The effects of low-intensity ultrasound on growing bone after sciatic neurectomy.

The purpose of this study was to investigate the therapeutic effects of low-intensity ultrasound (US) on the sciatic-neurectomy-induced bone mass decrement in growing rats. A total of 20 male Sprague-Dawley rats (166.7+/-11.3 g) underwent right leg sciatic neurectomy. They were randomly assigned into two groups, US treatment group (UST) and control group (CON). The rats receiving US treatment were treated with a 125 mW/cm2 continuous low-intensity US stimulation for 15 min/day on the lateral site of the right leg. The control rats did not receive any US treatment. All the animals were euthanized after 4-week US treatment. Both the original data and bilateral difference ratio of femur or tibia weight, histomorphometry data and bone densitometry data showed that the sciatic neurectomy obviously reduced bone mass in the operated limbs of both groups. However, the continuous low-intensity US treatment did not ameliorate the neurectomy-induced loss of bone mass. Thus, the low-intensity US generated micromechanical strains might not induce enough bone formation activity to reverse the bone loss in this model of intact bones.