Each year, 40 to 60 percent of American adults suffer from chronic back pain. More than one million spine surgery procedures are performed annually, with medical costs to treat back pain approaching $24 billion per year. With age and injury, discs located between the vertebrae in the spine might eventually wear-down?a process termed degenerative disc disease. Due to the lack of padding, vertebrae bones slip and rub together. This leads to excruciating and disabling pain, and may cause sciatica (leg pain) due to pressure on the sciatic nerve?resulting in cramping, pain and numbness along the lower back and back of the thigh.