His hocks xrayed clean and he flexed clean on them but we already injected with his SI like I said in the post. 

I have the xrays that shows the vertabra's almost touching.  I was told he has about a 50/50 chance of the surgery working and he'd need injections as well.  I'm so at a loss and sad. 

Have you checked into PSSM?  Possibly PSSM1, but more likely PSSM2 variant.  A good riding horse can turn into a major bronc when they become symptomatic.  And not all have the same symptoms.  For the naysayers, Univ of MN is doing a major research study now on horses with symptoms (it's free to put your horse in), whether they've had any kind of diagnosis or not.  Once their whole study is done, it will turn many people inside out after denying it's existence.  Smart people are starting to get their stock "cleaned up" now so they are ahead of the game.  Something for you to consider/look in to.

I know this is probably an overrun thing, but especially when you said he came back 200lbs thin. I had one that was nice as a 2yr old, sent off to be broke then a nut job. Not buck but suddenly bolted. Xrayed everything and couldnt really find much. It was epm. He was seeing things we think and bolted. 

I'm well versed in PSSM and he has no suspects in his lineage and both sire and dam are 5 panel negative. I know there's more variants than that, but like I said, he has no suspects in his lineage. We also have 3 other colts that are out of this mare and have no issues. Thanks though. 

I would think this is a possibility too, but as soon as he was back at my place he gained weight like no other. I don't feed him anything special, literally just turned him out to pasture. 

Bottom photo is a week after he came back, he'd probably already gained 75lbs. Top photo is the next week after out to pasture at my house. Now I don't expect a horse in work to come back looking like a fat hog - but I do expect him after 3 weeks off to come home in decent shape and certainly no poverty lines like he was showing. His hair was matted as all get out (I don't normally touch this horses mane and tail, I'm not one for a whole ton of grooming) and in the year and a half he's been at my house he's NEVER had issues with his mane matting. 

Top photo is what he looked like after coming back from the cowhorse trainer and me riding for 45 days. He also looked like this coming back from his most recent trainer. Bottom photo is again, a week after I got him back from the barrel trainer after she hadn't worked him for 3 weeks. 

This is what he looks like currently. Just don't think he's an EPM horse but if it continues I'll look into it. 

IPersonally I think he looks like a EPM horse.  His hip is the main sign.  It drops off.  No muscle.  I would treat.  It won’t hurt.  Deanna Harrison’s Stabilize works and it’s very affordable.  

Did your vet suggest injections and rehab to build up his topline?  There is a lot of success stories with doing this.  

She did say we could do surgery along with injections and a rigorous exercise program but there were no guarantees he would stay pain free.  She suggested a vet in Texas if I chose to go that route.  The last time he bucked me off was enough for me, it was pretty bad.  I feel bad for him because I was pretty hard on him and rode him for another 45 minutes hard.  He bucked because he hurt.  Other than that he's in your pocket kind of horse.  I'm at the stage of my life, I don't need to hit the ground like this anymore.  He's such a nice horse.

Gorgeous. You're in Iowa? Kendall Road by Chicago specializes in KS, like its **** near the only thing Dr. Vacek does. And they're super affordable. I only go to them or Wisconsin Equine for my horses. And if my horse with touching vertebrae plus a few of them also being fractured, got a solid 100% recovery diagnosis, I don't see hows yours wouldn't do fine as well. I'm not doing surgery on mine yet, but she does just fine with the injections and they're not expensive to do at all 

The only picture he's been truly "worked" in is the one where he's fuzzy. I guess I dont see it. He has his sires hip which he actually exceeds. Can you pinpoint exactly what you're saying? 

Bumping this up because I'm curious about your reply

How are things going with your horse now? I have a very simular story with my 4 year old. Last spring he started coming up sore, in his lumbar and SI. Pulled blood for Lymes, tried two weeks of robaxin and bute,  then x rays for KS, PSSM, HYPP testing, Chiro, Magna Wave, Massage, saddle fitted and evaluated (he exhibits the symptoms in both an engish and western saddle both with a rider and lunging) then settled on injecting his SI when we didn't get any results. Unfortunately, that didn't help either. We have looked at everything, he is fit as a fiddle (not lame in the slightest anywhere). So gave him another month off, would palpate before each ride and he seemed good. However, when you would get on him for the first 10 to 15 minutes he would feel super tight (even after hand walking him for 10 minutes and slowly tightening his cinch a little at a time), almost like riding a watermelon with a hump in his back) once we started trotting he would work out of it. So, I took him to a couple of exhibitions and he would buck when pushed to go a little faster than a slow lope. He would come unglued... Sent him to a trainer for about 40 days as vet thought this might just be bad behavior, trainer sent him back after he started palpating sore again and still bucking when pressed. Second vet came out and he palpated sore again over his lower lumbar, decided at this point to either do a bone scan or give him 6 months off. Vet actually recommended the 6 months off and said that I spent enough on vet bills trying to figure this out (and at this point some time is only costing me the feed I am putting into him, LOL) Just wanted to say I commiserate with you! If anyone has suggestions please send them my way. The plan is to restart him in late April, fingers crossed this does the trick! This horse is super talented, I would hate for him to have to be a lawn orniment for this useful life... Picture of my guy in question below...

Since you mentioned PEMF, I wanted to let you know that it worked for my SI horse.  I had been getting injections for him for a couple years.  All of a sudden, the injection didn't work.  What to do.  Tried PEMF treatments, he's only had probably less than 10 in three years, but so far, it has worked for him.  Hasn't been injected in three years.  He was never a bucker, tho.

Thanks! I forgot to mention that a girl at the barn Just purchased a BEMER blanket. So, before wo brought him back we were going to start introducing this as part of his routine as well.