Thats good you are covering all the bases with vets checks, its too bad that everyone dont do this while looking to buy, there sure would be alot less upset people, lol. I know kissing spine is kinda hard to find unless done the right way, Good Luck on finding that one horse you are looking for

I'm curious how they discovered the kissing spines? Did they x-ray the back? I didn't think it was common to x-ray the back in a PPE. What there something they saw that led them to do that x-ray?

During the PPE my vet does, she palpates very carefully the entire spine starting way up all the way back. There are LOTS of reasons horses can have sore backs but my vet says there are ways you can palpate that might indicate Kissing spine. My guess thats what the vet did, but I hope she responds, I would love to know how they found it to for my own knowledge. 

To answer your question, the vet called me and told me that he had palpated the upper(Around the withers) and lower back and the horse basically dropped at the feeling of pressure. He expressed that he wants to xray his spine, I did give him limitations as the horse was already a bit over budget so he had to pick where he wanted xrays. 

The vet was spot on, and there was a touch of kissing spine in his wither and about 3-4 spots that were touching in his lower back area (basically where I would be sitting in the saddle) and ranked his kissing spine on a scale from 1-10, at a 4. With this I went ahead and consulted two other veterinarians, in which one of them consulted another vet who does kissing spine surgery's and all three of them told me that they would not buy this horse. That what they see worries them, and it will not get better and even with surgery there is no saying if it would be effective, and there is no saying the vertebrae will not return to their original position. Also one of my vet's, who I have known since I was a teenager and is one of the best lameness vets that I know, also stated there was some scar tissue left behind and it looked like the horse had possibly been injected before. 

ETA: Also, I do recall when I looked at the horse originally, there was a scar on his back about the middle of his spine. I showed it to my trainer and we didn't think anything of it at the time. May have possible been a scar from injections, but can't be sure. 

So glad you had a lameness exam done!  I bet you anything the people selling this horse knew without a doubt this horse had kissing spine and that is probably why they wanted you to take it to their vet.

I can't say for sure, the owner put on a pretty good show of being surprised with this diagnosis. However, she did promise me that she did not know about this and she would never sell a horse without disclosing. She also said that she was going to take his ad down immediately to get it addressed. 

I just looked up his ad on BHW as this thread reminded me of that, he is still listed. So sad.