Bone mineral status after pediatric spinal cord injury

The impact of spinal cord injury (SCI) on later bone mineral status was studied in 35 adults who had sustained their injury in childhood. The median age of the patients was 31 years, the median age at injury 12.9 years and the median time period from injury was 19 years. The methods used in the study were clinical interview and examination, measurement of bone mineral density (BMD) of the lumbar spine and the proximal femur with dual energy X-ray absorptiometry (DEXA) and estimation of bone turnover with biochemical markers. The densitometric examination revealed that the BMD at the lumbar spine was within the normal range but grossly decreased in the femoral region. Moreover, there was a significant difference in BMD between patients with high (C2-T6) and low (below T6) lesions in the lumbar spine as well as in the femoral region. Patients with lower lesions had higher BMD values. The markers of bone turnover which were studied were serum and urinary calcium and phosphate, serum alkaline phosphatase and its isoenzymes, osteocalcin, carboxyterminal propeptide of human type I procollagen (PICP), carboxyterminal telopeptide of type I collagen (ICTP) and urinary deoxypyridinoline. These markers of bone metabolism showed no signs of ongoing accelerated bone formation or resorption. The present study suggests that caution should be observed in weight bearing training or mobilisation of patients with pediatric SC or perhaps with long standing SCI because of increased fracture risk. The prevention of dissociated osteoporosis should be investigated further in order to avoid fractures of weakened bones. The modes of prevention might be found in the use of modern pharmacotherapy of osteoporosis and from correctly dosaged physical training.