What constitutes a “very large breast reduction” and the need for a FNG?

Almost nobody "needs" a free-nipple graft procedure in breast reduction.  If you are told that then I would recommend getting a second opinion.  

Free
nipple grafts are rarely used for breast reductions.  Unfortunately, you have not provided
photographs but at size J, I have never needed a free nipple graft.  I recommend The Bellesoma Method to reduce
and reshape your breast tissue creating upper pole fullness without implants,
elevate them higher on the chest wall and more medial to increase your
cleavage.  The weight of the breast is
transferred to the underlying pectoralis major muscle resulting in pain relief
without excessive reduction.  Vertical
scars are avoided, nipple sensation and the ability to breast feed are
maintained.  Best Wishes,Gary Horndeski, M.D.

There is no specific breast weight cutoff that requires a free nipple graft.  Breast measurements and desired breast size are all factors. It is rare to need a free nipple graft. Schedule a consultation with a board-certified plastic surgeon to discuss your options.  Best wishes to you.

Thanks for your question, tlhslp.
It’s good that you have already scheduled your first consultation because to be honest, only your plastic surgeon can answer your question if you need a free nipple graft or not.
Breast sizes are extremely tricky, and cup sizes are subjective. What might be a D cup to one bra company might be a C cup to another, so we discourage using cup sizes as basis for your breast reduction.
What you should do when you go for a consultation is to bring photos of the breast size that you want to achieve so that he can estimate your reduction. It’s also helpful to focus on your breasts and try wearing a tight-fitting compression bra that gives you the breast size that you want.
I’m sure that as you discuss your expectations during your consult, your plastic surgeon will tell you if you need a free nipple graft or not, and what your options are when if you want to avoid it.
Good luck!

Hello
and thank you for this excellent question. Regardless of breast size, my
patients do better with a standard pattern breast reduction, instead of a free
nipple graft.  While patients should be aware that this procedure is a
possibility, I virtually never perform it any more. It is
essential that you have an in-person consultation to develop a treatment plan
that specifically addresses your personal surgical goals, and your body’s
anatomy. I recommend that you find a board-certified, or board-eligible plastic
surgeon with whom you are comfortable. Be sure to have all of your questions
answered during a face-to-face meeting with your surgeon, and review before and
after pictures of similar patients whom have had this procedure.
If you have any questions, call our office for assistance at
(817)484-0169. Good luck!
Best,
Jon Ver Halen, MD FACS
Harvard educated plastic surgeon
Texas “Top Doc”
RealSelf100
America’s Top Plastic Surgeons, Consumer’s Research Council