Orthopedics - Oleksa A.P. 2006

Congenital spinal deformities

Among Developmental anomalies of the spine, structural defects of the vertebrae deserve primary attention.

In clinical practice, supernumerary posterior and lateral hemivertebrae occur, which cause corresponding spinal curvatures.

A posterior wedge-shaped hemivertebra causes a fixed-form bend in the affected segment of the spine. The posterior hemivertebra is clearly visible on lateral spinal radiographs. The body of the hemivertebra is significantly reduced in size and preserved only in its posterior part. The posterior complex of the vertebra may be somewhat smaller, though it is more frequently normal. This anomaly results in congenital angular or arcuate Kyphosis.

A congenital lateral supernumerary hemivertebra can be located in any part of the spine (Fig. 249). It has a wedge shape, and the hemi-body is connected to its lateral components. A lateral hemivertebra in the thoracic and lower cervical regions typically features an additional unpaired rib. In some cases, radiographic examinations reveal supernumerary hemivertebrae simultaneously across all spinal segments, though they are most common in the lower cervical and upper thoracic regions. The supernumerary hemivertebra connects to adjacent vertebrae via a Y-shaped disc, as it is positioned across half of normal vertebrae and encompasses the hemivertebra on both sides (Fig. 250).

Class="center">

Fig. 249. Lateral wedge-shaped hemivertebra between D₁₂- L₁(a). Diagram of wedge-shaped vertebra variants (b).

In such cases, the wedge-shaped hemivertebra contains two growth plates that drive much faster growth compared to the hemisegment of normally contacting vertebrae. This triggers a rapid, progressive spinal deformity. Slowed progression occurs when the growth plates of the hemivertebra are underdeveloped or when the hemivertebra fuses with an adjacent normal vertebra. In the latter case, deformity progression does not occur, as the growth activity of both the normal vertebra and the hemivertebra remains equal.

Fig. 250. Butterfly vertebra anomaly (S.A. Reinberg).

Fig. 251. Congenital vertebral clefts: A-G – posterior, D-ZH – anterior.

A supernumerary hemivertebra can be a cause of dysplastic Scoliosis.