Systems and methods for introducing a bone anchor

1. A guide assembly for introducing a bone anchor to an operative target site, the bone anchor including a housing having a pair of opposed arms defined by first and second opposed slots formed in the housing, comprising:

an outer sleeve having a distal end, a proximal end, a central passage extending from the distal end to the proximal end, the outer sleeve being divided into a first outer arm and a second outer arm, the first outer arm and second outer arm being separated by a third slot open at the distal end and a fourth slot opposite the third slot and open at the distal end, wherein the first outer arm includes a first projection at the distal end extending into the central passage and the second outer arm includes a second projection at the distal end extending into the central passage, the first and second projections configured to engage first and second recesses formed in the housing arms, a first inner arm slidably coupled to the first outer arm such that the first inner arm translates longitudinally relative to the first outer arm, and a second inner arm slidably coupled to the second outer arm such that the second inner arm translates longitudinally relative to the second outer arm, the first inner arm and second inner arm being separated by a fifth slot and a sixth slot, the fifth slot being aligned with the third slot of the outer sleeve and the sixth slot being aligned with the fourth slot of the outer sleeve, the third and fifth slot together being aligned with the first slot of the housing and the fourth and sixth slot together being aligned with the second slot of the housing when the first and second projections are engaged in the first and second recesses of the housing, the first inner arm and second inner arm moveable between an open position and a closed position for temporarily fixing the housing to the guide assembly, the first inner arm having a first longitudinally extending engagement feature configured to slideably engage a complementary first longitudinally extending engagement feature on the housing when the first inner arm moves from the open position, the second inner arm having a second longitudinally extending engagement feature configured to slideably engage a complementary second longitudinally extending engagement feature on the housing when the second inner arm moves from the open position.

2. The guide assembly of claim 1 , wherein the first inner arm includes a first distal extension with the first longitudinally extending engagement feature situated thereon and the second inner arm includes a second distal extension with the second longitudinally extending engagement feature situated thereon.

3. The guide assembly of claim 2 , wherein the distal end of the outer sleeve includes a cutout between the first outer arm and second outer arm, the first distal extension and second distal extension being situated within the cutout region.

4. The guide assembly of claim 3 , wherein the cutout region is dimensioned to pass the bone anchor housing such that said housing is permitted to be introduced into the central passageway from the side.

5. The guide assembly of claim 4 , wherein the first distal extension and the second distal extension fill the cutout region when the inner sleeve is moved into the closed position and capture the housing in the central passageway.

6. The guide assembly of claim 1 , further comprising a locking mechanism to prevent the first inner arm and second inner arm from moving from the closed position until the locking mechanism is disengaged.

7. The guide assembly of claim 6 , wherein the locking mechanism automatically engages when the first inner arm and second inner arm move into the closed position.

8. The guide assembly of claim 1 , further including an internally threaded region on the outer sleeve and a proximal body threadedly mated to the outer sleeve and rotatable to translate the first inner arm and the second inner arm.

9. The guide assembly of claim 8 , wherein the proximal body rotates freely relative to the first inner arm and second inner arm while being longitudinally fixed relative to the first inner arm and second inner arm.

10. The guide assembly of claim 9 , comprising a locking mechanism to prevent the proximal body from rotating to translate the first inner arm and second inner arm from the closed position until the locking mechanism is disengaged.

11. The guide assembly of claim 10 , wherein the locking mechanism includes a cap coupled to the proximal body.

12. The guide assembly of claim 11 , wherein the proximal end of the outer sleeve comprises a set of proximal facing teeth and a distal end of the cap includes a complementary set of distal facing teeth.

13. The guide assembly of claim 12 , wherein the proximal facing teeth and distal facing teeth each include a perpendicular face and a sloped face such that the sloped faces slide past each other when the cap is rotated in one direction and the perpendicular faces engage each other when the cap is rotated in the opposite direction.

14. The guide assembly of claim 13 , wherein the cap is spring biased distally.

15. The guide assembly of claim 13 , wherein the cap includes at least two apertures that receive corresponding tabs extending from the proximal body to couple the cap to the proximal body.

16. The guide assembly of claim 9 , wherein an inner surface of the proximal body includes a circumferential groove that receives ridges associated with the first and second inner arms to longitudinally fix the first and second inner arms to the proximal body.

17. The guide assembly of claim 1 , wherein the first inner arm includes a longitudinal channel that receives a longitudinal projection on an inner surface of the first outer arm and the second inner arm includes a longitudinal channel that receives a longitudinal projection on an inner surface of the second outer arm.

18. The guide assembly of claim 17 , wherein the longitudinal channels and longitudinal projections have a dovetail configuration.

19. The guide assembly of claim 1 , wherein the distal end of the outer sleeve includes third and fourth longitudinally extending engagement features configured to slideably engage complementary third and fourth longitudinally extending engagement features on the housing.