You show up at a Midtown Manhattan emergency room at 2 a.m. with the worst back pain of your life, numbness spreading between your legs, and trouble starting a urine stream. The doctor diagnoses a lumbar strain, hands you muscle relaxers, and sends you home. Two days later you can't urinate at all, you've lost feeling in your groin, and an MRI finally reveals a massive disc herniation crushing the nerves at the base of your spine. By then, the damage is permanent. If this sou