Polyaxial bone anchoring device

A method of connecting a rod to a bone via a polyaxial bone anchoring device, the bone anchoring device comprising a bone anchoring element having a shank and a head, a receiving part configured to pivotably receive the head, the receiving part having a first end, a second end, a central axis, and a channel at the first end for receiving the rod, a pressure member positionable in the receiving part to exert pressure onto the head to clamp the head in the receiving part, the pressure member comprising a deformable portion, and a locking member insertable into the channel to contact the pressure member, the method comprising:

• anchoring the shank of the bone anchoring device to the bone when the head and the pressure member are in the receiving part;
• adjusting an angular position of the receiving part relative to the bone anchoring element;
• inserting the rod in the channel of the receiving part;
• inserting the locking member in the channel;
• moving the locking member along the central axis to a first position, wherein at least part of the bone anchoring element is configured to directly contact the receiving part while the locking member contacts and is restricted by the deformable portion of the pressure member from moving further axially towards the second end of the receiving part;
• moving the locking member to a second position that is closer to the second end of the receiving part than the first position, wherein the head is clamped in the receiving part while the locking member contacts and deforms the deformable portion of the pressure member radially outwardly compared to the first position to permit further axial movement of the locking member towards the second end of the receiving part;
• and
• moving the locking member to a third position that is closer to the second end of the receiving part than the second position, such that the locking member comes into contact with the rod and clamps the rod.

A polyaxial bone anchoring device comprising:

• a rod;
• a receiving part configured to pivotably receive a head of a bone anchoring element, the receiving part having a first end, a second end, a central axis, and a channel at the first end for receiving the rod;
• a pressure member positionable in the receiving part to exert pressure onto the head to clamp the head in the receiving part, the pressure member comprising an annular portion and an elastically deformable portion;
• and
• a locking member insertable into the channel to contact the pressure member;
• wherein when the pressure member, the rod, and the locking member are in the receiving part, the locking member is movable in the channel of the receiving part along the central axis from a first position wherein the locking member contacts and is restricted by the deformable portion of the pressure member from moving further axially towards the second end of the receiving part, to a second position that is closer to the second end of the receiving part than the first position wherein the locking member contacts and deforms the deformable portion of the pressure member to permit further axial movement of the locking member towards the second end of the receiving part for the locking member to come into contact with the rod and clamp the rod;
• wherein in the second position, at least part of the deformable portion of the pressure member is spaced apart from the receiving part in a radial direction, while a free end of the deformable portion extends both closer axially to the first end of the receiving part and farther radially from the central axis than the entire rod.