Dear Fiona, the issue of breast surgery and continuing lactation is at best
not well understood by breast surgeons who I have met. I recently got a
call from a patient  who was at the University Hospital here in town
because she had a breast abscess I and D'd, and her doctors didn't know
what to tell her about breastfeeding continuation. She asked them to call
me, and they wouldn't because they didn't know me, but if they would have,
they would have found out that I am on staff with the med school. In other
words, not even interesting in seeking the info. Of course it is easy to
tell a woman to wean, as breast surgeons only know the breasts in their
nonfunctional state.
I think the patient you have is comparable to a breast abscess patient. I
see no reason to wean, and I see no reason to tell her that she can't nurse
in the future. I am at home and without my references, but the incisions
that pose the the most risk for future failed lactation are the periareolar
ones, or ones that result in decrease in nipple sensation, due to lack of
neural feedback to give rises in prolactin and oxytocin. Her breast should
heal while she is still nursing. For her to stop nursing may result in
engorgement, and increase risk of infection/sepsis. There are really not
alot of studies on this, as I did try to dig up info on this topic 3 months
ago for a talk. Hope this helps-Anne EglashMD