Pedicle screw with tulip

An instrument set for connecting vertebral bodies, comprising a screw which has a screw head and a shaft and is screwable into a pedicle, a head piece which is connectable polyaxially to the screw for coupling to a rod system and which has a sleeve-shaped tulip having a first insertion opening for insertion of the screw head in an insertion direction,

• and a tool,
• wherein the head piece has a saddle in the interior region of the tulip, the saddle is situated rotationally fixed in the tulip and has a receiving region for receiving the screw head in a first end region that faces the first insertion opening and a coupling region to be coupled to a coupling member of the tool in a second end region opposite the receiving region, and the saddle is movable between a released position, which is reachable by inserting the screw head, and a locked position, which is reachable by moving the screw head out of the released position in the direction opposite the insertion direction,
• wherein when the saddle is in the locked position, the screw head held in the receiving region is not to be disengaged from the receiving region, and
• wherein when the coupling member of the tool is coupled to the coupling region of the saddle, the saddle is to be fixed in the released position that enables the release of the screw head from the receiving region such that the head piece and the screw are to be separated,
• wherein the coupling member is rotatable around a longitudinal axis and the rotational movement of the coupling member is converted to an axial movement of the saddle between the released position and the locked position without rotation of the saddle,
• wherein an inner diameter of the tulip is minimal at the first insertion opening, and an inner diameter of the tulip is maximal in a plane defined by the receiving opening of the saddle in the released position.

An instrument set for connecting vertebral bodies, comprising a screw which has a screw head and a shaft and is screwable into a pedicle, a head piece which is connectable polyaxially to the screw for coupling to a rod system and which has a sleeve-shaped tulip having a first insertion opening for insertion of the screw head in an insertion direction,

• and a tool,
• wherein the head piece has a saddle in the interior region of the tulip, the saddle is situated rotationally fixed in the tulip and has a receiving region for receiving the screw head in a first end region that faces the first insertion opening and a coupling region to be coupled to a coupling member of the tool in a second end region opposite the receiving region, and the saddle is movable between a released position, which is reachable by inserting the screw head, and a locked position, which is reachable by moving the screw head out of the released position in the direction opposite the insertion direction,
• wherein when the saddle is in the locked position, the screw head held in the receiving region is not to be disengaged from the receiving region, and
• wherein when the coupling member of the tool is coupled to the coupling region of the saddle, the saddle is to be fixed in the released position that enables the release of the screw head from the receiving region such that the head piece and the screw are to be separated,
• wherein the coupling member is rotatable around a longitudinal axis and the rotational movement of the coupling member is converted to an axial movement of the saddle between the released position and the locked position without rotation of the saddle,
• wherein the axial movement of the saddle in the tulip is limited between a first position and a second position, wherein the first position coincides with the released position, wherein the saddle has at least one projection between the receiving region and the coupling region, projecting toward a wall of the tulip and engaging in a recess that is formed in the wall of the tulip, wherein the projection, which abuts against first and second stop regions that delimit the recess in the axial direction when the saddle is moved axially, limits the movement of the saddle between the first position and the second position.

A method for removing a head piece from a screw that is screwed into a vertebral body, wherein the screw has a screw head and a shaft and is screwable into a pedicle, wherein the head piece is connectable polyaxially to the screw for coupling to a rod system and which has a sleeve-shaped tulip having a first insertion opening for insertion of the screw head in an insertion direction,

• and a tool,
• wherein the head piece has a saddle in the interior region of the tulip, the saddle is situated rotationally fixed in the tulip and has a receiving region for receiving the screw head in a first end region that faces the first insertion opening and a coupling region to be coupled to a coupling member of the tool in a second end region opposite the receiving region, and the saddle is movable between a released position, which is reachable by inserting the screw head, and a locked position, which is reachable by moving the screw head out of the released position in the direction opposite the insertion direction,
• wherein when the saddle is in the locked position, the screw head held in the receiving region is not to be disengaged from the receiving region, and
• wherein when the coupling member of the tool is coupled to the coupling region of the saddle, the saddle is to be fixed in the released position that enables the release of the screw head from the receiving region such that the head piece and the screw are to be separated,
• wherein the coupling member is rotatable around a longitudinal axis and the rotational movement of the coupling member is converted to an axial movement of the saddle between the released position and the locked position without rotation of the saddle,
• wherein the method comprises:
• coupling the tool with the tulip of the head piece in a rotationally fixed manner;
• coupling the coupling member of the tool with the coupling region of the saddle;
• rotating the coupling member wherein the rotational movement of the coupling member is converted into an axial movement of the saddle such that the saddle is moved into the released position;
• and
• disengaging the head piece from the screw head.