Tissue Liquefaction for Disaggregation of Adipocytes in Fat Grafting Procedures

By Marissa Tenenbaum, MD

Marissa Tenenbaum, MD is an assistant professor at the Washington University School of Medicine. She is in practice in St. Louis, MO.

Fat grafting has been around for close to two decades, and if there is a trend evident in these procedures, it is that they are getting more popular with time. The versatility of fat grafting is evident in its many applications, including facial rejuvenation, cosmetic breast surgery, and contour deformities, including those due to soft tissue and tumor resection, to name just a few.

Whether autologous fat grafting is combined with other procedures to address underlying medical pathology or performed as a cosmetic enhancement, patients fundamentally expect restoration of natural contour and a high quality aesthetic outcome. Fortunately for patients, the means to do so are multiple, as the options for fat harvesting and processing have expanded to include several options in addition to suction-assisted (SAL) liposuction. The question for surgeons is whether to use ultrasound liposuction (UAL), power-assisted liposuction (PAL), tissue liquefaction (TLL; HydraSolve), or another mechanism in a particular setting and for a given purpose. Differences in the various mechanisms of action of available technologies suggest different roles in liposuction versus fat grafting procedures, as the latter may require different approaches to adipocyte preparation to assure cell viability for autologous injection.

As important as surgical technology is, however, technique is equally if not more important in the final outcome. Getting patients the result they want is facilitated by putting the right technology into well-trained hands. Other elements in this equation are proper patient selection and choosing the right approach given the particulars of the case.

Yet, because not all fat cells are created equal, and because some anatomic sites are inherently more difficult to work on than others, there is no one size fits all approach. Indeed, several factors could potentially inform a decision on what platform technology to use for fat extraction, including the volume of aspirate, anatomic site, and whether there is intent to use the fat for autologous grafting. In my surgeries, I prefer to use PAL for the lion's share of lipoplasty procedures, ultrasound-assisted liposuction in certain revision settings (and particularly in more fibrous tissue, such as gynecomastia), and TLL for fat grafting applications. My sense is that if fat cells are to be reintroduced to a recipient site, then they should be extracted in a minimally traumatic fashion—something that TLL appears to provide.

Fat Cell Viability and Predictability

One of the shortcomings with modern fat grafting procedures is that we still are not entirely able to predict the quality of fat in the lipoaspirate, nor how viable it will be once it is injected at the recipient site. In my experience, however, I have found that TLL most consistently yields the kind of creamy fat necessary for grafting compared to the various technologies I have tried. I am hopeful that in the future we will have more science to bolster that claim; for now, I have to believe what my own eyes tell me.

One can also look to the scientific rationale of various liposuction techniques to start to understand which ones might seem more favorable for fat grafting. For instance, TLL offers a more efficient but less abrasive mechanism for fat harvesting. The system uses a warmed, pulsed, low-pressure saline stream contained inside the cannula, so that as fat tissue is drawn to the aperture by suction, adhesive glycoproteins located on the surface of cell membranes and in the extracellular matrix are disaggregated. The resulting aspirate is an aqueous multicellular suspension containing small particle sized fat cells (roughly 0.5-2.0mm). Because TLL does not cause breakdown of blood vessels and connective tissue, there may be minimal need for processing beyond gravity separation, as well as less iatrogenic trauma at the harvest site.

At the current time, there is incomplete understanding of the mechanisms of cell viability at the recipient site. It could be that local growth factors and/or hormones, either extracted at the donor site and present in the autologous injection or else present at the recipient bed, are influential on whether fat cells survive after injection. Yet, it stands to reason that fat cells that experienced less turbulence at the harvest site have a better chance of survival at the recipient site.

The minimal requirement for processing after a TLL procedure is another reason to believe it may produce a more suitable medium for autologous transfer. This somewhat assumes that the viability of the extracted cells is a significant factor in how healthy they are at the recipient site, a notion that is widely held but not proven beyond doubt. Nevertheless, lessening the requirement for processing does save time and places less stress on the surgical staff. In many cases, I am able to harvest fat into a sterile canister and allow it to gravity separate, in essence creating a closed system, which may have some benefit for autologous transfer.

Conclusion

In any discussion of technologies for use in fat grafting and liposuction procedures, it is important to keep in mind that equipment is only part of the equation (and, arguably, only a small part), whereas the skills of the surgeon performing the fat grafting are crucial for achieving a quality outcome. Again, adding the right tools to well trained hands is the most likely formula for great long-term success with fat grafting procedures.

When thought of in this light, TLL seems to offer a few advantages as a tool to equip the surgeon. The quality of the extracted lipoaspirate seems in my hands superior to other techniques, thus more viable and better suited for grafting. This is a difficult aspect of fat grafting to quantify, although ongoing research should help us understand whether this technique or others provide us the best possible fat for grafting. At the very least, the TLL lipoaspirate requires little if any processing, which should minimize handling and time outside the body.

The efficiency of fat removal using TLL cannot be overlooked, which may translate to less trauma to the donor site, and an overall easier recovery for patients. Adding to this is that using TLL is easier on the surgeon, both minimizing the risk for repetitive stress injuries, while also lowering the exertion necessary to remove fat. Surgeons will invariably fatigue at different rates, but at the least, having a system that exerts less stress on my body gives me a good chance at being as fresh for the fifth surgery during the day as it does the first.

In truth, a diligent surgeon can achieve amazing long-term results with almost any platform if the proper techniques are employed. That said, using the right tool for the job would seem to increase the chances of achieving the high quality aesthetic result patients are looking for.