A Practical Method for Purification of Fat Grafts Using Gelatin Sponge

Öz Perçin Karakol1, Mehmet Bozkurt1, Emin Kapı2 1Health Science University Bağcılar Education and Training Hospital, Department of Plastic, Reconstructive and Aesthetic Surgery, İstanbul, Turkey 2Adana Education and Training Hospital, Clinic of Plastic, Reconstructive and Aesthetic Surgery, Adana, Turkey LETTER TO THE EDITOR Address for Correspondence: Perçin Karakol, Health Science University Bağcılar Education and Training Hospital, Department of Plastic, Reconstructive and Aesthetic Surgery, İstanbul, Turkey E-mail: ppercin@gmail.com ORCID ID: orcid.org/0000-0003-0068-2139 Received: 06.02.2020 Accepted: 21.04.2020 Cite this article as: Karakol P, Bozkurt M, Kapı E. A Practical Method for Purification of Fat Grafts Using Gelatin Sponge. ©Copyright 2020 by the Health Sciences University, Bagcilar Training and Research Hospital Bagcilar Medical Bulletin published by Galenos Publishing House. Dear Editor, Fat grafting has dramatically become popular during recent years; not only in plastic surgery, but also in other medical fields. Processing of fat grafts can be done in different ways, either with filtering, cotton-gauze rolling, or centrifugation methods (1). A major focus was the use of centrifugation or other methods to separate the aqueous and oil components before injection because this stage is the most important part for fat graft survival (2). There is no consensus on the various techniques, neither a gold standard technique for processing stage. In this letter, we aimed to use an alternative method for purification and filtering of fat grafts using gelatin sponge for low quantities of fat grafts. Our standard tumescent solution is injected into the harvest site. Fat is aspirated by hand using 60 mL syringe and harvesting cannula. In this method, fat lobules are removed through fibrous septas by degrading. For this reason, fat grafts obtained are free of fibrous septa and have a homogenic formation. A gelatin sponge with dimensions of 80×50×10 mm is divided transversely into two parts with using no:10 blades for enlarging the surface area used (Figure 1a, b). The rough surface of the gelatin sponge is used as it is more absorbent. The hand-suctioned specimens are divided into lesser parts and poured onto surface of the sponge. The specimens are rolled with forceps for about 3 minutes until all blood, aqueous and oil components are absorpted and separated (Figure 1c, d). The purified fat grafts area filled to 2 mL syringes using Bagcilar Med Bull DO I: 10.4274/BMB.galenos.2020.02.02 Karakol et al. Gelatine Sponge Bagcilar Medical Bulletin, curettes. The purified and unprocessed fat graft is seen in Figure 2. The gelatin sponge for purifying fat grafts is a cheap, quick method and it is quite easy to apply. Gelatin sponge (Spongostan®, Ferrosan A/S, Denmark) is an absorbable hemostatic agent derived from pig skin collagen and is widely used in humans for over 60 years (3). It is a material that can be absorbed between 4-6 weeks, and sponge-like that contains hemostatic gelatin. It has porous formation. It promotes platelet aggregation and increases the matrix formation of fibrin (4). It is cheap (0.30 € per one) and commercially available, can be found easily almost in every hospital. The surgeon himself can easily perform the technique without any help. Although fat grafting which is performed by closed system has been regarded as ideal, there has not been any kind of evidence that indicates infection is increased through desiccation air oxidation or decreases fat graft viability. (1). As far as the study of the Kuran et al. (5), although the application period is 15-20 minutes, there has been available data that shows air exposure does not increase bacterial growth. In our study, as gelatin sponge has a fast absorbent character, execution time is shorter and thus we believe that potential risks are minimized. The common agreed methods for fat processing are the cotton gauze rolling and centrifugation; and also filtration which is less commonly used. According to literature, there are conflict reports that one of them has superiority to another (1,6). The filtration method has an advantage to process large volumes efficiently and quickly same time. It may be safer for infection and increases graft viability but there is not enough evidence for these situations. It is not widely available, not suitable for little volumes; and also expensive (1). Kuran et al. (5) also described a filtration method inspired by yogurt concentration methods in Anatolia; that’s believed to prevent the adverse effects of centrifugation. The centrifugation and cotton gauze rolling methods are useful for little amounts of fat. The cotton gauze derived technique of Telfa (Covidien, Mansfield, Mass.) commercially available in local market. It is disposable. It is proved to be the best option for removing oil fraction (1). The centrifugation method (Coleman’s technique) is as efficient to purify and drained fat by gravity as the cotton gauze method. It can be found easily, but requires a centrifugation machine and cannot be performed by the surgeons self during the operation. In the comparison of filtering, centrifugation, cotton gauze rolling and gelatin sponge methods; the processing time, residual oil ratio contained in the graft after processing, removing of aqueous oil degree, the fat grafts volume retention percentile which was observed 6 weeks after application were compared (Table 1). According to this, in the cotton gauze sponge and gelatin sponge techniques it was seen that both period of time was shortened and the most favorable results were obtained in terms of efficacy. Compared to all groups, in gelatine sponge group adipocytes were evaluated by looking at the presence of needle-shaped fissure formations, which contain nuclei in terms of viability and the radial distribution formed by dissolving the triglyceride crystals. In terms of this parameter, adipocyte viability was found to be high in fat graft samples. It is noteworthy that fibrotic areas are in narrower areas, and capillary blood vessels are much denser among adipocytes. Minimal necrosis was observed when staining with hematoxylin eosin (Figure 3). As the processes of cotton gauze and filtration a drain work is performed by making the fat grafts held or mixed. In spite of a long holding duration for these works, it can be faced by the situations that the liquid side of the fat is Figure 1. a) View of the gelatin sponge b) View of the division of gelatin sponge c) The appearance of the pouring of the fat grafts d) The appearance of the rolling of the fat grafts with forceps Figure 2. The appearance of the purified fat graft Karakol et al. Gelatine Sponge Bagcilar Medical Bulletin, not absorbed efficiently. As the content of gelatin sponge is of the characteristic for rather absorbing and spongeporous, it absorbs the liquid quickly and it makes fat graft concentrated. In addition to this, the possibility that gauze particles may remain between the fat tissues in cotton gauze method, it brings about the foreign-body reaction risk. Since gelatin sponge is of the kind that melts, we are of the opinion that the tendency of forming foreign-body reaction in the long term period is lower. At the same time, besides mechanical effect over the fat graft application; because of the contribution to fibrin formation, we think that fat grafts increases the penetration to tissue and decreases the melting rate (5). The most important limitation of this method is that it allows little amounts of fat purification. A single gelatin sponge can purify about 10 mL of fat and about 3-4 mL purified fat graft is obtained. We use purified fat grafts into facial areas especially nasolabial sulcus and malar area and the obtained amounts are usually sufficient. If greater amounts are required, it may not be favorable, because of timely and personal constraints; other purification techniques like filtration may be used. Further studies must be performed for the effectiveness and showing the advantages and disadvantages; short and long term results may be helpful for comparison. For the parameters which are the matters in question, performing experimental work is more convenient. For this issue, a more detailed study has been planned. Although, the cotton gauze rolling and centrifugation have become established methods for removing unwanted oil and aqueous fluid from the lipo-aspirate to purify the fat before grafting, the presented gelatin sponge method may be kept in mind as an alternative due to its easiness, cheapness especially for small amounts of fat grafts. The manuscript does not contain clinical studies or patient data.