Classic history and presentation: By definition, scoliosis refers to spines with a lateral curvature that is measured to be more than 10 degrees. About 75%-85% of scoliosis is idiopathic, with the rest categorized as pathologic, degenerative, congenital, or neuromuscular scoliosis. Idiopathic scoliosis is further subdivided based on the age of onset. All cases with onset in patients aged younger than 10 years are characterized as early-onset scoliosis. This group can be further subdivided into infantile (onset in patients aged 3 years and younger) and juvenile (onset in ages 4-9 years). Adolescent is onset in patients aged 10 years and older. About 90% of idiopathic cases are diagnosed as adolescent idiopathic scoliosis (AIS).

Most patients do not experience any clinically significant symptoms; however, the most severely affected can have difficulty breathing, chest deformities, back pain, and cosmetic defects. In the most extreme cases, patients can develop paralysis due to spinal cord or nerve compression.

Patients classically present due to a positive screening examination at school / pediatrician assessment or due to a truncal asymmetry noticed by a family member. Only about 25% of patients will have any pain. Risk of curvature progression depends on the patient's skeletal maturity at onset of diagnosis.

Screening recommendations vary. The United States Preventive Services Task Force and the American Academy of Family Physicians recommend against routine screening in asymptomatic children, while many other organizations, including the American Academy of Orthopaedic Surgeons and the American Academy of Pediatrics, believe that all children, regardless of symptomatology, should undergo basic screening. Screening examination is done using the Adam's forward bend test and a scoliometer to identify higher-risk patients who may require further intervention.

Prevalence: Scoliosis is estimated to affect 2%-4% of adolescents. Although males and females have the same overall incidence of scoliosis onset, females are 10 times more likely to have progression of their curvature when compared to males.

Pathophysiology: While the pathophysiology is still unclear, it seems that idiopathic scoliosis is multifactorial but that there is a large genetic component.

Grade / classification system: The Lenke and King-Moe classification systems are commonly used in AIS.