Coupling device for coupling a bone anchor to a rod and bone anchoring device with such a coupling device

A coupling device for coupling a bone anchor to a rod, the coupling device comprising:

• a receiving part having a first end, a second end below the first end, a longitudinal axis extending through the first and second ends, a channel at the first end for receiving a rod, and an accommodation space at the second end for pivotably holding a head of the bone anchor;
• a pressure member positionable in the receiving part, the pressure member comprising a first portion configured to exert pressure on the head, a deformable portion that extends upwardly from the first portion to a free end, and a downwardly facing surface formed separately from the deformable portion for holding the rod;
• and
• a locking member insertable into and movable axially in the channel, the locking member comprising a lower surface for engaging the pressure member;
• wherein when the pressure member is in the receiving part, at least part of the locking member is movable downward in the channel to exert a force on the deformable portion of the pressure member for adjusting the deformable portion from a first configuration where the head is pivotable relative to the receiving part to a second configuration where the head is locked relative to the receiving part, while a shape of the downwardly facing surface for holding the rod is configured to remain constant.

A coupling device polyaxially connectable to a bone anchor, the coupling device comprising:

• a receiving part having a first end, a second end below the first end, a longitudinal axis extending through the first and second ends, a U-shaped channel at the first end that extends laterally through the receiving part, and an accommodation space at the second end for pivotably holding a head of the bone anchor;
• a pressure member positionable in the receiving part, the pressure member comprising a first portion configured to exert pressure on the head, and a deformable portion;
• and
• a locking member insertable into and movable axially in the channel, the locking member comprising a lower surface for engaging the pressure member;
• wherein when the pressure member is in the receiving part, the pressure member is configured to assume an insertion position for inserting the head into the accommodation space, wherein a first abutment restricts upward movement of the pressure member from the insertion position out of the receiving part;
• wherein the pressure member is movable downwards from the insertion position to a second position where the head is held in and prevented from removal from the accommodation space and where a second abutment restricts upward movement of the pressure member from the second position back towards the insertion position;
• and
• wherein the deformable portion of the pressure member is adjustable from a first configuration where the head is pivotable relative to the receiving part, to a second configuration where the head is locked relative to the receiving part, while the pressure member remains in contact with the second abutment.