BONE SUPPORT APPARATUS

• US 20090149887A1
• Filed: 09/22/2006
• Published: 06/11/2009
• Est. Priority Date: 09/23/2005
• Status: Active Grant

• Current Assignee: Synthes USA LLC (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Schlaepfer, Fridolin, De Franceschi, Renzo
• Granted Patent: US 8,197,519 B2
• Time in Patent Office: Days
• US Class Current: 606/278
• CPC Class Codes: A61B 17/7034 characterised by a lateral opening
• CPC Class Codes: A61B 17/7037 wherein pivoting is blocked when the rod is clamped
• CPC Class Codes: A61B 17/7086 Rod reducers, i.e. devices providing a mechanical advantage to allow a user to force a rod into or onto an anchor head other than by means of a rod-to-bone anchor locking element; rod removers
• CPC Class Codes: A61B 17/7091 for applying, tightening or removing longitudinal element-to-bone anchor locking elements, e.g. caps, set screws, nuts or wedges

Abstract

An apparatus for connecting a bone anchor to a support rod includes a connector body and a cap. The connector body has a channel to receive and locate the support rod relative to the bone anchor. The cap is moveable longitudinally into a partially installed position in the channel, and snaps into non-threaded engagement with the connector body by rotating from the partially installed position to an installed position without moving axially relative to the connector body. In some embodiments, a sleeve fits over a socket portion of the connector body in a temporary position in which the sleeve permits insertion of the bone anchor into the socket. The sleeve engages the connector body so as to be restrained from axial and rotational movement relative to the connector body when in the temporary position. Tools are provided for installing the connector body, sleeve, cap, and support rod.

Claims

1-41. -41. (canceled)

42. An apparatus for connecting a bone anchor to a support rod, comprising:

a connector body having an upper portion, a middle portion, and a lower portion, the lower portion including a socket for polyaxially receiving a head portion of the bone anchor, the upper portion including a pair of diametrically opposed arms defining a rod-receiving channel for receiving the support rod, each arm including an inner surface, an outer surface, opposite edge surfaces, a rim projecting radially inward, and a recess formed in the rim; and

a cap sized and configured to engage the inner surfaces of the arms, the cap including a pair of bosses projecting radially outward, a pair of stoppers projecting radially outward, and a pair of flanges projecting radially outward;

wherein the cap is receivable in the channel in a partially installed position in which the bosses, stoppers and flanges are located circumferentially between the arms of the connector body, and wherein when the cap is rotatable from the partially installed position to an installed position, the bosses are received in the recesses, the stopper abuts a side edge of an arm, and the flanges are located beneath the rims.

43. The apparatus of claim 42, wherein when the cap is rotated from the partially installed position to the installed position, the cap is rotated relative to the connector body but the cap does not move axially relative to the connector body.

44. The apparatus of claim 42, wherein when the cap is rotated from the partially installed position to the installed position, the bosses contact and deflect the arms radially outward to enlarge the channel so that the flanges formed on the cap can be circumferentially aligned with the rim formed on the arms.

45. The apparatus of claim 44, wherein when the cap is located in the installed position, the bosses are received in the recesses formed on the rim so that the arms will return to their original undeflected conditions causing the rim formed on the connector body to engage at least a portion of the flange formed on the cap.

46. The apparatus as claim 45, wherein the bosses project radially outward in diametrically opposed positions on the cap, the stoppers project radially outward in diametrically opposed positions on the cap, the stoppers are circumferentially offset about 45 degrees from the bosses, and the flanges extend about 90 degrees about the periphery of the cap.

47. The apparatus of claim 42, wherein the cap is axially movable into the partially installed position without rotating relative to the connector body.

48. The apparatus of claim 42, wherein when the cap is rotated from the partially installed position to the installed position, the flanges are configured to move circumferentially beneath the rims without camming action.

49. The apparatus of claim 42, wherein when the cap is rotated from the partially installed position to the installed position, the bosses formed on the cap are configured to snap into the recesses formed on the arms while the flanges formed on the cap are configured to move circumferentially beneath the rims formed on the arms.

50. The apparatus of claim 42, wherein the arms are configured to deflect radially outward under the influence of the bosses when the cap is rotated from the partially installed position to the installed position, and to snap back inward to capture the bosses in the recesses when the cap reaches the installed position.

51. The apparatus of claim 50, wherein the arms are located in the rotational path of movement of the flanges when the cap is in the partially installed position, and the bosses are configured to deflect the arms radially outward to provide clearance for the flanges to move beneath the rims as the cap is rotated into the installed position.

52. The apparatus of claim 42, wherein when the cap is rotated from the partially installed position to the installed position, the stoppers move into abutment with the connector body to block continued rotation of the cap beyond the installed position.

53. The apparatus of claim 42, further comprising a sleeve receivable over at least a portion of the lower portion of the connector body, the sleeve being moveable between (i) a temporary position in which the sleeve permits insertion of the bone anchor, (ii) a provisional locking position in which the sleeve permits polyaxial angulation of the bone anchor with respect to the connector body but prevents removal of the bone anchor from the connector body, and (iii) a locking position in which the sleeve prevents both polyaxial angulation and removal of the bone anchor with respect to the connector body.

54. The apparatus of claim 53, wherein the sleeve includes a plurality of inwardly projecting retainer flanges receivable against the connector body in an interference fit from which the sleeve is releasable for movement toward the locking position.

55. The apparatus of claim 54, wherein the connector body has a substantially cylindrical outer surface with an upper step portion and a lower step portion, and the retainer flanges are deflectable to establish the interference fit upon moving axially onto the step portions of the cylindrical outer surface.

56. The apparatus of claim 55, wherein the middle section of the connector body comprises the substantially cylindrical outer surface, the connector body comprising a concave transition portion between the lower portion and the middle portion, the projecting retainer flanges receivable in the concave transition portion to prevent the sleeve from moving axially and for contacting the substantially cylindrical outer surface.

57. The apparatus of claim 53, wherein the sleeve is prevented from axial and rotational movement with respect to the connector body when in the temporary position.

58. The apparatus of claim 53, wherein the sleeve engages the connector body via an interference fit in the temporary position.

59. The apparatus of claim 53, wherein the sleeve is further configured to fit over the connector body in a preliminary position in which the sleeve is freely movable axially and rotationally relative to the connector body, and to move axially to the temporary position.

60. The apparatus of claim 53, wherein the connector body has a substantially cylindrical outer surface with one or more radially raised step portions, and the sleeve has one or more inner retainer portions that are moveable axially against the step portions of the cylindrical outer surface to establish an interference fit with the connector body upon movement of the sleeve axially from the preliminary position to the temporary position.

61. The apparatus of claim 53, wherein the sleeve is configured (i) to be received over the connector body in a first preliminary position upon movement of the sleeve axially over the connector body in a first direction, (ii) to be rotated from the first preliminary position to a second preliminary position, and (iii) to move from the second preliminary position to the temporary position, onward to the provisional locking position, and further to the locking position upon movement of the sleeve axially over the connector body in a second direction opposite the first direction.