The severity of Scoliosis is determined by two factors. The first is the angle of the curvature, which is measured on x-ray, the second one is the rotation of the spine. As the lateral curve increases, the vertebrae will start to rotate more, and the ribcage rotates with it, resulting in the characteristic “rib hump”.
Scoliosis is considered mild when the curves are less than 20 degrees. Some specialists consider curves of less than 10 degrees as normal variations of the spinal curves, and do not consider treatment necessary at this point.
Curves from 20 to 40 degrees are considered moderate. At this stage, structural changes in the vertebrae and rib cage may be seen.
From 40 to 50 degrees onwards Scoliosis is described as severe. In severe Scoliosis significant deformity of the vertebrae and ribs can be observed. Adults suffering from severe Scoliosis often experience pain, and are at an increased risk of degenerative joint disease of the spine. In curves of 60 to 70 degrees secondary changes such as decreased vital capacity and total lung capacity may occur, and the inner organs may be compressed. At this point usually the quality of life deteriorates.
The lateral curvatures of the spine are measured on X-Ray. The most used method is the Cobb method.
To determine the rotation of the vertebrae, the position of the pedicles is determined. In the normal spine, the pedicles are placed symmetrical on either side of the spinous process of each vertebrae, but in Scoliosis the pedicles and spinous processes are positioned asymmetrically towards the side of the concavity.