Bone anchoring device for coupling a rod to a bone anchoring element

A method of adjusting a bone anchoring device comprising a bone anchoring element having a shank for anchoring to bone and a head, a receiving part having a first end, a second end below the first end, a central axis that extends between the first and second ends, and an accommodation space at the second end for pivotably accommodating the head of the bone anchoring element, a pressure element movable in the receiving part to engage and exert pressure on the head to clamp the head at an angular position relative to the receiving part, wherein the pressure element defines at least one opening that provides access laterally through the pressure element to the head when the pressure element engages the head in the receiving part, and at least one restraining element separate from the pressure element and positionable and movable relative to the pressure element in the receiving part, the method comprising:

• inserting the head of the bone anchoring element from the second end of the receiving part into the accommodation space when the pressure element is at an insertion position relative to the receiving part;
• adjusting the pressure element from the insertion position to a pre-locking position where the head is prevented from being removed from the accommodation space;
• and
• selectively moving the restraining element relative to the pressure element from a first position where the restraining element is spaced apart from the head in the receiving part and the head is pivotable relative to the receiving part, to a second position where the restraining element engages the head laterally through the opening of the pressure element to restrict the pivoting of the head relative to the receiving part in at least one radial direction relative to the central axis while the head remains pivotable in at least one other radial direction relative to the central axis.

A bone anchoring device comprising:

• a bone anchoring element having a shank for anchoring to bone and a head;
• a receiving part having a first end, a second end below the first end, a central axis that extends between the first and second ends, and an accommodation space at the second end for pivotably accommodating the head of the bone anchoring element;
• a monolithic pressure element movable in the receiving part and comprising a rod contacting surface for engaging a rod that is connectable to the receiving part and a head contacting surface configured to extend below a portion of the head having a greatest diameter measured in a direction perpendicular to the central axis to exert pressure on the head to clamp the head at an angular position relative to the receiving part;
• and
• at least one restraining element separate from the pressure element and movable in the receiving part to engage the head to restrict the pivoting of the head relative to the receiving part in at least one radial direction relative to the central axis while the head remains pivotable in at least one other radial direction relative to the central axis.