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Congenital Kyphosis

Congenital anomalies of the spine are due to abnormal vertebral development and result in growth asymmetry. Congenital kyphosis is defined as an abnormal sagittal curvature of the spine due to congenital vertebral anomalies that result in sagittal growth asymmetry. The etiology of the spinal anomaly is congenital, due to an event that occurs between 4 and 6 weeks of gestation. The overall incidence is unknown, but these anomalies are relatively rare. In the thoracic spine, the incidence is ~0.5 per 1000. Isolated anomalies (hemivertebra) are sporadic with no familial or genetic tendencies. The presence of multiple location complex anomalies is related to a 5 to 10% risk of a similar lesion in siblings or subsequent generations, as well as an increased risk of neural tube defects. In addition, those organ systems developing at the same time of gestation may also demonstrate congenital anomalies, with up to 60% of children having malformations in other organ systems. The most commonly affected systems beside the remainder of the musculoskeletal system are the genitourinary, cardiovascular, and central nervous systems.

MRI scans are recommended for all children with congenital kyphosis. This is to assess for dural compression and the presence of other spinal cord anomalies.

Like congenital scoliosis, these are classified as failure of formation, failure of segmentation, and mixed. Failure of formation nearly always occurs in the thoracic and thoracolumbar spine; failure of segmentation type is most common in the lumbar and thoracolumbar areas; mixed types typically occur at the thoracolumbar junction.

1.Defects of Segmentation

2.Defects of Formation

The treatment of congenital kyphosis is in most cases surgical. The surgical options depend upon the child's age, type of deformity, and magnitude of deformity. For those children with failure of formation who are younger than 5 years and have a kyphosis <55 degrees, posterior spinal fusion in situ (one level above to one level below) allows for improvement with growth. For those children older than 5 years with failure of formation and/or whose curve is >55 degrees, anterior and posterior spinal fusion with or without instrumentation is indicated.

In children with failure of segmentation and kyphosis <50 degrees, posterior spinal fusion with compression instrumentation (one level above to one level below) is typically performed, especially when the patient is older than 10 years of age. For those with a severe deformity and in whom correction is desired, then anterior vertebral osteotomy with posterior spinal fusion and compression instrumentation is required; again, these procedures are technically challenging and neurologically risky.