http://aes.sagepub.com/Aesthetic Surgery Journal

http://aes.sagepub.com/content/34/3/438The online version of this article can be found at:

DOI: 10.1177/1090820X14524416

2014 34: 438Aesthetic Surgery JournalConnor

Heather Ansorge, Jaime R. Garza, Michael C. McCormack, Patrick Leamy, Sana Roesch, Aaron Barere and Jeromean Animal Model

Autologous Fat Processing Via the Revolve System: Quality and Quantity of Fat Retention Evaluated in

Published by:

http://www.sagepublications.com

On behalf of:

American Society for Aesthetic Plastic Surgery

can be found at:Aesthetic Surgery JournalAdditional services and information for

http://aes.sagepub.com/cgi/alertsEmail Alerts:

http://aes.sagepub.com/subscriptionsSubscriptions:

http://www.sagepub.com/journalsReprints.navReprints:

http://www.sagepub.com/journalsPermissions.navPermissions:

What is This?

- Mar 27, 2014Version of Record >>

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

Aesthetic Surgery Journal2014, Vol. 34(3) 438 –447© 2014 The American Society for Aesthetic Plastic Surgery, Inc.Reprints and permission: http://www .sagepub.com/journalsPermissions.navDOI: 10.1177/1090820X14524416www.aestheticsurgeryjournal.com

Research

The use of soft tissue fillers to treat volume and contour defects is among the fastest growing, minimally invasive cosmetic procedures in the United States.1 In particular, the application of autologous adipose tissue as soft tissue filler is gaining popularity; more than 71,000 procedures were performed in 2012.1 Fat is an attractive filler because it is biocompatible, abundantly available, and easily harvested. Adipose tissue for fat grafting has been used for various indications, including facial rejuvenation,2 facial lipodys-trophy,3,4 hand rejuvenation,5,6 lower limb augmentation/atrophy,7,8 buttock aesthetic augmentation,9,10 and aes-thetic or reconstructive breast surgery.11,12 Despite its

524416AESXXX10.1177/1090820X14524416Aesthetic Surgery JournalAnsorge et alresearch-article2014

Dr Ansorge is a Senior Product Development Engineer, Dr Leamy is a Staff Scientist, Ms Roesch is a Senior Clinical Scientist, Mr Barere is a Director of Product Development, and Dr Connor is a Senior Director from the Department of Research and Development, LifeCell Corporation, Bridgewater, New Jersey. Mr McCormack is an Independent Consultant for LifeCell Corporation, Boston, Massachusetts. Dr Garza is a Clinical Professor of Surgery, Clinical Professor of Otolaryngology, and Assistant Dean, School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, Texas.

Corresponding Author:Dr Jerome Connor, LifeCell Corporation, 95 Corporate Dr, Bridgewater, NJ 08807, USA. E-mail: jconnor@lifecell.com

Autologous Fat Processing Via the Revolve System: Quality and Quantity of Fat Retention Evaluated in an Animal Model

Heather Ansorge, PhD; Jaime R. Garza, MD, DDS; Michael C. McCormack, MBA; Patrick Leamy, PhD; Sana Roesch, BS; Aaron Barere, BS; and Jerome Connor, PhD

AbstractBackground: Currently, fat graft viability and retention cannot be reliably predicted. The reasons for this variability are not fully understood, although fat processing has been implicated.Objectives: The authors compare the in vitro quantity and in vivo fat retention from lipoaspirate processed by the Revolve system (LifeCell, Bridgewater, New Jersey) compared with centrifugation and decantation.Methods: Ten patients were enrolled in this prospective study. Lipoaspirate from each patient was processed by each of 3 methods: decantation, centrifugation, and the Revolve system. Biochemical characteristics and free oil, adipose, and aqueous phases of the processed fats were determined. Fat grafts were implanted in nude mice; volume retention and quality of the fat grafts were evaluated after 28 days. Viability of retained fat was demonstrated by intact adipocytes and neovascularization on histology.Results: Of the 10 patients, 9 were women and 1 was a man. Mean patient age was 40.7 ± 8.9 years (range, 30-55 years). Fat tissue obtained from all methods had good physiological properties with neutral pH and isotonic salt concentrations. The Revolve system yielded significantly less blood cell debris, a higher percentage of adipose tissue, and a lower percentage of free oil compared with the other 2 methods. Fat tissue retention from Revolve samples was significantly higher (73.2%) than that from decanted samples (37.5%) and similar to that from centrifuged samples (67.7%).Conclusions: The Revolve system produced physiologically compatible, preinjection fat with reduced contaminants and free oil in conjunction with high fat content. In an animal model, volume retention of Revolve-processed fat grafts was significantly greater than decanted samples. The Revolve system presents a fat-processing option that was less time-consuming, easier to use, and more efficient in this study than standard centrifugation or decantation.

Keywordsautologous fat processing, Revolve system, fat retention, animal model, fat graft viability, lipoaspiration, adipose tissue, centrifugation, decantation

Accepted for publication August 28, 2013.

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

Ansorge et al 439

popularity and clinical applications, fat grafting is not without problems. This procedure’s highly variable out-comes present a significant concern. Poor fat graft reten-tion affects clinical outcomes, sometimes requiring additional grafting procedures to achieve optimal results.2,11 At present, fat graft viability and retention cannot be reli-ably predicted, and reasons for the variability are not fully understood; however, fat processing methodology has been implicated as a possible cause.13,14

Various fat-processing techniques range from simple decantation15 to centrifugation,16-18 washing with physio-logic solutions,19 and filtration with a dense cloth or a com-mon strainer.20,21 However, centrifugation is generally considered the standard fat-processing method.22 Recently, a new fat-processing system, Revolve (LifeCell, Bridgewater, New Jersey), has been developed. Revolve incorporates the harvesting, filtering, and washing steps into a single unit, thus simplifying fat processing. The purpose of this study was to compare quantity and quality of processed fat obtained via the Revolve system with samples from cen-trifugation and decantation methods and to analyze fat retention after implantation in an animal model.

METHODS

Study SubjectsTen subjects voluntarily consented to elective abdominal liposuction surgery. Individuals who were smokers or who had a body mass index (BMI) >35 kg/m2, history of bleeding disorder, human immunodeficiency virus (HIV), diabetes, or lipoatrophy disorders were excluded from the study. The local Institutional Review Board at Renew in San Antonio, Texas, approved this study under protocol number LCELL_120328. Figure 1 displays the study design.

Autologous Fat HarvestingLiposuction was performed by a single surgeon (J.R.G.) using a standard procedure. The liposuction site was pre-pared with 1% xylocaine with 1:100 000 epinephrine solu-tion. A standard tumescent fluid was used that included Lactated Ringer’s solution, 50 mg of 1% lidocaine, and 1 mL of 1:1000 epinephrine. The VentX aspiration system (Solta, Hayward, California) was applied with a 3.2-mm cannula, with approximately ½ atmosphere of negative pressure. Lipoaspirate was obtained from contralateral sides of the abdomen; half was collected directly into the Revolve sys-tem and the other half into a sterile canister for processing by decantation and centrifugation methods. Lipoaspirate from each patient was processed by each of the 3 methods: decantation, centrifugation, and the Revolve system.

Decantation MethodIn total, 500 mL of lipoaspirate collected into the decanta-tion container (Fluid Management System; Medela, McHenry, Illinois) was allowed to settle for 10 minutes, resulting in lipoaspirate separation into an aqueous phase, a fat phase, and a free oil phase. The aqueous phase was drained from the bottom and discarded. The retained fat sample represented the decantation arm of the study.

Centrifugation MethodA portion of the fat phase obtained from the decantation method was transferred into 20-mL syringes and centri-fuged at 1200 g for 3 minutes (Thermo Scientific Medilite centrifuge; Thermo Fisher Scientific, Waltham, Massachusetts). The resulting lower aqueous phase was expressed, the upper oil phase was wicked away, and the middle fat phase was retained. This retained fat sample represented the centrifugation arm of the study.

Revolve SystemRevolve is an inline fat-processing system in which lipoaspirate is harvested directly into the device (Figure 2). The Revolve device consists of an outer canister and an inner filter basket (200-µm pores) that allows fat to be sep-arated from the tumescent fluid immediately. Once at least 300 mL of fat was collected in the inner filter, 400 mL of Lactated Ringer’s solution at 37°C was added, and the fat was washed for 15 ± 5 seconds. The Revolve device con-tains rotating paddles within the filter basket, which gently agitated the tissue and ensured the fat was thoroughly washed. The fluid was then vacuum-aspirated for 60 ± 5 seconds. The wash was repeated a total of 3 times. Following the final wash, the fat sample was aspirated through the collection port into syringes for in vitro and in vivo analyses. Total processing time for the Revolve system was approximately 10 minutes. The fat sample collected in syringes represented the Revolve arm of the study.

Figure 1. Flowchart of study design. Lipoaspirate was obtained from 10 patients (9 women and 1 man, ranging in age from 30-55 years old) and subjected to 3 parallel processing procedures. As described in the Methods section, the processed fat tissue was analyzed for quality by both in vitro and in vivo techniques.

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

440 Aesthetic Surgery Journal 34(3)

In Vitro AssessmentsApproximately 30 mL of processed fat from each method was reserved for in vitro assessments. For the animal stud-ies, twelve 3-mL syringes were loaded with 1 mL fat from each processing method for implantation into nude mice. Immediately after processing, composition and physiologi-cal quality of fat from the 3 methods were assessed. For quantitative assessments of the fat graft’s composition, sam-ples were centrifuged at 5000 g for 5 minutes to separate the aqueous, fat, and free oil phases. A centrifugation speed of 5000 g was chosen to separate the fat graft phases for in vitro assessment only, not for grafting. The volume of the 3 phases was measured, and composition of fat from the 3 processing methods was compared. The aqueous phase was retained for pH, osmolality, and hematocrit assays.

The pH was determined using a standard pH meter; pH test strips were used when insufficient aqueous phase was available. Osmolality was measured in triplicate from the aqueous phase of the fat samples with a Wescor osmome-ter (Vapro 5520; ELItech Group, Princeton, New Jersey).

Hematocrit was measured in triplicate by enzyme-linked immunosorbent assay according to manufacturer instructions (Bethyl E80-135; Bethyl Laboratories, Montgomery, Texas).

In Vivo AssessmentsAll animal procedures were performed in compliance with Institutional Animal Care and Use Committee protocols at

the University of Texas at San Antonio. Nude mice (5-6 weeks old) were implanted with 1-mL fat grafts as a single bolus. The fat bolus was injected subcutaneously into the flanks using a 14-gauge angiocatheter and a 3-mL syringe, as described previously.23 The nude mouse model was developed to model fat graft retention and health but is not intended to model clinical fat grafting techniques. In this study, percent retention of fat grafts was calculated from the weight of each graft at injection and at explant. The weight of each fat graft injected was determined by weigh-ing syringes on a scale, pre- and postinjection, and sub-tracting the difference. Each tissue donor (cohort) was paired across the 3 processing methods. Fat from each pro-cessing arm was implanted into 8 animals for a total of 24 animals per cohort. Thus, the 10-subject study scheme yielded a total of 240 mice. A prior power analysis per-formed on pilot data using a power of 80% and an α of 0.1% determined that a sample size of 8 mice per group per patient was the minimal sample size necessary to detect a 5% difference across groups.

Mice were euthanized at 28 days postimplantation, and the fat grafts were excised and weighed. Percent fat reten-tion was calculated by comparing final graft weight with the weight of implanted fat grafts. Gross observations were made on both intact and bisected fat grafts.

Histology samples of fat grafts were taken of both pre-implanted fat and 28 days after implantation. Samples were processed via standard histological procedures and stained with hematoxylin and eosin. Histological samples were evaluated by 3 experts (M.C.M. and 2 external histo-pathologists associated with CRO [InCell, San Antonio, Texas]), with slides randomized, blinded, and rated accord-ing to the relative presence or absence of cysts/vacuoles, fibrosis, and inflammation as evidenced by infiltration of lymphocytes and macrophages. After initial grading, slides were sorted into experimental groups (group identity was blinded), and the experts made a subjective determination of the fat quality of each group.

Statistical AnalysisThe average and standard deviation was calculated for all quantitative measures. Relative standard deviation of per-cent fat retention was calculated (mean/standard devia-tion) to assess predictability in all test arms. A 1-way analysis of variance (ANOVA) test across groups was con-ducted with α set at 0.05.

RESULTS

SubjectsNine women and 1 man, all between ages 30 and 55 years (mean, 40.7 ± 8.9 years) and with a BMI of 21 to 33 kg/m2,

Figure 2. The Revolve fat processing system. Figure reprinted with permission from LifeCell Corporation (Bridgewater, New Jersey).

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

Ansorge et al 441

participated in this study. While 11 patients consented to participate, 1 was excluded due to a scheduling conflict. Individuals who were smokers or who had a BMI >35 kg/m2, history of bleeding disorder, human immunodeficiency virus (HIV), diabetes, or lipoatrophy disorders were excluded from the study. Patients were not tracked for any outcomes related to this study but received standard follow-up care.

In Vitro AssessmentsGross ObservationsFat processed by the 3 methods was examined grossly prior to implantation to determine the tissue’s overall quality. Figure 3 displays representative fat tissue processed by the 3 methods. Compared with the decantation and centrifuga-tion processing methods, fat obtained via the Revolve sys-tem was visibly whiter and more compact. Quantitative

assessment of fat tissue components demonstrated statisti-cally significant different amounts among the 3 methods (Figure 4). Fat from the Revolve system contained little free oils (0 ± 1%), while fat from the decantation and centrifu-gation methods had statistically higher (P < .05) amounts of free oils (8% ± 5% and 20% ± 4%, respectively). Furthermore, fat from the Revolve system had statistically higher (P < .05) adipose tissue content (79% ± 7% vs 59% ± 8% for decantation and 72% ± 4% for centrifuga-tion). In contrast, fat from centrifugation had statistically lower (P < .05) aqueous content (8% ± 3% vs 33 ± 7% for decantation and 21 ± 7% for the Revolve system).

Aqueous Phase CharacterizationThe aqueous phase from the preimplant fat samples was collected and measured for markers of physiological qual-ity—specifically, pH, osmolality, and hematocrit. Fat obtained from the Revolve system had a statistically lower (P < .05) pH compared with fat from decantation and cen-trifugation. Fat pH from the Revolve system was 6.9, while that from the other 2 processing methods was 7.3. It should be noted that the Lactate Ringer’s wash solution has a pH of 6.8. Fat obtained from the Revolve system had a statisti-cally lower (P < .05) hematocrit compared with decanta-tion and centrifugation. The hematocrit of fat from the Revolve system was 0.02% ± 0.01%, while that from the decantation and centrifugation methods was 0.47% ± 0.38% and 0.42% ± 0.31, respectively. The 3 methods showed no difference in fat osmolality. Osmolalities of 242 ± 31, 249 ± 23, and 259 ± 18 mmol/kg for the Revolve, centrifugation, and decantation methods, respectively, are all considered iso-osmotic and represent physiologic

Figure 3. Representative samples of fat tissue processed by each of the 3 methods: (A) Revolve method, (B) centrifugation method, and (C) decantation method. After processing, the grafts were placed into 3-mL syringes for implantation into nude mice.

Figure 4. Composition of processed fat tissue. The lipoaspirated fat tissue was processed by all 3 methods; afterward, as described in the Methods section, the percent volume fraction of major fat components was measured (red = aqueous phase; blue = adipose phase; yellow = oil phase; n = 9 for all groups). *P < .05.

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

442 Aesthetic Surgery Journal 34(3)

osmolality. (Table 1 outlines the biochemical results of the processes.)

In Vivo AssessmentGross ObservationsTwo mice were euthanized early due to complications unrelated to the study. All other animals tolerated the pro-cedure and remained healthy postimplantation up to euth-anization at day 28. At the time of fat excision, fat boluses from both the Revolve system and centrifugation method were observed to be yellow and of normal appearance with visible surface vascularization; there was no gross evi-dence of encapsulation or adverse immunological response. Excised fat boluses from the decanted group displayed similar gross observations, but on bisection of the fat grafts, large oil cysts were observed as pooled free oil (Figure 5).

Fat RetentionPercent fat retention following the 28-day implantation was calculated from the pre- and postinjection fat weights. Percent fat retention with the Revolve system was not sta-tistically different from centrifugation, at 73.2% ± 14.7% (n = 79) and 67.7% ± 16.9% (n = 80), respectively (Figure 6). In contrast, fat retention was statistically lower (P < .05) with the decantation method at 37.5% ± 13.3% (n = 77) compared with both other methods. The relative standard deviation of percent fat retention was similar between the Revolve system (20%) and the centrifugation method (25%) but higher with the decantation method (35%). Although relative standard deviation cannot be compared statistically across groups, the difference indi-cates that both the Revolve system and centrifugation method provide more reliable and reproducible fat graft retention compared with the decantation method.

Histological AssessmentExplanted fat graft histology was reviewed by 3 experts in fat physiology (M.C.M. and 2 external histopathologists

associated with CRO [InCell]) and scored for attributes critical for fat tissue viability. Figure 7 displays representa-tive images from the 3 processing systems. Overall, the 3 methods yielded histologically similar fat grafts; a com-parison of histological scoring values from the 3 systems yielded no major difference in histological characteristics (data not shown). Histologically, fat grafts from all sam-ples demonstrated areas of healthy vascularized fat tissue, along with some areas of mild fibrosis and inflammation.

DISCUSSIONAutologous fat grafting for soft tissue augmentation is a common procedure in plastic surgery. A major obstacle reducing this procedure’s clinical efficacy is loss of graft volume over time.13,24 Volume loss arises as a result of fat necrosis and resorption; causes include donor site variabil-ity, aspiration technique, fat-processing method, and injection techniques.24 Currently, the 2 most common fat-processing methods are decantation and centrifugation. The literature shows that in the clinic, these methods yield fat retention rates ranging from 20% to 90%.13 This study compares fat graft quality (pre- and postinjection) and volume retention in 3 fat processing methods—decantation, centrifugation, and the Revolve system—in an established preclinical model.

Our study demonstrated that the Revolve system yields clean adipose tissue with a higher preimplant fat content than the standard of care centrifugation method. Several features make the Revolve system unique from other fat-processing methods. First, the internal filter basket collects fat during liposuction and allows unwanted tumescent fluid to be immediately removed. Second, the fat is washed with Lactated Ringer’s solution, which maintains the cells under physiologic conditions and could optimize cell via-bility. Third, protein material (collagen strands), inadver-tently harvested as a result of cannula motion during lipoaspiration, is subsequently isolated on the Revolve unit’s internal paddles during the washing phase. This is a benefit because protein strands can clog the syringe needle during grafting. Last, the Revolve system is designed to process large fat volumes in less than 10 minutes, decreas-ing operative time required for fat grafting procedures.

The underlying principle of fat processing is to eliminate contaminants—such as tumescent fluid, blood, cell frag-ments, and free oil—and to retain viable adipocytes.24 Contaminants in grafts are believed to induce an inflamma-tory response, leading to diminished fat retention.25 Keeping adipocytes in a physiologic state and away from contami-nants is thought to contribute to the fat graft’s health. The Revolve system maintains physiologic conditions for adipo-cytes by immediately removing unwanted components (tumescent fluid, cell debris, blood, free oils) during lipo-suction. The significantly reduced hematocrit serves as a

Table 1. Biochemical Characterization of Processed Fat Tissue

Biochemical Characterization of Processed Fat Tissue, Mean ± Standard Deviation

Processing Method pH Osmolality Hematocrit

Revolve 6.9 ± 0.1a 242 ± 31 0.02 ± 0.01a

Centrifugation 7.3 ± 0.2 249 ± 23 0.42 ± 0.31

Decantation 7.3 ± 0.2 259 ± 18 0.47 ± 0.38

Fat tissue samples were obtained immediately postprocessing by the 3 methods. As described in the Methods section, samples were analyzed for retention of aqueous phase physiological properties, as well as presence of red cell debris (n = 10 for each arm).aP < .05.

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

Ansorge et al 443

Figure 5. Representative samples of explanted fat grafts. Following 28 days of subcutaneous implantation in nude mice, fat grafts from the 3 processing methods were explanted and photographs were taken for gross assessment: (A, B) Revolve method, intact and bisected explant, respectively; (C, D) decantation method, intact and bisected explant, respectively; and (E, F) centrifugation method, intact and bisected explant, respectively.

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

444 Aesthetic Surgery Journal 34(3)

surrogate marker for other circulating blood cells (platelets and leukocytes), the inclusion of which in an implanted graft could promote an inflammatory response.

Preinjection fat graft quality depends not only on con-taminant removal but also on the injected fat graft’s com-position. A higher fat content could support a more significant retention of injected tissue since the placed vol-ume will represent adipose rather than fluid phase compo-nents that will either dissipate (aqueous phase) or elicit an inflammatory response (free oils). High fat content with a low oil concentration, an optimal combination, was obtained only with the Revolve system, thus indicating that it more effectively cleans adipose tissue than does centrifugation or decantation.

Both the decantation and centrifugation methods have advantages and limitations. The centrifugation method is the most common fat-processing technique, but it can be cumber-some and time-consuming, particularly if higher volumes of fat graft are required.16,18,26 Moreover, as shown in this study, centrifugation is not effective in eliminating free oil and blood contaminants from fat grafts. Alternatively, decanting is a sim-ple method involving minimal steps, but quality of the pro-cessed fat grafts is not optimal, as the graft tissue contains cell remnants and a low adipose content.

In this study, the relative standard deviation (or percent relative standard deviation) of volume retention was calcu-lated as a tool to predict reproducibility of fat graft retention. The relative standard deviation determines the variation from the mean value in relationship to the standard devia-tion. This value indicates outcome reproducibility between samples within each arm of the study. The Revolve system demonstrated a relative standard deviation of 20%, com-pared with 25% and 35% for centrifugation and decanta-tion, respectively. While these values cannot be compared statistically, our study demonstrated that in this model, fat

grafts processed with the Revolve system led to more pre-dictable results than either of the other 2 methods.

Adipose tissue contains stem cells, which are believed to play a role in graft retention.27-29 For stem cells to con-tribute postimplantation, they must retain cell viability during processing of the adipose tissue. The combination of rapidly removed tumescence, introduction of physiologi-cal buffers, and removal of pro-oxidant red cell debris should support good cell viability. Furthermore, stem cells are known to be structurally bound to the intra-adipose matrix30; thus, the Revolve washing process should not remove these cells from the fat graft samples. However, no evaluations were conducted during this study to confirm that stem cells were present in the Revolve fat grafts.

Grossly and histologically, retained fat from the Revolve and centrifugation methods showed minimal differences. Interestingly, while retained fat from the decantation method did not appear visibly different, bisection released significant amounts of free oils from internal oil cysts. Oil cysts in fat grafts indicate poor adipocyte health, possibly contributing to implanted adipocyte apoptosis and result-ing in reduced fat retention. A drawback of our study is that nude mice have limited immunological response; thus, any significant immune cell response to the free oils cannot be determined with this particular animal model.

Histology was carefully assessed in this study, and all 3 methods showed similar results at 1 month postimplant in the nude mouse model. This indicates that retained fat tis-sue evaluated in this model at 28 days was relatively healthy. Note that in this model, fat grafts were injected in a single large bolus, whereas fat grafts are injected clinically in small droplets or strings. Blood supply to a single large bolus is limited and therefore stresses the fat graft’s health more than may be expected in clinical fat grafting. This additional stress is an intentional factor in the single-bolus, small-ani-mal model used in this study. A benefit to this animal model is that the intentional stress on the graft allows inherent dif-ferences in fat quality to be assessed, while these differences may be masked in other animal fat grafting models. The mild fibrosis and inflammation seen across all specimens histologically is typical of the response seen with this model, while the volume retention shows a differential response.

Our end point to evaluate fat retention in this mouse model was 28 days. Previous studies in rodents have set end points ranging from 10 days to 12 weeks.18,22,23,31-33 We chose the 28-day end point in this study because any initial apoptosis or graft necrosis was resolved and only revascu-larized, healthy graft remained. Previous studies have demonstrated that retention differences were consistent at early and late time points.22 While 28 days is not represen-tative of a long-term outcome, the large sample size and paired study design presented in the current study, in con-junction with previous results, lend confidence that differ-ences seen at 28 days would be similar to differences at

Figure 6. Percent of implanted fat retention. As described in the Methods section, following 28 days of subcutaneous implantation in nude mice, fat grafts from the 3 processing methods were explanted and the percentage retention of the implanted fat was measured. *P < .05; n values are provided within each bar.

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

Ansorge et al 445

Figure 7. Representative micrographs of explanted fat grafts. As described in the Methods section, after 28 days of subcutaneous implantation in nude mice, fat grafts from the 3 processing methods were explanted and processed for histology. Histology slides were reviewed to determine the quality of each fat graft: (A, B) Revolve method, display magnification 40× and 100×, respectively; (C, D) decantation method, display magnification 40× and 100×, respectively; (E, F) centrifugation method, display magnification 40× and 100×, respectively.

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

446 Aesthetic Surgery Journal 34(3)

later time points. Future clinical studies should be con-ducted to determine volume retention from standard graft-ing techniques in humans. Moreover, in the clinical setting, where larger volumes of fat undergo processing, the ability to remove blood and oil from adipose tissue may more profoundly affect grafting outcomes.

CONCLUSIONSCompared with the decantation and centrifugation meth-ods of fat processing, the Revolve system produced prein-jection fat grafts of higher quality; this was demonstrated by significantly higher percentages of adipose tissue and significantly less blood cell debris and free oil. The volume retention of fat grafts from the Revolve system in an animal model was similar to centrifugation and significantly greater than fat grafts from the decantation method. The Revolve system presents a fat-processing option that is less time-consuming, easier to use, and more efficient than standard centrifugation or decantation methods.

AcknowledgmentWe thank Dr Mary Pat Moyer and the staff at InCell (San Antonio, Texas) for support in execution of the animal study. InCell executed the study in that they coordinated the acquisi-tion and maintenance of the animals and performed the implantation and harvesting of the samples.

DisclosuresDr Ansorge, Dr Leamy, Ms Roesch, Mr Aaron Barere, and Dr Connor are employees of LifeCell Corporation, the manufac-turer of the products discussed in this study. Mr McCormack is a paid consultant to LifeCell Corporation and received com-pensation for preclinical method development activities and for providing expert analysis of histology related to the study. Dr Garza is a speaker and consultant for LifeCell, in addition to being a consultant for Allergan. Dr Garza holds no stocks in any company in the aesthetic industry.

FundingDr Garza received funding to support the lipoaspiration proce-dure and fat processing, along with operating room costs related to the study. Dr Garza did not receive personal com-pensation for this study. This study was sponsored by LifeCell Corporation. LifeCell Corporation employees who are named authors on this manuscript (Heather Ansorge, Patrick Leamy, Sana Roesch, Aaron Barere, and Jerome Connor) designed the study; collected, analyzed, and interpreted the data; wrote the report; and made the decision to submit the report for publi-cation in conjunction with the other authors.

REFERENCES 1. American Society for Aesthetic Plastic Surgery. Cosmetic

surgery national data bank: statistics 2012. Aesthetic Surg J. 2013;33(2)(suppl):1S-21S.

2. Xie Y, Zheng DN, Li QF, et al. An integrated fat grafting technique for cosmetic facial contouring. J Plast Reconstr Aesthetic Surg. 2010;63:270-276.

3. Serra-Renom JM, Fontdevila J. Treatment of facial fat atrophy related to treatment with protease inhibi-tors by autologous fat injection in patients with human immunodeficiency virus infection. Plast Reconstr Surg. 2004;114:551-555.

4. Hunstad JP, Shifrin DA, Kortesis BG. Successful treat-ment of Parry-Romberg syndrome with autologous fat grafting: 14-year follow-up and review. Ann Plast Surg. 2011;67:423-425.

5. Butterwick KJ. Lipoaugmentation for aging hands: a comparison of the longevity and aesthetic results of centrifuged versus noncentrifuged fat. Dermatol Surg. 2002;28:987-991.

6. Coleman SR. Hand rejuvenation with structural fat graft-ing. Plast Reconstr Surg. 2002;110:1731-1744.

7. Veber M Jr, Mojallal A. Calf augmentation with autologous tissue injection. Plast Reconstr Surg. 2010;125:423-424.

8. Mojallal A, Veber M, Shipkov C, Ghetu N, Foyatier JL, Braye F. Analysis of a series of autologous fat tissue transfer for lower limb atrophies. Ann Plast Surg. 2008;61:537-543.

9. Cárdenas-Camarena L, Arenas-Quintana R, Robles-Cervantes JA. Buttocks fat grafting: 14 years of evolution and experience. Plast Reconstr Surg. 2011;128:545-555.

10. Cardenas Restrepo JC, Muñoz Ahmed JA. Large-volume lipoinjection for gluteal augmentation. Aesthetic Surg J. 2002;22:33-38.

11. Illouz YG, Sterodimas A. Autologous fat transplantation to the breast: a personal technique with 25 years of expe-rience. Aesthetic Plast Surg. 2009;33:706-715.

12. Seth AK, Hirsch EM, Kim JY, Fine NA. Long-term out-comes following fat grafting in prosthetic breast recon-struction: a comparative analysis. Plast Reconstr Surg. 2012;130:984-990.

13. Gir P, Brown SA, Oni G, Kashefi N, Mojallal A, Rohrich RJ. Fat grafting: evidence-based review on autologous fat harvesting, processing, reinjection, and storage. Plast Reconstr Surg. 2012;130:249-258.

14. Smith P, Adams WP Jr, Lipschitz AH, et al. Autologous human fat grafting: effect of harvesting and preparation techniques on adipocyte graft survival. Plast Reconstr Surg. 2006;117:1836-1844.

15. Condé-Green A, de Amorim NF, Pitanguy I. Influence of decantation, washing and centrifugation on adipocyte and mesenchymal stem cell content of aspirated adipose tissue: a comparative study. J Plast Reconstr Aesthetic Surg. 2010;63:1375-1381.

16. Coleman SR. Long-term survival of fat transplants: controlled demonstrations. Aesthetic Plast Surg. 1995;19:421-425.

17. Fulton JE, Parastouk N. Fat grafting. Dermatol Clin. 2001;19:523-530.

18. Kurita M, Matsumoto D, Shigeura T, et al. Influences of centrifugation on cells and tissues in liposuction aspi-rates: optimized centrifugation for lipotransfer and cell isolation. Plast Reconstr Surg. 2008;121:1033-1041.

19. Shiffman MA, Mirrafati S. Fat transfer techniques: the effect of harvest and transfer methods on adipocyte

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from

Ansorge et al 447

viability and review of the literature. Dermatol Surg. 2001;27:819-826.

20. Carraway JH, Mellow CG. Syringe aspiration and fat con-centration: a simple technique of fat autologous fat injec-tion. Ann Plast Surg. 1990;24:293-296.

21. Botti G, Pascali M, Botti C, Bodog F, Cervelli V. A clini-cal trial in facial fat grafting: filtered and washed versus centrifuged fat. Plast Reconstr Surg. 2011;127:2464-2473.

22. Allen RJ Jr, Canizares O Jr, Scharf C, et al. Grading lipoaspirate: is there an optimal density for fat grafting? Plast Reconstr Surg. 2013;131:38-45.

23. Medina MA III, Nguyen JT, Kirkham JC, et al. Polymer therapy: a novel treatment to improve fat graft viability. Plast Reconstr Surg. 2011;127:2270-2282.

24. Gutowski KA; ASPS Fat Graft Task Force. Current appli-cations and safety of autologous fat grafts: a report of the ASPS fat graft task force. Plast Reconstr Surg. 2009;124:272-280.

25. Boschert MT, Beckert BW, Puckett CL, Concannon MJ. Analysis of lipocyte viability after liposuction. Plast Reconstr Surg. 2002;109:761-765.

26. Kim IH, Yang JD, Lee DG, Chung HY, Cho BC. Evaluation of centrifugation technique and effect of epinephrine on fat cell viability in autologous fat injection. Aesthetic Surg J. 2009;29:35-39.

27. Matsumoto D, Sato K, Gonda K, et al. Cell-assisted lipo-transfer: supportive use of human adipose-derived cells

for soft tissue augmentation with lipoinjection. Tissue Eng. 2006;12:3375-3382.

28. Yoshimura K, Sato K, Aoi N, et al. Cell-assisted lipo-transfer for facial lipoatrophy: efficacy of clinical use of adipose-derived stem cells. Dermatol Surg. 2008;34:1178-1185.

29. Zhu M, Zhou Z, Chen Y, et al. Supplementation of fat grafts with adipose-derived regenerative cells improves long-term graft retention. Ann Plast Surg. 2010;64:222-228.

30. Brown SA, Levi B, Lequeux C, Wong WW, Mojallal A, Longaker MT. Basic science review on adipose tissue for clinicians. Plast Reconstr Surg. 2010;126:1936-1946.

31. Hoareau L, Bencharif K, Girard AC, et al. Effect of cen-trifugation and washing on adipose graft viability: a new method to improve graft efficiency. J Plast Reconstr Aesthetic Surg. 2013;66:712-719.

32. Condé-Green A, Wu I, Graham I, et al. Comparison of 3 techniques of fat grafting and cell-supplemented lipo-transfer in athymic rats: a pilot study. Aesthetic Surg J. 2013;33:713-721.

33. Fisher C, Grahovac T, Schafer M, Shippert R, Marra KG, Rubin JP. Comparison of harvest and processing tech-niques for fat grafting and adipose stem cell isolation. Plast Reconstr Surg. 2013;132(2):351-361.

at LOMA LINDA UNIV LIBRARY on April 9, 2014aes.sagepub.comDownloaded from