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Congenital anomalies of the spine are due to abnormal vertebral development and result in growth asymmetry. Although the vertebral anomalies are present at birth, the deformity may not be diagnosed until later in life. These anomalies can be divided into three major categories: scoliosis, kyphosis, and lordosis. Scoliosis and kyphosis often occur together in the same patient. Congenital scoliosis is defined as a lateral curvature of the spine due to congenital vertebral anomalies that result in frontal plane 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. The location of the vertebral anomaly does not correlate with the genitourinary or cardiovascular anomalies.
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.
The anomalies are classified as failure of formation, failure of segmentation, and both failures of formation and segmentation (mixed). Example of failures of formation are hemivertebra and wedge vertebra. Examples of failures of segmentation are a unilateral unsegmented bar and block vertebra. Mixed anomalies represent a mumbo jumbo, with combinations of both segmentation and formation failures (e.g., a unilateral unsegmented bar with contralateral hemivertebra).
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