BLISKUNOV DEVICE FOR ELONGATING LONG BONES Russian patent published in 2008 - IPC A61B17/72 

FIELD: medicine, traumatology.

SUBSTANCE: invention contains external and internal cylinder pullout hollow cases connected with each other, which are made with projection and groove. In internal case there are through holes for fixing screws. In wall of external case there is threaded hole, in which screw-bracket is installed, containing supporting and threaded screw parts, ratchet-and-pawl mechanism and telescopic expandable rod-drive. Ratchet-and-pawl mechanism is connected with external case and includes drive ratchet-wheel with ratchet-teeth containing case; driven ratchet-wheel with teeth, containing case; locking ratchet wheel; lead screw located inside cases connected by threaded connection with internal pullout hollow case and made with figure non-round section shank for interaction with analogous figure hole made in case of driven ratchet wheel; supporting ring for lead screw, which is made integral with external case. Telescopic expandable rod-drive includes case and rod capable of moving in case and connected on one side by means of eyes through axis with finger, and on the other side through ball of joint coupling with drive ratchet wheel of ratchet-and-pawl mechanism, which, in its turn, is connected with external case by means of bayonet connection. Case of drive ratchet wheel, on its surface, features non-through in length and depth grooves facing end face. Drive ratchet wheel contains bush, furnished, from one side, with end face projections for grooves made in case of drive ratchet wheel, elements of bush fixation to case of drive ratchet wheel and spring, located in bush, in which, on the other side, end face ratchet teeth are made. On one side on end face of case of driven ratchet wheel there are ratchet teeth for interaction with ratchet teeth of bush of drive ratchet wheel, while on the other side of case of driven ratchet wheel on its surface there are non-through in length and depth grooves, which face end face. Driven ratchet wheel also contains bush, in which on one side end face projections for grooves of case of driven ratchet wheel are made; elements of fixation of bush of driven ratchet wheel to case of driven ratchet wheel; spring, which is also placed in this bush, on the other side of which there are also end face ratchet teeth, their direction being opposite to that of ratchet teeth of bush of drive ratchet wheel. Locking ratchet wheel is made in the form of locking bush, which, on one end face, has ratchet teeth for interaction with bush of driven ratchet wheel, and on the other end face, projection for groove, which is made in supporting ring for lead screw made integral with external case. Projection of external case is made in the form of semi-prismatic key, whose three sides have flat surfaces. On external surface of the fourth lateral side, which corresponds to internal surface of external case, there are projections of cylinder form made integral with key and capable of entering into through holes of external case. Height of key projections corresponds to thickness of external case wall. In grooves of cases of ratchet wheels additional recesses of closed contour are made. Projections of bushes of ratchet wheels are furnished with holes. Elements of fixation of bushes of ratchet wheels to cases of ratchet wheels represent pins, which are installed in projection holes and which enter into made additional recesses of grooves, so that bushes can move freely towards cases. Axis of threaded screw part is spaced apart from axis of supporting part of screw-bracket for 0.5-0.8 mm. On external case in region of threaded hole, in which screw-bracket is installed, projection is made. In finger, connected through axis with rod, from the side of the latter, there are clamp and end face hole, in which plate is screwed under eyes with hole for axis, and through threaded transversal hole for blocking screw of pectineal line of iliac bone is made.

EFFECT: reduction of time for performing operation and reduction of traumaticity due to increased reliability of device when working in implanted state under action of force load.

12 dwg