1. Of 117 cases of scoliosis treated by spine fusion, the growth of the fused segment of the spine in young patients was absent or minimal except when pseudarthrosis occurred.
2. Pseudarthrosis was related to the mobility of the fused spinal segment and to the extent of the fusion. It was very common in fusions of the lumbar spine, but infrequent in fusions of the thoracic spine alone. Spontaneous closure of the pseudarthrosis was often observed when the scoliosis became stabilized.
3. In idiopathic thoracic and thoracolumbar and paralytic thoracolumbar curve patterns, shlort fusions of the main curve and one vertebra and belove it gave the most satisfactory results.
4. Increase of the scoliosis following spine fusion was seen when the fused area was either too long or too short. In extensive fusions, increased scoliosis was associated with pseudarthrosis, bending of the graft, or with the addition of more vertebrae to the curve. Where fusion did not reach the ends of the curve, increase occurred above or below the fused segment.