Rod locking instrument
View Patent ↗Instruments and methods are provided for securing a spinal rod in one or more coupling devices secured to the spine by one or more anchor members. The instruments include members for grasping the coupling device and members for shifting one or more elements along a linear path to fix the position of an anchor member and/or fix the position of the rod with respect to the vertebra.
1. An instrument for locking a spinal rod to a rod coupling device, the instrument comprising: an elongate instrument body having an axis; at least one grasping member for securing the coupling device in a fixed position with respect to the instrument body; a drive member for advancing a cap member in an axial direction toward the coupling device secured by the grasping member; a shiftable reducing member for engaging the spinal rod and driving the spinal rod in the axial direction into engagement with the coupling device; and a drive coupler for coupling the reducing member to the drive member so that the reducing member advances in the axial direction simultaneously with the drive member, the drive coupler having at least one portion that disengages from the reducing member with the reducing member advanced to a predetermined axial position with respect to the drive member so that the drive member is free to advance in the axial direction without further advancement of the reducing member in the axial direction.
2. The instrument of claim 1 , wherein the drive coupler comprises a pin member coupling a coupling sleeve member to the drive member and a shifting element configured to shift away from the coupling sleeve member to disengage the reducing member from the drive member.
3. The instrument of claim 1 , further comprising an inhibitor switch that is shifted to a first position to limit axial advancement of the drive member by a first amount, and shifted to a second position to permit advancement by a second amount, the second amount being greater than the first amount.
4. The instrument of claim 1 , further comprising a ratchet device for allowing sequential advancement of the drive member through a plurality of predetermined positions.
5. The instrument of claim 1 , wherein the reducing member is an elongate hollow cylinder disposed about the drive member.
6. The instrument of claim 5 , wherein the reducing member includes at least one slit to allow axial compression of the reducing member in an axial direction.
7. The instrument of claim 5 , wherein the at least one slit is helical.
8. An instrument for locking a spinal rod to a rod coupling device, the instrument comprising: an elongate instrument body having an axis; at least one grasping member for securing the coupling device in a fixed position with respect to the instrument body; a drive member for advancing a cap member in an axial direction toward the coupling device secured by the grasping member; a shiftable reducing member for engaging the spinal rod and driving the spinal rod in the axial direction into engagement with the coupling device, the reducing member forming an elongate hollow cylinder disposed about the drive member and including at least one slit to allow axial compression of the reducing member in an axial direction; and a drive coupler for coupling the reducing member to the drive member so that the reducing member advances in the axial direction simultaneously with the drive member, the drive coupler having at least one portion that disengages from the reducing member with the reducing member advanced to a predetermined axial position with respect to the drive member so that the drive member is free to advance in the axial direction without further advancement of the reducing member in the axial direction.
9. The instrument of claim 8 , wherein the drive coupler comprises a pin member coupling a coupling sleeve member to the drive member and a shifting element configured to shift away from the coupling sleeve member to disengage the reducing member from the drive member.
10. The instrument of claim 8 , further comprising a ratchet device for allowing sequential advancement of the drive member through a plurality of predetermined positions.
11. The instrument of claim 8 , wherein the at least one slit is helical.
12. An instrument for locking a spinal rod to a rod coupling device, the instrument comprising: an elongate instrument body having an axis; at least one grasping member for securing the coupling device in a fixed position with respect to the instrument body; a drive member for advancing a cap member in an axial direction toward the coupling device secured by the grasping member; a shiftable reducing member for engaging the spinal rod and driving the spinal rod in the axial direction into engagement with the coupling device; a ratchet device for allowing sequential advancement of the drive member to a plurality of predetermined positions; and a drive coupler for releasably coupling the reducing member to the drive member, the drive coupler comprising a pin member coupling a coupling sleeve member to the drive member and a shifting element configured to shift away from the coupling sleeve member to disengage the reducing member from the drive member when the drive member and reducing member arrive at a predetermined disengagement position.
13. The instrument of claim 12 , wherein the reducing member is an elongate hollow cylinder disposed about the drive member.
14. An instrument for locking a spinal rod to a rod coupling device, the instrument comprising: an elongate instrument body having an axis; at least one grasping member for securing the coupling device in a fixed position with respect to the instrument body; a drive member for advancing a cap member in an axial direction toward the coupling device secured by the grasping member; a shiftable reducing member for engaging the spinal rod and driving the spinal rod in the axial direction into engagement with the coupling device; a ratchet device for allowing sequential advancement of the drive member to a plurality of predetermined positions; the reducing member including at least one slit to allow axial compression of the reducing member in the axial direction.