Dynamic support system
A spinal stabilization system including an insert positionable in the channel of the housing of a vertebral anchor, and an associated support construct including a spacer and at least one cord extending through the insert. In some instances the construct includes first and second cords extending through first and second bores of the insert. A clamping member clamps the cord(s) in the insert. In some instances the clamping member includes first and second tabs movable in channels in first and second flanges of the insert.
1. A spinal system comprising:
a threaded fastener;
a housing of a vertebral anchor, the housing comprising two upwardly extending arms, each upwardly extending arm comprising an inner threaded surface to engage the threaded fastener;
an insert positionable to extend through a channel formed by the two upwardly extending arms, the insert comprising:
a first bore extending through the insert parallel to an insert longitudinal axis;
a first flange positionable on a first exterior side of the housing of the vertebral anchor, a first interior surface of the first flange including a first channel extending outward from the first bore transverse to the insert longitudinal axis, wherein opposing sidewalls of the first channel are transverse to adjacent portions of the first interior surface along a length of the first channel;
a second flange positionable on a second exterior side of the housing of the vertebral anchor, a second interior surface of the second flange including a second channel extending outward from the first bore transverse to the insert longitudinal axis, the first interior surface being in an opposing relationship with the second interior surface, wherein opposing sidewalls of the second channel are transverse to adjacent portions of the second interior surface along a length of the second channel and to first and second exterior surfaces opposing the first and second interior surfaces, respectively;
a medial portion extending between the first flange and the second flange along the insert longitudinal axis that is transverse to an anchor longitudinal axis when positioned within the channel of the housing, the medial portion including an open superior portion, wherein the opposing sidewalls of each of the first and second channels extend towards a corresponding one of the first and second exterior surfaces of the first and second flanges, respectively; and
a clamping member positionable within the open superior portion of the medial portion, the clamping member including a first tab and a second tab, the first tab configured to engage the first channel by being received within the first channel and the second tab configured to engage the second channel by being received within the second channel, the clamping member including a body portion extending between the first tab and the second tab comprising a lower surface and configured to engage a cord extending through the first bore and an upper surface configured to engage the threaded fastener, wherein the first and second channels retain and guide movement of the first and second tab, respectively, along the length of the first and second channels, respectively, in a radial direction transverse to the insert longitudinal axis and restrict movement of the first and second tab, respectively, in a lateral direction transverse to the radial direction, wherein the first and second channels each intersect the first bore, where each of the first and second channels extends from the first bore to an outer edge of the first flange and second flange, respectively, wherein the medial portion includes a rounded inferior portion configured to conform to the channel of the housing of the vertebral anchor, and wherein advancement of the threaded fastener relative to the inner threaded surfaces of the two upwardly extending arms to engage the upper surface of the clamping member simultaneously immobilizes the clamping member relative to the housing and the cord relative to the clamping member.
2. The spinal system of claim 1 , wherein a plane of a first exterior surface of the first flange is transverse to an opposing plane of the first interior surface and a plane of a second exterior surface of the second flange is transverse to an opposing plane of the second interior surface and wherein the clamping member includes a flat superior surface extending between the first flange and the second flange.
3. The spinal system of claim 1 , wherein each of the first and second channels terminates interiorly of an outer edge of the first flange and second flange, respectively, and wherein the clamping member includes a concave inferior surface configured to engage the cord.
4. The spinal system of claim 3 , wherein a width of each of the first and second channels varies along a length of the first and second channels, respectively and wherein the concave inferior surface includes a plurality of raised gripping features adapted to engage the cord when the cord is extending through the first bore.
5. The spinal system of claim 4 , wherein a width of an outer portion of each of the first and second channels is less than a width of an inner portion of each of the first and second channels, respectively and wherein the plurality of raised gripping features include a plurality of ribs aligned with the insert longitudinal axis upon insertion into an opening of the first bore.
6. The spinal system of claim 4 , wherein the plurality of raised gripping features are selected from a group of raised gripping features including:
ribs;
projecting grooves;
teeth;
posts;
spikes; and
serrations.
7. The spinal system of claim 4 , wherein each of the first and second tabs comprises more than one tab and each of the first and second channels comprise more than one channel to receive the first and second tabs, respectively, and wherein the plurality of raised gripping features are lands of a screw thread cut into the concave inferior surface.
8. The spinal system of claim 1 , wherein the first and second channels each extends from an outer edge of the first flange and second flange, respectively, inwardly towards the first bore and terminates interiorly of the first bore, wherein an edge formed at an intersection of the first tab and a first end of an intermediate portion of the clamping member is generally parallel to the first channel, wherein an edge formed at an intersection of the second tab and an opposing second end of the intermediate portion of the clamping member is generally parallel to the second channel, and wherein the first tab and the second tab of the clamping member move along the anchor longitudinal axis to engage the cord.
9. The spinal system of claim 1 , wherein each of the first and second channels intersects the first interior surface and opposing second exterior surface of a corresponding one of the first and second flanges, wherein the first bore comprises plural bores to receive plural cords, and wherein the clamping member includes a superior surface of the body portion configured to enable a set screw threaded into the housing of the vertebral anchor to engage the superior surface and drive the clamping member into the cord.
10. An insert adapted to be received within a saddle portion of a vertebral anchor, the insert comprising:
a first flange configured to engage a first exterior side of the saddle portion of the vertebral anchor;
a second flange configured to engage a second exterior side of the saddle portion of the vertebral anchor;
a medial portion extending between the first flange and the second flange along an insert longitudinal axis that is transverse to an anchor longitudinal axis of the vertebral anchor when positioned within the saddle portion, the medial portion including a U-shaped body conforming to the saddle portion of the vertebral anchor;
a first bore extending through the first flange, the medial portion, and the second flange parallel to the insert longitudinal axis, and adapted to receive a cord extending through the insert; and
a clamping member including opposing tabs configured to engage a first channel in a first interior sidewall of the first flange and a second channel in an opposing second interior sidewall of the second flange, the clamping member configured to engage the cord through an opening in the U-shaped body of the medial portion, wherein a base of each of the first and second channels is spatially offset from an adjacent portion of a corresponding one of the first and second opposing interior sidewalls of the first and second flanges and extends outwardly from the first bore transverse to the insert longitudinal axis, wherein the first and second channels retain and guide movement of the first and second tabs, respectively, along a length of the first and second channels, respectively, in a radial direction transverse to the insert longitudinal axis and restrict movement of the first and second tabs, respectively, in a lateral direction transverse to the radial direction; wherein the first and second channels each intersects and extends from the first bore to an outer edge of the first flange and second flange, respectively, and wherein the first channel and the second channel each extends radially outward from the first bore along the first and second opposing interior sidewalls of the first flange and the second flange, respectively.
11. The insert of claim 10 , wherein a plane of a first exterior sidewall of the first flange is transverse to an opposing plane of the first interior sidewall and a plane of a second exterior sidewall of the second flange is transverse to an opposing plane of the second interior sidewall and wherein the first interior sidewall engages the first exterior side of the saddle portion.
12. The insert of claim 11 , wherein the first channel is indented in a portion of the first interior sidewall and wherein the first channel terminates interiorly of an outer edge of the first flange.
13. The insert of claim 11 , wherein the first and second channels each extends from an outer edge of the first flange and second flange, respectively, inwardly towards the first bore and terminates interiorly of the first bore, and wherein the first exterior sidewall forms an oblique angle with respect to the insert longitudinal axis, and the first interior sidewall is perpendicular to the insert longitudinal axis.
14. The insert of claim 10 , wherein a width of each of the first and second channels varies along a length of the first and second channels, respectively and wherein an inferior surface of the clamping member forms a concave engagement surface.
15. The insert of claim 14 , wherein a width of an outer portion of each of the first and second channels is less than a width of an inner portion of each of the first and second channels, respectively and wherein the concave engagement surface includes a plurality of raised gripping features adapted to engage the cord when extended through the first bore.
16. The insert of claim 15 , wherein an edge formed at an intersection of the first tab and a first end of an intermediate portion of the clamping member is generally parallel to the first channel, wherein an edge formed at an intersection of the second tab and an opposing second end of the intermediate portion of the clamping member is generally parallel to the second channel, and wherein the plurality of raised gripping features include a plurality of ribs aligned with the insert longitudinal axis upon insertion into the opening.
17. The insert of claim 15 , wherein the plurality of raised gripping features are selected from a group of gripping features including:
ribs;
projecting grooves;
teeth;
posts;
spikes; and
serrations.
18. The insert of claim 15 , wherein each of the first and second tabs comprises more than one tab and each of the first and second channels comprise more than one channel to receive the first and second tabs, respectively, and wherein the plurality of raised gripping features are formed by a screw thread cut into the concave engagement surface.
19. The insert of claim 15 , wherein the first bore comprises plural bores to receive plural cords and wherein the first bore includes a second plurality of raised gripping features along a length opposite the clamping member.
20. A spinal system comprising:
an insert positionable to extend through a channel formed by two upward extending arms of a housing of a vertebral anchor, the insert comprising:
a first bore extending through the insert parallel to an insert longitudinal axis;
a first flange positionable on a first exterior side of the housing of the vertebral anchor, a first interior surface of the first flange including a first channel intersecting and extending outward from the first bore transverse to the insert longitudinal axis;
a second flange positionable on a second exterior side of the housing of the vertebral anchor, a second interior surface of the second flange including a second channel intersecting and extending outward from the first bore transverse to the insert longitudinal axis, the first interior surface being in an opposing relationship with the second interior surface;
a medial portion extending between the first flange and the second flange along the insert longitudinal axis that is transverse to an anchor longitudinal axis when positioned within the channel of the housing, the medial portion including an open superior portion; and
a clamping member including a first tab and a second tab, the first tab configured to engage the first channel and the second tab configured to engage the second channel, the clamping member including a body portion extending between the first tab and the second tab and configured to engage a cord extending through the first bore, wherein the first and second channels retain and guide movement of the first and second tab, respectively, transverse to the insert longitudinal axis, wherein a width of an outer portion of each of the first and second channels is less than a width of an inner portion of each of the first and second channels, respectively.