Percutaneous Access Devices And Bone Anchor Assemblies

A bone anchor assembly comprising:

• a bone anchor having a proximal head and a distal bone engaging portion;
• and
• a receiving member having a proximal end and a distal end,
• the proximal head of the bone anchor seated within the distal end of the receiver member and the distal bone engaging portion of the bone anchor extending through an opening in the distal end of the receiver member,
• the receiver member having a substantially U-shaped cross-section defined by two legs separated by a recess for receiving a spinal fixation element, each leg being free at the proximal end of the receiving member, the bone anchor being adjustable relative to the receiving member,
• an exterior surface of the proximal end of a first one of the legs including a first groove and an exterior surface of the proximal end of a second one of the legs including a second groove,
• the first groove having a proximal surface and a distal surface opposite the proximal surface and the second groove having a proximal surface and a distal surface opposite the proximal surface,
• the distal surface of the first groove being angled distally toward the exterior surface of the first leg and being oriented at an angle greater than 0 degrees relative to an orthogonal line that is oriented perpendicular to a longitudinal axis of the receiving member,
• the distal surface of the second groove being angled distally toward the exterior surface of the second leg and being oriented at an angle greater than 0 degrees relative to an orthogonal line that is oriented perpendicular to a longitudinal axis of the receiving member.

A bone anchor assembly comprising:

• a bone anchor having a proximal head and a distal bone engaging portion;
• and
• a receiving member having a proximal end and a distal end, the proximal head of the bone anchor seated within the distal end of the receiver member and the distal bone engaging portion of the bone anchor extending through an opening in the distal end of the receiver member, the receiver member having a substantially U-shaped cross-section defined by two legs separated by a recess for receiving a spinal fixation element, each leg being free at the proximal end of the receiving member, the bone anchor being adjustable relative to the receiving member, and
• a closure mechanism has an external thread that engage an internal thread provided on an interior surface of the legs of the receiver member,
• an exterior surface of the proximal end of a first one of the legs of the receiver member including a first groove and an exterior surface of the proximal end of a second one of the legs of the receiver member including a second groove,
• the first groove having a proximal surface and a distal surface opposite the proximal surface and the second groove having a proximal surface and a distal surface opposite the proximal surface,
• the distal surface of the first groove being angled distally toward the exterior surface of the first leg and being oriented at an angle between approximately 30 degrees to 40 degrees relative to an orthogonal line that is oriented perpendicular to a longitudinal axis of the receiving member,
• the distal surface of the second groove being angled distally toward the exterior surface of the second leg and being oriented at an angle between approximately 30 degrees to 40 degrees relative to an orthogonal line that is oriented perpendicular to a longitudinal axis of the receiving member.