I don't know if you saw my post about scoliosis and lifting a while ago, but to make a long story short, I went to a neck and spine specialist. They took an X-ray, and it turns out my scoliosis has progressed considerably over the past two years. I saw the X-ray, and it was just plain painful to look at. I told him about my lifting and how squatting and deadlifting was causing problems. The doctor basically said that since I didn't have normal spine mechanics it's not safe for me to do these lifts, and they'll only make my pain worse. The point is, I'll never be able to squat or deadlift again. Ever. There's no way to correct scoliosis (except for a brutal back surgery for really severe cases), so I'm stuck with it for the rest of my life.
I've read so many articles about how squatting and deadlifting are safe if you do them properly. Well, that's not always true. I wish I would have known that.