Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 65. Spinal disorders are among the most common medical conditions with significant impact on health related quality of life, use of health care resources and socio-economic costs. Spinal surgery is still one of the fastest growing areas in clinical medicine. | Idiopathic Scoliosis Chapter 23 633 a Compensated double major curve. b Decompensated thoracic curve. c Risser sign I-II arrows . d Sagittal profile with a flat back. e f Thoracic and lumbar side bending views. g Silhouette radiograph demonstrating a rib cage deformity. 634 Section Spinal Deformities and Malformations Figure 4. Radiographic assessments a Cobb measurement. b Risser sign. c Vertebral rotation according to Nash Moe the more rotated the vertebra the more the pedicle at the convexity passes towards and beyond the midlineand the pedicle at the concavity disappears. d Vertebral rotation according to Perdriolle the radiograph of the target vertebra is superimposed by a torsionometer. The intersection of the pedicle at the convexity with the respective line of the torsionometer determines the rotation. cation of the apophysis of the iliac crest 185 . This apophysis first appears ante-rosuperiorly of the iliac crest and progresses towards posterior before it fuses with the iliac spine. According to Risser the iliac crest is divided into four quarters in the anteroposterior radiograph. If none of the quarters is calcified Risser stage is 0 if one quarter is calcified Risser stage is 1 and so on. If the complete apophysis is fused with the iliac crest Risser stage is 5. Idiopathic Scoliosis Chapter 23 635 Two methods are commonly used to assess vertebral rotation on standard anteroposterior radiographs Nash Moe method Perdriolle method The technique by Nash and Moe determines vertebral rotation according to the pedicles into five grades 150 Fig. 4c . In grade 0 neutral both pedicles show a symmetric distance from the lateral borders of the vertebral bodies. In grade I and II the pedicle on the convex side translates towards the middle line of the vertebral body whereas the one on the concave side begins to disappear. In grade III the pedicle of the convex side lies in the midline of the vertebral body and in grade IV and V it passes the midline towards the .
