1. Fusion of the spine may be accomplished by the Hibbs operation in practically all cases. (In a series of 221 operated cases, including both those of scoliosis and tuberculosis, failure of fusion occurred in only one case.)
2. The cause of failure to obtain fusion in the few instances in which it occurs is either inaccurate operative technic in securing bone contact, or infection.
3. There is no difficulty in obtaining fusion in young children.
4. The process of bone repair resulting in fusion proceeds much more rapidly in children than in adults, and therefore children are the most favorable subjects in whom to obtain spine fusion.
5. It is practically impossible to determine by x-ray examination whether or not fusion has occurred as a result of operation in a given area.
6. It is not more difficult to effect fusion in the lumbar region than in other parts of the spine.