Percutaneous access devices and bone anchor assemblies
A percutaneous access device includes an inner tube and an outer tube disposed about at least a portion of the inner tube. The outer tube may be sized to span from a skin incision in a patient to a site proximate the spine of the patient. The distal end of the outer tube may be adapted to releasably engage a bone anchor. The inner tube may be adjustable relative to the outer tube between a first position and a second position in which the distal end of the inner tube contacts the bone anchor. A bone anchor assembly includes a bone anchor having a distal bone engaging portion and a receiving member having a recess for receiving a spinal fixation element. The proximal end of the receiving member may have an arcuate groove formed on an exterior surface thereof to facilitate connection of an instrument to the receiving member.
1. A percutaneous access device, comprising:
an inner tube having a proximal end, a distal end, and a sidewall extending therebetween to define a lumen having a first longitudinal axis, the sidewall having one or more slots extending longitudinally along the sidewall from the distal end;
an outer tube disposed about at least a portion of the inner tube, the outer tube having a proximal end, a distal end, and a sidewall extending therebetween to define a lumen having a second longitudinal axis, the second longitudinal axis being parallel to the first longitudinal axis, the sidewall having one or more slots extending longitudinally from the distal end such that the slots of the outer tube are aligned with the slots of the inner tube along at least a portion of the longitudinal axis of the percutaneous access device; and
an adjustment mechanism that includes a cap having a singular inner surface configured to engage a corresponding surface of both the inner tube and the outer tube to adjust the relative position of the inner tube to the outer tube.
2. The device of claim 1 , wherein one or more of the inner surface of the cap and the corresponding surface is threaded.
3. The device of claim 1 , wherein the proximal end of the inner tube further comprises one or more resilient tabs formed on an outer surface thereof, the resilient tabs having a projection thereon to connect the proximal end of the inner tube to the cap.
4. The device of claim 1 , wherein the inner tube further comprises one or more tabs received in corresponding openings in the outer tube, the tabs having a projection that is configured to be received in one or more slots in the outer tube to limit the relative motion between the inner tube and the outer tube to movement along the longitudinal axis of the device.
5. The device of claim 1 , wherein the distal end of the outer tube further comprises a pair of opposed longitudinally extending tabs configured to engage a bone anchor.
6. The device of claim 5 , wherein the pair of opposed longitudinally extending tabs are defined by the sidewall of the outer tube and separated by the one or more slots of the outer tube.
7. The device of claim 6 , wherein the pair of opposed longitudinally extending tabs are configured to flex apart in the radial direction from a first, related position to a second, spread position to facilitate advancement of the tabs longitudinally over a bone anchor.
8. The device of claim 7 , wherein the pair of opposed longitudinally extending tabs further include one or more radially inward-facing projections configured to be seated in a receiving portion of the bone anchor.
9. The device of claim 8 , wherein the inward-facing projections have a cross-section that is complementary to a groove formed in the portion.
10. The device of claim 8 , wherein the inward-facing projections include a distal surface, a proximal surface, and a radially facing connecting surface oriented parallel to the longitudinal axis of the outer tube and perpendicular to one or more of the distal surface and the proximal surface.
11. The device of claim 10 , wherein the proximal surface is oriented at an oblique angle with respect to the longitudinal axis of the outer tube.
12. The device of claim 11 , wherein the proximal surface is oriented at angle in a range of approximately 5 degrees to approximately 30 degrees to an orthogonal line that is perpendicular to the longitudinal axis of the outer tube.
13. The device of claim 1 , wherein the distal end of the inner tube includes two opposing arcuate contact surfaces oriented perpendicular to the longitudinal axis of the inner tube.
14. The device of claim 1 , wherein the distal end of the inner tube further comprises one or more finger extensions extending axially from the distal end to engage a bone anchor and inhibit rotation of the bone anchor relative to the percutaneous access device.
15. A percutaneous access device, comprising:
an inner tube having a proximal end, a distal end, and a sidewall extending therebetween to define a lumen having a first longitudinal axis, the sidewall having one or more slots extending longitudinally along the sidewall from the distal end;
an outer tube disposed about at least a portion of the inner tube, the outer tube having a proximal end, a distal end, and a sidewall extending therebetween to define a lumen having a second longitudinal axis, the second longitudinal axis being parallel to the first longitudinal axis, the sidewall having one or more slots extending longitudinally from the distal end such that the slots of the outer tube are aligned with the slots of the inner tube along at least a portion of the longitudinal axis of the percutaneous access device; and
an adjustment mechanism that includes a cap having an inner surface configured to engage a corresponding surface of one or more of the inner tube and the outer tube to adjust the relative position of the inner tube to the outer tube,
wherein the proximal end of the inner tube further comprises one or more resilient tabs formed on an outer surface thereof, the resilient tabs having a projection thereon to connect the proximal end of the inner tube to the cap.
16. A percutaneous access device, comprising:
an inner tube having a proximal end, a distal end, and a sidewall extending therebetween to define a lumen having a first longitudinal axis, the sidewall having one or more slots extending longitudinally along the sidewall from the distal end;
an outer tube disposed about at least a portion of the inner tube, the outer tube having a proximal end, a distal end, and a sidewall extending therebetween to define a lumen having a second longitudinal axis, the second longitudinal axis being parallel to the first longitudinal axis, the sidewall having one or more slots extending longitudinally from the distal end such that the slots of the outer tube are aligned with the slots of the inner tube along at least a portion of the longitudinal axis of the percutaneous access device; and
an adjustment mechanism that includes a cap having an inner surface configured to engage a corresponding surface of one or more of the inner tube and the outer tube to adjust the relative position of the inner tube to the outer tube,
wherein the inner tube further comprises one or more tabs received in corresponding openings in the outer tube, the tabs having a projection that is configured to be received in one or more slots in the outer tube to limit the relative motion between the inner tube and the outer tube to movement along the longitudinal axis of the device.