Many different forms of scoliosis exists, but the adolescent idiopathic scoliosis is present in 2 to 4 percent of children between 10 and 16 years of age (Reamy et Slakey 2001). Of these, only 10% have curve progression requiring medical intervention (Miller 1999). The girl:boys ratio for small curves is equal but increases to a ratio of 10 girls for every one boy with curves greater than 30 degrees (Roach 1999). The incidence of chronic pain is three times higher in scoliosis patients than in the normal population (Grivas et al. 2006).
Scoliosis can simply be defined as a lateral curvature of the spine (Magee 2006), but the deformity is far more complex and has to be observed in three dimensions/plans for adequate deformity measurements and deformity quantification (Asher et al. 2006). The Scoliosis Research Society defines scoliosis as a curvature of the spine measuring 10 degrees or greater on x-ray. The term “Cobb Angle” is used worldwide to measure and quantify the magnitude of spinal deformities. The most obvious abnormality is in the frontal plane, however the rotation of the vertebrae makes it a three-dimensional deformity (Eurospine 2007). Basically, there are two types of scoliosis, non-structural scoliosis and structural scoliosis, which manifests itself by the presence of bony deformity (Magee 2006). A structural scoliosis gives range of motion problems, and the curve does not disappear with forward flexion. It can be progressive, contrary to non-structural scoliosis. Here, the spine shows segmental limitations, but side bending is symmetrical and the curve disappears with forward flexion. This type of scoliosis is found in all three spine areas (Magee 2006).
The cause of most scoliosis is unknown and since about 1922 such patients have been diagnosed as having idiopathic scoliosis (Kleinberg 1922). According to Prof. Dr. Harms (2007) and to Weiss (2012), 80%-90% of all scoliosis are idiopathic, while Magee (2006) states that 75%-85% of all structural scoliosis are idiopathic. Scoliosis is further classified in different categories according to age of onset (e.g. infantile, juvenile, adolescent, adult) or to its cause (congentital, neuromuscular, acquired, degenerative etc.) but explaining the differences goes beyond the scope of this paper. Secondary causes of scoliosis include inherited disorders of connective tissue (such as Marfan syndrome, Homocystinuria…), neurologic disorders (such as syringomyelia, spinal tumor, neurofibromatosis, muscular dystrophy, cerebral palsy…) or musculoskeletal problems (including leg length discrepancy, developmental dysplasia of the hip…) (Reamy et Slakey 2001). Scoliosis can be progressive, the main determinants of progression are patient gender, future growth potential and the curve magnitude at the time of diagnosis (Miller 1999).