VIBRATION EXTRACTOR FOR REMOVAL OF THREADED FRAGMENTS OF PEDICLE SCREWS

This invention relates to orthopedics, traumatology and vertebrology and is intended to extract threaded pedicle screws from bone fragments which remain therein as a result of fatigue fracture and have no structural elements to facilitate their capture and unscrewing by known tools. The invention is characterized in that the design of the tool, which comprises a handle to generate torque, a head in the form of a cup with holes in the bottom for end tabs of engagement elements consisting of removable inserts in the form of segments with screw projections (blades) on the inner conical surfaces as well as a groove and slots for the insert retainers shaped as a fashioned annular spring; wherein, pursuant to the invention, the pivotal portion of the tool between the handle and the head consists of a hollow cylinder with openings for cooling and a tubular head adapter arranged successively on the same axis and interconnected by a flange formed in oscillation node plane, a cylinder-shaped, stepped half-wave longitudinal vibration concentrator, a larger diameter end of which is coupled with a magnetostrictive energy converter in the form of a two-leg frame core with extensional mechanic oscillation excitation windings installed in the cylinder cavity, and a smaller diameter end located in the tubular adapter is in contact with insert deflectors that are spring-loaded in the axial direction by the inner parts of the fashioned annular spring (lock), and the end surfaces of the concentrator are located in the planes of oscillation antinodes. The inner parts of the spring, which is in a free state, designed to be placed in the grooves on the outer surfaces of the inserts, while its external parts designed to fit in the annular groove and in the head cup openings are at different levels. Owing to vibration of the engagement elements, the design of the extractor improves the reliability of the capture and unscrewing of threaded screw fragments differing in diameter and having no special structural elements for transmission of torque. Изобретение относится к ортопедии, травматологии и вертебрологии и предназначено для извлечения из костной ткани резьбовых фрагментов транспедикулярных шурупов, которые находятся в ней в результате усталостного разрушения и не имеют конструктивных элементов, способствующих их захвату и вывинчивания с помощью известных инструментов. Суть изобретения заключается в том, что в конструкции инструмента, которая содержит рукоятку для создания крут