Hi dear,
I hope your puppy is better now. In case it's not, I suggest you to ask for an endoscopy instead of surgery.
My dog has serious problems with diarrhea and the doctors have tried everything without results. Until they made an endoscopy and found the origin/reason of that.
Unfortunately she has a chronic disease in her intestine which is serious, but at least now she can be treated properly, before they had no idea what it was.
She has linfangiectasis, which I have read it's a common disease in Basenjis.
Good luck and please let us know how he/she is.