Shields and colleagues have found that early intervention and long-term treatment with electrical stimulation, which causes muscle contraction and exerts mechanical loading on the targeted bone, can significantly reduce the loss of bone mineral density (BMD) in SCI patients.
Virtually every SCI patient develops severe osteoporosis and muscle atrophy after injury. The bone thinning, which occurs very rapidly -- an average loss of 30 percent in BMD in just three years -- makes the paralyzed limbs particularly vulnerable to fracture.
"The question is will an 18 year old injured today be a good candidate for that cure or repair if their bone is so brittle that it can't bear weight or their muscles are virtually useless?" Shields asks.
In addition, secondary complications, including multiple fractures leading to amputation, and kidney problems caused by excess calcium leached from the bones into the blood, can seriously impair the health of SCI patients. Thus, maintaining the integrity of bone has important implications for improving health of SCI patients.
"The long-range issues relate to helping people injured now remain good candidates for a future cure. The short-term effects are improving the patient's health quality and preventing secondary complications," Shields said.
Muscle contraction exerts forces greater than body weight to bones and is the best way to apply therapeutic stresses to keep the skeletal system (bone) healthy. This simple biomechanical principle comes into play whenever exercise is used to strengthen bones and muscles.