Patent ID: 8449543
Filing Date: 2013-05-28
Classification: A61B

Abstract:
1. A lengthening device configured for placement inside an intramedullary canal of a bone having first and second separate sections comprising: a housing configured for attachment to one of the first and second separate bone sections; a distraction shaft having an internal cavity along a length thereof and configured for attachment to the other of the first and second separate bone sections; a permanent magnet disposed in the housing and configured for rotation and having at least two poles, the permanent magnet coupled to an axle comprising a sun gear; and a first planetary gear set comprising a plurality of planetary gears disposed within the housing wherein the sun gear of the axle interfaces with the planetary gears of the first planetary gear set; a second planetary gear set comprising a plurality of planetary gears disposed within the housing adjacent to the first planetary gear set wherein an output of the first planetary gear set interfaces with the planetary gears of the second planetary gear set; and an output shaft operatively coupled to the planetary gears of the second planetary gear set, the output shaft operatively coupled to a lead screw, the lead screw interfacing with a threaded portion of the internal cavity of the distraction shaft.