I had fat removed from my thigh and injected into my face in March 2008. Some of it was stored and frozen. Is the frozen, stored fat safe to inject again? My fat has been frozen now for 10 months.
Is Stored Fat Safe to Use for Fat Transfer?
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Safety of stored fat
Fat grafting has been performed by plastic surgeons for decades. There is no question that fat is the ideal material for soft tissue augmentation, and that the results obtained with fat grafting are the most natural-appearing. However, one problem with this procedure in years past has been resorption (breakdown) of the grafted fat, so that the resulting improvement is not permanent. The grafted fat must gain its own blood supply in its new location in order to persist long-term, and this generally is not possible when large amounts are injected at once and when specialized instrumentation and techniques are not employed.
In order for fat to persist, small amounts (less than 0.1 cc at a time) of fat are carefully microinjected in a series of discrete layers to gradually 'build' new soft tissue structure. As there is space between each microinjection, new blood vessels are able to grow into the grafted fat, allowing it to persist. If this process of blood vessel ingrowth (neovascularization) does not occur, then the injected tissue cannot truly be considered a 'graft' and is instead just another 'soft tissue filler' of limited duration.
Stored fat viability
The longer fat is stored, the more of it dies, and the more temporary the results from fat injection are.
Many patients believe that when fat is taken from one part of the body and placed elsewhere, that fat will "take".
This is not true.
Most fat that is harvested from one are of the body is dead. Fat is delicate biologic tissue that exists in a complex biologic environment in the body. Fat injection technique works by first aspirating (sucking) the fat out of the body with a vacuum (syringe), purifying it in some fashion, and then injecting it back into the patient.
The percentage of live cells is debatable. In our research (which we have presented at national meetings and published in Plastic and Reconstructive Surgery journal), the viability is 20%. The rest of the fat cells are dead and are either metabolized away or walled off eventually. In other studies, the viability rates are as low as 3% if you measure the metabolism of the cells (ability to "breathe").
We prefer LiveFill grafts, nontraumatized fascial fat grafts, for volume augmentation in the face, since they are alive. The long term survival is far higher than that of traumatized grafts.
Also, the swelling at the time of insertion is less than that of fat injection because the body does not have to deal with metabolizing away a large amount of dead cells. The disadvantage of LiveFill is its greater cost than fat injection.
If you do choose to have the fat transplantation method, the more time the fat sits in the refrigerator, the more of it dies.
Although unlikely, it is possible that the patient's fat samples could be mixed up with those of another patient. Such errors are possible even in the most highly monitored blood banks at the best institutions, so they are possible in an unmonitored doctor's office. For that reason, to minimize the risk to patients, we do not store patient's samples for reinjection.
Frozen fat for fat grafting
Fat grafting is fickle. Frozen fat would not be expected to have the same viability as freshly harvested fat. A better strategy would be to harvest only the amount of fat that is being transferred in the same setting.
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I do not know of any research that shows that conventional freezing of fat will result in viable (non-dead) fat tissue. When cells are frozen and then thawed, there is a lot of damage to the cell membrane. Think frost bite. In my opinion, fat transfer is a very finicky procedure with a lot of variables. I would not put a patient through a fat transfer procedure knowing that the fat I injected was probably dead.
I use the method developed by Dr. Sydney Coleman who has pretty much devoted his career to figuring out how best to get the fat to survive. He calls his procedure "Lipostructure". It is so much more than sucking the fat and then injecting it. His technique is time consuming and tedious, both the harvest of the fat and the injection but provides the most predictability and long term benefit. When I went to New York City to learn Dr. Coleman's method, I was just blown away by his results and by his methodical and long term evaluation of his patients and his techniques and equipment. When Dr. Coleman comes out with evidence that there is a good way to preserve fat for a future injection, I will look into it.
I honestly think some surgeons do not have the temperment to take on such a fussy and finicky procedure. Some are either taking short cuts (that are not proven effective) or they are not providing long enough follow-up on their patients. All patients look improved at 3 months because of the swelling. But at three years?????
A question any surgeon thinking about performing fat tranfer should ask themself is this "Do I enjoy doing embroidery?" If you don't enjoy embroidery, you will hate doing fat transfer the proper way!
I would not go to a surgeon who says he or she can do the procedure quickly, that your recovery will be rapid and that they will "just freeze the extra".
Lisa Lynn Sowder, M.D., a surgeon who loves to embroider.
Frozen Fat -a Bad Idea.
Freezing fat in the doctors office frig and reusing it does not make any sense although there are people who advocate it. Simply put freezing and thawing ruptures the cell membrane killing the cell unless it is done by freezing techniques used freeze embryos, eggs, etc in a proper lab setting. Other wise you are getting injected with dead oily glob which is hopefully removed by your phahgocytes. You may also end up having a sterile abcess which calcifies leaving a hard lump
Frozen Fat Can Work But Be Careful
Several studies have suggested that frozen fat can survive without a problem. Unfortunately, the results will depend on the method for preserving the fat. As Dr. Lam points out, high standards should be observed to ensure sterility and viability are preserved. Unfortunately, most physicians offices are not monitored to ensure this reliability as it can be quite expensive to keep up the standard. Overall, I prefer to simply harvest fat at each session as this has been shown to have a greater viability than preserved fat in any circumstance.
Frozen Fat is dead fat!
There are studies that demonstrate how to preserve the viability of fat after freezing. However, current methods in the US are not these techniques. Fat requires a preservative called Trehalose. I am not aware of anyone using this substance. Most just stick it in a freezer and thaw. Think of the freezer burn! not good!
Storing fat for re-injection
Fat can be frozen and re-injected with good results. The method of cryopreservation of fat is very important. A standard compact or household freezer stores fat at -20 degrees C which is not ideal for storage of fat. For long-term storage of fat the ideal temperature is -75 to –80 degrees C.
Storing Fat for Later Transfer
Thanks for your question -
There have been several studies examining using cryo-preserved fat for tissue augmentation. It does seem that fat can be stored for a period of time and still be viable (though not as well as fresh fat).
Fat that has been cryopreserved has an even lower survivability.
Most surgeons who are performing autologous fat transfer are using the tissue immediately upon harvest for the most consistent results.
I hope this helps.