Device For Injecting Bone Cement

Abstract

In a device for injecting bone cement, the discharge direction of the bone cement after insertion of the cannula should be controllable in a certain region. This is made possible through a radial exit aperture ( 5 ) which is provided on the front end of the cannula ( 3 ). Since the cannula is inserted with the aid of a guide wire ( 1 ), it has an orifice ( 4 ) on its front end, which orifice must be closed off by means of a ball ( 15 ) prior to the injection. A plunger serves to insert the ball ( 15 ). So that the situation of the radial aperture ( 5 ) is known at all times, even with inserted cannula, the handle ( 17 ) of the cannula has an asymmetrical shape.

What is claimed: 
     
         1 . Device for injecting bone cement, containing a guide wire ( 1 ) and a cannula ( 3 ) fitting snugly on the guide wire ( 1 ) at least with the inner diameter of its front axial orifice ( 4 ), characterized in that there are closing off means ( 9 ,  15 ) with which the front axial orifice ( 4 ) of the cannula ( 3 ) is closable after removal of the guide wire ( 1 ), and in that the cannula ( 3 ) has a radial aperture ( 5 ), near the front, axial orifice ( 4 ), for exit of the bone cement. 
     
     
         2 . Device according to  claim 1 , characterized in that the closing off means is an inner cannula ( 9 ) closed at its front end, which inner cannula is insertable into the cannula ( 3 ) in such a way that its front end ( 10 ) tightly closes off the orifice ( 4 ) of the cannula ( 3 ) and has a radial aperture ( 11 ) near its front, closed end ( 10 ). 
     
     
         3 . Device according to  claim 1 , characterized in that the diameter of the front, axial orifice of the cannula is smaller than the inner diameter of the cannula and in that the closing off means is a stopper ( 15 ) the largest diameter of which is greater than the diameter of the front, axial orifice ( 4 ) of the cannula. 
     
     
         4 . Device according to  claim 3 , characterized in that the stopper ( 15 ) has the shape of a ball. 
     
     
         5 . Device for injecting bone cement, containing a guide wire ( 1 ) and a cannula ( 20 ) fitting snugly on the guide wire at least with the inner diameter of its front axial orifice ( 24 ), characterized by an inner cannula ( 25 ), closed at its front end ( 27 ), which inner cannula has near the front closed end ( 27 ) a radial aperture ( 28 ) for the exit of the bone cement, and which, at least in a region near the edge remote from its front end, of the radial aperture ( 28 ) fits snugly in the front axial orifice ( 24 ) of the cannula, whereby, after the removal of the guide wire ( 1 ), the inner cannula ( 25 ) is insertable so far into the cannula ( 20 ) that its radial aperture extends beyond the axial orifice ( 24 ) of the cannula.