Locking assembly for a polyaxial bone anchoring device

A polyaxial bone anchoring device comprising:

• a bone anchoring element having a shank to be anchored in a bone and a head;
• a receiving part configured to be coupled to the bone anchoring element and to pivotably receive the head, the receiving part having a recess with a substantially U-shaped cross-section for receiving a rod, the recess defining two legs, the legs having an internal advancement structure;
• a pressure element configured to contact the head to exert pressure on the head to lock an angular position of the head relative to the receiving part;
• and
• a locking assembly comprising:
• a first locking element having a first end, a second end, and a longitudinal axis, an outer surface with an external advancement structure configured to cooperate with the internal advancement structure of the legs, an inner wall defining a coaxial bore extending through the first locking element along the longitudinal axis, an internal advancement structure on a portion of the inner wall, and an engagement portion for a tool for advancing the first locking element relative to the receiving part;
• and
• a second locking element configured to be arranged at least partially in the first locking element, the second locking element having a first end configured to be oriented towards the first end of the first locking element, and an opposite second end, an outer surface with an external advancement structure configured to cooperate with the internal advancement structure of the first locking element, and a portion at the second end having a width greater than a greatest width of the external advancement structure of the second locking element to prevent the second locking element from rotating relative to the receiving part when the locking assembly is inserted into the bone anchoring device;
• wherein when the locking assembly is in the receiving part and the first locking element is advanced axially in the receiving part at a first speed, the second locking element is configured to move axially relative to the receiving part at a speed different than the first speed.

A method of coupling a rod to a bone or vertebra 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 be coupled to the bone anchoring element and to pivotably receive the head, the receiving part having a recess with a substantially U-shaped cross-section for receiving a rod, the recess defining two legs, the legs having an internal advancement structure, a pressure element configured to contact the head to exert pressure on the head to lock an angular position of the head relative to the receiving part, and a locking assembly comprising a first locking element having a first end, a second end, and a longitudinal axis, an outer surface with an external advancement structure configured to cooperate with the internal advancement structure of the legs, an inner wall defining a coaxial bore extending through the first locking element along the longitudinal axis, an internal advancement structure on a portion of the inner wall, and an engagement portion for a tool for advancing the first locking element relative to the receiving part, and a second locking element configured to be arranged at least partially in the first locking element, the second locking element having a first end configured to be oriented towards the first end of the first locking element, and an opposite second end, an outer surface with an external advancement structure configured to cooperate with the internal advancement structure of the first locking element, and a portion to prevent the second locking element from rotating relative to the receiving part when the locking assembly is inserted into the bone anchoring device, the method comprising:

• inserting the shank of the bone anchoring element into a bone or vertebra when the head is in the receiving part;
• adjusting the receiving part relative to the bone anchoring element;
• inserting a rod into the recess of the receiving part, wherein the pressure element is positioned between the head and the rod;
• inserting the locking assembly into the recess;
• advancing the locking assembly in the receiving part towards the head, such that the first locking element is advanced axially in the receiving part at a first speed, and the second locking element moves axially relative to the receiving part at a speed different than the first speed, until the second locking element locks the head and the first locking element locks the rod relative to the receiving part.

A locking assembly for securing a rod in a rod receiving channel of a polyaxial bone anchoring device for use in spinal or trauma surgery, the locking assembly comprising:

• a first locking element having a first end, a second end, and a longitudinal axis, an outer surface with an external advancement structure, an inner wall defining a coaxial bore extending through the first locking element along the longitudinal axis, and an internal advancement structure on a portion of the inner wall;
• and
• a second locking element configured to be arranged at least partially in the first locking element, the second locking element having a first end configured to be oriented towards the first end of the first locking element, and an opposite second end, an outer surface with an external advancement structure configured to cooperate with the internal advancement structure of the first locking element, and a portion to prevent the second locking element from rotating when the locking assembly is inserted into a bone anchoring device;
• wherein a single engagement portion is provided at the first locking element for engaging a tool for advancing the locking assembly, such that when the second locking element is in the first locking element and the first locking element is advanced axially in a bone anchoring device at a first speed, the second locking element is configured to move axially relative to the bone anchoring device at a speed different than the first speed.