Twenty-nine patients (mean age 12 years) with severe thoracolumbar and lumbar scoliosis due to myelomeningocele were treated by spinal fusion (7 by posterior arthrodesis with instrumentation, 3 by anterior arthrodesis with instrumentation, 19 by combined anterior and posterior fusion with instrumentation). Fusion was extended to the sacrum in 15 patients. Mean period of follow-up was 6.2 years. The average Cobb angle changes were as follows: thoracic and thoracolumbar curves preoperatively 86 degrees to 45 degrees at follow-up (the final average curve correction was 47%); lumbar curves preoperatively 97 degrees to 48 degrees at follow-up (the final average curve correction was 50%). Average pelvis obliquity changed from 26 degrees to 13 degrees at follow-up with an average correction of 49%. The combined anterior and posterior instrumentation and fusion gave the best correction of deformity (the final average thoracic and thoracolumbar curve correction was 55%; the final average lumbar curve correction was 61%). Independent of the method of stabilization, post-operative wound infection was a serious problem (24%). The combined fusion-instrumentation method reduced the rate of pseudoarthrosis to 14%.