Bone elongating devices and methods of use

Abstract

An implantable bone elongation device including an inner rod defining an internal cavity housing a rotational actuator having an output shaft connected to a lead screw disposed at the end of the inner rod and in threaded engagement with a threaded inner surface of an outer rod. Rotation of the lead screw converts rotation motion into linear motion resulting in telescopic movement of the outer rod relative to the inner rod. Rotational motion is converted into linear motion by components disposed in a parallel configuration thereby minimizing the overall length of the bone elongating device while maintaining a maximum stroke length. In various embodiments, additional components, such as electronic circuit boards, electrical power supply or battery power source, may be housed within the internal cavity formed by the inner rod. The bone elongation device of the present invention may be affixed to a bone in a variety of configurations including implantation into a medullary cavity of the bone, attached to an outer surface of the bone, or attached to the bone as an extramedullary plate.