VIBROEXTRACTOR WITH COMBINED MOVEMENT OF ENGAGEMENT ELEMENTS FOR THREADED FRAGMENTS OF TRANSPEDICULAR SCREWS Russian patent published in 2017 - IPC A61B17/88 

FIELD: medicine.

SUBSTANCE: invention relates to medicine and can be used for extraction from bone tissue of threaded fragments of transpedicular screws, which are located in it as a result of fatigue fracture and do not have constructive elements aiding their gripping and screwing out by means of known instruments that serve the said purpose. Vibroextractor represents rod construction, which includes handle for creation of axial effort and torque, magnetostrictive converter of electromagnetic energy into mechanical longitudinal vibrations, half-wavelength conic concentrator for enhancing thereof, tubular waveguide with spiral slots and with fixed on the end cup-shaped head with engagement elements, which form internal multistart tapered thread, opposite in direction to the fragment thread. After installation of head on the end of screw threaded fragment, magnetostrictive converter (vibrator) is used to create longitudinal mechanical vibrations, which are amplified by concentrator, transmitted to waveguide and by means of spiral bridges formed by slots are converted into screw-like, i.e. combined vibrations of head, contributing to its threading on the end of threaded element, formation of depressions on its thread loops and reduction of applied to handle axial effort and screwing out moment. Pulse character of screwing out moment and forces of cutting-in of head engagement elements into threaded fragment material causes weakening (disruption) of mechanical connection of screw thread loops with bone tissue as a result of friction force reduction, increases reliability of fragment gripping without cutting off thread loops, reduces forcer load on spine and internal organs of human patient and operation time.

EFFECT: invention makes it possible to reduce force load on person's spine and internal organs and to reduce operation time.

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