Locking assembly for securing a rod member in a receiver part for use in spinal or trauma surgery, bone anchoring device with such a locking assembly and tool therefor

A bone anchoring device comprising:

• a shank to be anchored in a bone;
• a receiving part coupled to the shank and configured to receive a rod, the receiving part comprising a recess having a substantially U-shaped cross section for receiving the rod with two open legs on one end and an internal thread on the open legs;
• and
• a locking assembly comprising:
• a first locking element having a first end and a second end and a longitudinal axis and an outer surface provided with an external thread, a coaxial bore passing entirely through said first locking element and an internal thread provided at said bore,
• a second locking element having a first end and a second end, a longitudinal axis and an outer surface with an external thread cooperating with the internal thread of said first locking element, wherein the first end has an engagement structure configured for engagement with a tool to permit rotation of the second locking element,
• wherein said first locking element has a recess extending from the first end in the direction of the second end and terminating in an annular bottom surface extending transverse to the longitudinal axis, said recess defining a circumferentially closed wall portion, wherein the interior of the wall portion has a longitudinally extending structure for engagement with a tool;
• wherein when the first end of the second locking element is aligned with the first end of the first locking element, the second locking element can be independently engaged and screwed into and out of the first locking element and the first locking element can be independently engaged and screwed into and out of the receiving part;
• and
• wherein the external thread of the first locking element cooperates with the internal thread provided on said legs.

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

• a first locking element having a first end and a second end and a longitudinal axis of rotation and a substantially cylindrical outer surface provided with an external thread, a coaxial bore passing entirely through said first locking element and an internal thread provided at said bore,
• a second locking element having a longitudinal axis of rotation and a substantially cylindrical outer surface with an external thread cooperating with the internal thread of said first locking element,
• wherein said first locking element has a recess extending from the first end in the direction of the second end and terminating in an annular bottom surface extending transverse to the longitudinal axis, said recess defining a circumferentially closed wall portion, wherein the interior of the wall portion has a longitudinally extending structure for engagement with a tool;
• and
• wherein an axial length of the second locking element is larger than an axial length of the first locking element.

A bone anchoring device comprising:

• a shank to be anchored in a bone;
• a receiving part coupled to the shank and configured to receive a rod, the receiving part comprising a recess having a substantially U-shaped cross section for receiving the rod with two open legs on one end and an internal thread on the open legs;
• and
• a locking assembly comprising:
• a first locking element having a first end and a second end and a longitudinal axis of rotation and a substantially cylindrical outer surface provided with an external thread, a coaxial bore passing entirely through said first locking element and an internal thread provided at said bore,
• a second locking element having a longitudinal axis of rotation and a substantially cylindrical outer surface with an external thread cooperating with the internal thread of said first locking element,
• wherein said first locking element has a recess extending from the first end in the direction of the second end and terminating in an annular bottom surface extending transverse to the longitudinal axis, said recess defining a circumferentially closed wall portion, wherein the interior of the wall portion has a longitudinally extending structure for engagement with a tool;
• wherein an axial length of the second locking element is larger than an axial length of the first locking element;
• and
• wherein the external thread of the first locking element cooperates with the internal thread provided on said legs.