Infantile Idiopathic Scoliosis

Infantile idiopathic scoliosis is a condition that affects children before age 3 and is characterized by an abnormal curvature of the spine to the right or left, in the shape of an S or a C. The condition is more common in boys than in girls. Those with the infantile form will generally fall into two groups: those whose curvature disappears with growth and those whose curvature becomes progressive. Most cases resolve spontaneously, but some may progress to more severe deformity. Treatment of infantile scoliosis may include observation, physical therapy, bracing, casting, and, under rare circumstances, surgery.

Basic Facts About Infantile Scoliosis

• Scoliosis is technically defined by the presence of a curve in the spine to the right or left of >10 degrees.
• Most infants who develop abnormal curves do so in the first 6 months of life.
• Infantile scoliosis is a rare condition, accounting for less than 1% of all cases of idiopathic scoliosis.
• The condition is more common in Europe than in the U.S.
• For unknown reasons, the spine tends to curve to the left in infants with scoliosis. However, girls who develop curves that bend to the right have a worse prognosis than other infants.
• For reasons not yet understood, it has been found that children who develop scoliosis before the age of 5 are more likely to have cardiopulmonary abnormalities in infancy.
• Infants with idiopathic scoliosis usually do not experience any pain from the condition.

What Causes Infantile Idiopathic Scoliosis?

The exact cause of infantile scoliosis is unknown. However, the extensive medical research into scoliosis has led to two main hypotheses about its causes.

There is evidence to suggest that intrauterine molding may be responsible for the development of infantile scoliosis. During fetal growth, intrauterine molding can affect the spine due to abnormal pressures exerted by the uterus on one side of the fetus’s body or to abnormal fetal positioning within the uterus. This hypothesis is supported by epidemiological data showing higher rates of plagiocephaly (a slight flattening of one side of the head) and developmental dysplasia of the hip (a condition affecting one hip) on the same side as the spinal curve in infants with idiopathic scoliosis.

A second theory suggests that postnatal external pressures are exerted on the spine after birth, perhaps due to an infant being positioned on his/her back for extended periods of time in the crib. A final hypothesis for a possible cause of infantile scoliosis is that of genetic inheritance. While the exact genes involved have yet to be identified, research has shown a higher incidence of the condition within some families, lending considerable weight to the likelihood of a genetic component.

Despite the substantial evidence for these hypotheses, much about the condition remains to be discovered and fully understood. As a result, ongoing research at a number of academic medical centers throughout the U.S. is seeking to further uncover the mechanisms underlying the development of infantile scoliosis and to improve its treatment and prevention.

How Is It Diagnosed?

Infantile scoliosis is usually first detected in the first 6 months of life during a standard physical examination by a pediatrician or noticed by a child’s parents. When scoliosis is suspected, a careful neurologic exam, as well as an exam of the head, back, and extremities, should follow to assess for plagiocephaly and to ensure the spinal cord is not affected by another disease. A spinal MRI, a sophisticated radiological imaging technique, is essential to confirm the findings of the neurological exam and rule out other potential causes of scoliosis. A series of X-rays should also be taken, allowing for a more precise measurement of the curvature's severity.

How Is It Treated?

Decisions regarding the appropriate treatment for infantile scoliosis depend primarily on the severity of the spinal curvature and the likelihood that it will worsen in the future. Because mild curves (10-25 degrees) very rarely progress to more severe curves and instead usually correct themselves, these children are treated only with observation. This entails that the child be seen regularly by an orthopaedic surgeon, who will monitor the possible progression of the curve with physical exams and x-rays. The scoliosis curve will be measured, along with the rib-vertebral angle difference (RVAD). The higher both of these numbers, the more likely the curve is to progress and the less likely that the curve will resolve on its own without intervention.

Infants with moderate and severe curves have a greater chance of progressing and often require casting and/or bracing treatment.

Whether the curve resolves or continues to progress, visits must continue even into adolescence, because growth spurts may trigger progression, even in a previously non-progressive curve.

Casting Treatment

Casting treatment consists of serial casting, which entails changing the cast every 6 to 12 weeks and applying a new one to gradually correct the curvature. The cast is made of plaster or fiberglass and applied in the operating room under general anesthesia, meaning the infant will be put to sleep during the application so as not to fuss or experience discomfort. Correction is usually achieved by around 18 months of age.

Casting treatment is followed by bracing, which is needed to maintain the correction. There are several braces available for the treatment of infantile scoliosis, and there is no consensus on which is best. Further, there is no scientific evidence that infant bracing alters the natural history of this condition. Except for bathing and exercise, the brace is to be worn all the time, usually for 2 to 3 years, after which the child is weaned off the brace, provided the curvature has been corrected.

Occasionally, curves recur after brace removal, which necessitates reinstitution of full-time bracing treatment, or curves progress during bracing treatment, in which case surgery is warranted.

Surgical Treatment

Surgical treatment options are generally the same for both infantile and juvenile idiopathic scoliosis.  Operations may consist of:

• Instrumentation, in which metal rods are attached to the spine to maintain curve correction, and/or
• Spinal fusion, in which two or more of the vertebrae are fused together with bone bridges made of bone grafts.

Surgeries may be performed through a posterior approach, with an incision in the back, or an anterior approach, which requires an opening in the chest wall to reach the front part of the spinal column. Because of the stability and effectiveness of the devices used in spine operations today, patients can be mobile the day following their surgery, and hospital stays are generally under 1 week.  

Our spinal deformity service has added another technique that uses instrumentation on the rib cage to provide growth of the spine and the chest without fusion. The technical name, distraction thoracoplasty, speaks to the dual goals of distracting the hemithorax to create space in the chest for lung growth and lengthening the spinal column to control the scoliosis.

Coping With Infantile Scoliosis

Managing the demands of bracing or casting for scoliosis can be difficult for infants and their parents alike. Surgery at such a young age, if necessary, can seem somewhat daunting as well. Research has shown that the various treatments for infantile idiopathic scoliosis are generally extremely successful. The vast majority of children grow up without any limitations to their activities and daily functioning, from simple outdoor games to competitive sports. Despite some challenging hurdles early in childhood, with treatment, your child may be expected to live a normal, healthy, active life, and walk tall into adolescence and adulthood