Sunday, June 10, 2012

Fat Grafting to the Breast—more article reviews

Catching up on some of my journals that have been stacking up, one PRS journal had four articles relevant to fat grafting.  If this topic is of interest to you, all four articles are worth the read but especially the second (which discusses the first) and third (great discussion on how fat survives or doesn’t).

1. Mammographic Changes after Fat Transfer to the Breast Compared with Changes after Breast Reduction: A Blinded Study; Rubin, J. Peter; Coon, Devin; Zuley, Margarita; Toy, Jonathan; Asano, Yuko; Kurita, Masakazu; Aoi, Noriyuki; Harii, Kiyonori; Yoshimura, Kotaro; Plastic & Reconstructive Surgery. 129(5):1029-1038, May 2012; doi: 10.1097/PRS.0b013e31824a2a8e
The study compared 27 women with normal preoperative mammograms who were then treated with fat grafting to the breast to a control group of 23 women who had breast reductions.  The preop and postop mammograms (done 12 months after surgery) were read by 8 academic breast imaging radiologists in a blinded fashion.  This is one of those articles where “reading between the lines” is important.  Keep these findings in mind as we move on to the next article:   scarring (85.6% in reduction group, 17.6% in fat grafting), calcification requiring surgery (1.6% R, 4.6$ F), and mass or distortion warranting biopsy (13.6% R, 2.8% F)
Here’s the authors conclusion
…..Lipoaugmentation of the breast has been controversial, however, due to concerns regarding its interference with mammography and cancer surveillance. We have demonstrated that when compared with a widely accepted surgical procedure of the breast, reduction mammaplasty, lipoaugmentation with autologous stem cell enrichment produces lower rates of radiographic abnormalities and a more favorable Breast Imaging Reporting and Data System score.

2.  Discussion: Mammographic Changes after Fat Transfer to the Breast Compared with Changes after Breast Reduction: A Blinded Study; Spear, Scott L.; Al-Attar, Ali; Plastic & Reconstructive Surgery. 129(5):1039-1041, May 2012; doi: 10.1097/PRS.0b013e31824a29ef
Dr. Spear has written a very thoughtful review which I wish I could just copy and paste here for you to read, but alas.  This one paragraph gives you a good overview of his concerns (the bold highlights are mine):
There are a number of interesting issues raised by this article. First, what is the ideal control or comparison group? Are patients who have had breast reduction surgery the best control? Second, although multiple radiologic abnormalities are evaluated in this study, the major concern with lipoaugmentation is the development of suspicious calcifications,10,11,14 and more attention could have been focused on that specific question and the almost three-fold higher incidence of this finding in lipoaugmentation patients. Third, the findings of the article raise significant questions as to where the fat is actually injected—that is, around versus into the breast parenchyma. Fourth, the study employs radiologists who are specifically trained in breast imaging, which might not reflect the skill sets of radiologists found at most diagnostic imaging centers across the United States today. In addition, even among this highly trained group of radiologists, intergrader variation was high. Finally, this study uses a lipoaugmentation technique (creating stromally enriched adipose tissue) that is presumed to concentrate stem cells; this protocol is not a widely used method, and it is not relevant to the main objective of the study.
3.   The Fate of Adipocytes after Nonvascularized Fat Grafting: Evidence of Early Death and Replacement of Adipocytes; Eto, Hitomi; Kato, Harunosuke; Suga, Hirotaka; Aoi, Noriyuki; Doi, Kentaro; Kuno, Shinichiro; Yoshimura, Kotaro; Plastic & Reconstructive Surgery. 129(5):1081-1092, May 2012; doi: 10.1097/PRS.0b013e31824a2b19
This study focused on the early phase (0=14 days) of the healing process after nonvascularized fat-grafting.  Adipocytes are most susceptible to death under ischemic conditions, although adipose-derived stromal cells can remain viable for 3 days.  The article includes a great figure (#6) which graphically illustrates the three zones of ischemia for fat grafts.  Think of a sphere with the 1st zone being on the outside:  1) “surviving zone” is the most superficial zone, is less than 300 μm thick, both adipocytes and adipose-derived stromal cells (ASCs) survive here, 2) “regenerating zone,” thickness varies depending on the microenvironmental conditions such as vascularity of and attachment to the surrounding tissue, in this zone adipocytes die as early as day 1, but adipose-derived stromal cells survive and provide new adipocytes to replace the dead ones, and 3) the most central zone is the “necrotic zone,” where both adipocytes and adipose-derived stromal cells die, no regeneration is expected, and the dead space will be absorbed or filled with scar formation.

4.  Discussion: The Fate of Adipocytes after Nonvascularized Fat Grafting: Evidence of Early Death and Replacement of Adipocytes; Pu, Lee L. Q.; Plastic & Reconstructive Surgery. 129(5):1093-1095, May 2012; doi: 10.1097/PRS.0b013e31824a2b4b
This article discusses article 3 and starts like this:
Fat grafting remains one of the most controversial procedures in plastic surgery because there is no standardized technique used by plastic surgeons to harvest, process, and place fat grafts. In addition, and most importantly, how the fat grafts survive after they are transplanted in vivo remains unclear and needs to be determined. The present study was conducted by Dr. Kotaro Yoshimura's group from the University of Tokyo, one of the most active teams in the field of fat grafting and adipose stem/stromal/progenitor cell (adipose-derived stromal cell) research. The study, composed of two parts, is another example of an important and well-conducted study in understanding the mechanism of how fat grafts survive after transplantation. ….. most adipocytes in the graft site begin to die on day 1 and only some of the adipocytes located within 300 μm of the tissue edge would survive. The number of proliferating cells increases from day 3, and increases in viable adipocyte areas can be detected from day 7.
And gives this recommendation:
Although the present study is well conducted, with sound and contemporary methodology, I would encourage the authors to perform a long-term in vivo study, such as 2 to 3 months in the same animal model, which may be equivalent to approximately 6 to 12 months in humans..

Related Posts
Fat Injections for Breast Augmentation (November 6, 2008)
Complications After Autologous Fat Injections to the Breast – an Article Review (April 2, 2009)
Recent NPR Stories on Plastic Surgery (June 3, 2009)
ASPS Task Force Updates Position on Fat Grafting  (August 13, 2009)
Risks of Fat Grafting in Breast Cancer Patients (November 22, 2010)
Update: Stem Cells and Fat Grafting (May 11, 2011)

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