DISTRACTION DEVICE WITH REFLECTOR

A system for evaluating the evolution of a subject's bone structure, including an implantable medical device and a calculation module for computing a parameter representative of the bone structure. The implantable medical device has a distraction body and reflector(s). The distraction body distracts osteotomically separated bone section bodies and includes first/second blocks for implantation and attachment to first/second bone sections, the second bone section separated from the first bone section by an osteotomy, and an actuator for adjusting space between the first/second blocks, enabling distraction between the first/second bone sections. Each reflector reflects an electromagnetic signal and is embedded in a surrounding tissue when the distraction body is attached to the bone. The parameter is computed from the reflected signal, of an excitation signal including a frequency in the characteristic frequency range of each reflector, the reflected signal being representative of a dielectric constant of the surrounding tissue.