Influence of therapeutic ultrasound on rabbits bone growth plate

Abstract

Therapeutic use of ultrasound on children's bones growth plates is still little studied as to its harmful effects, hence many children fail to be treated with it. This study evaluated the influence of applying ultrasonic energy, in its continuous and pulsed forms, onto the growth plate of growing rabbits' tibias, to identify doses that might produce macro and/or microscopic changes, thus harming the normal bone growth. Thirty-two 8-week old rabbits were used, divided into three groups, which received each different radiation areas and intensities of continuous and pulsed ultrasound on the medial face of the right tibia upper end. The three groups' left tibias were used as control. X-rays of right and left tibias and femurs of all animals were taken two days previous to the first ultrasound application and at the age of 16 weeks; growth plates histomorphometric analysis was made in order to assess lateral and medial areas microscopic fields. In the first group, which received pulsed ultrasound, no statistically significant differences were found between values obtained from the right and left sides, in all analyses made. The same did not happen to the other groups (treated with continuous ultrasound), in which changes were found, including X-ray alterations. In rabbits, thus, treatment with pulsed ultrasound in 20% with 2w/cm2 (ISATP) does not have harmful effects onto bones growth plate.