just a thought, take it for what it's worth, people divide nems by cutting through the center of the mouth and making two halves. The foot is cut in half, the nems survive and heal up. I have done this myself with success.
If your rbta does well and heals up great, if it starts to decline then take it to the chopping block and toss out the damaged side and hope for the best.
once again just a thought
I have had bta get sucked into a powerhead and survive, I have stuck my fingernail through the foot and lost them ??