Spinal correction tensioning system
A vertebral column correction system for correcting a spinal deformity without fusing the joint segments is disclosed. The vertebral column correction system may have first and second vertebral anchors secured to first and second vertebrae. The vertebral column correction system may further comprise one or more intermediate vertebral anchors secured to vertebrae between the first and second vertebrae. A connection member may be disposed within a head portion of the vertebral anchors. At least a portion of the connection member may be a flexible member, such as a flexible cord, configured for tensioning between at least two vertebral anchors for providing a desired amount of tension to apply a correctional force to the spinal column. A spring member, or other tensioning member, may maintain the tension of the connection member.
1 . A vertebral anchor system comprising:
a threaded shank comprising a proximal shank portion and a distal shank portion configured to engage bone;
a head including two open sides, the head comprising:
a distal head portion couplable to the proximal shank portion;
a proximal head portion open at a proximal end;
an interior head portion extending along a longitudinal axis between the proximal head portion and the distal head portion; and
a channel extending along a transverse axis orthogonal to the longitudinal axis and in communication with the interior head portion and configured to receive a connection member therethrough;
a bushing receivable within the interior head portion to partially enclose the two open sides, the bushing to locate the connection member within the channel, the bushing comprising:
a medial portion; and
a first flared end comprising:
a first end coupled with the medial portion;
a second end opposite the first end; and
a surface extending between the first end and the second end, wherein a diameter of the surface along a plane normal to the transverse axis increases as the surface extends between the first end and the second end; and
an engaging member receivable within the interior head portion to retain the bushing within the distal head portion.
2 . The vertebral anchor system of claim 1 , the bushing further comprising:
a medial portion alignable with the channel, the engaging member able to make contact with the medial portion to retain the bushing within the head.
3 . The vertebral anchor system of claim 1 , wherein the interior head portion is configured to receive distal portions of the engaging member therein to limit movement of the engaging member and the bushing within the head.
4 . The vertebral anchor system of claim 3 , the engaging member further comprising threading to engage the head to retain the engaging member within the head.
5 . The vertebral anchor system of claim 1 , the engaging member further comprising:
threading to engage the head to retain the engaging member within the head.
6 . The vertebral anchor system of claim 1 , the bushing further comprising:
flared regions extending from the bushing and configured to engage the head to limit displacement of the bushing relative to the interior head portion along a longitudinal axis of the connecting member.
7 . The vertebral anchor system of claim 1 , further comprising:
a tensioning member positioned proximate to the head, wherein the tensioning member is able to receive the connection member.
8 . The vertebral anchor system of claim 7 , wherein the tensioning member is a spring member or a spacer able to be loaded with an applied force.
9 . The vertebral anchor system of claim 7 , wherein the tensioning member is disposed over the connection member proximate to a side surface of the head.
10 . A vertebral anchor system comprising:
a shank configured to engage bone;
a head including two open sides and a distal head portion couplable to the shank, the head comprising:
an interior head portion; and
a channel within the interior head portion and configured to receive a connection member therethrough;
a bushing receivable within the interior head portion to partially enclose the two open sides, the bushing configured to locate the connection member within the channel and comprising:
a medial portion; and
a first flared end comprising:
a first end coupled with the medial portion;
a second end opposite the first end; and
a surface extending between the first end and the second end, wherein a diameter of the surface along a plane normal to the transverse axis increases as the surface extends between the first end and the second end; and
an engaging member receivable within the interior head portion to retain the bushing within the distal head portion.
11 . The vertebral anchor system of claim 10 , the bushing further comprising:
a medial portion alignable with the channel, the engaging member able to make contact with the medial portion to retain the bushing within the head.
12 . The vertebral anchor system of claim 11 , the bushing further comprising:
flared regions extending from the bushing and configured to engage the head to limit displacement of the bushing relative to the interior head portion along a longitudinal axis of the connecting member.
13 . The vertebral anchor system of claim 10 , wherein the interior head portion is configured to receive the engaging member therein to limit movement of the engaging member and the bushing within the head.
14 . The vertebral anchor system of claim 13 , the engaging member further comprising:
threading to engage the head to retain the engaging member within the head.
15 . The vertebral anchor system of claim 10 , further comprising:
a tensioning member disposed over the connection member proximate to a side surface of the head.
16 . The vertebral anchor system of claim 15 , wherein the tensioning member is a spring member or is a spacer able to be loaded with an applied force.
17 . A vertebral column correction system comprising:
a connection member;
a first vertebral anchor and a second vertebral anchor, each vertebral anchor comprising:
a threaded shank comprising a proximal shank portion and a distal shank portion configured to engage bone;
a head including two open sides, the head comprising:
a distal head portion couplable to the proximal shank portion;
a proximal head portion open at a proximal end;
an interior head portion extending between the proximal head portion and the distal head portion and substantially forming a U shape between the two open sides; and
a channel within the interior head portion at the distal head portion, the channel configured to receive the connection member therethrough;
a bushing receivable within the interior head portion to partially enclose the two open sides, the bushing to locate the connection member within the concave channel and comprising:
a medial portion; and
a pair of flared ends extending from the medial portion and configured to engage the head to limit displacement of the bushing relative to the interior head portion along a longitudinal axis of the connection member, wherein each flared end comprises:
a first end coupled with the medial portion;
a second end opposite the first end; and
a surface extending between the first end and the second end, wherein a diameter of the surface along a plane normal to a central axis of the medial portion increases as the surface extends between the first end and the second end; and
an engaging member receivable in the interior head portion to retain the bushing within the interior head portion; and
a tensioning member positioned proximate to the head of the first vertebral anchor and able to receive the connection member;
wherein the connection member is extendable through the distal head portion and the proximal head portion of each head of the first vertebral anchor and the second vertebral anchor.
18 . The vertebral column correction system of claim 17 , wherein the medial portion is alignable with the concave channel; and
wherein the engaging member is able to make contact with the medial portion to retain the bushing within the head.
19 . The vertebral column correction system of claim 17 , wherein the tensioning member is a spring member or a spacer able to be loaded with an applied force.
20 . The vertebral column correction system of claim 17 , wherein the tensioning member is disposed over the connection member proximate to a side surface of a side of the two open sides of the head of the first vertebral anchor.