Skeletal bony maturity to determine the scoliosis treatment
The Risser sign was developed by Joseph Ch. Risser in the context of scoliosis therapy as a diagnostic tool for determining bone maturity. Risser was an American surgeon specializing in the treatment of idiopathic scoliosis (three-dimensional spinal curvature). He has also developed the so-called Risser plaster to correct the spine of his scoliosis patients. With the Risser sign, the degree of ossification of the iliac crest is determined on the basis of an X-ray. The different stages of the crack mark give conclusions about the bone maturity and thus on the expected skeletal growth. The stages of incipient ossification up to the complete fusion of the apophysis with the ilium (Os Ilium) are classified in Europe in a scale of Risser 0 to 5. In the United States, 4 stadiums are defined. The Risser sign can be used to define the correctability of the spinal column in scoliosis patients. It is thus an important diagnostic procedure to plan a scoliosis treatment. It is a clear indicator of whether corset treatment is necessary or useful. Under normal conditions starting from Risser 3 to 4 no correction of the spine is possible anymore because the growth is already finished. From this stage, the compression of the bones has usually already begun. A correction can only take place with the spine still growing. For this, the Risser Stadium 0 to 2 is most suitable. For a precise planning of scoliosis therapy but other parameters, such as general physical maturity and the X-ray of the carpal bones are taken into account.
- Stage 0: The apophysis is not yet visible.
- Stage I: The apophysis begins to develop in the anterior region of the iliac crest (early ossification).
- Stage II: The apophysis covers half of the iliac crest. Stage III: The apophysis now extends to three quarters of the iliac crest.
- Stage IV: The iliac crest fully covers the iliac crest. The merger begins in the back segment.
- Stage V: The ilium (Os Ilium) is completely fused with the iliac crest.
How Risser 0 is distinguished from Risser 5
In Risser 0 (left) the iliac crest is still irregular – whereas in stage 5 (right) it is evenly shaped. In practice, there are always situations in which the physical maturity signs of scoliosis patients required for the diagnosis deviate significantly from the normal agreement with the chronological age. This means that there can sometimes be big differences between the skeletal bony maturity and the outer maturity signs and the Mensis. In such cases, the Risser stage can be assigned on the basis of the regularity of the iliac crest. In Risser 0, the iliac crest is still irregular, especially in the anterior region – in Risser 5, the margin is evenly formed over the entire iliac margin.