Scoliosis is a medical condition defined by an abnormal, sideways curvature of the spine that measures ten degrees or more, accompanied by a rotational component of the vertebrae. Medical professionals use a precise, multi-layered naming convention that combines the condition’s cause, the patient’s age at onset, and the curve’s anatomical location to accurately describe the specific presentation. This comprehensive classification informs the prognosis, predicts the likelihood of curve progression, and dictates the most appropriate treatment strategy for the individual patient.
Naming Based on Cause or Origin
The first component of the scoliosis name establishes the underlying reason for the spinal curvature. The largest group, accounting for approximately 80% of all cases, is classified as idiopathic scoliosis, meaning the cause remains unknown. This suggests a complex interplay of genetic and environmental factors.
Congenital scoliosis arises from malformations of the vertebrae that occur during the third to sixth weeks of fetal development. These structural abnormalities can involve a failure of a vertebra to form completely or a failure of the vertebrae to segment properly, leading to an immediate and fixed spinal deformity. Neuromuscular scoliosis is secondary to conditions that affect the nerves and muscles supporting the spine. This type is seen in patients with disorders such as cerebral palsy, muscular dystrophy, or spinal cord trauma.
The cause of the scoliosis fundamentally influences the treatment approach and the potential for curve progression. Therefore, establishing the origin is the foundational step in the classification process and the most important factor in determining the full medical name.
Naming Based on the Age of Onset
The second layer of classification specifies the patient’s age at the time the scoliosis is diagnosed. This distinction is important because the risk and speed of curve progression are directly related to the amount of skeletal growth remaining.
The age-based classifications for idiopathic scoliosis include:
- Infantile idiopathic scoliosis is diagnosed in children from birth up to three years of age and often has a unique natural history, sometimes resolving spontaneously.
- Juvenile idiopathic scoliosis is the term used for children diagnosed between the ages of four and nine years. Curves appearing during this stage are often considered more concerning because the patient has many years of growth remaining.
- Adolescent idiopathic scoliosis (AIS) is the most frequently diagnosed form, occurring between the age of ten and skeletal maturity, typically around 18 years old.
- Scoliosis diagnosed after skeletal maturity is simply termed adult scoliosis, where the concerns shift from preventing growth-driven progression to managing pain and degenerative changes.
Combining the cause and age creates a more specific diagnosis, such as “Juvenile Idiopathic Scoliosis,” which immediately conveys important clinical information. This combination helps physicians predict the curve’s behavior and determine whether aggressive intervention, like bracing, is warranted during the patient’s remaining growth period.
Anatomical Description of the Spinal Curve
The final part of the classification provides a precise anatomical description of the curve, including its location in the spine and the direction in which it bends. The spine is divided into three main regions: the thoracic spine (mid-back), the lumbar spine (lower back), and the thoracolumbar region (where the two sections meet). The location is determined by the vertebra at the apex, or the peak, of the curve.
The curve’s direction is named based on the side toward which the convexity points. A curve that bends to the right is called a right curve or dextroscoliosis, while one that bends to the left is called a left curve or levoscoliosis. Some patients have a single, C-shaped curve, while others exhibit double curves, often forming an S-shape, where one curve is typically in the thoracic region and the other is in the lumbar region.
Another crucial descriptor is the severity of the curve, quantified using the Cobb angle measurement on a standing X-ray. This angle is determined by drawing lines from the most tilted vertebrae above and below the apex of the curve. A measurement of 10–24 degrees is generally considered mild, 25–40 degrees moderate, and over 40 degrees severe. By combining all these descriptive elements, a full medical name can be constructed, such as “Right Thoracic Adolescent Idiopathic Scoliosis.”