Oh Nancy,
Poor Sprite. This has to be such a hard decision for you. Knowing Sprite and how good she seems in all other aspects it may be worth doing for her. Questions, though, that came to mind - did the vet have any idea on how he would expect her to react to the surgery, i.e. could it be a longer recovery than expected, very painful, etc. This surgery wouldn't be effective in slowing the tumor growth, it's to help close the surgery site, right? I know from your posts that the tumors do grow back. Did the vet know how long it could be before the tumors come back again? Do you think Sprite would do okay being a temporary tripod?
I'm sure these are all questions you've thought of yourself - I'm just thinking out loud here. From the last time I saw her, Sprite seems to take things in stride and handles whatever comes her way.
Sprite's name fits her so well - she's such a little "sprite". You're in my thoughts as you go through this, Nancy.
Pat