How is the fat is prepped for a BBL?

   I use gravity sedimentation to separate the fat as it causes minimal disruption of fat cells.Kenneth Hughes, MD

Fat processing is critical for good take of the fat.  A closed system where fat is collected, purified, and then reinjected expedictiously without contact with the outside environment is optimal.

Fat processing will vary from one surgeon to another. The ultimate goal is to obtain as pure and consistent a sample as possible in order to optimize graft take. The harvest is typically washed and filtered in order to remove blood and other non-viable tissue and fat prior to transfer. Some surgeons will spin/centrifuge the fat in order to remove the oil layer, while others will use gravity.With regards to your specific question, the devices used for processing fat are, in a technical sense, not very different from a cell saver. They are an intermediary between the patient and the liposuction disposal canister saving the viable fat for transfer. However, they are likely significant differences over and beyond the more obvious similarities (filter/mesh size etc).As always, discuss your concerns with a board certified plastic surgeon (ABPS).

The cell saver is not a standard way to prepare fat for large volume fat transfer. There are actual systems designed for this type of procedure that involves a closed system and gravity separation. Some PS use centrifuge or straining. 

There are many ways to treat the fat before injecting.  I do not think any one way is that much better.  Focus on doctors that good results. Good luck.

This is a very good question. There are lots of different methods and filtration systems used to purity fat for fat transfer. To my knowledge the cell saver system is not used for fat transfer. Some plastic surgeons use centrifuges, others used closed systems, some do not purify the fat at all.
If you are considering a procedure I would recommend going to a Board Certified Plastic Surgeon who has experience with BBLs and with fat transfer. In my opinion, fat purification improves results and we do so for all of our BBL patients. 
I hope this helps!