The normal interpediculate space in the spines of infants and children.

Abstract

An original study by Elsberg and Dyke (3, 4) in 1934 pointed out the rarity of destructive bone changes in certain types of spinal cord tumors. Also noted was the need for other roentgen findings which might contribute to the diagnosis of spinal cord tumor without contrast studies, inasmuch as a thorough clinical and plain roentgenographic study should be undertaken before the final diagnostic step. Accordingly, these two authors measured the interpediculate spaces in roentgenograms of 100 normal spines in subjects above the age of twelve years. Plotting the measurements on a graph, they obtained the interpediculate space curve (Fig. 1) which has since been widely used as a standard normal. The two curves on the graph indicate “usual” and “extreme” normal interpediculate distances for each vertebra from the lower cervical level to the sacral region. No minimum normal measurement curve was plotted. It was found that the first three cervical pedicles could almost never be adequately visualized for measurement and that frequently the fourth, fifth, and sixth cervical were visualized with difficulty. Particular attention was also called to the fact that differences in the interpediculate distances from one level to the next of the magnitude of 2 to 4 mm. cannot readily be detected without actual careful measurement. Differences of 1 mm. can safely be allowed as coming within the limits of normal error in measuring. Anderson and Carson (1) in their excellent recent review, Camp (2) in a paper some years ago, and Olsson (7), among others, have stressed the importance of careful measurement of the interpediculate spaces. Camp, particularly, notes the value of change in contour of the pedicles. Anderson and Carson make the significant point, perhaps too little known, that physical and neurological findings may be minimal even after definite roentgenographic changes are detectable. Even the spinal fluid examination and Queckenstedt test may be equivocal after x-ray findings are positive and clear-cut. In several cases in the literature minimal symptoms were present over a period of years before a diagnosis was made, though a review of films revealed diagnostic local widening of the interpediculate spaces early in the disease. It has been shown (1) that a high percentage of infants and children with spinal cord tumors reveal pathological roentgen diagnostic changes at the appropriate level. Many of them have no changes aside from those in the interpediculate spaces. French and Peyton (6) reported normal interpediculate measurements from the seventh thoracic to the fifth lumbar vertebral level in 50 children from birth to five years and in 50 children from five to ten years of age. Since no similar study and no study of the entire spine was discovered in the literature, the present investigation was undertaken, in the belief that normal interpediculate distance curves in children from birth to twelve years should be of considerable diagnostic value.