Between 1954 and 1970, 351 patients with severe paralytic scoliosis were treated at Rancho Los Amigos Hospital. During this time the treatment evolved through five stages: body cast alone, halo cast, halo cast with buttons and traction wires, Harrington instrumentation, and finally preoperative halo-femoral traction and Harrington instrumentation. Coincident with this evolution, correction improved from 20 to 57 per cent, the incidence of curve progression dropped from 38 to 0 per cent, and curve extension decreased from 25 to 0 per cent, while postoperative recumbency was reduced from one year to about three weeks. In addition, complications changed, in general decreasing except for the rate of pseudarthrosis, which remained essentially the same. Clinically significant hyperlordosis involving the thoracic and lumbar spine was seen in sixteen patients who had long fusions from the fourth cervical vertebra and above to the fourth lumbar vertebra or the sacrum.