I had a herniated disc in my lower lumbar that smashed in the nerve cluster at the base of my spine and started shaving them off. It's called cauda equina syndrome, and I can't imagine being in more pain than than that while awake/coherent. I had a 9 hour emergency surgery to fix it, and of course I developed an infection. After 2 more surgeries including a muscle flap and over a month on-and-off in the hospital, I'm pretty fine. Have some nerve damage, but consider myself extraordinarily lucky. I've also been hit by a car, stabbed in the armpit with a rod-iron pipe (about a millimeter from hitting my lung), and been bit in the face by a Rottweiler (all considerably less pain) and had 21 stitches in my face and mouth (and no-one can tell now but me). I'm pretty damn lucky to be alive, walking, and not horrifically scarred.