Changes of the lumbar spinal canal proximal to spina bifida occulta. An archaeologic study with clinical significance.

STUDY

DESIGN

This archaeologic study, based on four populations, examines the incidence of spina bifida occulta in the lumbar spine and the size of the vertebral canal proximal to the lesion.

OBJECTIVES

To ascertain any significant change in the dimensions of the lumbar spinal canal of skeletons with spina bifida occulta. The incidence of the lesion also was compared in the separate genetic groups.

METHODS

Central canals of 1760 lumbar vertebrae were examined. Silhouette, unmagnified pictures of the vertebral canals were measured by computerized image analysis.

RESULTS

The mid-sagittal diameter at L4 and L5 and the cross-sectional area at L5 were found to be significantly larger proximal to the lesion compared with the unaffected spines. The overall incidence was 18%.

CONCLUSIONS

The capacity of the lumbar canal is greater proximal to spina bifida occulta. Therefore, delayed closure of the neural arch at a single segment has morphologic significance to the more proximal spine.