Causes and Risk Factors for Scoliosis
In most cases, the cause for scoliosis is unknown (called idiopathic scoliosis). Idiopathic scoliosis usually develops in children between 10 and 12 years of age and adolescents, usually during a growth spurt (adolescent scoliosis).
Idiopathic scoliosis may have a genetic (inherited) link. It often runs in familiesas many as 30 percent of children with idiopathic scoliosis have a family member (e.g., parent, sibling) who also has the condition.
Causes for scoliosis can be classified as structural or nonstructural. In structural scoliosis, a fixed curve develops in the spine, often as a result of a congenital abnormality. This type accounts for about 5 percent of scoliosis cases.
Structural scoliosis often is associated with medical conditions, such as neuromuscular disease (e.g., cerebral palsy, muscular dystrophy, poliomyelitis), connective tissue disorder (e.g., Marfan syndrome), birth defect (e.g., malformation of a vertebra [hemivertibra]), and rheumatic disease (e.g., rheumatoid arthritis). It also can develop with no known cause or as a result of an injury, infection, or tumor that affects the spine or spinal cord. Neurofibromatosis is an inherited condition that can cause spinal cord tumors and increase the risk for scoliosis.
Nonstructural scoliosis, also called functional scoliosis, is not caused by a structural spine abnormality, but develops as a result of temporary pressure on the spine. Acute inflammatory conditions (e.g., appendicitis), uneven growth that results in one leg being shorter than the other, and severe muscle spasms near the spine can cause nonstructural scoliosis. Nonstructural scoliosis often can be corrected by treating the underlying condition.
Infantile scoliosis (develops in children under the age of 3; more common in boys than in girls) and juvenile scoliosis (develops in children between 3 and 10 years of age) can be idiopathic or may occur with a known cause. These conditions are relatively uncommon. Mild cases of infantile scoliosis and juvenile scoliosis usually resolve without treatment (if the condition is idiopathic) or when the underlying cause is treated.