques, allowing the evaluation of fat graft survival.

LEVEL OF EVIDENCE: 4

Efficacy of breast reconstruction with fat grafting: A systematic review and meta-analysis

BACKGROUND

Breast reconstruction with fat grafting is a new alternative to prosthetic implants and flaps for women with breast cancer. In this study, we investigate the efficacy of fat grafting for breast reconstruction in a meta-analysis.

METHODS

The study followed the PRISMA and MOOSE guidelines for systematic reviews and meta-analyses. Studies were included if the patients underwent complete breast reconstruction with fat grafting as the only treatment modality. The number of fat grafting treatments needed to complete a breast reconstruction was modeled in a meta-analysis for five treatment categories: modified radical mastectomy, skin-sparing mastectomy, and breast-conserving surgery; the two mastectomy groups were subdivided into nonirradiated and irradiated.

RESULTS

Twenty-one studies were included in the meta-analysis. The studies comprised 1011 breast reconstructions in 834 patients. The estimated numbers of treatments to complete a reconstruction were 2.84-4.66 in the mastectomy groups and 1.72 in the breast-conserving surgery group. The number of fat grafting sessions needed to complete a breast reconstruction was significantly higher for the irradiated patients than for the nonirradiated patients (p < 0.05). There was no significant difference in the number of fat grafting sessions needed to complete a breast reconstruction after a modified radical mastectomy versus a skin-sparing mastectomy.

CONCLUSIONS

This study provides an evidence-based foundation for several practical issues related to breast reconstruction with fat grafting. The analysis showed that radiotherapy is the most important factor associated with the number of treatment sessions needed to complete a breast reconstruction and with the rate of complications.

A Novel Porcine Model for Future Studies of Cell-enriched Fat Grafting

Supplemental Digital Content is available in the text.

Background:

Cell-enriched fat grafting has shown promising results for improving graft survival, although many questions remain unanswered. A large animal model is crucial for bridging the gap between rodent studies and human trials. We present a step-by-step approach in using the Göttingen minipig as a model for future studies of cell-enriched large volume fat grafting.

Methods:

Fat grafting was performed as bolus injections and structural fat grafting. Graft retention was assessed by magnetic resonance imaging after 120 days. The stromal vascular fraction (SVF) was isolated from excised fat and liposuctioned fat from different anatomical sites and analyzed. Porcine adipose-derived stem/stromal cells (ASCs) were cultured in different growth supplements, and population doubling time, maximum cell yield, expression of surface markers, and differentiation potential were investigated.

Results:

Structural fat grafting in the breast and subcutaneous bolus grafting in the abdomen revealed average graft retention of 53.55% and 15.28%, respectively, which are similar to human reports. Liposuction yielded fewer SVF cells than fat excision, and abdominal fat had the most SVF cells/g fat with SVF yields similar to humans. Additionally, we demonstrated that porcine ASCs can be readily isolated and expanded in culture in allogeneic porcine platelet lysate and fetal bovine serum and that the use of 10% porcine platelet lysate or 20% fetal bovine serum resulted in population doubling time, maximum cell yield, surface marker profile, and trilineage differentiation that were comparable with humans.

Conclusions:

The Göttingen minipig is a feasible and cost-effective, large animal model for future translational studies of cell-enriched fat grafting.

Systematic review of patient factors affecting adipose stem cell viability and function: implications for regenerative therapy

BACKGROUND

The applications for fat grafting have increased recently, within both regenerative and reconstructive surgery. Although fat harvesting, processing and injection techniques have been extensively studied and standardised, this has not had a big impact on the variability of outcome following fat grafting. This suggests a possible larger role of patient characteristics on adipocyte and adipose-derived stem cell (ADSC) viability and function. This systematic review aims to collate current evidence on the effect of patient factors on adipocyte and ADSC behaviour.

METHODS

A systematic literature review was performed using MEDLINE, Cochrane Library and EMBASE. It includes outcomes observed in in vitro analyses, in vivo animal studies and clinical studies. Data from basic science work have been included in the discussion to enhance our understanding of the mechanism behind ADSC behaviour.

RESULTS

A total of 41 papers were included in this review. Accumulating evidence indicates decreased proliferation and differentiation potential of ADSCs with increasing age, body mass index, diabetes mellitus and exposure to radiotherapy and Tamoxifen, although this was not uniformly seen across all studies. Gender, donor site preference, HIV status and chemotherapy did not show a significant influence on fat retention. Circulating oestrogen levels have been shown to support both adipocyte function and graft viability. Evidence so far suggests no significant impact of total cholesterol, hypertension, renal disease, physical exercise and peripheral vascular disease on ADSC yield.

CONCLUSIONS

A more uniform comparison of all factors highlighted in this review, with the application of a combination of tests for each outcome measure, is essential to fully understand factors that affect adipocyte and ADSC viability, as well as functionality. As these patient factors interact, future studies looking at adipocyte viability need to take them into consideration for conclusions to be meaningful. This would provide crucial information for surgeons when deciding appropriate volumes of lipoaspirate to inject, improve patient selection, and counsel patient expectations with regards to outcomes and likelihood for repeat procedures. An improved understanding will also assist in identification of patient groups that would benefit from graft enrichment and cryopreservation techniques.