[Effect of axial loading on bone mineral density in patients with traumatic spinal cord injury]

Osteoporosis occurs in paralyzed extremities secondary to immobilization following spinal cord injury (SCI). Bone mineral density (BMD) is rapidly lost after SCI. Loss of BMD may reach fracture threshold although it slows with time. This study was planned to investigate the option of impediment of osteoporosis by early axial loading in immobilized patients.

Fifteen patients with complete paraplegia having spinal cord lesion between T4-L1 and 15 normal volunteers were included into the study. Time, mechanism and type of injury, BMD, serum calcium, phosphorus and alkaline phosphatase levels were undertaken as variables. BMD was measured by dual energy X-ray absorbtiometry (DEXA) in the femoral neck, trochanteric region and T1 and L3 spine.

The BMD values were lower in the femoral neck and trochanteric region, but there were no significant differences at T1 and L3 spine in paraplegics.

BMD decreases in the femoral neck and trochanteric region, secondary to immobilization. Absence of significant differences of BMD values at T1 and L3 spine in the study and control groups might be due to early rehabilitation. Sitting exercises early after stabilization might impede of the loss of BMD by axial loading to the spine. Thus, complications such as osteoporosis and pathological fractures can be prevented.