Should the V.A. be responsible for surgery that resulted in paralysis?

I was injured at work that required neck surgery. The surgery was successful. However, 10 years after the surgery I was assaulted by two people and I was hit in the head around 10 times. My neck was injured and required surgery once again. I did not have private insurance and was treated at the V.A. Hospital in San Antonio, Texas. After an six hour surgery, I was fitted with Two rods, twelve screws, and a plate. A month after my surgery, my left hand was paralyzed. My Surgeon guaranteed me I would regain full use of my hand after six months. The strange part was he wanted to perform surgery a month after my initial surgery. I know that he made a mistake during my first surgery and tried to correct it. Sadly, I agreed and the surgery did not help me regain full function of my left hand. The surgeon said I would never regain full use of my hand and I was permanently paralyzed. I put a claim for service connected disability because my Dav said because it aggravated my injury I would be able to make a claim. Surprise, surprise, they denied my claim. Do Y'all think I had a right to put the claim in or not? By the way, I am 70 percent disabled due to Ptsd. I welcome all responses. Thank you.