Radiographically, we have frequently noted spiny bifida occulta of posterior lumbar and/or sacral spine in anteroposterior views of the pelvis in Perthes' patients. We reviewed the relation between Spina bifida occulta and Perthes' disease. A high incidence of 80% of spina bifida occulta was shown in 230 Perthes' patients whose age at diagnosis ranged from 2-16 years and averaged 7.4 years. Fusion of the posterior elements progressed with growth; whereas at follow-up 94% of 125 patients before 14 years were unfused and 48% of 58 patients aged over 15 years were fused. Growth retardation due to delayed general skeletal maturity in Parthes' patients exists in the posterior lumbosacral area.
