The effect of muscular contraction on the changes of bone mineralization after paralysis was studied in seven spinal cord injury paraplegic rabbits using functional electrical stimulation. The paralyzed quadriceps femoris muscle of one side was contracted by electrical stimulation for 30 minute daily and the other side was not stimulated for comparison. The bone mineral density(BMD) was measured by Dual Photon Absorptiometry(Lunar DPA) in each lower limb before and after the spinal cord injury about one or two weeks intervals for the survival periods.
In the 7 rabbits included in this study, the bone mineral density of both sides was decreased in all the rabbits 4 weeks after spinal cord injury. The decrements of BMD for stimulated and nonstimulated limb were 8.07±7.01 % and 10.66±8.13%, respectively during first 4 weeks after spinal cord injury. The BMD of stimulated side limb was decreased significantly less than that of the other side (p<0.001).
These findings suggest that the early muscular contraction by functional electrical stimulation is beneficial to lessen the osteoporotic changes in paralyzed limbs of spinal cord injury.
