An approach for determining quantitative measures for bone volume and bone mass in the pediatric spina bifida population

• We present a method of quantifying bone mass along the entire length of a long bone.
• The methodology is based on the analysis of CT scans.
• We present results for ambulatory and non-ambulatory children with spina bifida.
• These results are compared to typically developing children.
• Results indicate that even limited ambulation may help build and maintain bone mass.

BackgroundThe pediatric spina bifida population suffers from decreased mobility and recurrent fractures. This study aimed to develop a method for quantifying bone mass along the entire tibia in youth with spina bifida. This will provide information about all potential sites of bone deficiencies.MethodsComputed tomography images of the tibia for 257 children (n = 80 ambulatory spina bifida, n = 10 non-ambulatory spina bifida, n = 167 typically developing) were analyzed. Bone area was calculated at regular intervals along the entire tibia length and then weighted by calibrated pixel intensity for density weighted bone area. Integrals of density weighted bone area were used to quantify bone mass in the proximal and distal epiphyses and diaphysis. Group differences were evaluated using analysis of variance.FindingsNon-ambulatory children suffer from decreased bone mass in the diaphysis and proximal and distal epiphyses compared to ambulatory and control children (P ≤ 0.001). Ambulatory children with spina bifida showed statistically insignificant differences in bone mass in comparison to typically developing children at these sites (P > 0.5).InterpretationThis method provides insight into tibial bone mass distribution in the pediatric spina bifida population by incorporating information along the whole length of the bone, thereby providing more information than dual-energy x-ray absorptiometry and peripheral quantitative computed tomography. This method can be applied to any population to assess bone mass distribution across the length of any long bone.