Spine fusion in young children; a long-term end-result study with particular reference to growth effects.

The growth effects of spine fusion in early childhood were observed and measured roentgenographically in fifteen patients who were operated upon for tuberculosis and who were followed into adolescence and adult life. In all fusion was successful and the disease of the spine healed; and, since in all of them at least two normal vertebrae had been included in the fusion above and below the diseased area, an unique opportunity was offered to study the effects of arthrodesis on growth in fused normal vertebrae as well as in diseased vertebrae. The growth changes observed were narrowing of the intervertebral disc spaces in the fusion area with occasional partial obliteration, a trapeziform development of the end vertebrae, and underdevelopment of the fused vertebral bodies in both the sagittal and frontal planes. Whenever possible, measurements were made from early postoperative and end-result lateral roentgenograms of the entire fusion area, the normal vertebrae that were included in the arthrodesis above and below the disease, and the normal contiguous spine segments. In order to eliminate the error of unknown early target-to-tube distance and an increase in the target-to-spine distance caused by growth its thickness of the patient, the measurements were expressed and compared as percentage change over 100. In fifteen of the patients, in each of whom it was possible to measure the entire fusion area, fused normal vertebral segments and normal vertebral segments either above or below the old diseased area, or both, it was found that considerable variation of growth occurred even in individuals of similar age at operation. On an average, the entire fusion area grew anteriorly 37 per cent less and posteriorly 45 per cent less than normal vertebrae. The fused normal vertebrae grew 23 per cent less anteriorly and 36 per cent less in the posterior elements than adjacent normal unfused vertebrae.