Spine deformity can happen when unnatural curvature occurs, as in scoliosis (side-to-side curvature) or kyphosis and Scheuermann's disease (front-to-back curvature). It also occurs due to defect (e.g. spondylolisthesis) or damage to the spine (if there are multiple fractures or ankylosing spondylitis). Deformities do not commonly cause pain unless the change in structure restricts movement or reduces room in the spinal canal and puts pressure on the nerves there.