Abstract: Devices for lengthening bone, particularly the mandible and other small bones, by distraction osteogenesis are presented. The devices are implantable in an appropriate surgical procedure, and provide for an optional flexible drive shaft, used to transmit controlled torque for elongation of the devices thereby effecting distraction osteogenesis, which optional flexible drive shaft may conveniently terminate within the oral or buccal cavity. In one embodiment, the devices provide a telescoping screw assembly and drive means, which drive means may be an angled gear drive. In another embodiment, a threaded flexible drive shaft is provided which provides for elongation of the devices thereby effecting distraction osteogenesis.