Scoliosis Research Society (SRS)
An International Organization Dedicated to the Education, Research and Treatment of Spinal Deformity
Our Mission is to Foster Optimal Care for All Patients with Spinal Deformities
The term "congenital scoliosis" refers to a spinal deformity caused by vertebrae that are not properly formed. This occurs very early in development--in the first six weeks of embryonic formation and often before the mother knows she is pregnant, and the cause is not known. Congenital scoliosis does not seem to run in families. Genetic studies to date have not yielded much evidence that this condition can be inherited. Although congenital scoliosis is often discovered during the infant or toddler period, in some children it does not appear until their adolescent years.
Spine surgeons describe congenital spinal anomalies based on which part of the vertebra is malformed or connected. Depending on the structure of the anomaly, the child may exhibit scoliosis (a curve to the right or left), kyphosis (rounded back), or lordosis (sway back). However, not all congenital anomalies fit neatly into these categories. There are often elements of more than one deformity, particularly scoliosis and kyphosis, occurring together.
Spine surgeons may refer to the spine anomaly as a "failure of segmentation." This means that one or more vertebrae are abnormally connected together on one side. This connection will slow growth on that side of the spine. Normal growth on one side with slowed growth on the other leads to a spinal deformity. "Failure of formation," the most common type of congenital problem, means that the normal shape of the vertebra is disrupted (Figure 1). On an X-ray view taken from front to back, these vertebra will look like triangles instead of rectangles. Regular X-rays, though, only show a two-dimensional picture of what is really a three-dimensional problem. The abnormally shaped vertebra may cause a wedge in the front, back, or either side, or a combination, tilting the spine at that level. Spine surgeons often use descriptive terms to describe how much growth potential may be in the congenital anomaly. The term "fully segmented" means that there is a growth plate and a disk on both the top and bottom of the abnormal vertebra. "Semi-segmented hemivertebra" have a disk and growth plate either above or below. "Non-segmented hemivertebra" are fused to the vertebra above and below. Since non-segmented hemivertebrae have no growth plates, the curves they cause are much less likely to progress than those due to semi-segmented hemivertebrae, which are less likely to progress than a fully segmented hemivertebra. A "block vertebra" means that there is a missing disk space. Block vertebrae essentially have no growth potential and therefore rarely cause a progressive deformity.
Figure 1: Types of congenital scoliosis