Adolescent idiopathic scoliosis
Adolescent idiopathic scoliosis (AIS) is a progressive growth disease that affects spinal anatomy, mobility, and left-right trunk symmetry. The disease can modify human gait.
Scoliosis in patients between 10 and 18 years of age is termed adolescent scoliosis.
By far the most common type of scoliosis is one in which the cause is not known. It is called “idiopathic” or adolescent idiopathic scoliosis (AIS). Although significant ongoing research continues in this area, including the genetic basis for AIS, there are no identifiable causes for this condition today. Despite this, we currently have accurate methods to determine the risk for curve progression of scoliosis and good methods of treatment.
Classification
Etiology
The pathophysiology appears to be disorganization in the growth plate with increased growth of the posterior vertebral body with respect to the anterior VB. Hueter-Volkmann law may apply: compression of the cartilaginous endplate (physes) at the anterior vertebral body inhibits longitudinal growth.
There are significant efforts being made toward identifying the cause of AIS, but to date there are no well-accepted causes for this particular type of scoliosis. The vast majority of patients are otherwise healthy and have no previous medical history. There are many theories about the cause of AIS including hormonal imbalance, asymmetric growth and muscle imbalance. Approximately 30% of AIS patients have some family history of scoliosis, and therefore there seems to be a genetic connection. Many Scoliosis Research Society members are working to identify the genes that cause AIS, and this knowledge continues to expand at a rapid pace. Most likely, there will be many genes associated with scoliosis and each may be helpful in detecting scoliosis and determining the risk for progression of the curve. A genetic screening test, called the ScoliScore™ is available as an adjunct to clinical and x-ray information to determine risk of progression in Adolescent Idiopathic Scoliosis. It is currently used in Caucasian (North American, European, Eastern European, Middle Eastern) patients between the ages of 9 and 13 years with a mild scoliotic curve (less than 25 degrees). The stated goal of the test is to determine the risk that the curve will increase to 40 degrees or more. Thus far independent verification of the test has not been done.
Clinical features
Adolescent idiopathic scoliosis generally does not result in pain or neurologic symptoms. The curve of the spine does not put pressure on organs, including the lung or heart, and symptoms such as shortness of breath are not seen with AIS. When scoliosis begins in adolescence patients often have some back pain, typically in the low back area. Although it is often associated with scoliosis, it is generally felt that the curvature does not result in pain.
Low back pain is not uncommon in adolescences in general. Many teens experience back pain due to participating in a large number of activities without having good core abdominal and back strength, as well as flexibility of the hamstrings. Adolescent idiopathic scoliosis generally does not result in pain or neurologic problems. If these symptoms occur, further evaluation and testing may be necessary to include an MRI.
Daryabor et al., selected 33 studies investigating the effect of scoliosis deformity on gait parameters and energy expenditure during walking. Most of the studies concluded no significant differences in walking speed, cadence and step width in scoliosis patients and normal participants. However, patients showed decreased hip and pelvic motion, excessive energy cost of walking, stepping pattern asymmetry and ground reaction force asymmetry.
There is a consistent lack evidence of the effect of scoliosis on temporal spatial and kinematic parameters in AIS patients as compared with normal people. However, further research is needed to assess the effect of scoliosis on gait and energy consumption 1).