The frequency of the operation for fusion of the spine has increased markedly in recent years, since its utilization for the treatment of scoliosis. As most fusion operations are performed on children during their active growing period, the question arises as to its influence on the growth in length of the vertebral column. If the fused spinous process should act as a brake on expansion of the corresponding bodies, the restriction of growth would be of considerable significance, particularly when one third or more of the processes are fused at one time.
In order to appreciate this investigation better it may be well to have some definite conception as to the mechanism of normal growth of the bodies of the vertebrae. It has been shown in dogs in some previous experiments that growth in length of the bodies takes place at the epiphysial cartilaginous plates in a manner similar to