Patent ID: 8029458

Claim:
A back injection device for injecting an implant into tissue, comprising: (a) a hollow main body movable from a distal position, prior to injection, to a proximal position, after injection; (b) a hollow needle permanently fixed to the hollow main body and having a hollow space into which the implant is introducable; (c) a secondary body arranged coaxially inside the main body and surrounding the entire body of the needle before and after injection; (d) a piston rod axially slidable inside the hollow needle; and (e) coupling means arranged on the main body, to couple the main body and the piston rod, wherein the injection device is movable between the following positions: (1) a starting position in which the injection device is pressable against tissue, wherein the implant is introduced into the hollow space of the needle, wherein the secondary body surrounds the entire body of the needle; (2) an injection position in which the main body is moved along the secondary body from the proximal position to the distal position to allow the needle to extend beyond the secondary body so as to be penetrable into tissue, wherein the coupling means couples the main body and the piston rod so that the movement of the main body is accompanied by a concomitant movement of the piston rod, until the main body reaches the distal end so as to allow the needle to reach a maximum extension or penetration in tissue; (3) a back injection position in which the coupling means is released from the piston rod, thereby causing the main body to move from the distal position toward the proximal position so as to allow the needle to retract, wherein the piston rod remains fixed and is positioned to maintain the implant at a required position even as the needle is retracted; and (4) an end position in which the main body returns from the distal position to the proximal position so that the piston rod and the needle completely retract into the secondary body, wherein the secondary body surrounds the entire body of the needle.