Infantile idiopathic scoliosis, unlike scoliosis (curvature of the spine) that occurs in older children, self-corrects in about 80 percent to 90 percent of children. Upon discovery of the spinal curve, for the diagnosis to be IIS, it must be found before the age of three years, however the majority are diagnosed between six and 12 months, with about five percent diagnosed in infants. The cause is unknown.
Also unlike scoliosis in older children, more boys are affected (three to two) than girls. Researchers have found that the thoracic curve is more often on the left side than the right, with a second curve below the thorax.
In order to diagnose IIS, physicians must rule out other factors that could contribute to the spinal deformation. These include neuromuscular (nerves and muscles) disorders, as well as those caused by a systemic or a genetic problem.
Children with IIS are often found to have other physical disorders as well. They include plagiocephaly (deformities of the skull), which is found in between 80 percent to 100 percent of cases. There are also many children with IIS who also have mental retardation and progressive curves. The incidence of hip problems is also increased five- to 10-fold. Another common finding in children with IIS is abnormalities in the neural axis. However, the children may show no signs of any neurological problems.
In an effort to determine the causes of IIS, some researchers have proposed that the deformity may have been caused while the fetus was in utero, while others felt it was caused by positioning on the back. However, the cause is not actually known.
The first step in management of IIS is to determine if it should be treated or if it will resolve on its own. Early research suggested that if a patient has a short curve length with a curve of more than 35 degrees, were younger on onset, and had other abnormalities, they were more likely to need treatment. The location of the curve and if there was a second curve below also played a role in if the condition would resolve itself.
Newer research proposed that x-rays showing where the head of the ribs were located could help determine if the curve would straighten on its own. A researcher studied 138 cases of IIS and found that all the patients who had two specific phases of curve patterns progressed rather than resolved.
No treatment is needed if the curves resolve, but if treatment is needed, the curves could reach an angle of 100 degrees or more. This, in turn, can cause cardiac and respiratory problems, resulting in death for some children. For this group, initial treatment should begin immediately, according to the author. This treatment involves bracing, under anesthetic. Future braces are fit as the child grows. Surgical techniques have had problems over the years. Initially, surgery was not recommended for children younger than 10 years, but with the improvements in surgery – including the Harrington rod – younger children were successfully undergoing surgical correction.
The newest approach is to use a vertical expandable prosthetic titanium rib that the author says, “appears to support more normal lung and spinal growth while adequately controlling spinal deformity in infants and young children.”