1. In a series of five cases of tuberculosis of the spine, four showed osseous bridging of vertebral bodies.
2. The fifth case showed abortive bony bridging which could not be considered to be actual spontaneous fusion.
3. The process described probably represents a reaction to irritation, with periosteal new-bone formation or ossification in ligamentous tissue, and is not evidence of a healing process.
4. In certain instances such bony bridging accomplishes fusion of vertebrae involved by tuberculosis as effectively as posterior surgical fusion.